diff --git a/BUILD b/BUILD
index c48b3b9..084d383 100644
--- a/BUILD
+++ b/BUILD
@@ -56,19 +56,22 @@
 API_DEPS = [
     "//java/com/google/gerrit/acceptance:framework_deploy.jar",
     "//java/com/google/gerrit/acceptance:libframework-lib-src.jar",
-    "//java/com/google/gerrit/acceptance:framework-javadoc",
     "//java/com/google/gerrit/extensions:extension-api_deploy.jar",
     "//java/com/google/gerrit/extensions:libapi-src.jar",
-    "//java/com/google/gerrit/extensions:extension-api-javadoc",
     "//plugins:plugin-api_deploy.jar",
     "//plugins:plugin-api-sources_deploy.jar",
+]
+
+API_JAVADOC_DEPS = [
+    "//java/com/google/gerrit/acceptance:framework-javadoc",
+    "//java/com/google/gerrit/extensions:extension-api-javadoc",
     "//plugins:plugin-api-javadoc",
 ]
 
 genrule2(
     name = "api",
     testonly = True,
-    srcs = API_DEPS,
+    srcs = API_DEPS + API_JAVADOC_DEPS,
     outs = ["api.zip"],
     cmd = " && ".join([
         "cp $(SRCS) $$TMP",
@@ -76,3 +79,15 @@
         "zip -qr $$ROOT/$@ .",
     ]),
 )
+
+genrule2(
+    name = "api-skip-javadoc",
+    testonly = True,
+    srcs = API_DEPS,
+    outs = ["api-skip-javadoc.zip"],
+    cmd = " && ".join([
+        "cp $(SRCS) $$TMP",
+        "cd $$TMP",
+        "zip -qr $$ROOT/$@ .",
+    ]),
+)
diff --git a/Documentation/access-control.txt b/Documentation/access-control.txt
index 95560e6..38720fe 100644
--- a/Documentation/access-control.txt
+++ b/Documentation/access-control.txt
@@ -93,8 +93,8 @@
 == Predefined Groups
 
 Predefined groups differs from system groups by the fact that they
-exist in the ACCOUNT_GROUPS table (like normal groups) but predefined groups
-are created on Gerrit site initialization and unique UUIDs are assigned
+exist in NoteDb under refs/meta/group-names (like normal groups) but predefined
+groups are created on Gerrit site initialization and unique UUIDs are assigned
 to those groups. These UUIDs are different on different Gerrit sites.
 
 Gerrit comes with two predefined groups:
diff --git a/Documentation/config-accounts.txt b/Documentation/config-accounts.txt
index b4a5cef..c6d9fb4 100644
--- a/Documentation/config-accounts.txt
+++ b/Documentation/config-accounts.txt
@@ -343,6 +343,12 @@
 The `accountId` field is mandatory. The `email` and `password` fields
 are optional.
 
+Note that git will automatically nest these notes at varying levels. If
+refs/meta/external-ids:7c/2a55657d911109dbc930836e7a770fb946e8ef is not
+found then check
+refs/meta/external-ids:7c/2a/55657d911109dbc930836e7a770fb946e8ef and
+so on.
+
 The external IDs are maintained by Gerrit. This means users are not
 allowed to manually edit their external IDs. Only users with the
 link:access-control.html#capability_accessDatabase[Access Database]
diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 0f4e319..b1f9a31 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -994,6 +994,11 @@
 be expensive to compute (60 or more seconds for a large history
 like the Linux kernel repository).
 
+cache `"comment_context"`::
++
+Caches the context lines of comments, which are the lines of the source file
+highlighted by the user when the comment was written.
+
 cache `"groups"`::
 +
 Caches the basic group information of internal groups by group ID,
@@ -1721,6 +1726,12 @@
 ----
   javaOptions = -Dlog4j.configuration=file:///home/gerrit/site/etc/log4j.properties
 ----
++
+Gerrit built-in loggers are then ignored: error logger (`error_log` file),
+link:#httpd.requestLog[httpd.requestLog] and
+link:#sshd.requestLog[sshd.requestLog]. The
+link:#log.jsonLogging[log.jsonLogging] and
+link:#log.textLogging[log.textLogging] options are also ignored.
 
 [[container.daemonOpt]]container.daemonOpt::
 +
@@ -2501,6 +2512,18 @@
 [[groups]]
 === Section groups
 
+[[groups.includeExternalUsersInRegisteredUsersGroup]]groups.includeExternalUsersInRegisteredUsersGroup::
++
+Controls whether external users (these are users we have sufficient
+knowledge about but who don't yet have a Gerrit account) are considered
+to be members of the `REGISTERED_USERS` group.
++
+This setting only makes sense if you run custom code (e.g. from a plugin
+or a custom authentication backend). By default, Gerrit core always requires
+users to register and doesn't use external users.
++
+By default, true.
+
 [[groups.newGroupsVisibleToAll]]groups.newGroupsVisibleToAll::
 +
 Controls whether newly created groups should be by default visible to
@@ -3312,6 +3335,19 @@
 +
 Defaults to 10000.
 
+[[elasticsearch.connectTimeout]]elasticsearch.connectTimeout::
++
+Sets the timeout for connecting to elasticsearch.
++
+Defaults to `1 second`.
+
+[[elasticsearch.socketTimeout]]elasticsearch.socketTimeout::
++
+Sets the timeout for the underlying connection. For more information, refer to
+link:#httpd.idleTimeout[`httpd.idleTimeout`].
++
+Defaults to `30 seconds`.
+
 ==== Elasticsearch Security
 
 When security is enabled in Elasticsearch, the username and password must be provided.
@@ -3823,8 +3859,13 @@
 
 [[log.jsonLogging]]log.jsonLogging::
 +
-If set to true, enables error, ssh and http logging in JSON format (file name:
-"logs/{error|sshd|httpd}_log.json").
+If set to true, enables error, ssh and http logging in JSON format (file names:
+`logs/error_log.json`, `logs/sshd_log.json` and `logs/httpd_log.json`).
++
+The option only applies to Gerrit built-in loggers. It is ignored when a log4j
+configuration is specified via
+link:#container.javaOptions[container.javaOptions], for example
+`-Dlog4j.configuration=file://etc/log4j.properties`.
 +
 Defaults to false.
 
@@ -3833,6 +3874,11 @@
 If set to true, enables error logging in regular plain text format. Can only be disabled
 if `jsonLogging` is enabled.
 +
+The option only applies to Gerrit built-in loggers. It is ignored when a log4j
+configuration is specified via
+link:#container.javaOptions[container.javaOptions], for example
+`-Dlog4j.configuration=file://etc/log4j.properties`.
++
 Defaults to true.
 
 [[log.compress]]log.compress::
diff --git a/Documentation/dev-bazel.txt b/Documentation/dev-bazel.txt
index 96cc67f..0ae038a 100644
--- a/Documentation/dev-bazel.txt
+++ b/Documentation/dev-bazel.txt
@@ -287,6 +287,18 @@
   bazel-bin/withdocs.war
 ----
 
+Alternatively, one can generate the documentation as flat files:
+
+----
+  bazel build Documentation:Documentation
+----
+
+The html, css, js files are placed in:
+
+----
+ `bazel-bin/Documentation/`
+----
+
 [[tests]]
 == Running Unit Tests
 
diff --git a/Documentation/dev-plugins.txt b/Documentation/dev-plugins.txt
index a68c38b..159e2fc 100644
--- a/Documentation/dev-plugins.txt
+++ b/Documentation/dev-plugins.txt
@@ -803,6 +803,35 @@
   }
 ----
 
+To provide additional Guice bindings for options to a command in another classloader, bind a
+ModulesClassNamesProvider which provides the name of your Modules needed for your DynamicBean
+in the other classLoader.
+
+Do this by binding to the name of the command you are going to bind to and providing an
+Iterable of Module names to instantiate and add to the Injector used to instantiate the
+DynamicBean in the other classLoader. This interface supports running LifecycleListeners
+which are defined by the Modules being provided. The duration of the lifecycle starts when
+a ssh or http request starts and ends when the request completes.
+
+[source, java]
+----
+  bind(DynamicOptions.DynamicBean.class)
+      .annotatedWith(Exports.named(
+          "com.google.gerrit.plugins.otherplugin.command"))
+      .to(MyOptionsModulesClassNamesProvider.class);
+
+  static class MyOptionsModulesClassNamesProvider implements DynamicOptions.ModulesClassNamesProvider {
+    {@literal @}Override
+    public String getClassName() {
+      return "com.googlesource.gerrit.plugins.myplugin.CommandOptions";
+    }
+    {@literal @}Override
+    public Iterable<String> getModulesClassNames()() {
+      return "com.googlesource.gerrit.plugins.myplugin.MyOptionsModule";
+    }
+  }
+----
+
 === Calling Command Options ===
 
 Within an OptionHandler, during the processing of an option, plugins can
@@ -978,17 +1007,9 @@
 Runtime exceptions generated by the implementors of ChangePluginDefinedInfoFactory
 are encapsulated in PluginDefinedInfo objects which are part of SSH/REST query output.
 
-==== ChangeAttributeFactory
-
-Alternatively, there is also `ChangeAttributeFactory` which takes in one single
-`ChangeData` at a time. `ChangePluginDefinedInfoFactory` should be preferred
-over this as it handles many changes at once which also decreases the round-trip
-time for queries resulting in performance increase for bulk queries.
-
-Implementors of the `ChangePluginDefinedInfoFactory` and `ChangeAttributeFactory`
-interfaces should check whether they need to contribute to the
-link:#change-etag-computation[change ETag computation] to prevent callers using
-ETags from potentially seeing outdated plugin attributes.
+Implementors of the `ChangePluginDefinedInfoFactory` interface should check whether
+they need to contribute to the link:#change-etag-computation[change ETag computation]
+to prevent callers using ETags from potentially seeing outdated plugin attributes.
 
 [[simple-configuration]]
 == Simple Configuration in `gerrit.config`
@@ -1424,6 +1445,19 @@
   [...]
 ----
 
+[post_review_extensions]
+== Post Review Extensions
+
+By implementing the `com.google.gerrit.server.restapi.change.OnPostReview`
+interface plugins can extend the change message that is being posted when the
+[post review](rest-api-changes.html#set-review) REST endpoint is invoked.
+
+This is useful if certain approvals have a special meaning (e.g. custom logic
+that is implemented in Prolog submit rules, signal for triggering an action
+like running CI etc.), as it allows the plugin to tell users about this meaning
+in the change message. This makes the effect of a given approval more
+transparent to the user. 
+
 [[ui_extension]]
 == UI Extension
 
@@ -2212,7 +2246,8 @@
   private String imageUrl = "http://placehold.it/16x16.gif";
 
   @Override
-  public WebLinkInfo getPatchSetWebLink(String projectName, String commit) {
+  public WebLinkInfo getPatchSetWebLink(String projectName, String commit,
+   String commitMessage, String branchName) {
     return new WebLinkInfo(name,
         imageUrl,
         String.format(placeHolderUrlProjectCommit, project, commit),
@@ -2427,6 +2462,32 @@
 Macros that start with `\` such as `\@KEEP@` will render as `@KEEP@`
 even if there is an expansion for `KEEP` in the future.
 
+Documentation should typically contain the following content:
+
+[width="100%",options="header"]
+|===================================================
+|File                                           | Content
+|`README.md`                                    | Home page of the plugin when browsing its source code on Git
+|`LICENSE`                                      | Open-source license
+|`resources/Documentation/about.md`             | Overview of the plugin and its purpose
+|`resources/Documentation/config.md`            | Plugin configuration settings and sample configs
+|`resources/Documentation/build.md`             | How to build the plugin
+|`resources/Documentation/cmd-<command>.md`     | SSH commands
+|`resources/Documentation/rest-api-<api>.md`    | REST API
+|`resources/Documentation/servlet-<servlet>.md` | HTTP Servlets
+|===================================================
+
+The documentation under resources/Documentation may contain macro that
+will be included and expanded by Gerrit once the plugin is loaded.
+
+The files in the root directory are not included in the plugin package
+and must not have any macro for expansion. It may also collect
+additional information that would make the plugin more discoverable, such as
+a more user-friendly description of its use-cases.
+
+The documentation can also include images that can help understanding more
+visually how the plugin can interact with the other Gerrit components.
+
 [[auto-index]]
 === Automatic Index
 
diff --git a/Documentation/dev-processes.txt b/Documentation/dev-processes.txt
index 5828cef..68e56ba 100644
--- a/Documentation/dev-processes.txt
+++ b/Documentation/dev-processes.txt
@@ -89,6 +89,15 @@
 already has dedicated seats in the steering committee (see section
 link:#steering-committee[steering committee]).
 
+If a non-Google seat on the steering committee becomes vacant before
+the current term ends, an exceptional election is conducted in order
+to replace the member(s) leaving the committee. The election will
+follow the same procedure as regular steering committee elections.
+The number of votes each maintainer gets in such exceptional election
+matches the number of seats to be filled. The term of the new member
+of the steering committee ends at the end of the current term of
+the steering committee when the next regular election concludes.
+
 [[contribution-process]]
 == Contribution Process
 
@@ -262,6 +271,15 @@
 It's also possible that the ESC decides that an issue is not a security issue
 and the embargo is lifted immediately.
 
+. Filing a CVE
++
+For every security issue a CVE that describes the issue and lists the affected
+releases should be filed. Filing a CVE can be done by any maintainer that works
+for an organization that can request CVE numbers (e.g. Googlers). The CVE
+number must be included in the release notes. The CVE itself is only made
+public after fixed released have been published and the embargo has been
+lifted.
+
 . Implementation of the security fix:
 +
 To keep the embargo intact, security fixes cannot be developed and reviewed in
@@ -307,6 +325,8 @@
 This ends the embargo and any issue that discusses the security vulnerability
 should be made public.
 
+. Publish the CVE
+
 . Follow-Up
 +
 The ESC should discuss if there are any learnings from the security
diff --git a/Documentation/js_licenses.txt b/Documentation/js_licenses.txt
index abfc878..48e729f 100644
--- a/Documentation/js_licenses.txt
+++ b/Documentation/js_licenses.txt
@@ -247,48 +247,15 @@
 ----
 
 
-[[isarray]]
-isarray
+[[Polymer-2014]]
+Polymer-2014
 
-* isarray
+* @polymer/paper-ripple
+* @polymer/paper-styles
 
-[[isarray_license]]
+[[Polymer-2014_license]]
 ----
-(MIT)
-
-Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>;
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-
-----
-
-
-[[Polymer-2018]]
-Polymer-2018
-
-* @webcomponents/webcomponentsjs
-* polymer-bridges
-* polymer-resin
-
-[[Polymer-2018_license]]
-----
-Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 
 This code may only be used under the BSD style license found at
 http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
@@ -326,266 +293,6 @@
 ----
 
 
-[[Polymer-2017]]
-Polymer-2017
-
-* @polymer/decorators
-* @polymer/polymer
-* @webcomponents/shadycss
-
-[[Polymer-2017_license]]
-----
-Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
-
-This code may only be used under the BSD style license found at
-http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
-http://polymer.github.io/AUTHORS.txt The complete set of contributors may be
-found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as
-part of the polymer project is also subject to an additional IP rights grant
-found at http://polymer.github.io/PATENTS.txt
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-----
-
-
-[[shadow-selection-polyfill]]
-shadow-selection-polyfill
-
-* shadow-selection-polyfill
-
-[[shadow-selection-polyfill_license]]
-----
-
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-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
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-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
-----
-
-
 [[Polymer-2015]]
 Polymer-2015
 
@@ -673,48 +380,16 @@
 ----
 
 
-[[ba-linkify]]
-ba-linkify
+[[Polymer-2017]]
+Polymer-2017
 
-* ba-linkify
+* @polymer/decorators
+* @polymer/polymer
+* @webcomponents/shadycss
 
-[[ba-linkify_license]]
+[[Polymer-2017_license]]
 ----
-Copyright (c) 2009 "Cowboy" Ben Alman
-
-Permission is hereby granted, free of charge, to any person
-obtaining a copy of this software and associated documentation
-files (the "Software"), to deal in the Software without
-restriction, including without limitation the rights to use,
-copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the
-Software is furnished to do so, subject to the following
-conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
-OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
-HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
-WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
-OTHER DEALINGS IN THE SOFTWARE.
-
-----
-
-
-[[Polymer-2014]]
-Polymer-2014
-
-* @polymer/paper-ripple
-* @polymer/paper-styles
-
-[[Polymer-2014_license]]
-----
-Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
 
 This code may only be used under the BSD style license found at
 http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
@@ -752,6 +427,86 @@
 ----
 
 
+[[Polymer-2018]]
+Polymer-2018
+
+* @webcomponents/webcomponentsjs
+* polymer-bridges
+* polymer-resin
+
+[[Polymer-2018_license]]
+----
+Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+
+This code may only be used under the BSD style license found at
+http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
+http://polymer.github.io/AUTHORS.txt The complete set of contributors may be
+found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as
+part of the polymer project is also subject to an additional IP rights grant
+found at http://polymer.github.io/PATENTS.txt
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----
+
+
+[[ba-linkify]]
+ba-linkify
+
+* ba-linkify
+
+[[ba-linkify_license]]
+----
+Copyright (c) 2009 "Cowboy" Ben Alman
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+----
+
+
 [[font-roboto-local-fonts-roboto]]
 font-roboto-local-fonts-roboto
 
@@ -1205,34 +960,112 @@
 ----
 
 
-[[path-to-regexp]]
-path-to-regexp
+[[isarray]]
+isarray
 
-* path-to-regexp
+* isarray
 
-[[path-to-regexp_license]]
+[[isarray_license]]
 ----
-The MIT License (MIT)
+(MIT)
 
-Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>;
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+----
+
+
+[[lit-element]]
+lit-element
+
+* lit-element
+
+[[lit-element_license]]
+----
+BSD 3-Clause License
+
+Copyright (c) 2017, The Polymer Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----
+
+
+[[lit-html]]
+lit-html
+
+* lit-html
+
+[[lit-html_license]]
+----
+BSD 3-Clause License
+
+Copyright (c) 2017, The Polymer Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----
 
@@ -1269,3 +1102,484 @@
 
 ----
 
+
+[[path-to-regexp]]
+path-to-regexp
+
+* path-to-regexp
+
+[[path-to-regexp_license]]
+----
+The MIT License (MIT)
+
+Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+----
+
+
+[[rxjs]]
+rxjs
+
+* rxjs
+
+[[rxjs_license]]
+----
+                               Apache License
+                         Version 2.0, January 2004
+                      http://www.apache.org/licenses/
+
+ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+ 1. Definitions.
+
+    "License" shall mean the terms and conditions for use, reproduction,
+    and distribution as defined by Sections 1 through 9 of this document.
+
+    "Licensor" shall mean the copyright owner or entity authorized by
+    the copyright owner that is granting the License.
+
+    "Legal Entity" shall mean the union of the acting entity and all
+    other entities that control, are controlled by, or are under common
+    control with that entity. For the purposes of this definition,
+    "control" means (i) the power, direct or indirect, to cause the
+    direction or management of such entity, whether by contract or
+    otherwise, or (ii) ownership of fifty percent (50%) or more of the
+    outstanding shares, or (iii) beneficial ownership of such entity.
+
+    "You" (or "Your") shall mean an individual or Legal Entity
+    exercising permissions granted by this License.
+
+    "Source" form shall mean the preferred form for making modifications,
+    including but not limited to software source code, documentation
+    source, and configuration files.
+
+    "Object" form shall mean any form resulting from mechanical
+    transformation or translation of a Source form, including but
+    not limited to compiled object code, generated documentation,
+    and conversions to other media types.
+
+    "Work" shall mean the work of authorship, whether in Source or
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+    (an example is provided in the Appendix below).
+
+    "Derivative Works" shall mean any work, whether in Source or Object
+    form, that is based on (or derived from) the Work and for which the
+    editorial revisions, annotations, elaborations, or other modifications
+    represent, as a whole, an original work of authorship. For the purposes
+    of this License, Derivative Works shall not include works that remain
+    separable from, or merely link (or bind by name) to the interfaces of,
+    the Work and Derivative Works thereof.
+
+    "Contribution" shall mean any work of authorship, including
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+    to that Work or Derivative Works thereof, that is intentionally
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+    the copyright owner. For the purposes of this definition, "submitted"
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+    subsequently incorporated within the Work.
+
+ 2. Grant of Copyright License. Subject to the terms and conditions of
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+
+ 3. Grant of Patent License. Subject to the terms and conditions of
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+    cross-claim or counterclaim in a lawsuit) alleging that the Work
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+    or contributory patent infringement, then any patent licenses
+    granted to You under this License for that Work shall terminate
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+
+ 4. Redistribution. You may reproduce and distribute copies of the
+    Work or Derivative Works thereof in any medium, with or without
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+    meet the following conditions:
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+    (a) You must give any other recipients of the Work or
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+
+    (b) You must cause any modified files to carry prominent notices
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+
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+
+    (d) If the Work includes a "NOTICE" text file as part of its
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+    the conditions stated in this License.
+
+ 5. Submission of Contributions. Unless You explicitly state otherwise,
+    any Contribution intentionally submitted for inclusion in the Work
+    by You to the Licensor shall be under the terms and conditions of
+    this License, without any additional terms or conditions.
+    Notwithstanding the above, nothing herein shall supersede or modify
+    the terms of any separate license agreement you may have executed
+    with Licensor regarding such Contributions.
+
+ 6. Trademarks. This License does not grant permission to use the trade
+    names, trademarks, service marks, or product names of the Licensor,
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+
+ 7. Disclaimer of Warranty. Unless required by applicable law or
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+
+ 8. Limitation of Liability. In no event and under no legal theory,
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+    defend, and hold each Contributor harmless for any liability
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+    of your accepting any such warranty or additional liability.
+
+ END OF TERMS AND CONDITIONS
+
+ APPENDIX: How to apply the Apache License to your work.
+
+    To apply the Apache License to your work, attach the following
+    boilerplate notice, with the fields enclosed by brackets "[]"
+    replaced with your own identifying information. (Don't include
+    the brackets!)  The text should be enclosed in the appropriate
+    comment syntax for the file format. We also recommend that a
+    file or class name and description of purpose be included on the
+    same "printed page" as the copyright notice for easier
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+
+ Copyright (c) 2015-2018 Google, Inc., Netflix, Inc., Microsoft Corp. and contributors
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ 
+
+----
+
+
+[[shadow-selection-polyfill]]
+shadow-selection-polyfill
+
+* shadow-selection-polyfill
+
+[[shadow-selection-polyfill_license]]
+----
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+----
+
+
+[[tslib]]
+tslib
+
+* tslib
+
+[[tslib_license]]
+----
+Copyright (c) Microsoft Corporation.
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+
+----
+
diff --git a/Documentation/licenses.txt b/Documentation/licenses.txt
index cc67f91..cd794b8 100644
--- a/Documentation/licenses.txt
+++ b/Documentation/licenses.txt
@@ -44,10 +44,12 @@
 
 * auto:auto-value
 * auto:auto-value-annotations
+* auto:auto-value-gson
 * commons:codec
 * commons:compress
 * commons:dbcp
 * commons:lang
+* commons:lang3
 * commons:net
 * commons:pool
 * commons:validator
@@ -3190,48 +3192,15 @@
 ----
 
 
-[[isarray]]
-isarray
+[[Polymer-2014]]
+Polymer-2014
 
-* isarray
+* @polymer/paper-ripple
+* @polymer/paper-styles
 
-[[isarray_license]]
+[[Polymer-2014_license]]
 ----
-(MIT)
-
-Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>;
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-
-----
-
-
-[[Polymer-2018]]
-Polymer-2018
-
-* @webcomponents/webcomponentsjs
-* polymer-bridges
-* polymer-resin
-
-[[Polymer-2018_license]]
-----
-Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 
 This code may only be used under the BSD style license found at
 http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
@@ -3269,266 +3238,6 @@
 ----
 
 
-[[Polymer-2017]]
-Polymer-2017
-
-* @polymer/decorators
-* @polymer/polymer
-* @webcomponents/shadycss
-
-[[Polymer-2017_license]]
-----
-Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
-
-This code may only be used under the BSD style license found at
-http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
-http://polymer.github.io/AUTHORS.txt The complete set of contributors may be
-found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as
-part of the polymer project is also subject to an additional IP rights grant
-found at http://polymer.github.io/PATENTS.txt
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-----
-
-
-[[shadow-selection-polyfill]]
-shadow-selection-polyfill
-
-* shadow-selection-polyfill
-
-[[shadow-selection-polyfill_license]]
-----
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
-----
-
-
 [[Polymer-2015]]
 Polymer-2015
 
@@ -3616,48 +3325,16 @@
 ----
 
 
-[[ba-linkify]]
-ba-linkify
+[[Polymer-2017]]
+Polymer-2017
 
-* ba-linkify
+* @polymer/decorators
+* @polymer/polymer
+* @webcomponents/shadycss
 
-[[ba-linkify_license]]
+[[Polymer-2017_license]]
 ----
-Copyright (c) 2009 "Cowboy" Ben Alman
-
-Permission is hereby granted, free of charge, to any person
-obtaining a copy of this software and associated documentation
-files (the "Software"), to deal in the Software without
-restriction, including without limitation the rights to use,
-copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the
-Software is furnished to do so, subject to the following
-conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
-OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
-HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
-WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
-OTHER DEALINGS IN THE SOFTWARE.
-
-----
-
-
-[[Polymer-2014]]
-Polymer-2014
-
-* @polymer/paper-ripple
-* @polymer/paper-styles
-
-[[Polymer-2014_license]]
-----
-Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
+Copyright (c) 2017 The Polymer Project Authors. All rights reserved.
 
 This code may only be used under the BSD style license found at
 http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
@@ -3695,6 +3372,86 @@
 ----
 
 
+[[Polymer-2018]]
+Polymer-2018
+
+* @webcomponents/webcomponentsjs
+* polymer-bridges
+* polymer-resin
+
+[[Polymer-2018_license]]
+----
+Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+
+This code may only be used under the BSD style license found at
+http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
+http://polymer.github.io/AUTHORS.txt The complete set of contributors may be
+found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as
+part of the polymer project is also subject to an additional IP rights grant
+found at http://polymer.github.io/PATENTS.txt
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----
+
+
+[[ba-linkify]]
+ba-linkify
+
+* ba-linkify
+
+[[ba-linkify_license]]
+----
+Copyright (c) 2009 "Cowboy" Ben Alman
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+----
+
+
 [[font-roboto-local-fonts-roboto]]
 font-roboto-local-fonts-roboto
 
@@ -4148,34 +3905,112 @@
 ----
 
 
-[[path-to-regexp]]
-path-to-regexp
+[[isarray]]
+isarray
 
-* path-to-regexp
+* isarray
 
-[[path-to-regexp_license]]
+[[isarray_license]]
 ----
-The MIT License (MIT)
+(MIT)
 
-Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>;
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+----
+
+
+[[lit-element]]
+lit-element
+
+* lit-element
+
+[[lit-element_license]]
+----
+BSD 3-Clause License
+
+Copyright (c) 2017, The Polymer Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----
+
+
+[[lit-html]]
+lit-html
+
+* lit-html
+
+[[lit-html_license]]
+----
+BSD 3-Clause License
+
+Copyright (c) 2017, The Polymer Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----
 
@@ -4213,6 +4048,487 @@
 ----
 
 
+[[path-to-regexp]]
+path-to-regexp
+
+* path-to-regexp
+
+[[path-to-regexp_license]]
+----
+The MIT License (MIT)
+
+Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+----
+
+
+[[rxjs]]
+rxjs
+
+* rxjs
+
+[[rxjs_license]]
+----
+                               Apache License
+                         Version 2.0, January 2004
+                      http://www.apache.org/licenses/
+
+ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+ 1. Definitions.
+
+    "License" shall mean the terms and conditions for use, reproduction,
+    and distribution as defined by Sections 1 through 9 of this document.
+
+    "Licensor" shall mean the copyright owner or entity authorized by
+    the copyright owner that is granting the License.
+
+    "Legal Entity" shall mean the union of the acting entity and all
+    other entities that control, are controlled by, or are under common
+    control with that entity. For the purposes of this definition,
+    "control" means (i) the power, direct or indirect, to cause the
+    direction or management of such entity, whether by contract or
+    otherwise, or (ii) ownership of fifty percent (50%) or more of the
+    outstanding shares, or (iii) beneficial ownership of such entity.
+
+    "You" (or "Your") shall mean an individual or Legal Entity
+    exercising permissions granted by this License.
+
+    "Source" form shall mean the preferred form for making modifications,
+    including but not limited to software source code, documentation
+    source, and configuration files.
+
+    "Object" form shall mean any form resulting from mechanical
+    transformation or translation of a Source form, including but
+    not limited to compiled object code, generated documentation,
+    and conversions to other media types.
+
+    "Work" shall mean the work of authorship, whether in Source or
+    Object form, made available under the License, as indicated by a
+    copyright notice that is included in or attached to the work
+    (an example is provided in the Appendix below).
+
+    "Derivative Works" shall mean any work, whether in Source or Object
+    form, that is based on (or derived from) the Work and for which the
+    editorial revisions, annotations, elaborations, or other modifications
+    represent, as a whole, an original work of authorship. For the purposes
+    of this License, Derivative Works shall not include works that remain
+    separable from, or merely link (or bind by name) to the interfaces of,
+    the Work and Derivative Works thereof.
+
+    "Contribution" shall mean any work of authorship, including
+    the original version of the Work and any modifications or additions
+    to that Work or Derivative Works thereof, that is intentionally
+    submitted to Licensor for inclusion in the Work by the copyright owner
+    or by an individual or Legal Entity authorized to submit on behalf of
+    the copyright owner. For the purposes of this definition, "submitted"
+    means any form of electronic, verbal, or written communication sent
+    to the Licensor or its representatives, including but not limited to
+    communication on electronic mailing lists, source code control systems,
+    and issue tracking systems that are managed by, or on behalf of, the
+    Licensor for the purpose of discussing and improving the Work, but
+    excluding communication that is conspicuously marked or otherwise
+    designated in writing by the copyright owner as "Not a Contribution."
+
+    "Contributor" shall mean Licensor and any individual or Legal Entity
+    on behalf of whom a Contribution has been received by Licensor and
+    subsequently incorporated within the Work.
+
+ 2. Grant of Copyright License. Subject to the terms and conditions of
+    this License, each Contributor hereby grants to You a perpetual,
+    worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+    copyright license to reproduce, prepare Derivative Works of,
+    publicly display, publicly perform, sublicense, and distribute the
+    Work and such Derivative Works in Source or Object form.
+
+ 3. Grant of Patent License. Subject to the terms and conditions of
+    this License, each Contributor hereby grants to You a perpetual,
+    worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+    (except as stated in this section) patent license to make, have made,
+    use, offer to sell, sell, import, and otherwise transfer the Work,
+    where such license applies only to those patent claims licensable
+    by such Contributor that are necessarily infringed by their
+    Contribution(s) alone or by combination of their Contribution(s)
+    with the Work to which such Contribution(s) was submitted. If You
+    institute patent litigation against any entity (including a
+    cross-claim or counterclaim in a lawsuit) alleging that the Work
+    or a Contribution incorporated within the Work constitutes direct
+    or contributory patent infringement, then any patent licenses
+    granted to You under this License for that Work shall terminate
+    as of the date such litigation is filed.
+
+ 4. Redistribution. You may reproduce and distribute copies of the
+    Work or Derivative Works thereof in any medium, with or without
+    modifications, and in Source or Object form, provided that You
+    meet the following conditions:
+
+    (a) You must give any other recipients of the Work or
+        Derivative Works a copy of this License; and
+
+    (b) You must cause any modified files to carry prominent notices
+        stating that You changed the files; and
+
+    (c) You must retain, in the Source form of any Derivative Works
+        that You distribute, all copyright, patent, trademark, and
+        attribution notices from the Source form of the Work,
+        excluding those notices that do not pertain to any part of
+        the Derivative Works; and
+
+    (d) If the Work includes a "NOTICE" text file as part of its
+        distribution, then any Derivative Works that You distribute must
+        include a readable copy of the attribution notices contained
+        within such NOTICE file, excluding those notices that do not
+        pertain to any part of the Derivative Works, in at least one
+        of the following places: within a NOTICE text file distributed
+        as part of the Derivative Works; within the Source form or
+        documentation, if provided along with the Derivative Works; or,
+        within a display generated by the Derivative Works, if and
+        wherever such third-party notices normally appear. The contents
+        of the NOTICE file are for informational purposes only and
+        do not modify the License. You may add Your own attribution
+        notices within Derivative Works that You distribute, alongside
+        or as an addendum to the NOTICE text from the Work, provided
+        that such additional attribution notices cannot be construed
+        as modifying the License.
+
+    You may add Your own copyright statement to Your modifications and
+    may provide additional or different license terms and conditions
+    for use, reproduction, or distribution of Your modifications, or
+    for any such Derivative Works as a whole, provided Your use,
+    reproduction, and distribution of the Work otherwise complies with
+    the conditions stated in this License.
+
+ 5. Submission of Contributions. Unless You explicitly state otherwise,
+    any Contribution intentionally submitted for inclusion in the Work
+    by You to the Licensor shall be under the terms and conditions of
+    this License, without any additional terms or conditions.
+    Notwithstanding the above, nothing herein shall supersede or modify
+    the terms of any separate license agreement you may have executed
+    with Licensor regarding such Contributions.
+
+ 6. Trademarks. This License does not grant permission to use the trade
+    names, trademarks, service marks, or product names of the Licensor,
+    except as required for reasonable and customary use in describing the
+    origin of the Work and reproducing the content of the NOTICE file.
+
+ 7. Disclaimer of Warranty. Unless required by applicable law or
+    agreed to in writing, Licensor provides the Work (and each
+    Contributor provides its Contributions) on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+    implied, including, without limitation, any warranties or conditions
+    of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+    PARTICULAR PURPOSE. You are solely responsible for determining the
+    appropriateness of using or redistributing the Work and assume any
+    risks associated with Your exercise of permissions under this License.
+
+ 8. Limitation of Liability. In no event and under no legal theory,
+    whether in tort (including negligence), contract, or otherwise,
+    unless required by applicable law (such as deliberate and grossly
+    negligent acts) or agreed to in writing, shall any Contributor be
+    liable to You for damages, including any direct, indirect, special,
+    incidental, or consequential damages of any character arising as a
+    result of this License or out of the use or inability to use the
+    Work (including but not limited to damages for loss of goodwill,
+    work stoppage, computer failure or malfunction, or any and all
+    other commercial damages or losses), even if such Contributor
+    has been advised of the possibility of such damages.
+
+ 9. Accepting Warranty or Additional Liability. While redistributing
+    the Work or Derivative Works thereof, You may choose to offer,
+    and charge a fee for, acceptance of support, warranty, indemnity,
+    or other liability obligations and/or rights consistent with this
+    License. However, in accepting such obligations, You may act only
+    on Your own behalf and on Your sole responsibility, not on behalf
+    of any other Contributor, and only if You agree to indemnify,
+    defend, and hold each Contributor harmless for any liability
+    incurred by, or claims asserted against, such Contributor by reason
+    of your accepting any such warranty or additional liability.
+
+ END OF TERMS AND CONDITIONS
+
+ APPENDIX: How to apply the Apache License to your work.
+
+    To apply the Apache License to your work, attach the following
+    boilerplate notice, with the fields enclosed by brackets "[]"
+    replaced with your own identifying information. (Don't include
+    the brackets!)  The text should be enclosed in the appropriate
+    comment syntax for the file format. We also recommend that a
+    file or class name and description of purpose be included on the
+    same "printed page" as the copyright notice for easier
+    identification within third-party archives.
+
+ Copyright (c) 2015-2018 Google, Inc., Netflix, Inc., Microsoft Corp. and contributors
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ 
+
+----
+
+
+[[shadow-selection-polyfill]]
+shadow-selection-polyfill
+
+* shadow-selection-polyfill
+
+[[shadow-selection-polyfill_license]]
+----
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+----
+
+
+[[tslib]]
+tslib
+
+* tslib
+
+[[tslib_license]]
+----
+Copyright (c) Microsoft Corporation.
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+
+----
+
+
 GERRIT
 ------
 Part of link:index.html[Gerrit Code Review]
diff --git a/Documentation/prolog-cookbook.txt b/Documentation/prolog-cookbook.txt
index 32c30b8..189ccfc 100644
--- a/Documentation/prolog-cookbook.txt
+++ b/Documentation/prolog-cookbook.txt
@@ -26,7 +26,7 @@
 link:https://groups.google.com/d/topic/repo-discuss/wJxTGhlHZMM/discussion[This
 discussion thread,role=external,window=_blank] explains why Prolog was chosen for the purpose of writing
 project specific submit rules.
-link:http://gerrit-documentation.googlecode.com/svn/ReleaseNotes/ReleaseNotes-2.2.2.html[Gerrit
+link:https://gerrit-documentation.storage.googleapis.com/ReleaseNotes/ReleaseNotes-2.2.2.html#_prolog[Gerrit
 2.2.2 ReleaseNotes,role=external,window=_blank] introduces Prolog support in Gerrit.
 
 [[SubmitType]]
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index 84e9c7b..3f0c751 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -15,7 +15,9 @@
 --
 
 The change input link:#change-input[ChangeInput] entity must be provided in the
-request body.
+request body. It is not allowed to create changes on refs/tags/* or Gerrit
+internal refs such as refs/changes/*, refs/meta/external-ids/*, refs/users/*,
+etc.. and the request would fail with `400 Bad Request` in this case.
 
 To create a change the calling user must be allowed to
 link:access-control.html#category_push_review[upload to code review].
@@ -222,15 +224,18 @@
 [[labels]]
 --
 * `LABELS`: a summary of each label required for submit, and
-  approvers that have granted (or rejected) with that label.
+  approvers that have granted (or rejected) with that label
+  as well as all reviewers by state, and reviewers that may
+  be removed by the current user.
 --
 
 [[detailed-labels]]
 --
 * `DETAILED_LABELS`: detailed label information, including numeric
   values of all existing approvals, recognized label values, values
-  permitted to be set by the current user, all reviewers by state, and
-  reviewers that may be removed by the current user.
+  permitted to be set by any reviewer and the change owner, all
+  reviewers by state, and reviewers that may be removed by the
+  current user.
 --
 
 [[current-revision]]
@@ -1391,6 +1396,8 @@
 
 The destination branch must be provided in the request body inside a
 link:#move-input[MoveInput] entity.
+Only veto votes that are blocking the change from submission are moved to
+the destination branch by default.
 
 .Request
 ----
@@ -2045,7 +2052,7 @@
 comments for each path are sorted by patch set number. Each comment has
 the `patch_set` and `author` fields set.
 
-If the `enable_context` request parameter is set to true, the comment entries
+If the `enable-context` request parameter is set to true, the comment entries
 will contain a list of link:#context-line[ContextLine] containing the lines of
 the source file where the comment was written.
 
@@ -5140,6 +5147,8 @@
 Different than the link:#get-ported-comments[Get Ported Comments] endpoint, the `author` of the
 returned comments is not filled for this endpoint as only comments of the calling user are returned.
 
+This endpoint requires authentication.
+
 .Request
 ----
   GET /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/revisions/674ac754f91e64a0efb8087e59a176484bd534d1/ported_drafts/ HTTP/1.0
@@ -5941,6 +5950,8 @@
 If a user is added while already in the attention set, the
 request is silently ignored.
 
+The user must be a reviewer, cc, uploader, or owner on the change.
+
 .Request
 ----
   POST /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/attention HTTP/1.0
@@ -6414,7 +6425,8 @@
 |`removable_reviewers`|optional|
 The reviewers that can be removed by the calling user as a list of
 link:rest-api-accounts.html#account-info[AccountInfo] entities. +
-Only set if link:#detailed-labels[detailed labels] are requested.
+Only set if link:#labels[labels] or
+link:#detailed-labels[detailed labels] are requested.
 |`reviewers`          |optional|
 The reviewers as a map that maps a reviewer state to a list of
 link:rest-api-accounts.html#account-info[AccountInfo] entities.
@@ -6423,13 +6435,15 @@
 `CC`: Users that were added to the change, but have not voted. +
 `REMOVED`: Users that were previously reviewers on the change, but have
 been removed. +
-Only set if link:#detailed-labels[detailed labels] are requested.
+Only set if link:#labels[labels] or
+link:#detailed-labels[detailed labels] are requested.
 |`pending_reviewers`  |optional|
 Updates to `reviewers` that have been made while the change was in the
 WIP state. Only present on WIP changes and only if there are pending
 reviewer updates to report. These are reviewers who have not yet been
 notified about being added to or removed from the change. +
-Only set if link:#detailed-labels[detailed labels] are requested.
+Only set if link:#labels[labels] or
+link:#detailed-labels[detailed labels] are requested.
 |`reviewer_updates`|optional|
 Updates to reviewers set for the change as
 link:#review-update-info[ReviewerUpdateInfo] entities.
@@ -6685,7 +6699,7 @@
 this comment applies.
 |`context_lines` |optional|
 A list of link:#context-line[ContextLine] containing the lines of the source
-file where the comment was written. Available only if the "enable_context"
+file where the comment was written. Available only if the "enable-context"
 parameter (see link:#list-change-comments[List Change Comments]) is set.
 
 |===========================
@@ -7350,6 +7364,11 @@
 |`destination_branch`||Destination branch
 |`message`           |optional|
 A message to be posted in this change's comments
+|`keep_all_votes`    |optional, defaults to false|
+By default, only veto votes that are blocking the change from submission are moved to
+the destination branch. Using this option is only allowed for administrators,
+because it can affect the submission behaviour of the change (depending on the label access
+configuration and submissions rules).
 |===========================
 
 [[notify-info]]
@@ -7668,7 +7687,8 @@
 `ready` and `work_in_progress` to be true.
 |`add_to_attention_set`                |optional|
 list of link:#attention-set-input[AttentionSetInput] entities to add
-to the link:#attention-set[attention set].
+to the link:#attention-set[attention set]. Users that are not reviewers,
+ccs, owner, or uploader are silently ignored.
 |`remove_from_attention_set`           |optional|
 list of link:#attention-set-input[AttentionSetInput] entities to remove
 from the link:#attention-set[attention set].
diff --git a/Documentation/rest-api-projects.txt b/Documentation/rest-api-projects.txt
index 92759b6..a809eab 100644
--- a/Documentation/rest-api-projects.txt
+++ b/Documentation/rest-api-projects.txt
@@ -1702,7 +1702,9 @@
 'GET /projects/link:#project-name[\{project-name\}]/branches/link:#branch-id[\{branch-id\}]'
 --
 
-Retrieves a branch of a project.
+Retrieves a branch of a project. For the "All-Users" repository, the magic
+branch "refs/users/self" is automatically resolved to the user branch of the
+calling user.
 
 .Request
 ----
@@ -1846,8 +1848,9 @@
 
 Gets whether the source is mergeable with the target branch.
 
-The `source` query parameter is required, which can be anything that could be
-resolved to a commit, see examples of the `source` attribute in
+The `source` query parameter is required, which can be anything that
+could be resolved to a commit, and is visible to the caller. See
+examples of the `source` attribute in
 link:rest-api-changes.html#merge-input[MergeInput].
 
 Also takes an optional parameter `strategy`, which can be `recursive`, `resolve`,
@@ -3393,6 +3396,8 @@
 |`status`                    ||The HTTP status code for the access.
 200 means success and 403 means denied.
 |`message`                   |optional|A clarifying message if `status` is not 200.
+|`debug_logs`                |optional|
+Debug logs that may help to understand why a permission is denied or allowed.
 |=========================================
 
 [[auto_closeable_changes_check_input]]
@@ -4194,7 +4199,9 @@
 repository.<name>.defaultSubmitType] is set to a different value.
 |`branches`                  |optional|
 A list of branches that should be initially created. +
-For the branch names the `refs/heads/` prefix can be omitted.
+For the branch names the `refs/heads/` prefix can be omitted. +
+The first entry of the list will be the default branch (ie. the target +
+of the `HEAD` symbolic ref).
 |`owners`                    |optional|
 A list of groups that should be assigned as project owner. +
 Each group in the list must be specified as
diff --git a/Documentation/user-named-destinations.txt b/Documentation/user-named-destinations.txt
index 1b6f143..a1ab258 100644
--- a/Documentation/user-named-destinations.txt
+++ b/Documentation/user-named-destinations.txt
@@ -13,6 +13,7 @@
 row in a destination file represents a single destination in the
 named set.  The left column represents the ref of the destination,
 and the right column represents the project of the destination.
+The named destinations can be publicly accessible by other users.
 
 Example destination file named `destinations/myreviews`:
 
diff --git a/Documentation/user-named-queries.txt b/Documentation/user-named-queries.txt
index e79b3da..c01f790 100644
--- a/Documentation/user-named-queries.txt
+++ b/Documentation/user-named-queries.txt
@@ -7,7 +7,8 @@
 link:intro-user.html#user-refs[user's ref] in the `All-Users` project.  The
 user's queries file is a 2 column tab delimited file.  The left
 column represents the name of the query, and the right column
-represents the query expression represented by the name.
+represents the query expression represented by the name. The named queries
+can be publicly accessible by other users.
 
 Example queries file:
 
diff --git a/Documentation/user-search.txt b/Documentation/user-search.txt
index 0c1ec2d..e02dc21 100644
--- a/Documentation/user-search.txt
+++ b/Documentation/user-search.txt
@@ -92,6 +92,18 @@
 format `2006-01-02[ 15:04:05[.890][ -0700]]`; omitting the time defaults
 to 00:00:00 and omitting the timezone defaults to UTC.
 
+[[mergedbefore]]
+mergedbefore:'TIME'::
++
+Changes merged before the given 'TIME'. The matching behaviour is consistent
+with `before:'TIME'`.
+
+[[mergedafter]]
+mergedafter:'TIME'::
++
+Changes merged after the given 'TIME'. The matching behaviour is consistent
+with `after:'TIME'`.
+
 [[change]]
 change:'ID'::
 +
@@ -106,9 +118,11 @@
 that was scraped out of the commit message.
 
 [[destination]]
-destination:'NAME'::
+destination:'[name=]NAME[,user=USER]'::
 +
-Changes which match the current user's destination named 'NAME'.
+Changes which match the specified USER's destination named 'NAME'. If 'USER'
+is unspecified, the current user is used. The named destinations can be
+publicly accessible by other users.
 (see link:user-named-destinations.html[Named Destinations]).
 
 [[owner]]
@@ -123,9 +137,11 @@
 Changes originally submitted by a user in 'GROUP'.
 
 [[query]]
-query:'NAME'::
+query:'[name=]NAME[,user=USER]'::
 +
-Changes which match the current user's query named 'NAME'
+Changes which match the specified USER's query named 'NAME'. If 'USER'
+is unspecified, the current user is used. The named queries can be
+publicly accessible by other users.
 (see link:user-named-queries.html[Named Queries]).
 
 [[reviewer]]
diff --git a/WORKSPACE b/WORKSPACE
index 76d1301..708d6f2 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -53,10 +53,10 @@
 
 http_archive(
     name = "com_google_protobuf",
-    sha256 = "71030a04aedf9f612d2991c1c552317038c3c5a2b578ac4745267a45e7037c29",
-    strip_prefix = "protobuf-3.12.3",
+    sha256 = "d0f5f605d0d656007ce6c8b5a82df3037e1d8fe8b121ed42e536f569dec16113",
+    strip_prefix = "protobuf-3.14.0",
     urls = [
-        "https://github.com/protocolbuffers/protobuf/archive/v3.12.3.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v3.14.0.tar.gz",
     ],
 )
 
@@ -66,8 +66,8 @@
 
 http_archive(
     name = "build_bazel_rules_nodejs",
-    sha256 = "5bf77cc2d13ddf9124f4c1453dd96063774d755d4fc75d922471540d1c9a8ea8",
-    urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/2.0.0/rules_nodejs-2.0.0.tar.gz"],
+    sha256 = "84b1d11b1f3bda68c24d992dc6e830bca9db8fa12276f2ca7fcb7761c893976b",
+    urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/3.0.0-rc.1/rules_nodejs-3.0.0-rc.1.tar.gz"],
 )
 
 # Golang support for PolyGerrit local dev server.
@@ -139,36 +139,6 @@
     sha1 = "83cd2cd674a217ade95a4bb83a8a14f351f48bd0",
 )
 
-GUICE_VERS = "4.2.3"
-
-GUICE_LIBRARY_SHA256 = "5168f5e7383f978c1b4154ac777b78edd8ac214bb9f9afdb92921c8d156483d3"
-
-http_file(
-    name = "guice-library-no-aop",
-    canonical_id = "guice-library-no-aop-" + GUICE_VERS + ".jar-" + GUICE_LIBRARY_SHA256,
-    downloaded_file_path = "guice-library-no-aop.jar",
-    sha256 = GUICE_LIBRARY_SHA256,
-    urls = [
-        "https://repo1.maven.org/maven2/com/google/inject/guice/" +
-        GUICE_VERS +
-        "/guice-" +
-        GUICE_VERS +
-        "-no_aop.jar",
-    ],
-)
-
-maven_jar(
-    name = "guice-assistedinject",
-    artifact = "com.google.inject.extensions:guice-assistedinject:" + GUICE_VERS,
-    sha1 = "acbfddc556ee9496293ed1df250cc378f331d854",
-)
-
-maven_jar(
-    name = "guice-servlet",
-    artifact = "com.google.inject.extensions:guice-servlet:" + GUICE_VERS,
-    sha1 = "8d6e7e35eac4fb5e7df19c55b3bc23fa51b10a11",
-)
-
 maven_jar(
     name = "javax_inject",
     artifact = "javax.inject:javax.inject:1",
@@ -213,14 +183,6 @@
     sha1 = "f645ed69d595b24d4cf8b3fbb64cc505bede8829",
 )
 
-load("//lib:guava.bzl", "GUAVA_BIN_SHA1", "GUAVA_VERSION")
-
-maven_jar(
-    name = "guava",
-    artifact = "com.google.guava:guava:" + GUAVA_VERSION,
-    sha1 = GUAVA_BIN_SHA1,
-)
-
 CAFFEINE_VERS = "2.8.5"
 
 maven_jar(
@@ -642,6 +604,38 @@
     sha1 = "eff48ed53995db2dadf0456426cc1f8700136f86",
 )
 
+AUTO_VALUE_GSON_VERSION = "1.3.0"
+
+maven_jar(
+    name = "auto-value-gson-runtime",
+    artifact = "com.ryanharter.auto.value:auto-value-gson-runtime:" + AUTO_VALUE_GSON_VERSION,
+    sha1 = "a69a9db5868bb039bd80f60661a771b643eaba59",
+)
+
+maven_jar(
+    name = "auto-value-gson-extension",
+    artifact = "com.ryanharter.auto.value:auto-value-gson-extension:" + AUTO_VALUE_GSON_VERSION,
+    sha1 = "6a61236d17b58b05e32b4c532bcb348280d2212b",
+)
+
+maven_jar(
+    name = "auto-value-gson-factory",
+    artifact = "com.ryanharter.auto.value:auto-value-gson-factory:" + AUTO_VALUE_GSON_VERSION,
+    sha1 = "b1f01918c0d6cb1f5482500e6b9e62589334dbb0",
+)
+
+maven_jar(
+    name = "javapoet",
+    artifact = "com.squareup:javapoet:1.13.0",
+    sha1 = "d6562d385049f35eb50403fa86bb11cce76b866a",
+)
+
+maven_jar(
+    name = "autotransient",
+    artifact = "io.sweers.autotransient:autotransient:1.0.0",
+    sha1 = "38b1c630b8e76560221622289f37be40105abb3d",
+)
+
 declare_nongoogle_deps()
 
 LUCENE_VERS = "6.6.5"
@@ -757,13 +751,6 @@
     sha1 = "b8ba1c1eb8b2e45cfd465d01218c6060e887572e",
 )
 
-# Keep this version of Soy synchronized with the version used in Gitiles.
-maven_jar(
-    name = "soy",
-    artifact = "com.google.template:soy:2019-10-08",
-    sha1 = "4518bf8bac2dbbed684849bc209c39c4cb546237",
-)
-
 maven_jar(
     name = "html-types",
     artifact = "com.google.common.html.types:types:1.0.8",
@@ -832,12 +819,6 @@
 # Test-only dependencies below.
 
 maven_jar(
-    name = "jimfs",
-    artifact = "com.google.jimfs:jimfs:1.1",
-    sha1 = "8fbd0579dc68aba6186935cc1bee21d2f3e7ec1c",
-)
-
-maven_jar(
     name = "junit",
     artifact = "junit:junit:4.12",
     sha1 = "2973d150c0dc1fefe998f834810d68f278ea58ec",
@@ -980,6 +961,7 @@
 
 yarn_install(
     name = "npm",
+    frozen_lockfile = False,
     package_json = "//:package.json",
     yarn_lock = "//:yarn.lock",
 )
@@ -987,18 +969,21 @@
 yarn_install(
     name = "ui_npm",
     args = ["--prod"],
+    frozen_lockfile = False,
     package_json = "//:polygerrit-ui/app/package.json",
     yarn_lock = "//:polygerrit-ui/app/yarn.lock",
 )
 
 yarn_install(
     name = "ui_dev_npm",
+    frozen_lockfile = False,
     package_json = "//:polygerrit-ui/package.json",
     yarn_lock = "//:polygerrit-ui/yarn.lock",
 )
 
 yarn_install(
     name = "tools_npm",
+    frozen_lockfile = False,
     package_json = "//:tools/node_tools/package.json",
     yarn_lock = "//:tools/node_tools/yarn.lock",
 )
@@ -1006,6 +991,7 @@
 yarn_install(
     name = "plugins_npm",
     args = ["--prod"],
+    frozen_lockfile = False,
     package_json = "//:plugins/package.json",
     yarn_lock = "//:plugins/yarn.lock",
 )
diff --git a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
index 4ab5d51..f59daf5 100644
--- a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -168,6 +168,8 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
 import org.eclipse.jgit.junit.TestRepository;
@@ -767,6 +769,58 @@
     return result;
   }
 
+  protected PushOneCommit.Result createNParentsMergeCommitChange(String ref, List<String> fileNames)
+      throws Exception {
+    // This method creates n different commits and creates a merge commit pointing to all n parents.
+    // Each commit will contain all the fileNames. Commit i will have the following file names and
+    // their contents:
+    // {$file_1_name, ${file_1_name}-1}
+    // {$file_2_name, ${file_2_name}-1}, etc...
+    // The merge commit will have:
+    // {$file_1_name, ${file_1_name}-1}
+    // {$file_2_name, ${file_2_name}-2},
+    // {$file_3_name, ${file_3_name}-3}, etc...
+    // i.e. taking the ith file from the ith commit.
+    int n = fileNames.size();
+    ObjectId initial = repo().exactRef(HEAD).getLeaf().getObjectId();
+
+    List<PushOneCommit.Result> pushResults = new ArrayList<>();
+
+    for (int i = 1; i <= n; i++) {
+      int finalI = i;
+      pushResults.add(
+          pushFactory
+              .create(
+                  admin.newIdent(),
+                  testRepo,
+                  "parent " + i,
+                  fileNames.stream().collect(Collectors.toMap(f -> f, f -> f + "-" + finalI)))
+              .to(ref));
+
+      // reset HEAD in order to create a sibling of the first change
+      if (i < n) {
+        testRepo.reset(initial);
+      }
+    }
+
+    PushOneCommit m =
+        pushFactory.create(
+            admin.newIdent(),
+            testRepo,
+            "merge",
+            IntStream.range(1, n + 1)
+                .boxed()
+                .collect(
+                    Collectors.toMap(
+                        i -> fileNames.get((int) i - 1),
+                        i -> fileNames.get((int) i - 1) + "-" + i)));
+
+    m.setParents(pushResults.stream().map(PushOneCommit.Result::getCommit).collect(toList()));
+    PushOneCommit.Result result = m.to(ref);
+    result.assertOkStatus();
+    return result;
+  }
+
   protected PushOneCommit.Result createCommitAndPush(
       TestRepository<InMemoryRepository> repo,
       String ref,
diff --git a/java/com/google/gerrit/acceptance/AbstractDynamicOptionsTest.java b/java/com/google/gerrit/acceptance/AbstractDynamicOptionsTest.java
new file mode 100644
index 0000000..a4ed80a
--- /dev/null
+++ b/java/com/google/gerrit/acceptance/AbstractDynamicOptionsTest.java
@@ -0,0 +1,117 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance;
+
+import static com.google.gerrit.sshd.CommandMetaData.Mode.MASTER_OR_SLAVE;
+
+import com.google.common.collect.Lists;
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.json.OutputFormat;
+import com.google.gerrit.server.DynamicOptions;
+import com.google.gerrit.sshd.CommandMetaData;
+import com.google.gerrit.sshd.CommandModule;
+import com.google.gerrit.sshd.SshCommand;
+import com.google.gson.reflect.TypeToken;
+import com.google.inject.AbstractModule;
+import com.google.inject.Inject;
+import java.io.BufferedWriter;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.util.Collections;
+import java.util.List;
+
+public class AbstractDynamicOptionsTest extends AbstractDaemonTest {
+  protected static final String LS_SAMPLES = "ls-samples";
+
+  protected interface Bean {
+    void setSamples(List<String> samples);
+  }
+
+  protected static class ListSamples implements Bean, DynamicOptions.BeanReceiver {
+    protected List<String> samples = Collections.emptyList();
+
+    @Override
+    public void setSamples(List<String> samples) {
+      this.samples = samples;
+    }
+
+    public void display(OutputStream displayOutputStream) throws Exception {
+      PrintWriter stdout =
+          new PrintWriter(new BufferedWriter(new OutputStreamWriter(displayOutputStream, "UTF-8")));
+      try {
+        OutputFormat.JSON
+            .newGson()
+            .toJson(samples, new TypeToken<List<String>>() {}.getType(), stdout);
+        stdout.print('\n');
+      } finally {
+        stdout.flush();
+      }
+    }
+
+    @Override
+    public void setDynamicBean(String plugin, DynamicOptions.DynamicBean dynamicBean) {}
+  }
+
+  @CommandMetaData(name = LS_SAMPLES, runsAt = MASTER_OR_SLAVE)
+  protected static class ListSamplesCommand extends SshCommand {
+    @Inject private ListSamples impl;
+
+    @Override
+    protected void run() throws Exception {
+      impl.display(out);
+    }
+
+    @Override
+    protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
+      parseCommandLine(impl, pluginOptions);
+    }
+  }
+
+  public static class PluginOneSshModule extends CommandModule {
+    @Override
+    public void configure() {
+      command(LS_SAMPLES).to(ListSamplesCommand.class);
+    }
+  }
+
+  protected static class ListSamplesOptions implements DynamicOptions.BeanParseListener {
+    @Override
+    public void onBeanParseStart(String plugin, Object bean) {
+      ((Bean) bean).setSamples(Lists.newArrayList("sample1", "sample2"));
+    }
+
+    @Override
+    public void onBeanParseEnd(String plugin, Object bean) {}
+  }
+
+  protected static class PluginTwoModule extends AbstractModule {
+    @Override
+    public void configure() {
+      bind(DynamicOptions.DynamicBean.class)
+          .annotatedWith(
+              Exports.named("com.google.gerrit.acceptance.AbstractDynamicOptionsTest.ListSamples"))
+          .to(ListSamplesOptionsClassNameProvider.class);
+    }
+  }
+
+  protected static class ListSamplesOptionsClassNameProvider
+      implements DynamicOptions.ClassNameProvider {
+    @Override
+    public String getClassName() {
+      return "com.google.gerrit.acceptance.AbstractDynamicOptionsTest$ListSamplesOptions";
+    }
+  }
+}
diff --git a/java/com/google/gerrit/acceptance/AbstractLifecycleListenersTest.java b/java/com/google/gerrit/acceptance/AbstractLifecycleListenersTest.java
new file mode 100644
index 0000000..6acf486
--- /dev/null
+++ b/java/com/google/gerrit/acceptance/AbstractLifecycleListenersTest.java
@@ -0,0 +1,109 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance;
+
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.extensions.events.LifecycleListener;
+import com.google.gerrit.server.DynamicOptions;
+import com.google.gerrit.server.restapi.change.QueryChanges;
+import com.google.gerrit.sshd.commands.Query;
+import com.google.inject.AbstractModule;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import com.google.inject.internal.UniqueAnnotations;
+import java.util.Collections;
+import org.kohsuke.args4j.Option;
+
+public class AbstractLifecycleListenersTest extends AbstractDaemonTest {
+  protected static class SimpleModule extends AbstractModule {
+    @Override
+    public void configure() {
+      bind(com.google.gerrit.server.DynamicOptions.DynamicBean.class)
+          .annotatedWith(Exports.named(Query.class))
+          .to(MyClassNameProvider.class);
+      bind(DynamicOptions.DynamicBean.class)
+          .annotatedWith(Exports.named(QueryChanges.class))
+          .to(MyClassNameProvider.class);
+    }
+  }
+
+  protected static class MyClassNameProvider implements DynamicOptions.ModulesClassNamesProvider {
+    @Override
+    public String getClassName() {
+      return "com.google.gerrit.acceptance.AbstractLifecycleListenersTest$MyOptions";
+    }
+
+    @Override
+    public Iterable<String> getModulesClassNames() {
+      return Collections.singleton(
+          "com.google.gerrit.acceptance.AbstractLifecycleListenersTest$MyOptions$MyOptionsModule");
+    }
+  }
+
+  public static class MyOptions implements DynamicOptions.DynamicBean {
+    @Option(name = "--opt")
+    public boolean opt;
+
+    public static class MyOptionsModule extends AbstractModule {
+      @Override
+      protected void configure() {
+        bind(LifecycleListener.class)
+            .annotatedWith(UniqueAnnotations.create())
+            .to(MyLifecycleListener.class);
+      }
+    }
+  }
+
+  protected static class MyLifecycleListener implements LifecycleListener {
+    protected final InvocationCheck invocationCheck;
+
+    @Inject
+    public MyLifecycleListener(InvocationCheck invocationCheck) {
+      this.invocationCheck = invocationCheck;
+    }
+
+    @Override
+    public void start() {
+      invocationCheck.setStartInvoked(true);
+    }
+
+    @Override
+    public void stop() {
+      invocationCheck.setStopInvoked(true);
+    }
+  }
+
+  @Singleton
+  public static class InvocationCheck {
+    private boolean isStartInvoked = false;
+    private boolean isStopInvoked = false;
+
+    public boolean isStartInvoked() {
+      return isStartInvoked;
+    }
+
+    public void setStartInvoked(boolean startInvoked) {
+      isStartInvoked = startInvoked;
+    }
+
+    public boolean isStopInvoked() {
+      return isStopInvoked;
+    }
+
+    public void setStopInvoked(boolean stopInvoked) {
+      isStopInvoked = stopInvoked;
+    }
+  }
+}
diff --git a/java/com/google/gerrit/acceptance/AbstractPluginFieldsTest.java b/java/com/google/gerrit/acceptance/AbstractPluginFieldsTest.java
index a91bc49..29dc6a3 100644
--- a/java/com/google/gerrit/acceptance/AbstractPluginFieldsTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractPluginFieldsTest.java
@@ -30,7 +30,6 @@
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.DynamicOptions.DynamicBean;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangePluginDefinedInfoFactory;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.restapi.change.GetChange;
@@ -40,7 +39,6 @@
 import com.google.gson.reflect.TypeToken;
 import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
-import com.google.inject.Module;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
@@ -86,21 +84,6 @@
     }
   }
 
-  protected static class NullAttributeModule extends AbstractModule {
-    @Override
-    public void configure() {
-      DynamicSet.bind(binder(), ChangeAttributeFactory.class).toInstance((cd, bp, p) -> null);
-    }
-  }
-
-  protected static class SimpleAttributeModule extends AbstractModule {
-    @Override
-    public void configure() {
-      DynamicSet.bind(binder(), ChangeAttributeFactory.class)
-          .toInstance((cd, bp, p) -> new MyInfo("change " + cd.getId()));
-    }
-  }
-
   protected static class PluginDefinedSimpleAttributeModule extends AbstractModule {
     @Override
     public void configure() {
@@ -170,21 +153,6 @@
     private String opt;
   }
 
-  protected static class OptionAttributeModule extends AbstractModule {
-    @Override
-    public void configure() {
-      DynamicSet.bind(binder(), ChangeAttributeFactory.class)
-          .toInstance(
-              (cd, bp, p) -> {
-                MyOptions opts = (MyOptions) bp.getDynamicBean(p);
-                return opts != null ? new MyInfo("opt " + opts.opt) : null;
-              });
-      bind(DynamicBean.class).annotatedWith(Exports.named(Query.class)).to(MyOptions.class);
-      bind(DynamicBean.class).annotatedWith(Exports.named(QueryChanges.class)).to(MyOptions.class);
-      bind(DynamicBean.class).annotatedWith(Exports.named(GetChange.class)).to(MyOptions.class);
-    }
-  }
-
   public static class BulkAttributeFactoryWithOption implements ChangePluginDefinedInfoFactory {
     protected MyOptions opts;
 
@@ -211,33 +179,6 @@
     }
   }
 
-  protected void getChangeWithNullAttribute(PluginInfoGetter getter) throws Exception {
-    Change.Id id = createChange().getChange().getId();
-    assertThat(getter.call(id)).isNull();
-
-    try (AutoCloseable ignored = installPlugin("my-plugin", NullAttributeModule.class)) {
-      assertThat(getter.call(id)).isNull();
-    }
-
-    assertThat(getter.call(id)).isNull();
-  }
-
-  protected void getChangeWithSimpleAttribute(PluginInfoGetter getter) throws Exception {
-    getChangeWithSimpleAttribute(getter, SimpleAttributeModule.class);
-  }
-
-  protected void getChangeWithSimpleAttribute(
-      PluginInfoGetter getter, Class<? extends Module> moduleClass) throws Exception {
-    Change.Id id = createChange().getChange().getId();
-    assertThat(getter.call(id)).isNull();
-
-    try (AutoCloseable ignored = installPlugin("my-plugin", moduleClass)) {
-      assertThat(getter.call(id)).containsExactly(new MyInfo("my-plugin", "change " + id));
-    }
-
-    assertThat(getter.call(id)).isNull();
-  }
-
   protected void getSingleChangeWithPluginDefinedBulkAttribute(BulkPluginInfoGetterWithId getter)
       throws Exception {
     Change.Id id = createChange().getChange().getId();
@@ -298,30 +239,6 @@
     assertThat(pluginInfos.get(changeWithInfo)).isNull();
   }
 
-  protected void getMultipleChangesWithPluginDefinedBulkAndChangeAttributes(
-      BulkPluginInfoGetter getter) throws Exception {
-    Change.Id id1 = createChange().getChange().getId();
-    Change.Id id2 = createChange().getChange().getId();
-
-    Map<Change.Id, List<PluginDefinedInfo>> pluginInfos = getter.call();
-    assertThat(pluginInfos.get(id1)).isNull();
-    assertThat(pluginInfos.get(id2)).isNull();
-
-    try (AutoCloseable ignored =
-            installPlugin("my-plugin-1", PluginDefinedSimpleAttributeModule.class);
-        AutoCloseable ignored1 = installPlugin("my-plugin-2", SimpleAttributeModule.class)) {
-      pluginInfos = getter.call();
-      assertThat(pluginInfos.get(id1)).contains(new MyInfo("my-plugin-1", "change " + id1));
-      assertThat(pluginInfos.get(id1)).contains(new MyInfo("my-plugin-2", "change " + id1));
-      assertThat(pluginInfos.get(id2)).contains(new MyInfo("my-plugin-1", "change " + id2));
-      assertThat(pluginInfos.get(id2)).contains(new MyInfo("my-plugin-2", "change " + id2));
-    }
-
-    pluginInfos = getter.call();
-    assertThat(pluginInfos.get(id1)).isNull();
-    assertThat(pluginInfos.get(id2)).isNull();
-  }
-
   protected void getMultipleChangesWithPluginDefinedBulkAttributeInSingleCall(
       BulkPluginInfoGetter getter) throws Exception {
     Change.Id id1 = createChange().getChange().getId();
@@ -345,22 +262,6 @@
     assertThat(pluginInfos.get(id2)).isNull();
   }
 
-  protected void getChangeWithOption(
-      PluginInfoGetter getterWithoutOptions, PluginInfoGetterWithOptions getterWithOptions)
-      throws Exception {
-    Change.Id id = createChange().getChange().getId();
-    assertThat(getterWithoutOptions.call(id)).isNull();
-
-    try (AutoCloseable ignored = installPlugin("my-plugin", OptionAttributeModule.class)) {
-      assertThat(getterWithoutOptions.call(id))
-          .containsExactly(new MyInfo("my-plugin", "opt null"));
-      assertThat(getterWithOptions.call(id, ImmutableListMultimap.of("my-plugin--opt", "foo")))
-          .containsExactly(new MyInfo("my-plugin", "opt foo"));
-    }
-
-    assertThat(getterWithoutOptions.call(id)).isNull();
-  }
-
   protected void getChangeWithPluginDefinedBulkAttributeOption(
       BulkPluginInfoGetterWithId getterWithoutOptions,
       BulkPluginInfoGetterWithIdAndOptions getterWithOptions)
@@ -455,11 +356,6 @@
   }
 
   @FunctionalInterface
-  protected interface PluginInfoGetter {
-    List<PluginDefinedInfo> call(Change.Id id) throws Exception;
-  }
-
-  @FunctionalInterface
   protected interface BulkPluginInfoGetter {
     Map<Change.Id, List<PluginDefinedInfo>> call() throws Exception;
   }
@@ -474,10 +370,4 @@
     Map<Change.Id, List<PluginDefinedInfo>> call(
         Change.Id id, ImmutableListMultimap<String, String> pluginOptions) throws Exception;
   }
-
-  @FunctionalInterface
-  protected interface PluginInfoGetterWithOptions {
-    List<PluginDefinedInfo> call(Change.Id id, ImmutableListMultimap<String, String> pluginOptions)
-        throws Exception;
-  }
 }
diff --git a/java/com/google/gerrit/acceptance/AbstractPluginLogFileTest.java b/java/com/google/gerrit/acceptance/AbstractPluginLogFileTest.java
new file mode 100644
index 0000000..60def29
--- /dev/null
+++ b/java/com/google/gerrit/acceptance/AbstractPluginLogFileTest.java
@@ -0,0 +1,112 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance;
+
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.extensions.events.LifecycleListener;
+import com.google.gerrit.extensions.systemstatus.ServerInformation;
+import com.google.gerrit.server.DynamicOptions;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.util.PluginLogFile;
+import com.google.gerrit.server.util.SystemLog;
+import com.google.gerrit.sshd.commands.Query;
+import com.google.inject.AbstractModule;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import com.google.inject.internal.UniqueAnnotations;
+import java.util.Collections;
+import org.apache.log4j.AsyncAppender;
+import org.apache.log4j.Layout;
+import org.apache.log4j.PatternLayout;
+import org.eclipse.jgit.lib.Config;
+import org.kohsuke.args4j.Option;
+
+public class AbstractPluginLogFileTest extends AbstractDaemonTest {
+  protected static class Module extends AbstractModule {
+    @Override
+    public void configure() {
+      bind(com.google.gerrit.server.DynamicOptions.DynamicBean.class)
+          .annotatedWith(Exports.named(Query.class))
+          .to(MyClassNameProvider.class);
+    }
+  }
+
+  protected static class MyClassNameProvider implements DynamicOptions.ModulesClassNamesProvider {
+    @Override
+    public String getClassName() {
+      return "com.google.gerrit.acceptance.AbstractPluginLogFileTest$MyOptions";
+    }
+
+    @Override
+    public Iterable<String> getModulesClassNames() {
+      return Collections.singleton(
+          "com.google.gerrit.acceptance.AbstractPluginLogFileTest$MyOptions$MyOptionsModule");
+    }
+  }
+
+  public static class MyOptions implements DynamicOptions.DynamicBean {
+    @Option(name = "--opt")
+    public boolean opt;
+
+    public static class MyOptionsModule extends AbstractModule {
+      @Override
+      protected void configure() {
+        bind(LifecycleListener.class)
+            .annotatedWith(UniqueAnnotations.create())
+            .to(MyPluginLogFile.class);
+      }
+    }
+  }
+
+  protected static class MyPluginLogFile extends PluginLogFile {
+    protected static final String logName = "test_log";
+
+    @Inject
+    public MyPluginLogFile(MySystemLog mySystemLog, ServerInformation serverInfo) {
+      super(mySystemLog, serverInfo, logName, new PatternLayout("[%d] [%t] %m%n"));
+    }
+  }
+
+  @Singleton
+  protected static class MySystemLog extends SystemLog {
+    protected InvocationCounter invocationCounter;
+
+    @Inject
+    public MySystemLog(SitePaths site, Config config, InvocationCounter invocationCounter) {
+      super(site, config);
+      this.invocationCounter = invocationCounter;
+    }
+
+    @Override
+    public AsyncAppender createAsyncAppender(
+        String name, Layout layout, boolean rotate, boolean forPlugin) {
+      invocationCounter.increment();
+      return super.createAsyncAppender(name, layout, rotate, forPlugin);
+    }
+  }
+
+  @Singleton
+  public static class InvocationCounter {
+    private int counter = 0;
+
+    public int getCounter() {
+      return counter;
+    }
+
+    public synchronized void increment() {
+      counter++;
+    }
+  }
+}
diff --git a/java/com/google/gerrit/acceptance/AccountCreator.java b/java/com/google/gerrit/acceptance/AccountCreator.java
index 3ab1cec..6897488 100644
--- a/java/com/google/gerrit/acceptance/AccountCreator.java
+++ b/java/com/google/gerrit/acceptance/AccountCreator.java
@@ -26,6 +26,7 @@
 import com.google.gerrit.server.ServerInitiated;
 import com.google.gerrit.server.account.AccountsUpdate;
 import com.google.gerrit.server.account.GroupCache;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.account.externalids.ExternalId;
 import com.google.gerrit.server.group.InternalGroup;
 import com.google.gerrit.server.group.db.GroupsUpdate;
@@ -110,7 +111,7 @@
           throw new NoSuchGroupException(n);
         }
         addGroupMember(group.get().getGroupUUID(), id);
-        if ("Service Users".equals(n)) {
+        if (ServiceUserClassifier.SERVICE_USERS.equals(n)) {
           tags.add("SERVICE_USER");
         }
       }
diff --git a/java/com/google/gerrit/acceptance/BUILD b/java/com/google/gerrit/acceptance/BUILD
index db0dc84..28f67b8 100644
--- a/java/com/google/gerrit/acceptance/BUILD
+++ b/java/com/google/gerrit/acceptance/BUILD
@@ -47,6 +47,7 @@
     "//lib/guice",
     "//lib/guice:guice-assistedinject",
     "//lib/guice:guice-servlet",
+    "//lib/log:log4j",
     "//lib/mail",
     "//lib/mina:sshd",
     "//lib:guava",
diff --git a/java/com/google/gerrit/acceptance/ExtensionRegistry.java b/java/com/google/gerrit/acceptance/ExtensionRegistry.java
index a5d8d19..5d01dcb 100644
--- a/java/com/google/gerrit/acceptance/ExtensionRegistry.java
+++ b/java/com/google/gerrit/acceptance/ExtensionRegistry.java
@@ -26,6 +26,7 @@
 import com.google.gerrit.extensions.events.GroupIndexedListener;
 import com.google.gerrit.extensions.events.ProjectIndexedListener;
 import com.google.gerrit.extensions.events.RevisionCreatedListener;
+import com.google.gerrit.extensions.events.TopicEditedListener;
 import com.google.gerrit.extensions.events.WorkInProgressStateChangedListener;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.registration.DynamicSet;
@@ -42,6 +43,7 @@
 import com.google.gerrit.server.git.validators.OnSubmitValidationListener;
 import com.google.gerrit.server.git.validators.RefOperationValidationListener;
 import com.google.gerrit.server.logging.PerformanceLogger;
+import com.google.gerrit.server.restapi.change.OnPostReview;
 import com.google.gerrit.server.rules.SubmitRule;
 import com.google.gerrit.server.validators.AccountActivationValidationListener;
 import com.google.gerrit.server.validators.ProjectCreationValidationListener;
@@ -58,6 +60,7 @@
   private final DynamicSet<GroupIndexedListener> groupIndexedListeners;
   private final DynamicSet<ProjectIndexedListener> projectIndexedListeners;
   private final DynamicSet<CommitValidationListener> commitValidationListeners;
+  private final DynamicSet<TopicEditedListener> topicEditedListeners;
   private final DynamicSet<ExceptionHook> exceptionHooks;
   private final DynamicSet<PerformanceLogger> performanceLoggers;
   private final DynamicSet<ProjectCreationValidationListener> projectCreationValidationListeners;
@@ -81,6 +84,7 @@
   private final DynamicMap<CapabilityDefinition> capabilityDefinitions;
   private final DynamicMap<PluginProjectPermissionDefinition> pluginProjectPermissionDefinitions;
   private final DynamicMap<ProjectConfigEntry> pluginConfigEntries;
+  private final DynamicSet<OnPostReview> onPostReviews;
 
   @Inject
   ExtensionRegistry(
@@ -89,6 +93,7 @@
       DynamicSet<GroupIndexedListener> groupIndexedListeners,
       DynamicSet<ProjectIndexedListener> projectIndexedListeners,
       DynamicSet<CommitValidationListener> commitValidationListeners,
+      DynamicSet<TopicEditedListener> topicEditedListeners,
       DynamicSet<ExceptionHook> exceptionHooks,
       DynamicSet<PerformanceLogger> performanceLoggers,
       DynamicSet<ProjectCreationValidationListener> projectCreationValidationListeners,
@@ -110,12 +115,14 @@
       DynamicSet<WorkInProgressStateChangedListener> workInProgressStateChangedListeners,
       DynamicMap<CapabilityDefinition> capabilityDefinitions,
       DynamicMap<PluginProjectPermissionDefinition> pluginProjectPermissionDefinitions,
-      DynamicMap<ProjectConfigEntry> pluginConfigEntries) {
+      DynamicMap<ProjectConfigEntry> pluginConfigEntries,
+      DynamicSet<OnPostReview> onPostReviews) {
     this.accountIndexedListeners = accountIndexedListeners;
     this.changeIndexedListeners = changeIndexedListeners;
     this.groupIndexedListeners = groupIndexedListeners;
     this.projectIndexedListeners = projectIndexedListeners;
     this.commitValidationListeners = commitValidationListeners;
+    this.topicEditedListeners = topicEditedListeners;
     this.exceptionHooks = exceptionHooks;
     this.performanceLoggers = performanceLoggers;
     this.projectCreationValidationListeners = projectCreationValidationListeners;
@@ -138,6 +145,7 @@
     this.capabilityDefinitions = capabilityDefinitions;
     this.pluginProjectPermissionDefinitions = pluginProjectPermissionDefinitions;
     this.pluginConfigEntries = pluginConfigEntries;
+    this.onPostReviews = onPostReviews;
   }
 
   public Registration newRegistration() {
@@ -168,6 +176,10 @@
       return add(commitValidationListeners, commitValidationListener);
     }
 
+    public Registration add(TopicEditedListener topicEditedListener) {
+      return add(topicEditedListeners, topicEditedListener);
+    }
+
     public Registration add(ExceptionHook exceptionHook) {
       return add(exceptionHooks, exceptionHook);
     }
@@ -262,6 +274,10 @@
       return add(pluginConfigEntries, pluginConfigEntry, exportName);
     }
 
+    public Registration add(OnPostReview onPostReview) {
+      return add(onPostReviews, onPostReview);
+    }
+
     private <T> Registration add(DynamicSet<T> dynamicSet, T extension) {
       return add(dynamicSet, extension, "gerrit");
     }
diff --git a/java/com/google/gerrit/acceptance/PushOneCommit.java b/java/com/google/gerrit/acceptance/PushOneCommit.java
index afd451a..4215255 100644
--- a/java/com/google/gerrit/acceptance/PushOneCommit.java
+++ b/java/com/google/gerrit/acceptance/PushOneCommit.java
@@ -43,8 +43,12 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.eclipse.jgit.api.TagCommand;
+import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
+import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.revwalk.RevBlob;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.transport.PushResult;
 import org.eclipse.jgit.transport.RemoteRefUpdate;
@@ -277,6 +281,19 @@
     return this;
   }
 
+  public PushOneCommit addSymlink(String path, String target) throws Exception {
+    RevBlob blobId = testRepo.blob(target);
+    commitBuilder.edit(
+        new PathEdit(path) {
+          @Override
+          public void apply(DirCacheEntry ent) {
+            ent.setFileMode(FileMode.SYMLINK);
+            ent.setObjectId(blobId);
+          }
+        });
+    return this;
+  }
+
   public Result to(String ref) throws Exception {
     for (Map.Entry<String, String> e : files.entrySet()) {
       commitBuilder.add(e.getKey(), e.getValue());
diff --git a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
index e56f470..44a377a 100644
--- a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
+++ b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
@@ -84,6 +84,9 @@
   protected static final String BULK = "_bulk";
   protected static final String MAPPINGS = "mappings";
   protected static final String ORDER = "order";
+  protected static final String DESC_SORT_ORDER = "desc";
+  protected static final String ASC_SORT_ORDER = "asc";
+  protected static final String UNMAPPED_TYPE = "unmapped_type";
   protected static final String SEARCH = "_search";
   protected static final String SETTINGS = "settings";
 
@@ -288,7 +291,7 @@
 
   protected JsonArray getSortArray(String idFieldName) {
     JsonObject properties = new JsonObject();
-    properties.addProperty(ORDER, "asc");
+    properties.addProperty(ORDER, ASC_SORT_ORDER);
 
     JsonArray sortArray = new JsonArray();
     addNamedElement(idFieldName, properties, sortArray);
diff --git a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
index 625a598..969ffa5 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
@@ -57,6 +57,9 @@
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
+import java.sql.Timestamp;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
 import java.util.Collections;
 import java.util.Optional;
 import java.util.Set;
@@ -133,14 +136,24 @@
 
   private JsonArray getSortArray() {
     JsonObject properties = new JsonObject();
-    properties.addProperty(ORDER, "desc");
+    properties.addProperty(ORDER, DESC_SORT_ORDER);
 
     JsonArray sortArray = new JsonArray();
     addNamedElement(ChangeField.UPDATED.getName(), properties, sortArray);
+    addNamedElement(ChangeField.MERGED_ON.getName(), getMergedOnSortOptions(), sortArray);
     addNamedElement(idField.getName(), properties, sortArray);
     return sortArray;
   }
 
+  private JsonObject getMergedOnSortOptions() {
+    JsonObject sortOptions = new JsonObject();
+    sortOptions.addProperty(ORDER, DESC_SORT_ORDER);
+    // Ignore the sort field if it does not exist in index. Otherwise the search would fail on open
+    // changes, because the corresponding documents do not have mergedOn field.
+    sortOptions.addProperty(UNMAPPED_TYPE, ElasticMapping.TIMESTAMP_FIELD_TYPE);
+    return sortOptions;
+  }
+
   @Override
   protected String getDeleteActions(Change.Id c) {
     return getDeleteRequest(c);
@@ -361,6 +374,10 @@
           cd);
     }
 
+    if (fields.contains(ChangeField.MERGED_ON.getName())) {
+      decodeMergedOn(source, cd);
+    }
+
     return cd;
   }
 
@@ -396,4 +413,18 @@
     }
     out.setUnresolvedCommentCount(count.getAsInt());
   }
+
+  private void decodeMergedOn(JsonObject doc, ChangeData out) {
+    JsonElement mergedOnField = doc.get(ChangeField.MERGED_ON.getName());
+
+    Timestamp mergedOn = null;
+    if (mergedOnField != null) {
+      // Parse from ElasticMapping.TIMESTAMP_FIELD_FORMAT.
+      // We currently use built-in ISO-based dateOptionalTime.
+      // https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html#built-in-date-formats
+      DateTimeFormatter isoFormatter = DateTimeFormatter.ISO_INSTANT;
+      mergedOn = Timestamp.from(Instant.from(isoFormatter.parse(mergedOnField.getAsString())));
+    }
+    out.setMergedOn(mergedOn);
+  }
 }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java b/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
index 06b128c..c4435297 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
@@ -26,8 +26,10 @@
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 import org.apache.http.HttpHost;
 import org.eclipse.jgit.lib.Config;
+import org.elasticsearch.client.RestClientBuilder;
 
 @Singleton
 class ElasticConfiguration {
@@ -41,12 +43,16 @@
   static final String KEY_NUMBER_OF_SHARDS = "numberOfShards";
   static final String KEY_NUMBER_OF_REPLICAS = "numberOfReplicas";
   static final String KEY_MAX_RESULT_WINDOW = "maxResultWindow";
+  static final String KEY_CONNECT_TIMEOUT = "connectTimeout";
+  static final String KEY_SOCKET_TIMEOUT = "socketTimeout";
 
   static final String DEFAULT_PORT = "9200";
   static final String DEFAULT_USERNAME = "elastic";
   static final int DEFAULT_NUMBER_OF_SHARDS = 1;
   static final int DEFAULT_NUMBER_OF_REPLICAS = 1;
   static final int DEFAULT_MAX_RESULT_WINDOW = 10000;
+  static final int DEFAULT_CONNECT_TIMEOUT = RestClientBuilder.DEFAULT_CONNECT_TIMEOUT_MILLIS;
+  static final int DEFAULT_SOCKET_TIMEOUT = RestClientBuilder.DEFAULT_SOCKET_TIMEOUT_MILLIS;
 
   private final Config cfg;
   private final List<HttpHost> hosts;
@@ -56,6 +62,8 @@
   final int numberOfShards;
   final int numberOfReplicas;
   final int maxResultWindow;
+  final int connectTimeout;
+  final int socketTimeout;
   final String prefix;
 
   @Inject
@@ -74,6 +82,22 @@
         cfg.getInt(SECTION_ELASTICSEARCH, null, KEY_NUMBER_OF_REPLICAS, DEFAULT_NUMBER_OF_REPLICAS);
     this.maxResultWindow =
         cfg.getInt(SECTION_ELASTICSEARCH, null, KEY_MAX_RESULT_WINDOW, DEFAULT_MAX_RESULT_WINDOW);
+    this.connectTimeout =
+        (int)
+            cfg.getTimeUnit(
+                SECTION_ELASTICSEARCH,
+                null,
+                KEY_CONNECT_TIMEOUT,
+                DEFAULT_CONNECT_TIMEOUT,
+                TimeUnit.MILLISECONDS);
+    this.socketTimeout =
+        (int)
+            cfg.getTimeUnit(
+                SECTION_ELASTICSEARCH,
+                null,
+                KEY_SOCKET_TIMEOUT,
+                DEFAULT_SOCKET_TIMEOUT,
+                TimeUnit.MILLISECONDS);
     this.hosts = new ArrayList<>();
     for (String server : cfg.getStringList(SECTION_ELASTICSEARCH, null, KEY_SERVER)) {
       try {
diff --git a/java/com/google/gerrit/elasticsearch/ElasticMapping.java b/java/com/google/gerrit/elasticsearch/ElasticMapping.java
index f8c4168..edd05c9 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticMapping.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticMapping.java
@@ -21,6 +21,10 @@
 import java.util.Map;
 
 class ElasticMapping {
+
+  protected static final String TIMESTAMP_FIELD_TYPE = "date";
+  protected static final String TIMESTAMP_FIELD_FORMAT = "dateOptionalTime";
+
   static MappingProperties createMapping(Schema<?> schema, ElasticQueryAdapter adapter) {
     ElasticMapping.Builder mapping = new ElasticMapping.Builder(adapter);
     for (FieldDef<?, ?> field : schema.getFields().values()) {
@@ -71,9 +75,9 @@
     }
 
     Builder addTimestamp(String name) {
-      FieldProperties properties = new FieldProperties("date");
-      properties.type = "date";
-      properties.format = "dateOptionalTime";
+      FieldProperties properties = new FieldProperties(TIMESTAMP_FIELD_TYPE);
+      properties.type = TIMESTAMP_FIELD_TYPE;
+      properties.format = TIMESTAMP_FIELD_FORMAT;
       fields.put(name, properties);
       return this;
     }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java b/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
index d05e91c..40ac603 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
@@ -29,7 +29,6 @@
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.index.query.RegexPredicate;
 import com.google.gerrit.index.query.TimestampRangePredicate;
-import com.google.gerrit.server.query.change.AfterPredicate;
 import java.time.Instant;
 
 public class ElasticQueryBuilder {
@@ -130,7 +129,9 @@
   private <T> QueryBuilder timestampQuery(IndexPredicate<T> p) throws QueryParseException {
     if (p instanceof TimestampRangePredicate) {
       TimestampRangePredicate<T> r = (TimestampRangePredicate<T>) p;
-      if (p instanceof AfterPredicate) {
+      if (r.getMaxTimestamp().getTime() == Long.MAX_VALUE) {
+        // The time range only has the start value, search from the start to the max supported value
+        // Long.MAX_VALUE
         return QueryBuilders.rangeQuery(r.getField().getName())
             .gte(Instant.ofEpochMilli(r.getMinTimestamp().getTime()));
       }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java b/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
index f635b23..b41f365 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
@@ -27,6 +27,7 @@
 import org.apache.http.auth.AuthScope;
 import org.apache.http.auth.UsernamePasswordCredentials;
 import org.apache.http.client.CredentialsProvider;
+import org.apache.http.client.config.RequestConfig;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
 import org.elasticsearch.client.Request;
@@ -128,10 +129,19 @@
 
   private RestClient build() {
     RestClientBuilder builder = RestClient.builder(cfg.getHosts());
+    setConfiguredTimeouts(builder);
     setConfiguredCredentialsIfAny(builder);
     return builder.build();
   }
 
+  private void setConfiguredTimeouts(RestClientBuilder builder) {
+    builder.setRequestConfigCallback(
+        (RequestConfig.Builder requestConfigBuilder) ->
+            requestConfigBuilder
+                .setConnectTimeout(cfg.connectTimeout)
+                .setSocketTimeout(cfg.socketTimeout));
+  }
+
   private void setConfiguredCredentialsIfAny(RestClientBuilder builder) {
     String username = cfg.username;
     String password = cfg.password;
diff --git a/java/com/google/gerrit/entities/BUILD b/java/com/google/gerrit/entities/BUILD
index 66d1869..c0f5de6 100644
--- a/java/com/google/gerrit/entities/BUILD
+++ b/java/com/google/gerrit/entities/BUILD
@@ -10,11 +10,13 @@
     deps = [
         "//java/com/google/gerrit/common:annotations",
         "//java/com/google/gerrit/extensions:api",
+        "//lib:gson",
         "//lib:guava",
         "//lib:jgit",
         "//lib:protobuf",
         "//lib/auto:auto-value",
         "//lib/auto:auto-value-annotations",
+        "//lib/auto:auto-value-gson",
         "//lib/errorprone:annotations",
         "//lib/flogger:api",
         "//proto:cache_java_proto",
diff --git a/java/com/google/gerrit/entities/Change.java b/java/com/google/gerrit/entities/Change.java
index 845a9bb..1fa099e 100644
--- a/java/com/google/gerrit/entities/Change.java
+++ b/java/com/google/gerrit/entities/Change.java
@@ -21,6 +21,9 @@
 import com.google.common.primitives.Ints;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.client.ChangeStatus;
+import com.google.gson.Gson;
+import com.google.gson.TypeAdapter;
+import com.google.gson.annotations.SerializedName;
 import java.sql.Timestamp;
 import java.util.Arrays;
 import java.util.Optional;
@@ -100,6 +103,7 @@
     return new AutoValue_Change_Id(id);
   }
 
+  /** The numeric change ID */
   @AutoValue
   public abstract static class Id {
     /**
@@ -283,6 +287,7 @@
       return Change.key(KeyUtil.decode(str));
     }
 
+    @SerializedName("id")
     abstract String key();
 
     public String get() {
@@ -307,6 +312,10 @@
     public final String toString() {
       return get();
     }
+
+    public static TypeAdapter<Key> typeAdapter(Gson gson) {
+      return new AutoValue_Change_Key.GsonTypeAdapter(gson);
+    }
   }
 
   /** Minimum database status constant for an open change. */
diff --git a/java/com/google/gerrit/entities/CommentContext.java b/java/com/google/gerrit/entities/CommentContext.java
new file mode 100644
index 0000000..183f6d0
--- /dev/null
+++ b/java/com/google/gerrit/entities/CommentContext.java
@@ -0,0 +1,29 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.entities;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableMap;
+
+/** An entity class representing all context lines of a comment. */
+@AutoValue
+public abstract class CommentContext {
+  public static CommentContext create(ImmutableMap<Integer, String> lines) {
+    return new AutoValue_CommentContext(lines);
+  }
+
+  /** Map of {line number, line text} of the context lines of a comment */
+  public abstract ImmutableMap<Integer, String> lines();
+}
diff --git a/java/com/google/gerrit/entities/CoreDownloadSchemes.java b/java/com/google/gerrit/entities/CoreDownloadSchemes.java
index 37c10f1..9bcd365 100644
--- a/java/com/google/gerrit/entities/CoreDownloadSchemes.java
+++ b/java/com/google/gerrit/entities/CoreDownloadSchemes.java
@@ -21,6 +21,7 @@
   public static final String HTTP = "http";
   public static final String SSH = "ssh";
   public static final String REPO_DOWNLOAD = "repo";
+  public static final String REPO = "repo";
 
   private CoreDownloadSchemes() {}
 }
diff --git a/java/com/google/gerrit/entities/EntitiesAdapterFactory.java b/java/com/google/gerrit/entities/EntitiesAdapterFactory.java
new file mode 100644
index 0000000..e6a06fd
--- /dev/null
+++ b/java/com/google/gerrit/entities/EntitiesAdapterFactory.java
@@ -0,0 +1,25 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.entities;
+
+import com.google.gson.TypeAdapterFactory;
+import com.ryanharter.auto.value.gson.GsonTypeAdapterFactory;
+
+@GsonTypeAdapterFactory
+public abstract class EntitiesAdapterFactory implements TypeAdapterFactory {
+  public static TypeAdapterFactory create() {
+    return new AutoValueGson_EntitiesAdapterFactory();
+  }
+}
diff --git a/java/com/google/gerrit/entities/Patch.java b/java/com/google/gerrit/entities/Patch.java
index e6b2167..856765b 100644
--- a/java/com/google/gerrit/entities/Patch.java
+++ b/java/com/google/gerrit/entities/Patch.java
@@ -160,5 +160,40 @@
     }
   }
 
+  /**
+   * Constants describing various file modes recognized by GIT. This is the Gerrit entity for {@link
+   * org.eclipse.jgit.lib.FileMode}.
+   */
+  public enum FileMode implements CodedEnum {
+    /** Mode indicating an entry is a tree (aka directory). */
+    TREE('T'),
+
+    /** Mode indicating an entry is a symbolic link. */
+    SYMLINK('S'),
+
+    /** Mode indicating an entry is a non-executable file. */
+    REGULAR_FILE('R'),
+
+    /** Mode indicating an entry is an executable file. */
+    EXECUTABLE_FILE('E'),
+
+    /** Mode indicating an entry is a submodule commit in another repository. */
+    GITLINK('G'),
+
+    /** Mode indicating an entry is missing during parallel walks. */
+    MISSING('M');
+
+    private final char code;
+
+    FileMode(char c) {
+      code = c;
+    }
+
+    @Override
+    public char getCode() {
+      return code;
+    }
+  }
+
   private Patch() {}
 }
diff --git a/java/com/google/gerrit/entities/Permission.java b/java/com/google/gerrit/entities/Permission.java
index 3f04fa5..322c79e 100644
--- a/java/com/google/gerrit/entities/Permission.java
+++ b/java/com/google/gerrit/entities/Permission.java
@@ -140,6 +140,7 @@
     return true;
   }
 
+  /** The permission name, eg. {@code Permission.SUBMIT} */
   public abstract String getName();
 
   protected abstract boolean isExclusiveGroup();
diff --git a/java/com/google/gerrit/entities/RefNames.java b/java/com/google/gerrit/entities/RefNames.java
index 5595bc7..522c60a 100644
--- a/java/com/google/gerrit/entities/RefNames.java
+++ b/java/com/google/gerrit/entities/RefNames.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.entities;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.common.UsedAt;
 
 /** Constants and utilities for Gerrit-specific ref names. */
@@ -105,6 +106,26 @@
   /** A change starred by a user */
   public static final String REFS_STARRED_CHANGES = "refs/starred-changes/";
 
+  /**
+   * List of refs managed by Gerrit. Covers all Gerrit internal refs.
+   *
+   * <p><b>Caution</b> Any ref not in this list will be served if the user was granted a READ
+   * permission on it using Gerrit's permission model.
+   */
+  public static final ImmutableList<String> GERRIT_REFS =
+      ImmutableList.of(
+          REFS_CHANGES,
+          REFS_EXTERNAL_IDS,
+          REFS_CACHE_AUTOMERGE,
+          REFS_DRAFT_COMMENTS,
+          REFS_DELETED_GROUPS,
+          REFS_SEQUENCES,
+          REFS_GROUPS,
+          REFS_GROUPNAMES,
+          REFS_USERS,
+          REFS_STARRED_CHANGES,
+          REFS_REJECT_COMMITS);
+
   public static String fullName(String ref) {
     return (ref.startsWith(REFS) || ref.equals(HEAD)) ? ref : REFS_HEADS + ref;
   }
@@ -255,6 +276,10 @@
     return ref.startsWith(REFS_USERS);
   }
 
+  public static boolean isRefsUsersSelf(String ref, boolean isAllUsers) {
+    return isAllUsers && REFS_USERS_SELF.equals(ref);
+  }
+
   /**
    * Whether the ref is a group branch that stores NoteDb data of a group. Returns {@code true} for
    * all refs that start with {@code refs/groups/}.
@@ -271,6 +296,16 @@
     return ref.startsWith(REFS_DELETED_GROUPS);
   }
 
+  /** Returns true if the provided ref is for draft comments. */
+  public static boolean isRefsDraftsComments(String ref) {
+    return ref.startsWith(REFS_DRAFT_COMMENTS);
+  }
+
+  /** Returns true if the provided ref is for starred changes. */
+  public static boolean isRefsStarredChanges(String ref) {
+    return ref.startsWith(REFS_STARRED_CHANGES);
+  }
+
   /**
    * Whether the ref is used for storing group data in NoteDb. Returns {@code true} for all group
    * branches, refs/meta/group-names and deleted group branches.
@@ -292,21 +327,11 @@
    * <p>Any ref for which this method evaluates to true will be served to users who have the {@code
    * ACCESS_DATABASE} capability.
    *
-   * <p><b>Caution</b>Any ref not in this list will be served if the user was granted a READ
+   * <p><b>Caution</b> Any ref not in this list will be served if the user was granted a READ
    * permission on it using Gerrit's permission model.
    */
   public static boolean isGerritRef(String ref) {
-    return ref.startsWith(REFS_CHANGES)
-        || ref.startsWith(REFS_EXTERNAL_IDS)
-        || ref.startsWith(REFS_CACHE_AUTOMERGE)
-        || ref.startsWith(REFS_DRAFT_COMMENTS)
-        || ref.startsWith(REFS_DELETED_GROUPS)
-        || ref.startsWith(REFS_SEQUENCES)
-        || ref.startsWith(REFS_GROUPS)
-        || ref.startsWith(REFS_GROUPNAMES)
-        || ref.startsWith(REFS_USERS)
-        || ref.startsWith(REFS_STARRED_CHANGES)
-        || ref.startsWith(REFS_REJECT_COMMITS);
+    return GERRIT_REFS.stream().anyMatch(internalRef -> ref.startsWith(internalRef));
   }
 
   static Integer parseShardedRefPart(String name) {
diff --git a/java/com/google/gerrit/extensions/BUILD b/java/com/google/gerrit/extensions/BUILD
index da5dc8b..21949f7 100644
--- a/java/com/google/gerrit/extensions/BUILD
+++ b/java/com/google/gerrit/extensions/BUILD
@@ -1,5 +1,5 @@
 load("@rules_java//java:defs.bzl", "java_binary", "java_library")
-load("//lib:guava.bzl", "GUAVA_DOC_URL")
+load("//tools:nongoogle.bzl", "GUAVA_DOC_URL")
 load("//tools/bzl:javadoc.bzl", "java_doc")
 
 _DOC_VERS = "5.5.0.201909110433-r"
diff --git a/java/com/google/gerrit/extensions/api/changes/MoveInput.java b/java/com/google/gerrit/extensions/api/changes/MoveInput.java
index 795642a..3d82990 100644
--- a/java/com/google/gerrit/extensions/api/changes/MoveInput.java
+++ b/java/com/google/gerrit/extensions/api/changes/MoveInput.java
@@ -17,4 +17,14 @@
 public class MoveInput {
   public String message;
   public String destinationBranch;
+  /**
+   * Whether or not to keep all votes in the destination branch. Keeping the votes can be confusing
+   * in the context of the destination branch, see
+   * https://gerrit-review.googlesource.com/c/gerrit/+/129171. That is why only the users with
+   * {@link com.google.gerrit.server.permissions.GlobalPermission#ADMINISTRATE_SERVER} permissions
+   * can use this option.
+   *
+   * <p>By default, only the veto votes that are blocking the change from submission are moved.
+   */
+  public boolean keepAllVotes;
 }
diff --git a/java/com/google/gerrit/extensions/api/config/AccessCheckInfo.java b/java/com/google/gerrit/extensions/api/config/AccessCheckInfo.java
index fab2ec4..423ac49 100644
--- a/java/com/google/gerrit/extensions/api/config/AccessCheckInfo.java
+++ b/java/com/google/gerrit/extensions/api/config/AccessCheckInfo.java
@@ -14,10 +14,15 @@
 
 package com.google.gerrit.extensions.api.config;
 
+import java.util.List;
+
 public class AccessCheckInfo {
   public String message;
   // HTTP status code
   public int status;
 
+  /** Debug logs that may help to understand why a permission is denied or allowed. */
+  public List<String> debugLogs;
+
   // for future extension, we may add inputs / results for bulk checks.
 }
diff --git a/java/com/google/gerrit/extensions/client/GeneralPreferencesInfo.java b/java/com/google/gerrit/extensions/client/GeneralPreferencesInfo.java
index 30514a6..4cb52b7 100644
--- a/java/com/google/gerrit/extensions/client/GeneralPreferencesInfo.java
+++ b/java/com/google/gerrit/extensions/client/GeneralPreferencesInfo.java
@@ -27,11 +27,12 @@
 
   /** Preferred method to download a change. */
   public enum DownloadCommand {
-    REPO_DOWNLOAD,
     PULL,
     CHECKOUT,
     CHERRY_PICK,
-    FORMAT_PATCH
+    FORMAT_PATCH,
+    BRANCH,
+    RESET,
   }
 
   public enum DateFormat {
diff --git a/java/com/google/gerrit/extensions/webui/ParentWebLink.java b/java/com/google/gerrit/extensions/webui/ParentWebLink.java
index dfc970d..9f2bc6e 100644
--- a/java/com/google/gerrit/extensions/webui/ParentWebLink.java
+++ b/java/com/google/gerrit/extensions/webui/ParentWebLink.java
@@ -30,10 +30,13 @@
    *
    * <p>
    *
-   * @param projectName Name of the project
-   * @param commit Commit sha1 of the parent revision
+   * @param projectName name of the project
+   * @param commit commit sha1 of the parent revision
+   * @param commitMessage the commit messsage of the change
+   * @param branchName target branch of the change
    * @return WebLinkInfo that links to parent commit in external service, null if there should be no
    *     link.
    */
-  WebLinkInfo getParentWebLink(String projectName, String commit);
+  WebLinkInfo getParentWebLink(
+      String projectName, String commit, String commitMessage, String branchName);
 }
diff --git a/java/com/google/gerrit/extensions/webui/PatchSetWebLink.java b/java/com/google/gerrit/extensions/webui/PatchSetWebLink.java
index 93fe8e1..0e8e28e 100644
--- a/java/com/google/gerrit/extensions/webui/PatchSetWebLink.java
+++ b/java/com/google/gerrit/extensions/webui/PatchSetWebLink.java
@@ -30,10 +30,13 @@
    *
    * <p>
    *
-   * @param projectName Name of the project
-   * @param commit Commit of the patch set
+   * @param projectName name of the project
+   * @param commit commit of the patch set
+   * @param commitMessage the commit message of the change
+   * @param branchName target branch of the change
    * @return WebLinkInfo that links to patch set in external service, null if there should be no
    *     link.
    */
-  WebLinkInfo getPatchSetWebLink(String projectName, String commit);
+  WebLinkInfo getPatchSetWebLink(
+      String projectName, String commit, String commitMessage, String branchName);
 }
diff --git a/java/com/google/gerrit/httpd/CacheBasedWebSession.java b/java/com/google/gerrit/httpd/CacheBasedWebSession.java
index 5c4830c..a3a67e5 100644
--- a/java/com/google/gerrit/httpd/CacheBasedWebSession.java
+++ b/java/com/google/gerrit/httpd/CacheBasedWebSession.java
@@ -28,6 +28,7 @@
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.PropertyMap;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.account.AuthResult;
 import com.google.gerrit.server.account.externalids.ExternalId;
@@ -161,15 +162,11 @@
   }
 
   @Override
-  public ExternalId.Key getLastLoginExternalId() {
-    return val != null ? val.getExternalId() : null;
-  }
-
-  @Override
   public CurrentUser getUser() {
     if (user == null) {
       if (isSignedIn()) {
-        user = identified.create(val.getAccountId());
+
+        user = identified.create(val.getAccountId(), getUserProperties(val));
       } else {
         user = anonymousProvider.get();
       }
@@ -177,6 +174,15 @@
     return user;
   }
 
+  private static PropertyMap getUserProperties(@Nullable WebSessionManager.Val val) {
+    if (val == null || val.getExternalId() == null) {
+      return PropertyMap.EMPTY;
+    }
+    return PropertyMap.builder()
+        .put(CurrentUser.LAST_LOGIN_EXTERNAL_ID_PROPERTY_KEY, val.getExternalId())
+        .build();
+  }
+
   @Override
   public void login(AuthResult res, boolean rememberMe) {
     Account.Id id = res.getAccountId();
@@ -194,7 +200,7 @@
     key = manager.createKey(id);
     val = manager.createVal(key, id, rememberMe, identity, null, null);
     saveCookie();
-    user = identified.create(val.getAccountId());
+    user = identified.create(val.getAccountId(), getUserProperties(val));
   }
 
   /** Set the user account for this current request only. */
@@ -202,7 +208,7 @@
   public void setUserAccountId(Account.Id id) {
     key = new Key("id:" + id);
     val = new Val(id, 0, false, null, 0, null, null);
-    user = identified.runAs(id, user);
+    user = identified.runAs(id, user, PropertyMap.EMPTY);
   }
 
   @Override
diff --git a/java/com/google/gerrit/httpd/HttpLogoutServlet.java b/java/com/google/gerrit/httpd/HttpLogoutServlet.java
index 1eaaba3..b56f973 100644
--- a/java/com/google/gerrit/httpd/HttpLogoutServlet.java
+++ b/java/com/google/gerrit/httpd/HttpLogoutServlet.java
@@ -73,11 +73,10 @@
 
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-
-    final String sid = webSession.get().getSessionId();
-    final CurrentUser currentUser = webSession.get().getUser();
-    final String what = "sign out";
-    final long when = TimeUtil.nowMs();
+    String sid = webSession.get().getSessionId();
+    CurrentUser currentUser = webSession.get().getUser();
+    String what = "sign out";
+    long when = TimeUtil.nowMs();
 
     try {
       doLogout(req, rsp);
diff --git a/java/com/google/gerrit/httpd/WebSession.java b/java/com/google/gerrit/httpd/WebSession.java
index e8b54fe..daf30ff 100644
--- a/java/com/google/gerrit/httpd/WebSession.java
+++ b/java/com/google/gerrit/httpd/WebSession.java
@@ -19,7 +19,6 @@
 import com.google.gerrit.server.AccessPath;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.AuthResult;
-import com.google.gerrit.server.account.externalids.ExternalId;
 
 public interface WebSession {
   boolean isSignedIn();
@@ -29,8 +28,6 @@
 
   boolean isValidXGerritAuth(String keyIn);
 
-  ExternalId.Key getLastLoginExternalId();
-
   CurrentUser getUser();
 
   void login(AuthResult res, boolean rememberMe);
diff --git a/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java b/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
index 509a9f1..e20c9b9 100644
--- a/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
+++ b/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
@@ -35,6 +35,7 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Locale;
+import java.util.Optional;
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
@@ -124,8 +125,8 @@
   }
 
   private static boolean correctUser(String user, WebSession session) {
-    ExternalId.Key id = session.getLastLoginExternalId();
-    return id != null && id.equals(ExternalId.Key.create(SCHEME_GERRIT, user));
+    Optional<ExternalId.Key> id = session.getUser().getLastLoginExternalIdKey();
+    return id.map(i -> i.equals(ExternalId.Key.create(SCHEME_GERRIT, user))).orElse(false);
   }
 
   String getRemoteUser(HttpServletRequest req) {
diff --git a/java/com/google/gerrit/httpd/raw/AuthorizationCheckServlet.java b/java/com/google/gerrit/httpd/raw/AuthorizationCheckServlet.java
index d92da18..e3e96df 100644
--- a/java/com/google/gerrit/httpd/raw/AuthorizationCheckServlet.java
+++ b/java/com/google/gerrit/httpd/raw/AuthorizationCheckServlet.java
@@ -43,8 +43,8 @@
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException {
     CacheHeaders.setNotCacheable(res);
-    res.setContentLength(0);
     if (user.get().isIdentifiedUser()) {
+      res.setContentLength(0);
       res.setStatus(HttpServletResponse.SC_NO_CONTENT);
     } else {
       res.setStatus(HttpServletResponse.SC_FORBIDDEN);
diff --git a/java/com/google/gerrit/httpd/restapi/ParameterParser.java b/java/com/google/gerrit/httpd/restapi/ParameterParser.java
index 172321d..3ab409e 100644
--- a/java/com/google/gerrit/httpd/restapi/ParameterParser.java
+++ b/java/com/google/gerrit/httpd/restapi/ParameterParser.java
@@ -32,7 +32,6 @@
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.MultimapBuilder;
 import com.google.gerrit.common.Nullable;
-import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.Url;
@@ -44,7 +43,7 @@
 import com.google.gson.JsonObject;
 import com.google.gson.JsonPrimitive;
 import com.google.inject.Inject;
-import com.google.inject.Injector;
+import com.google.inject.Singleton;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.util.HashSet;
@@ -149,24 +148,32 @@
   }
 
   private final CmdLineParser.Factory parserFactory;
-  private final Injector injector;
-  private final DynamicMap<DynamicOptions.DynamicBean> dynamicBeans;
 
   @Inject
-  ParameterParser(
-      CmdLineParser.Factory pf,
-      Injector injector,
-      DynamicMap<DynamicOptions.DynamicBean> dynamicBeans) {
+  ParameterParser(CmdLineParser.Factory pf) {
     this.parserFactory = pf;
-    this.injector = injector;
-    this.dynamicBeans = dynamicBeans;
   }
 
+  /**
+   * Parses query parameters ({@code in}) into annotated option fields of {@code param}.
+   *
+   * @return true if parsing was successful. Requesting help is considered failure and returns
+   *     false.
+   */
   <T> boolean parse(
-      T param, ListMultimap<String, String> in, HttpServletRequest req, HttpServletResponse res)
+      T param,
+      DynamicOptions pluginOptions,
+      ListMultimap<String, String> in,
+      HttpServletRequest req,
+      HttpServletResponse res)
       throws IOException {
+    if (param.getClass().getAnnotation(Singleton.class) != null) {
+      // Command-line parsing mutates the object, so we can't have options on @Singleton.
+      return true;
+    }
     CmdLineParser clp = parserFactory.create(param);
-    DynamicOptions pluginOptions = new DynamicOptions(param, injector, dynamicBeans);
+    pluginOptions.setBean(param);
+    pluginOptions.startLifecycleListeners();
     pluginOptions.parseDynamicBeans(clp);
     pluginOptions.setDynamicBeans();
     pluginOptions.onBeanParseStart();
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index 3b4aa01..51e032a 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -103,6 +103,7 @@
 import com.google.gerrit.server.AccessPath;
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.ExceptionHook;
 import com.google.gerrit.server.OptionUtil;
 import com.google.gerrit.server.RequestInfo;
@@ -146,6 +147,7 @@
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.stream.MalformedJsonException;
 import com.google.inject.Inject;
+import com.google.inject.Injector;
 import com.google.inject.Provider;
 import com.google.inject.TypeLiteral;
 import com.google.inject.util.Providers;
@@ -250,6 +252,8 @@
     final ChangeFinder changeFinder;
     final RetryHelper retryHelper;
     final PluginSetContext<ExceptionHook> exceptionHooks;
+    final Injector injector;
+    final DynamicMap<DynamicOptions.DynamicBean> dynamicBeans;
 
     @Inject
     Globals(
@@ -265,7 +269,9 @@
         DynamicSet<PerformanceLogger> performanceLoggers,
         ChangeFinder changeFinder,
         RetryHelper retryHelper,
-        PluginSetContext<ExceptionHook> exceptionHooks) {
+        PluginSetContext<ExceptionHook> exceptionHooks,
+        Injector injector,
+        DynamicMap<DynamicOptions.DynamicBean> dynamicBeans) {
       this.currentUser = currentUser;
       this.webSession = webSession;
       this.paramParser = paramParser;
@@ -280,6 +286,8 @@
       this.retryHelper = retryHelper;
       this.exceptionHooks = exceptionHooks;
       allowOrigin = makeAllowOrigin(config);
+      this.injector = injector;
+      this.dynamicBeans = dynamicBeans;
     }
 
     private static Pattern makeAllowOrigin(Config cfg) {
@@ -498,105 +506,116 @@
             return;
           }
 
-          if (!globals.paramParser.get().parse(viewData.view, qp.params(), req, res)) {
-            return;
+          try (DynamicOptions pluginOptions =
+              new DynamicOptions(globals.injector, globals.dynamicBeans)) {
+            if (!globals
+                .paramParser
+                .get()
+                .parse(viewData.view, pluginOptions, qp.params(), req, res)) {
+              return;
+            }
+
+            if (viewData.view instanceof RestReadView<?> && isRead(req)) {
+              response =
+                  invokeRestReadViewWithRetry(
+                      req,
+                      traceContext,
+                      viewData,
+                      (RestReadView<RestResource>) viewData.view,
+                      rsrc);
+            } else if (viewData.view instanceof RestModifyView<?, ?>) {
+              @SuppressWarnings("unchecked")
+              RestModifyView<RestResource, Object> m =
+                  (RestModifyView<RestResource, Object>) viewData.view;
+
+              Type type = inputType(m);
+              inputRequestBody = parseRequest(req, type);
+              response =
+                  invokeRestModifyViewWithRetry(
+                      req, traceContext, viewData, m, rsrc, inputRequestBody);
+
+              if (inputRequestBody instanceof RawInput) {
+                try (InputStream is = req.getInputStream()) {
+                  ServletUtils.consumeRequestBody(is);
+                }
+              }
+            } else if (viewData.view instanceof RestCollectionCreateView<?, ?, ?>) {
+              @SuppressWarnings("unchecked")
+              RestCollectionCreateView<RestResource, RestResource, Object> m =
+                  (RestCollectionCreateView<RestResource, RestResource, Object>) viewData.view;
+
+              Type type = inputType(m);
+              inputRequestBody = parseRequest(req, type);
+              response =
+                  invokeRestCollectionCreateViewWithRetry(
+                      req, traceContext, viewData, m, rsrc, path.get(0), inputRequestBody);
+              if (inputRequestBody instanceof RawInput) {
+                try (InputStream is = req.getInputStream()) {
+                  ServletUtils.consumeRequestBody(is);
+                }
+              }
+            } else if (viewData.view instanceof RestCollectionDeleteMissingView<?, ?, ?>) {
+              @SuppressWarnings("unchecked")
+              RestCollectionDeleteMissingView<RestResource, RestResource, Object> m =
+                  (RestCollectionDeleteMissingView<RestResource, RestResource, Object>)
+                      viewData.view;
+
+              Type type = inputType(m);
+              inputRequestBody = parseRequest(req, type);
+              response =
+                  invokeRestCollectionDeleteMissingViewWithRetry(
+                      req, traceContext, viewData, m, rsrc, path.get(0), inputRequestBody);
+              if (inputRequestBody instanceof RawInput) {
+                try (InputStream is = req.getInputStream()) {
+                  ServletUtils.consumeRequestBody(is);
+                }
+              }
+            } else if (viewData.view instanceof RestCollectionModifyView<?, ?, ?>) {
+              @SuppressWarnings("unchecked")
+              RestCollectionModifyView<RestResource, RestResource, Object> m =
+                  (RestCollectionModifyView<RestResource, RestResource, Object>) viewData.view;
+
+              Type type = inputType(m);
+              inputRequestBody = parseRequest(req, type);
+              response =
+                  invokeRestCollectionModifyViewWithRetry(
+                      req, traceContext, viewData, m, rsrc, inputRequestBody);
+              if (inputRequestBody instanceof RawInput) {
+                try (InputStream is = req.getInputStream()) {
+                  ServletUtils.consumeRequestBody(is);
+                }
+              }
+            } else {
+              throw new ResourceNotFoundException();
+            }
+
+            if (response instanceof Response.Redirect) {
+              CacheHeaders.setNotCacheable(res);
+              String location = ((Response.Redirect) response).location();
+              res.sendRedirect(location);
+              logger.atFinest().log("REST call redirected to: %s", location);
+              return;
+            } else if (response instanceof Response.Accepted) {
+              CacheHeaders.setNotCacheable(res);
+              res.setStatus(response.statusCode());
+              res.setHeader(HttpHeaders.LOCATION, ((Response.Accepted) response).location());
+              logger.atFinest().log("REST call succeeded: %d", response.statusCode());
+              return;
+            }
+
+            statusCode = response.statusCode();
+            configureCaching(req, res, traceContext, rsrc, viewData, response.caching());
+            res.setStatus(statusCode);
+            logger.atFinest().log("REST call succeeded: %d", statusCode);
           }
 
-          if (viewData.view instanceof RestReadView<?> && isRead(req)) {
-            response =
-                invokeRestReadViewWithRetry(
-                    req, traceContext, viewData, (RestReadView<RestResource>) viewData.view, rsrc);
-          } else if (viewData.view instanceof RestModifyView<?, ?>) {
-            @SuppressWarnings("unchecked")
-            RestModifyView<RestResource, Object> m =
-                (RestModifyView<RestResource, Object>) viewData.view;
-
-            Type type = inputType(m);
-            inputRequestBody = parseRequest(req, type);
-            response =
-                invokeRestModifyViewWithRetry(
-                    req, traceContext, viewData, m, rsrc, inputRequestBody);
-
-            if (inputRequestBody instanceof RawInput) {
-              try (InputStream is = req.getInputStream()) {
-                ServletUtils.consumeRequestBody(is);
-              }
+          if (response != Response.none()) {
+            Object value = Response.unwrap(response);
+            if (value instanceof BinaryResult) {
+              responseBytes = replyBinaryResult(req, res, (BinaryResult) value);
+            } else {
+              responseBytes = replyJson(req, res, false, qp.config(), value);
             }
-          } else if (viewData.view instanceof RestCollectionCreateView<?, ?, ?>) {
-            @SuppressWarnings("unchecked")
-            RestCollectionCreateView<RestResource, RestResource, Object> m =
-                (RestCollectionCreateView<RestResource, RestResource, Object>) viewData.view;
-
-            Type type = inputType(m);
-            inputRequestBody = parseRequest(req, type);
-            response =
-                invokeRestCollectionCreateViewWithRetry(
-                    req, traceContext, viewData, m, rsrc, path.get(0), inputRequestBody);
-            if (inputRequestBody instanceof RawInput) {
-              try (InputStream is = req.getInputStream()) {
-                ServletUtils.consumeRequestBody(is);
-              }
-            }
-          } else if (viewData.view instanceof RestCollectionDeleteMissingView<?, ?, ?>) {
-            @SuppressWarnings("unchecked")
-            RestCollectionDeleteMissingView<RestResource, RestResource, Object> m =
-                (RestCollectionDeleteMissingView<RestResource, RestResource, Object>) viewData.view;
-
-            Type type = inputType(m);
-            inputRequestBody = parseRequest(req, type);
-            response =
-                invokeRestCollectionDeleteMissingViewWithRetry(
-                    req, traceContext, viewData, m, rsrc, path.get(0), inputRequestBody);
-            if (inputRequestBody instanceof RawInput) {
-              try (InputStream is = req.getInputStream()) {
-                ServletUtils.consumeRequestBody(is);
-              }
-            }
-          } else if (viewData.view instanceof RestCollectionModifyView<?, ?, ?>) {
-            @SuppressWarnings("unchecked")
-            RestCollectionModifyView<RestResource, RestResource, Object> m =
-                (RestCollectionModifyView<RestResource, RestResource, Object>) viewData.view;
-
-            Type type = inputType(m);
-            inputRequestBody = parseRequest(req, type);
-            response =
-                invokeRestCollectionModifyViewWithRetry(
-                    req, traceContext, viewData, m, rsrc, inputRequestBody);
-            if (inputRequestBody instanceof RawInput) {
-              try (InputStream is = req.getInputStream()) {
-                ServletUtils.consumeRequestBody(is);
-              }
-            }
-          } else {
-            throw new ResourceNotFoundException();
-          }
-
-          if (response instanceof Response.Redirect) {
-            CacheHeaders.setNotCacheable(res);
-            String location = ((Response.Redirect) response).location();
-            res.sendRedirect(location);
-            logger.atFinest().log("REST call redirected to: %s", location);
-            return;
-          } else if (response instanceof Response.Accepted) {
-            CacheHeaders.setNotCacheable(res);
-            res.setStatus(response.statusCode());
-            res.setHeader(HttpHeaders.LOCATION, ((Response.Accepted) response).location());
-            logger.atFinest().log("REST call succeeded: %d", response.statusCode());
-            return;
-          }
-
-          statusCode = response.statusCode();
-          configureCaching(req, res, traceContext, rsrc, viewData, response.caching());
-          res.setStatus(statusCode);
-          logger.atFinest().log("REST call succeeded: %d", statusCode);
-        }
-
-        if (response != Response.none()) {
-          Object value = Response.unwrap(response);
-          if (value instanceof BinaryResult) {
-            responseBytes = replyBinaryResult(req, res, (BinaryResult) value);
-          } else {
-            responseBytes = replyJson(req, res, false, qp.config(), value);
           }
         }
       } catch (MalformedJsonException | JsonParseException e) {
@@ -1633,9 +1652,6 @@
           "Invalid authentication method. In order to authenticate, "
               + "prefix the REST endpoint URL with /a/ (e.g. http://example.com/a/projects/).");
     }
-    if (user.isIdentifiedUser()) {
-      user.setLastLoginExternalIdKey(globals.webSession.get().getLastLoginExternalId());
-    }
   }
 
   private List<String> getParameterNames(HttpServletRequest req) {
diff --git a/java/com/google/gerrit/index/query/TimestampRangePredicate.java b/java/com/google/gerrit/index/query/TimestampRangePredicate.java
index 38b2b73..42f8aa8 100644
--- a/java/com/google/gerrit/index/query/TimestampRangePredicate.java
+++ b/java/com/google/gerrit/index/query/TimestampRangePredicate.java
@@ -34,6 +34,10 @@
     super(def, name, value);
   }
 
+  protected Timestamp getValueTimestamp(I object) {
+    return (Timestamp) this.getField().get(object);
+  }
+
   public abstract Date getMinTimestamp();
 
   public abstract Date getMaxTimestamp();
diff --git a/java/com/google/gerrit/lucene/ChangeSubIndex.java b/java/com/google/gerrit/lucene/ChangeSubIndex.java
index e51a91a7..43daf25 100644
--- a/java/com/google/gerrit/lucene/ChangeSubIndex.java
+++ b/java/com/google/gerrit/lucene/ChangeSubIndex.java
@@ -17,6 +17,7 @@
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static com.google.gerrit.lucene.LuceneChangeIndex.ID2_SORT_FIELD;
 import static com.google.gerrit.lucene.LuceneChangeIndex.ID_SORT_FIELD;
+import static com.google.gerrit.lucene.LuceneChangeIndex.MERGED_ON_SORT_FIELD;
 import static com.google.gerrit.lucene.LuceneChangeIndex.UPDATED_SORT_FIELD;
 import static com.google.gerrit.server.index.change.ChangeSchemaDefinitions.NAME;
 
@@ -110,6 +111,9 @@
     } else if (f == ChangeField.UPDATED) {
       long t = ((Timestamp) getOnlyElement(values.getValues())).getTime();
       doc.add(new NumericDocValuesField(UPDATED_SORT_FIELD, t));
+    } else if (f == ChangeField.MERGED_ON) {
+      long t = ((Timestamp) getOnlyElement(values.getValues())).getTime();
+      doc.add(new NumericDocValuesField(MERGED_ON_SORT_FIELD, t));
     }
     super.add(doc, values);
   }
diff --git a/java/com/google/gerrit/lucene/LuceneChangeIndex.java b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
index bf1a166..f4b9e69 100644
--- a/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -72,6 +72,7 @@
 import com.google.protobuf.MessageLite;
 import java.io.IOException;
 import java.nio.file.Path;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -110,6 +111,7 @@
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   static final String UPDATED_SORT_FIELD = sortFieldName(ChangeField.UPDATED);
+  static final String MERGED_ON_SORT_FIELD = sortFieldName(ChangeField.MERGED_ON);
   static final String ID_SORT_FIELD = sortFieldName(ChangeField.LEGACY_ID);
   static final String ID2_SORT_FIELD = sortFieldName(ChangeField.LEGACY_ID_STR);
 
@@ -140,6 +142,7 @@
   private static final String UNRESOLVED_COMMENT_COUNT_FIELD =
       ChangeField.UNRESOLVED_COMMENT_COUNT.getName();
   private static final String ATTENTION_SET_FULL_FIELD = ChangeField.ATTENTION_SET_FULL.getName();
+  private static final String MERGED_ON_FIELD = ChangeField.MERGED_ON.getName();
 
   @FunctionalInterface
   static interface IdTerm {
@@ -320,6 +323,7 @@
   private Sort getSort() {
     return new Sort(
         new SortField(UPDATED_SORT_FIELD, SortField.Type.LONG, true),
+        new SortField(MERGED_ON_SORT_FIELD, SortField.Type.LONG, true),
         new SortField(idSortFieldName, SortField.Type.LONG, true));
   }
 
@@ -563,6 +567,9 @@
     if (fields.contains(REF_STATE_PATTERN_FIELD)) {
       decodeRefStatePatterns(doc, cd);
     }
+    if (fields.contains(MERGED_ON_FIELD)) {
+      decodeMergedOn(doc, cd);
+    }
 
     decodeUnresolvedCommentCount(doc, cd);
     decodeTotalCommentCount(doc, cd);
@@ -719,6 +726,16 @@
     }
   }
 
+  private void decodeMergedOn(ListMultimap<String, IndexableField> doc, ChangeData cd) {
+    IndexableField mergedOnField =
+        Iterables.getFirst(doc.get(MERGED_ON_FIELD), /* defaultValue= */ null);
+    Timestamp mergedOn = null;
+    if (mergedOnField != null && mergedOnField.numericValue() != null) {
+      mergedOn = new Timestamp(mergedOnField.numericValue().longValue());
+    }
+    cd.setMergedOn(mergedOn);
+  }
+
   private static <T> List<T> decodeProtos(
       ListMultimap<String, IndexableField> doc, String fieldName, ProtoConverter<?, T> converter) {
     return doc.get(fieldName).stream()
diff --git a/java/com/google/gerrit/pgm/util/BatchProgramModule.java b/java/com/google/gerrit/pgm/util/BatchProgramModule.java
index e9c0136..894757b 100644
--- a/java/com/google/gerrit/pgm/util/BatchProgramModule.java
+++ b/java/com/google/gerrit/pgm/util/BatchProgramModule.java
@@ -39,7 +39,6 @@
 import com.google.gerrit.server.account.externalids.ExternalIdModule;
 import com.google.gerrit.server.cache.CacheRemovalListener;
 import com.google.gerrit.server.cache.mem.DefaultMemoryCacheModule;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangeKindCacheImpl;
 import com.google.gerrit.server.change.MergeabilityCacheImpl;
@@ -116,8 +115,6 @@
     bind(new TypeLiteral<List<CommentLinkInfo>>() {})
         .toProvider(CommentLinkProvider.class)
         .in(SINGLETON);
-    bind(new TypeLiteral<DynamicSet<ChangeAttributeFactory>>() {})
-        .toInstance(DynamicSet.emptySet());
     bind(new TypeLiteral<DynamicMap<RestView<CommitResource>>>() {})
         .toInstance(DynamicMap.emptyMap());
     bind(String.class)
diff --git a/java/com/google/gerrit/server/BUILD b/java/com/google/gerrit/server/BUILD
index 069006b..b7a00dd 100644
--- a/java/com/google/gerrit/server/BUILD
+++ b/java/com/google/gerrit/server/BUILD
@@ -113,6 +113,7 @@
         "//lib/commons:compress",
         "//lib/commons:dbcp",
         "//lib/commons:lang",
+        "//lib/commons:lang3",
         "//lib/commons:net",
         "//lib/commons:validator",
         "//lib/errorprone:annotations",
diff --git a/java/com/google/gerrit/server/CommentContextLoader.java b/java/com/google/gerrit/server/CommentContextLoader.java
index bbc7cf3..68a80c3 100644
--- a/java/com/google/gerrit/server/CommentContextLoader.java
+++ b/java/com/google/gerrit/server/CommentContextLoader.java
@@ -17,18 +17,20 @@
 import static java.util.stream.Collectors.groupingBy;
 
 import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Streams;
 import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.entities.Comment;
+import com.google.gerrit.entities.CommentContext;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.exceptions.StorageException;
-import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.ContextLineInfo;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.patch.Text;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -48,7 +50,6 @@
 
   private final GitRepositoryManager repoManager;
   private final Project.NameKey project;
-  private Map<ContextData, List<ContextLineInfo>> candidates;
 
   public interface Factory {
     CommentContextLoader create(Project.NameKey project);
@@ -58,81 +59,66 @@
   CommentContextLoader(GitRepositoryManager repoManager, @Assisted Project.NameKey project) {
     this.repoManager = repoManager;
     this.project = project;
-    this.candidates = new HashMap<>();
   }
 
   /**
-   * Returns an empty list of {@link ContextLineInfo}. Clients are expected to call this method one
-   * or more times. Each call returns a reference to an empty {@link List
-   * List&lt;ContextLineInfo&gt;}.
+   * Load the comment context for multiple comments at once. This method will open the repository
+   * and read the source files for all necessary comments' file paths.
    *
-   * <p>A single call to {@link #fill()} will cause all list references returned from this method to
-   * be populated. If a client calls this method again with a comment that was passed before calling
-   * {@link #fill()}, the new populated list will be returned.
-   *
-   * @param comment the comment entity for which we want to load the context
-   * @return a list of {@link ContextLineInfo}
+   * @param comments a list of comments.
+   * @return a Map where all entries consist of the input comments and the values are their
+   *     corresponding {@link CommentContext}.
    */
-  public List<ContextLineInfo> getContext(CommentInfo comment) {
-    ContextData key =
-        ContextData.create(
-            comment.id,
-            ObjectId.fromString(comment.commitId),
-            comment.path,
-            getStartAndEndLines(comment));
-    List<ContextLineInfo> context = candidates.get(key);
-    if (context == null) {
-      context = new ArrayList<>();
-      candidates.put(key, context);
-    }
-    return context;
-  }
+  public Map<Comment, CommentContext> getContext(Iterable<Comment> comments) {
+    ImmutableMap.Builder<Comment, CommentContext> result =
+        ImmutableMap.builderWithExpectedSize(Iterables.size(comments));
 
-  /**
-   * A call to this method loads the context for all comments stored in {@link
-   * CommentContextLoader#candidates}. This is useful so that the repository is opened once for all
-   * comments.
-   */
-  public void fill() {
     // Group comments by commit ID so that each commit is parsed only once
-    Map<ObjectId, List<ContextData>> commentsByCommitId =
-        candidates.keySet().stream().collect(groupingBy(ContextData::commitId));
+    Map<ObjectId, List<Comment>> commentsByCommitId =
+        Streams.stream(comments).collect(groupingBy(Comment::getCommitId));
 
     try (Repository repo = repoManager.openRepository(project);
         RevWalk rw = new RevWalk(repo)) {
       for (ObjectId commitId : commentsByCommitId.keySet()) {
         RevCommit commit = rw.parseCommit(commitId);
-        for (ContextData k : commentsByCommitId.get(commitId)) {
-          if (!k.range().isPresent()) {
+        for (Comment comment : commentsByCommitId.get(commitId)) {
+          Optional<Range> range = getStartAndEndLines(comment);
+          if (!range.isPresent()) {
             continue;
           }
-          try (TreeWalk tw = TreeWalk.forPath(rw.getObjectReader(), k.path(), commit.getTree())) {
+          // TODO(ghareeb): We can further group the comments by file paths to avoid opening
+          // the same file multiple times.
+          try (TreeWalk tw =
+              TreeWalk.forPath(rw.getObjectReader(), comment.key.filename, commit.getTree())) {
             if (tw == null) {
               logger.atWarning().log(
                   "Failed to find path %s in the git tree of ID %s.",
-                  k.path(), commit.getTree().getId());
+                  comment.key.filename, commit.getTree().getId());
               continue;
             }
             ObjectId id = tw.getObjectId(0);
             Text src = new Text(repo.open(id, Constants.OBJ_BLOB));
-            List<ContextLineInfo> contextLines = candidates.get(k);
-            Range r = k.range().get();
-            for (int i = r.start(); i <= r.end(); i++) {
-              contextLines.add(new ContextLineInfo(i, src.getString(i - 1)));
+            Range r = range.get();
+            ImmutableMap.Builder<Integer, String> context =
+                ImmutableMap.builderWithExpectedSize(r.end() - r.start());
+            for (int i = r.start(); i < r.end(); i++) {
+              context.put(i, src.getString(i - 1));
             }
+            result.put(comment, CommentContext.create(context.build()));
           }
         }
       }
+      return result.build();
     } catch (IOException e) {
       throw new StorageException("Failed to load the comment context", e);
     }
   }
 
-  private static Optional<Range> getStartAndEndLines(CommentInfo comment) {
+  private static Optional<Range> getStartAndEndLines(Comment comment) {
     if (comment.range != null) {
-      return Optional.of(Range.create(comment.range.startLine, comment.range.endLine));
-    } else if (comment.line != null) {
-      return Optional.of(Range.create(comment.line, comment.line));
+      return Optional.of(Range.create(comment.range.startLine, comment.range.endLine + 1));
+    } else if (comment.lineNbr > 0) {
+      return Optional.of(Range.create(comment.lineNbr, comment.lineNbr + 1));
     }
     return Optional.empty();
   }
@@ -143,23 +129,10 @@
       return new AutoValue_CommentContextLoader_Range(start, end);
     }
 
+    /** Start line of the comment (inclusive). */
     abstract int start();
 
+    /** End line of the comment (exclusive). */
     abstract int end();
   }
-
-  @AutoValue
-  abstract static class ContextData {
-    static ContextData create(String id, ObjectId commitId, String path, Optional<Range> range) {
-      return new AutoValue_CommentContextLoader_ContextData(id, commitId, path, range);
-    }
-
-    abstract String id();
-
-    abstract ObjectId commitId();
-
-    abstract String path();
-
-    abstract Optional<Range> range();
-  }
 }
diff --git a/java/com/google/gerrit/server/CurrentUser.java b/java/com/google/gerrit/server/CurrentUser.java
index 75afc04..afbc74e 100644
--- a/java/com/google/gerrit/server/CurrentUser.java
+++ b/java/com/google/gerrit/server/CurrentUser.java
@@ -14,7 +14,7 @@
 
 package com.google.gerrit.server;
 
-import com.google.gerrit.common.Nullable;
+import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.account.externalids.ExternalId;
@@ -31,17 +31,19 @@
  * @see IdentifiedUser
  */
 public abstract class CurrentUser {
-  /** Unique key for plugin/extension specific data on a CurrentUser. */
-  public static final class PropertyKey<T> {
-    public static <T> PropertyKey<T> create() {
-      return new PropertyKey<>();
-    }
+  public static final PropertyMap.Key<ExternalId.Key> LAST_LOGIN_EXTERNAL_ID_PROPERTY_KEY =
+      PropertyMap.key();
 
-    private PropertyKey() {}
+  private final PropertyMap properties;
+  private AccessPath accessPath = AccessPath.UNKNOWN;
+
+  protected CurrentUser() {
+    this.properties = PropertyMap.EMPTY;
   }
 
-  private AccessPath accessPath = AccessPath.UNKNOWN;
-  private PropertyKey<ExternalId.Key> lastLoginExternalIdPropertyKey = PropertyKey.create();
+  protected CurrentUser(PropertyMap properties) {
+    this.properties = properties;
+  }
 
   /** How this user is accessing the Gerrit Code Review application. */
   public final AccessPath getAccessPath() {
@@ -127,35 +129,40 @@
         getClass().getSimpleName() + " is not an IdentifiedUser");
   }
 
+  /**
+   * Returns all email addresses associated with this user. For {@link AnonymousUser} and other
+   * users that don't represent a person user or service account, this set will be empty.
+   */
+  public ImmutableSet<String> getEmailAddresses() {
+    return ImmutableSet.of();
+  }
+
+  /**
+   * Returns all {@link ExternalId.Key}s associated with this user. For {@link AnonymousUser} and
+   * other users that don't represent a person user or service account, this set will be empty.
+   */
+  public ImmutableSet<ExternalId.Key> getExternalIdKeys() {
+    return ImmutableSet.of();
+  }
+
   /** Check if the CurrentUser is an InternalUser. */
   public boolean isInternalUser() {
     return false;
   }
 
   /**
-   * Lookup a previously stored property.
+   * Lookup a stored property.
    *
-   * @param key unique property key.
-   * @return previously stored value, or {@code Optional#empty()}.
+   * @param key unique property key. This key has to be the same instance that was used to store the
+   *     value when constructing the {@link PropertyMap}
+   * @return stored value, or {@code Optional#empty()}.
    */
-  public <T> Optional<T> get(PropertyKey<T> key) {
-    return Optional.empty();
-  }
-
-  /**
-   * Store a property for later retrieval.
-   *
-   * @param key unique property key.
-   * @param value value to store; or {@code null} to clear the value.
-   */
-  public <T> void put(PropertyKey<T> key, @Nullable T value) {}
-
-  public void setLastLoginExternalIdKey(ExternalId.Key externalIdKey) {
-    put(lastLoginExternalIdPropertyKey, externalIdKey);
+  public <T> Optional<T> get(PropertyMap.Key<T> key) {
+    return properties.get(key);
   }
 
   public Optional<ExternalId.Key> getLastLoginExternalIdKey() {
-    return get(lastLoginExternalIdPropertyKey);
+    return get(LAST_LOGIN_EXTERNAL_ID_PROPERTY_KEY);
   }
 
   /**
diff --git a/java/com/google/gerrit/server/DynamicOptions.java b/java/com/google/gerrit/server/DynamicOptions.java
index 41dc082..db0aa70 100644
--- a/java/com/google/gerrit/server/DynamicOptions.java
+++ b/java/com/google/gerrit/server/DynamicOptions.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.lifecycle.LifecycleManager;
 import com.google.gerrit.server.plugins.DelegatingClassLoader;
 import com.google.gerrit.util.cli.CmdLineParser;
 import com.google.inject.Injector;
@@ -29,7 +30,7 @@
 import java.util.WeakHashMap;
 
 /** Helper class to define and parse options from plugins on ssh and RestAPI commands. */
-public class DynamicOptions {
+public class DynamicOptions implements AutoCloseable {
   /**
    * To provide additional options, bind a DynamicBean. For example:
    *
@@ -98,7 +99,9 @@
    *
    * <p>Do this by binding to the name of the command you are going to bind to and providing an
    * Iterable of Module names to instantiate and add to the Injector used to instantiate the
-   * DynamicBean in the other classLoader. For example:
+   * DynamicBean in the other classLoader. This interface supports running LifecycleListeners which
+   * are defined by the Modules being provided. The duration of the lifecycle starts when a ssh or
+   * http request starts and ends when the request completes. For example:
    *
    * <pre>
    *   bind(com.google.gerrit.server.DynamicOptions.DynamicBean.class)
@@ -106,7 +109,7 @@
    *           "com.google.gerrit.plugins.otherplugin.command"))
    *       .to(MyOptionsModulesClassNamesProvider.class);
    *
-   *   static class MyOptionsModulesClassNamesProvider implements DynamicOptions.ClassNameProvider {
+   *   static class MyOptionsModulesClassNamesProvider implements DynamicOptions.ModulesClassNamesProvider {
    *     {@literal @}Override
    *     public String getClassName() {
    *       return "com.googlesource.gerrit.plugins.myplugin.CommandOptions";
@@ -190,13 +193,17 @@
   protected Object bean;
   protected Map<String, DynamicBean> beansByPlugin;
   protected Injector injector;
+  protected DynamicMap<DynamicBean> dynamicBeans;
+  protected LifecycleManager lifecycleManager;
 
   /**
    * Internal: For Gerrit to include options from DynamicBeans, setup a DynamicMap and instantiate
    * this class so the following methods can be called if desired:
    *
    * <pre>
-   *    DynamicOptions pluginOptions = new DynamicOptions(bean, injector, dynamicBeans);
+   *    DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans);
+   *    pluginOptions.setBean(bean);
+   *    pluginOptions.startLifecycleListeners();
    *    pluginOptions.parseDynamicBeans(clp);
    *    pluginOptions.setDynamicBeans();
    *    pluginOptions.onBeanParseStart();
@@ -206,10 +213,15 @@
    *    pluginOptions.onBeanParseEnd();
    * </pre>
    */
-  public DynamicOptions(Object bean, Injector injector, DynamicMap<DynamicBean> dynamicBeans) {
-    this.bean = bean;
+  public DynamicOptions(Injector injector, DynamicMap<DynamicBean> dynamicBeans) {
     this.injector = injector;
+    this.dynamicBeans = dynamicBeans;
+    lifecycleManager = new LifecycleManager();
     beansByPlugin = new HashMap<>();
+  }
+
+  public void setBean(Object bean) {
+    this.bean = bean;
     Class<?> beanClass =
         (bean instanceof BeanReceiver)
             ? ((BeanReceiver) bean).getExportedBeanReceiver()
@@ -255,9 +267,10 @@
             modules.add(modulesInjector.getInstance(mClass));
           }
         }
-        return modulesInjector
-            .createChildInjector(modules)
-            .getInstance((Class<DynamicOptions.DynamicBean>) loader.loadClass(className));
+        Injector childModulesInjector = modulesInjector.createChildInjector(modules);
+        lifecycleManager.add(childModulesInjector);
+        return childModulesInjector.getInstance(
+            (Class<DynamicOptions.DynamicBean>) loader.loadClass(className));
       } catch (ClassNotFoundException e) {
         throw new RuntimeException(e);
       }
@@ -300,6 +313,14 @@
     }
   }
 
+  public void startLifecycleListeners() {
+    lifecycleManager.start();
+  }
+
+  public void stopLifecycleListeners() {
+    lifecycleManager.stop();
+  }
+
   public void onBeanParseStart() {
     for (Map.Entry<String, DynamicBean> e : beansByPlugin.entrySet()) {
       DynamicBean instance = e.getValue();
@@ -319,4 +340,9 @@
       }
     }
   }
+
+  @Override
+  public void close() {
+    stopLifecycleListeners();
+  }
 }
diff --git a/java/com/google/gerrit/server/ExternalUser.java b/java/com/google/gerrit/server/ExternalUser.java
new file mode 100644
index 0000000..9680f3e
--- /dev/null
+++ b/java/com/google/gerrit/server/ExternalUser.java
@@ -0,0 +1,90 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server;
+
+import static com.google.common.flogger.LazyArgs.lazy;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.server.account.GroupBackend;
+import com.google.gerrit.server.account.GroupMembership;
+import com.google.gerrit.server.account.externalids.ExternalId;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+import java.util.Collection;
+
+/**
+ * Represents a user that does not have a Gerrit account.
+ *
+ * <p>This user is limited in what they can do on Gerrit. For now, we only guarantee that permission
+ * checking - including ref filtering works.
+ *
+ * <p>This class is thread-safe.
+ */
+public class ExternalUser extends CurrentUser {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  public interface Factory {
+    ExternalUser create(
+        Collection<String> emailAddresses,
+        Collection<ExternalId.Key> externalIdKeys,
+        PropertyMap propertyMap);
+  }
+
+  private final GroupBackend groupBackend;
+  private final ImmutableSet<String> emailAddresses;
+  private final ImmutableSet<ExternalId.Key> externalIdKeys;
+
+  private GroupMembership effectiveGroups;
+
+  @Inject
+  public ExternalUser(
+      GroupBackend groupBackend,
+      @Assisted Collection<String> emailAddresses,
+      @Assisted Collection<ExternalId.Key> externalIdKeys,
+      @Assisted PropertyMap propertyMap) {
+    super(propertyMap);
+    this.groupBackend = groupBackend;
+    this.emailAddresses = ImmutableSet.copyOf(emailAddresses);
+    this.externalIdKeys = ImmutableSet.copyOf(externalIdKeys);
+  }
+
+  @Override
+  public ImmutableSet<String> getEmailAddresses() {
+    return emailAddresses;
+  }
+
+  @Override
+  public ImmutableSet<ExternalId.Key> getExternalIdKeys() {
+    return externalIdKeys;
+  }
+
+  @Override
+  public GroupMembership getEffectiveGroups() {
+    synchronized (this) {
+      if (effectiveGroups == null) {
+        effectiveGroups = groupBackend.membershipsOf(this);
+        logger.atFinest().log(
+            "Known groups of %s: %s", getLoggableName(), lazy(effectiveGroups::getKnownGroups));
+      }
+    }
+    return effectiveGroups;
+  }
+
+  @Override
+  public Object getCacheKey() {
+    return this; // Caching is tied to this exact instance.
+  }
+}
diff --git a/java/com/google/gerrit/server/IdentifiedUser.java b/java/com/google/gerrit/server/IdentifiedUser.java
index 7cafdc0..34f0eb5 100644
--- a/java/com/google/gerrit/server/IdentifiedUser.java
+++ b/java/com/google/gerrit/server/IdentifiedUser.java
@@ -15,13 +15,16 @@
 package com.google.gerrit.server;
 
 import static com.google.common.base.MoreObjects.firstNonNull;
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.flogger.LazyArgs.lazy;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.common.UsedAt;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.account.AccountState;
@@ -29,6 +32,7 @@
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.account.ListGroupMembership;
 import com.google.gerrit.server.account.Realm;
+import com.google.gerrit.server.account.externalids.ExternalId;
 import com.google.gerrit.server.config.AnonymousCowardName;
 import com.google.gerrit.server.config.AuthConfig;
 import com.google.gerrit.server.config.CanonicalWebUrl;
@@ -46,8 +50,6 @@
 import java.net.SocketAddress;
 import java.net.URL;
 import java.util.Date;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.TimeZone;
@@ -105,12 +107,26 @@
       return create(null, id);
     }
 
+    @VisibleForTesting
+    @UsedAt(UsedAt.Project.GOOGLE)
+    public IdentifiedUser forTest(Account.Id id, PropertyMap properties) {
+      return runAs(null, id, null, properties);
+    }
+
     public IdentifiedUser create(SocketAddress remotePeer, Account.Id id) {
       return runAs(remotePeer, id, null);
     }
 
     public IdentifiedUser runAs(
         SocketAddress remotePeer, Account.Id id, @Nullable CurrentUser caller) {
+      return runAs(remotePeer, id, caller, PropertyMap.EMPTY);
+    }
+
+    private IdentifiedUser runAs(
+        SocketAddress remotePeer,
+        Account.Id id,
+        @Nullable CurrentUser caller,
+        PropertyMap properties) {
       return new IdentifiedUser(
           authConfig,
           realm,
@@ -121,7 +137,8 @@
           enableReverseDnsLookup,
           Providers.of(remotePeer),
           id,
-          caller);
+          caller,
+          properties);
     }
   }
 
@@ -163,20 +180,10 @@
     }
 
     public IdentifiedUser create(Account.Id id) {
-      return new IdentifiedUser(
-          authConfig,
-          realm,
-          anonymousCowardName,
-          canonicalUrl,
-          accountCache,
-          groupBackend,
-          enableReverseDnsLookup,
-          remotePeerProvider,
-          id,
-          null);
+      return create(id, PropertyMap.EMPTY);
     }
 
-    public IdentifiedUser runAs(Account.Id id, CurrentUser caller) {
+    public <T> IdentifiedUser create(Account.Id id, PropertyMap properties) {
       return new IdentifiedUser(
           authConfig,
           realm,
@@ -187,7 +194,23 @@
           enableReverseDnsLookup,
           remotePeerProvider,
           id,
-          caller);
+          null,
+          properties);
+    }
+
+    public IdentifiedUser runAs(Account.Id id, CurrentUser caller, PropertyMap properties) {
+      return new IdentifiedUser(
+          authConfig,
+          realm,
+          anonymousCowardName,
+          canonicalUrl,
+          accountCache,
+          groupBackend,
+          enableReverseDnsLookup,
+          remotePeerProvider,
+          id,
+          caller,
+          properties);
     }
   }
 
@@ -212,7 +235,6 @@
   private boolean loadedAllEmails;
   private Set<String> invalidEmails;
   private GroupMembership effectiveGroups;
-  private Map<PropertyKey<Object>, Object> properties;
 
   private IdentifiedUser(
       AuthConfig authConfig,
@@ -235,7 +257,8 @@
         enableReverseDnsLookup,
         remotePeerProvider,
         state.account().id(),
-        realUser);
+        realUser,
+        PropertyMap.EMPTY);
     this.state = state;
   }
 
@@ -249,7 +272,9 @@
       Boolean enableReverseDnsLookup,
       @Nullable Provider<SocketAddress> remotePeerProvider,
       Account.Id id,
-      @Nullable CurrentUser realUser) {
+      @Nullable CurrentUser realUser,
+      PropertyMap properties) {
+    super(properties);
     this.canonicalUrl = canonicalUrl;
     this.accountCache = accountCache;
     this.groupBackend = groupBackend;
@@ -357,6 +382,7 @@
     return false;
   }
 
+  @Override
   public ImmutableSet<String> getEmailAddresses() {
     if (!loadedAllEmails) {
       validEmails.addAll(realm.getEmailAddresses(this));
@@ -365,6 +391,11 @@
     return ImmutableSet.copyOf(validEmails);
   }
 
+  @Override
+  public ImmutableSet<ExternalId.Key> getExternalIdKeys() {
+    return state().externalIds().stream().map(ExternalId::key).collect(toImmutableSet());
+  }
+
   public String getName() {
     return getAccount().getName();
   }
@@ -463,40 +494,6 @@
     return true;
   }
 
-  @Override
-  public synchronized <T> Optional<T> get(PropertyKey<T> key) {
-    if (properties != null) {
-      @SuppressWarnings("unchecked")
-      T value = (T) properties.get(key);
-      return Optional.ofNullable(value);
-    }
-    return Optional.empty();
-  }
-
-  /**
-   * Store a property for later retrieval.
-   *
-   * @param key unique property key.
-   * @param value value to store; or {@code null} to clear the value.
-   */
-  @Override
-  public synchronized <T> void put(PropertyKey<T> key, @Nullable T value) {
-    if (properties == null) {
-      if (value == null) {
-        return;
-      }
-      properties = new HashMap<>();
-    }
-
-    @SuppressWarnings("unchecked")
-    PropertyKey<Object> k = (PropertyKey<Object>) key;
-    if (value != null) {
-      properties.put(k, value);
-    } else {
-      properties.remove(k);
-    }
-  }
-
   /**
    * Returns a materialized copy of the user with all dependencies.
    *
diff --git a/java/com/google/gerrit/server/PropertyMap.java b/java/com/google/gerrit/server/PropertyMap.java
new file mode 100644
index 0000000..da3a2495
--- /dev/null
+++ b/java/com/google/gerrit/server/PropertyMap.java
@@ -0,0 +1,84 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server;
+
+import com.google.common.collect.ImmutableMap;
+import java.util.Optional;
+
+/**
+ * Immutable map that holds a collection of random objects allowing for a type-safe retrieval.
+ *
+ * <p>Intended to be used in {@link CurrentUser} when the object is constructed during login and
+ * holds per-request state. This functionality allows plugins/extensions to contribute specific data
+ * to {@link CurrentUser} that is unknown to Gerrit core.
+ */
+public class PropertyMap {
+  /** Empty instance to be referenced once per JVM. */
+  public static final PropertyMap EMPTY = builder().build();
+
+  /**
+   * Typed key for {@link PropertyMap}. This class intentionally does not implement {@link
+   * Object#equals(Object)} and {@link Object#hashCode()} so that the same instance has to be used
+   * to retrieve a stored value.
+   *
+   * <p>We require the exact same key instance because {@link PropertyMap} is implemented in a
+   * type-safe fashion by using Java generics to guarantee the return type. The generic type can't
+   * be recovered at runtime, so there is no way to just use the type's full name as key - we'd have
+   * to pass additional arguments. At the same time, this is in-line with how we'd want callers to
+   * use {@link PropertyMap}: Instantiate a static, per-JVM key that is reused when setting and
+   * getting values.
+   */
+  public static class Key<T> {}
+
+  public static <T> Key<T> key() {
+    return new Key<>();
+  }
+
+  public static class Builder {
+    private ImmutableMap.Builder<Object, Object> mutableMap;
+
+    private Builder() {
+      this.mutableMap = ImmutableMap.builder();
+    }
+
+    /** Adds the provided {@code value} to the {@link PropertyMap} that is being built. */
+    public <T> Builder put(Key<T> key, T value) {
+      mutableMap.put(key, value);
+      return this;
+    }
+
+    /** Builds and returns an immutable {@link PropertyMap}. */
+    public PropertyMap build() {
+      return new PropertyMap(mutableMap.build());
+    }
+  }
+
+  private final ImmutableMap<Object, Object> map;
+
+  private PropertyMap(ImmutableMap<Object, Object> map) {
+    this.map = map;
+  }
+
+  /** Returns a new {@link Builder} instance. */
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  /** Returns the requested value wrapped as {@link Optional}. */
+  @SuppressWarnings("unchecked")
+  public <T> Optional<T> get(Key<T> key) {
+    return Optional.ofNullable((T) map.get(key));
+  }
+}
diff --git a/java/com/google/gerrit/server/WebLinks.java b/java/com/google/gerrit/server/WebLinks.java
index 88b0b21..e66e7f5 100644
--- a/java/com/google/gerrit/server/WebLinks.java
+++ b/java/com/google/gerrit/server/WebLinks.java
@@ -86,19 +86,29 @@
   /**
    * @param project Project name.
    * @param commit SHA1 of commit.
+   * @param commitMessage the commit message of the commit.
+   * @param branchName branch of the commit.
    * @return Links for patch sets.
    */
-  public ImmutableList<WebLinkInfo> getPatchSetLinks(Project.NameKey project, String commit) {
-    return filterLinks(patchSetLinks, webLink -> webLink.getPatchSetWebLink(project.get(), commit));
+  public ImmutableList<WebLinkInfo> getPatchSetLinks(
+      Project.NameKey project, String commit, String commitMessage, String branchName) {
+    return filterLinks(
+        patchSetLinks,
+        webLink -> webLink.getPatchSetWebLink(project.get(), commit, commitMessage, branchName));
   }
 
   /**
    * @param project Project name.
    * @param revision SHA1 of the parent revision.
+   * @param commitMessage the commit message of the parent revision.
+   * @param branchName branch of the revision (and parent revision).
    * @return Links for patch sets.
    */
-  public ImmutableList<WebLinkInfo> getParentLinks(Project.NameKey project, String revision) {
-    return filterLinks(parentLinks, webLink -> webLink.getParentWebLink(project.get(), revision));
+  public ImmutableList<WebLinkInfo> getParentLinks(
+      Project.NameKey project, String revision, String commitMessage, String branchName) {
+    return filterLinks(
+        parentLinks,
+        webLink -> webLink.getParentWebLink(project.get(), revision, commitMessage, branchName));
   }
 
   /**
diff --git a/java/com/google/gerrit/server/account/AccountResolver.java b/java/com/google/gerrit/server/account/AccountResolver.java
index f861ea7..8c957ec 100644
--- a/java/com/google/gerrit/server/account/AccountResolver.java
+++ b/java/com/google/gerrit/server/account/AccountResolver.java
@@ -492,7 +492,7 @@
   }
 
   /**
-   * Resolves all accounts matching the input string.
+   * Resolves all accounts matching the input string, visible to the current user.
    *
    * <p>The following input formats are recognized:
    *
diff --git a/java/com/google/gerrit/server/account/GroupBackend.java b/java/com/google/gerrit/server/account/GroupBackend.java
index 545da6e..d6360c5 100644
--- a/java/com/google/gerrit/server/account/GroupBackend.java
+++ b/java/com/google/gerrit/server/account/GroupBackend.java
@@ -19,7 +19,7 @@
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
 import com.google.gerrit.extensions.annotations.ExtensionPoint;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.project.ProjectState;
 import java.util.Collection;
 
@@ -42,7 +42,7 @@
   Collection<GroupReference> suggest(String name, @Nullable ProjectState project);
 
   /** @return the group membership checker for the backend. */
-  GroupMembership membershipsOf(IdentifiedUser user);
+  GroupMembership membershipsOf(CurrentUser user);
 
   /** @return {@code true} if the group with the given UUID is visible to all registered users. */
   boolean isVisibleToAll(AccountGroup.UUID uuid);
diff --git a/java/com/google/gerrit/server/account/IncludingGroupMembership.java b/java/com/google/gerrit/server/account/IncludingGroupMembership.java
index 6dc7976..9cb11a6 100644
--- a/java/com/google/gerrit/server/account/IncludingGroupMembership.java
+++ b/java/com/google/gerrit/server/account/IncludingGroupMembership.java
@@ -14,11 +14,12 @@
 
 package com.google.gerrit.server.account;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.gerrit.entities.AccountGroup;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.group.InternalGroup;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
@@ -40,18 +41,18 @@
  */
 public class IncludingGroupMembership implements GroupMembership {
   public interface Factory {
-    IncludingGroupMembership create(IdentifiedUser user);
+    IncludingGroupMembership create(CurrentUser user);
   }
 
   private final GroupCache groupCache;
   private final GroupIncludeCache includeCache;
-  private final IdentifiedUser user;
+  private final CurrentUser user;
   private final Map<AccountGroup.UUID, Boolean> memberOf;
   private Set<AccountGroup.UUID> knownGroups;
 
   @Inject
   IncludingGroupMembership(
-      GroupCache groupCache, GroupIncludeCache includeCache, @Assisted IdentifiedUser user) {
+      GroupCache groupCache, GroupIncludeCache includeCache, @Assisted CurrentUser user) {
     this.groupCache = groupCache;
     this.includeCache = includeCache;
     this.user = user;
@@ -93,7 +94,7 @@
         if (!group.isPresent()) {
           continue;
         }
-        if (group.get().getMembers().contains(user.getAccountId())) {
+        if (user.isIdentifiedUser() && group.get().getMembers().contains(user.getAccountId())) {
           memberOf.put(id, true);
           return true;
         }
@@ -124,7 +125,10 @@
 
   private ImmutableSet<AccountGroup.UUID> computeKnownGroups() {
     GroupMembership membership = user.getEffectiveGroups();
-    Collection<AccountGroup.UUID> direct = includeCache.getGroupsWithMember(user.getAccountId());
+    Collection<AccountGroup.UUID> direct =
+        user.isIdentifiedUser()
+            ? includeCache.getGroupsWithMember(user.getAccountId())
+            : ImmutableList.of();
     direct.forEach(groupUuid -> memberOf.put(groupUuid, true));
     Set<AccountGroup.UUID> r = Sets.newHashSet(direct);
     r.remove(null);
diff --git a/java/com/google/gerrit/server/account/InternalGroupBackend.java b/java/com/google/gerrit/server/account/InternalGroupBackend.java
index c520c96..8761081 100644
--- a/java/com/google/gerrit/server/account/InternalGroupBackend.java
+++ b/java/com/google/gerrit/server/account/InternalGroupBackend.java
@@ -20,7 +20,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.group.InternalGroup;
 import com.google.gerrit.server.group.InternalGroupDescription;
 import com.google.gerrit.server.group.db.Groups;
@@ -97,7 +97,7 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
+  public GroupMembership membershipsOf(CurrentUser user) {
     return groupMembershipFactory.create(user);
   }
 
diff --git a/java/com/google/gerrit/server/account/ServiceUserClassifier.java b/java/com/google/gerrit/server/account/ServiceUserClassifier.java
index c8314c8..2d2a646 100644
--- a/java/com/google/gerrit/server/account/ServiceUserClassifier.java
+++ b/java/com/google/gerrit/server/account/ServiceUserClassifier.java
@@ -17,6 +17,11 @@
 import com.google.gerrit.entities.Account;
 
 public interface ServiceUserClassifier {
+  /**
+   * Name of the Service Users group used by this class to determine whether an account is a service
+   * user; if an account is a part of this group, that account is considered a service user.
+   */
+  public static final String SERVICE_USERS = "Service Users";
   /** Returns {@code true} if the given user is considered a {@code Service User} user. */
   boolean isServiceUser(Account.Id user);
 
diff --git a/java/com/google/gerrit/server/account/ServiceUserClassifierImpl.java b/java/com/google/gerrit/server/account/ServiceUserClassifierImpl.java
index 255467c..3ee2c54 100644
--- a/java/com/google/gerrit/server/account/ServiceUserClassifierImpl.java
+++ b/java/com/google/gerrit/server/account/ServiceUserClassifierImpl.java
@@ -63,7 +63,7 @@
 
   @Override
   public boolean isServiceUser(Account.Id user) {
-    Optional<InternalGroup> maybeGroup = groupCache.get(AccountGroup.nameKey("Service Users"));
+    Optional<InternalGroup> maybeGroup = groupCache.get(AccountGroup.nameKey(SERVICE_USERS));
     if (!maybeGroup.isPresent()) {
       return false;
     }
diff --git a/java/com/google/gerrit/server/account/UniversalGroupBackend.java b/java/com/google/gerrit/server/account/UniversalGroupBackend.java
index a35b0ac..5bd9bea 100644
--- a/java/com/google/gerrit/server/account/UniversalGroupBackend.java
+++ b/java/com/google/gerrit/server/account/UniversalGroupBackend.java
@@ -27,7 +27,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.StartupCheck;
 import com.google.gerrit.server.StartupException;
 import com.google.gerrit.server.config.GerritServerConfig;
@@ -94,14 +94,14 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
+  public GroupMembership membershipsOf(CurrentUser user) {
     return new UniversalGroupMembership(user);
   }
 
   private class UniversalGroupMembership implements GroupMembership {
     private final Map<GroupBackend, GroupMembership> memberships;
 
-    private UniversalGroupMembership(IdentifiedUser user) {
+    private UniversalGroupMembership(CurrentUser user) {
       ImmutableMap.Builder<GroupBackend, GroupMembership> builder = ImmutableMap.builder();
       backends.runEach(g -> builder.put(g, g.membershipsOf(user)));
       this.memberships = builder.build();
diff --git a/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java b/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
index 235537c..30021e6 100644
--- a/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
+++ b/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
@@ -61,6 +61,8 @@
  * <p>Other comment lines are ignored on read, and are not written back when the file is modified.
  */
 public class VersionedAuthorizedKeys extends VersionedMetaData {
+
+  /** Read/write SSH keys by user ID. */
   @Singleton
   public static class Accessor {
     private final GitRepositoryManager repoManager;
diff --git a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
index 0992bcd..d349dda 100644
--- a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
@@ -177,6 +177,8 @@
   private final Provider<GetPureRevert> getPureRevertProvider;
   private final StarredChangesUtil stars;
   private final DynamicOptionParser dynamicOptionParser;
+  private final Injector injector;
+  private final DynamicMap<DynamicOptions.DynamicBean> dynamicBeans;
 
   @Inject
   ChangeApiImpl(
@@ -230,7 +232,9 @@
       Provider<GetPureRevert> getPureRevertProvider,
       StarredChangesUtil stars,
       DynamicOptionParser dynamicOptionParser,
-      @Assisted ChangeResource change) {
+      @Assisted ChangeResource change,
+      Injector injector,
+      DynamicMap<DynamicOptions.DynamicBean> dynamicBeans) {
     this.changeApi = changeApi;
     this.revert = revert;
     this.revertSubmission = revertSubmission;
@@ -282,6 +286,8 @@
     this.stars = stars;
     this.dynamicOptionParser = dynamicOptionParser;
     this.change = change;
+    this.injector = injector;
+    this.dynamicBeans = dynamicBeans;
   }
 
   @Override
@@ -500,10 +506,10 @@
   public ChangeInfo get(
       EnumSet<ListChangesOption> options, ImmutableListMultimap<String, String> pluginOptions)
       throws RestApiException {
-    try {
+    try (DynamicOptions dynamicOptions = new DynamicOptions(injector, dynamicBeans)) {
       GetChange getChange = getChangeProvider.get();
       options.forEach(getChange::addOption);
-      dynamicOptionParser.parseDynamicOptions(getChange, pluginOptions);
+      dynamicOptionParser.parseDynamicOptions(getChange, pluginOptions, dynamicOptions);
       return getChange.apply(change).value();
     } catch (Exception e) {
       throw asRestApiException("Cannot retrieve change", e);
@@ -759,8 +765,6 @@
   @Singleton
   static class DynamicOptionParser {
     private final CmdLineParser.Factory cmdLineParserFactory;
-    private final Injector injector;
-    private final DynamicMap<DynamicOptions.DynamicBean> dynamicBeans;
 
     @Inject
     DynamicOptionParser(
@@ -768,14 +772,14 @@
         Injector injector,
         DynamicMap<DynamicOptions.DynamicBean> dynamicBeans) {
       this.cmdLineParserFactory = cmdLineParserFactory;
-      this.injector = injector;
-      this.dynamicBeans = dynamicBeans;
     }
 
-    void parseDynamicOptions(Object bean, ListMultimap<String, String> pluginOptions)
+    void parseDynamicOptions(
+        Object bean, ListMultimap<String, String> pluginOptions, DynamicOptions dynamicOptions)
         throws BadRequestException {
       CmdLineParser clp = cmdLineParserFactory.create(bean);
-      DynamicOptions dynamicOptions = new DynamicOptions(bean, injector, dynamicBeans);
+      dynamicOptions.setBean(bean);
+      dynamicOptions.startLifecycleListeners();
       dynamicOptions.parseDynamicBeans(clp);
       dynamicOptions.setDynamicBeans();
       dynamicOptions.onBeanParseStart();
diff --git a/java/com/google/gerrit/server/api/changes/ChangesImpl.java b/java/com/google/gerrit/server/api/changes/ChangesImpl.java
index d6ef61c..0596524 100644
--- a/java/com/google/gerrit/server/api/changes/ChangesImpl.java
+++ b/java/com/google/gerrit/server/api/changes/ChangesImpl.java
@@ -26,15 +26,18 @@
 import com.google.gerrit.extensions.client.ListChangesOption;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeInput;
+import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
 import com.google.gerrit.extensions.restapi.Url;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.api.changes.ChangeApiImpl.DynamicOptionParser;
 import com.google.gerrit.server.restapi.change.ChangesCollection;
 import com.google.gerrit.server.restapi.change.CreateChange;
 import com.google.gerrit.server.restapi.change.QueryChanges;
 import com.google.inject.Inject;
+import com.google.inject.Injector;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.util.List;
@@ -46,6 +49,8 @@
   private final CreateChange createChange;
   private final DynamicOptionParser dynamicOptionParser;
   private final Provider<QueryChanges> queryProvider;
+  private final Injector injector;
+  private final DynamicMap<DynamicOptions.DynamicBean> dynamicBeans;
 
   @Inject
   ChangesImpl(
@@ -53,12 +58,16 @@
       ChangeApiImpl.Factory api,
       CreateChange createChange,
       DynamicOptionParser dynamicOptionParser,
-      Provider<QueryChanges> queryProvider) {
+      Provider<QueryChanges> queryProvider,
+      Injector injector,
+      DynamicMap<DynamicOptions.DynamicBean> dynamicBeans) {
     this.changes = changes;
     this.api = api;
     this.createChange = createChange;
     this.dynamicOptionParser = dynamicOptionParser;
     this.queryProvider = queryProvider;
+    this.injector = injector;
+    this.dynamicBeans = dynamicBeans;
   }
 
   @Override
@@ -123,34 +132,36 @@
   }
 
   private List<ChangeInfo> get(QueryRequest q) throws RestApiException {
-    QueryChanges qc = queryProvider.get();
-    if (q.getQuery() != null) {
-      qc.addQuery(q.getQuery());
-    }
-    qc.setLimit(q.getLimit());
-    qc.setStart(q.getStart());
-    qc.setNoLimit(q.getNoLimit());
-    for (ListChangesOption option : q.getOptions()) {
-      qc.addOption(option);
-    }
-    dynamicOptionParser.parseDynamicOptions(qc, q.getPluginOptions());
-
-    try {
-      List<?> result = qc.apply(TopLevelResource.INSTANCE).value();
-      if (result.isEmpty()) {
-        return ImmutableList.of();
+    try (DynamicOptions dynamicOptions = new DynamicOptions(injector, dynamicBeans)) {
+      QueryChanges qc = queryProvider.get();
+      if (q.getQuery() != null) {
+        qc.addQuery(q.getQuery());
       }
+      qc.setLimit(q.getLimit());
+      qc.setStart(q.getStart());
+      qc.setNoLimit(q.getNoLimit());
+      for (ListChangesOption option : q.getOptions()) {
+        qc.addOption(option);
+      }
+      dynamicOptionParser.parseDynamicOptions(qc, q.getPluginOptions(), dynamicOptions);
 
-      // Check type safety of result; the extension API should be safer than the
-      // REST API in this case, since it's intended to be used in Java.
-      Object first = requireNonNull(result.iterator().next());
-      checkState(first instanceof ChangeInfo);
-      @SuppressWarnings("unchecked")
-      List<ChangeInfo> infos = (List<ChangeInfo>) result;
+      try {
+        List<?> result = qc.apply(TopLevelResource.INSTANCE).value();
+        if (result.isEmpty()) {
+          return ImmutableList.of();
+        }
 
-      return ImmutableList.copyOf(infos);
-    } catch (Exception e) {
-      throw asRestApiException("Cannot query changes", e);
+        // Check type safety of result; the extension API should be safer than the
+        // REST API in this case, since it's intended to be used in Java.
+        Object first = requireNonNull(result.iterator().next());
+        checkState(first instanceof ChangeInfo);
+        @SuppressWarnings("unchecked")
+        List<ChangeInfo> infos = (List<ChangeInfo>) result;
+
+        return ImmutableList.copyOf(infos);
+      } catch (Exception e) {
+        throw asRestApiException("Cannot query changes", e);
+      }
     }
   }
 }
diff --git a/java/com/google/gerrit/server/api/projects/BranchApiImpl.java b/java/com/google/gerrit/server/api/projects/BranchApiImpl.java
index c7cca6f..78f5c5f 100644
--- a/java/com/google/gerrit/server/api/projects/BranchApiImpl.java
+++ b/java/com/google/gerrit/server/api/projects/BranchApiImpl.java
@@ -16,6 +16,7 @@
 
 import static com.google.gerrit.server.api.ApiUtil.asRestApiException;
 
+import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.extensions.api.projects.BranchApi;
 import com.google.gerrit.extensions.api.projects.BranchInfo;
 import com.google.gerrit.extensions.api.projects.BranchInput;
@@ -126,6 +127,10 @@
 
   private BranchResource resource()
       throws RestApiException, IOException, PermissionBackendException {
-    return branches.parse(project, IdString.fromDecoded(ref));
+    String refName = ref;
+    if (RefNames.isRefsUsersSelf(ref, project.getProjectState().isAllUsers())) {
+      refName = RefNames.refsUsers(project.getUser().getAccountId());
+    }
+    return branches.parse(project, IdString.fromDecoded(refName));
   }
 }
diff --git a/java/com/google/gerrit/server/auth/ldap/FakeLdapGroupBackend.java b/java/com/google/gerrit/server/auth/ldap/FakeLdapGroupBackend.java
index 63cd426..f806756 100644
--- a/java/com/google/gerrit/server/auth/ldap/FakeLdapGroupBackend.java
+++ b/java/com/google/gerrit/server/auth/ldap/FakeLdapGroupBackend.java
@@ -20,7 +20,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.account.ListGroupMembership;
@@ -76,7 +76,7 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
+  public GroupMembership membershipsOf(CurrentUser user) {
     return new ListGroupMembership(Collections.emptyList());
   }
 
diff --git a/java/com/google/gerrit/server/auth/ldap/LdapGroupBackend.java b/java/com/google/gerrit/server/auth/ldap/LdapGroupBackend.java
index 180612c..d5da406 100644
--- a/java/com/google/gerrit/server/auth/ldap/LdapGroupBackend.java
+++ b/java/com/google/gerrit/server/auth/ldap/LdapGroupBackend.java
@@ -29,7 +29,6 @@
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
 import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.account.externalids.ExternalId;
@@ -45,6 +44,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import javax.naming.InvalidNameException;
@@ -178,21 +178,13 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
-    String id = findId(user.state().externalIds());
-    if (id == null) {
+  public GroupMembership membershipsOf(CurrentUser user) {
+    Optional<ExternalId.Key> id =
+        user.getExternalIdKeys().stream().filter(e -> e.isScheme(SCHEME_GERRIT)).findAny();
+    if (!id.isPresent()) {
       return GroupMembership.EMPTY;
     }
-    return new LdapGroupMembership(membershipCache, projectCache, id, gerritConfig);
-  }
-
-  private static String findId(Collection<ExternalId> extIds) {
-    for (ExternalId extId : extIds) {
-      if (extId.isScheme(SCHEME_GERRIT)) {
-        return extId.key().id();
-      }
-    }
-    return null;
+    return new LdapGroupMembership(membershipCache, projectCache, id.get().id(), gerritConfig);
   }
 
   private Set<GroupReference> suggestLdap(String name) {
diff --git a/java/com/google/gerrit/server/change/ChangeAttributeFactory.java b/java/com/google/gerrit/server/change/ChangeAttributeFactory.java
deleted file mode 100644
index 663d7aa..0000000
--- a/java/com/google/gerrit/server/change/ChangeAttributeFactory.java
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.change;
-
-import com.google.gerrit.extensions.common.PluginDefinedInfo;
-import com.google.gerrit.server.DynamicOptions.BeanProvider;
-import com.google.gerrit.server.query.change.ChangeData;
-
-/**
- * Interface for plugins to provide additional fields in {@link
- * com.google.gerrit.extensions.common.ChangeInfo ChangeInfo}.
- *
- * <p>Register a {@code ChangeAttributeFactory} in a plugin {@code Module} like this:
- *
- * <pre>
- * DynamicSet.bind(binder(), ChangeAttributeFactory.class).to(YourClass.class);
- * </pre>
- *
- * <p>See the <a
- * href="https://gerrit-review.googlesource.com/Documentation/dev-plugins.html#query_attributes">plugin
- * developer documentation for more details and examples.
- */
-@Deprecated
-public interface ChangeAttributeFactory {
-
-  /**
-   * Create a plugin-provided info field.
-   *
-   * <p>Typically, implementations will subclass {@code PluginDefinedInfo} to add additional fields.
-   *
-   * @param cd change.
-   * @param beanProvider provider of {@code DynamicBean}s, which may be used for reading options.
-   * @param plugin plugin name.
-   * @return the plugin's special change info.
-   */
-  PluginDefinedInfo create(ChangeData cd, BeanProvider beanProvider, String plugin);
-}
diff --git a/java/com/google/gerrit/server/change/ChangeJson.java b/java/com/google/gerrit/server/change/ChangeJson.java
index 8323cfd..02da518 100644
--- a/java/com/google/gerrit/server/change/ChangeJson.java
+++ b/java/com/google/gerrit/server/change/ChangeJson.java
@@ -158,17 +158,12 @@
     }
 
     public ChangeJson create(Iterable<ListChangesOption> options) {
-      return factory.create(options, Optional.empty(), Optional.empty());
+      return factory.create(options, Optional.empty());
     }
 
     public ChangeJson create(
-        Iterable<ListChangesOption> options,
-        PluginDefinedAttributesFactory pluginDefinedAttributesFactory,
-        PluginDefinedInfosFactory pluginDefinedInfosFactory) {
-      return factory.create(
-          options,
-          Optional.of(pluginDefinedAttributesFactory),
-          Optional.of(pluginDefinedInfosFactory));
+        Iterable<ListChangesOption> options, PluginDefinedInfosFactory pluginDefinedInfosFactory) {
+      return factory.create(options, Optional.of(pluginDefinedInfosFactory));
     }
 
     public ChangeJson create(ListChangesOption first, ListChangesOption... rest) {
@@ -179,7 +174,6 @@
   public interface AssistedFactory {
     ChangeJson create(
         Iterable<ListChangesOption> options,
-        Optional<PluginDefinedAttributesFactory> pluginDefinedAttributesFactory,
         Optional<PluginDefinedInfosFactory> pluginDefinedInfosFactory);
   }
 
@@ -226,7 +220,6 @@
   private final TrackingFooters trackingFooters;
   private final Metrics metrics;
   private final RevisionJson revisionJson;
-  private final Optional<PluginDefinedAttributesFactory> pluginDefinedAttributesFactory;
   private final Optional<PluginDefinedInfosFactory> pluginDefinedInfosFactory;
   private final boolean includeMergeable;
   private final boolean lazyLoad;
@@ -244,14 +237,13 @@
       Provider<ConsistencyChecker> checkerProvider,
       ActionJson actionJson,
       ChangeNotes.Factory notesFactory,
-      LabelsJson.Factory labelsJsonFactory,
+      LabelsJson labelsJson,
       RemoveReviewerControl removeReviewerControl,
       TrackingFooters trackingFooters,
       Metrics metrics,
       RevisionJson.Factory revisionJsonFactory,
       @GerritServerConfig Config cfg,
       @Assisted Iterable<ListChangesOption> options,
-      @Assisted Optional<PluginDefinedAttributesFactory> pluginDefinedAttributesFactory,
       @Assisted Optional<PluginDefinedInfosFactory> pluginDefinedInfosFactory) {
     this.userProvider = user;
     this.changeDataFactory = cdf;
@@ -261,7 +253,7 @@
     this.checkerProvider = checkerProvider;
     this.actionJson = actionJson;
     this.notesFactory = notesFactory;
-    this.labelsJson = labelsJsonFactory.create(options);
+    this.labelsJson = labelsJson;
     this.removeReviewerControl = removeReviewerControl;
     this.trackingFooters = trackingFooters;
     this.metrics = metrics;
@@ -269,7 +261,6 @@
     this.options = Sets.immutableEnumSet(options);
     this.includeMergeable = MergeabilityComputationBehavior.fromConfig(cfg).includeInApi();
     this.lazyLoad = containsAnyOf(this.options, REQUIRE_LAZY_LOAD);
-    this.pluginDefinedAttributesFactory = pluginDefinedAttributesFactory;
     this.pluginDefinedInfosFactory = pluginDefinedInfosFactory;
 
     logger.atFine().log("options = %s", options);
@@ -602,24 +593,18 @@
                 ? labelsJson.permittedLabels(user.getAccountId(), cd)
                 : ImmutableMap.of();
       }
+    }
 
+    if (has(LABELS) || has(DETAILED_LABELS)) {
       out.reviewers = reviewerMap(cd.reviewers(), cd.reviewersByEmail(), false);
       out.pendingReviewers = reviewerMap(cd.pendingReviewers(), cd.pendingReviewersByEmail(), true);
       out.removableReviewers = removableReviewers(cd, out);
     }
 
     setSubmitter(cd, out);
-    if (pluginDefinedAttributesFactory.isPresent()) {
-      out.plugins = pluginDefinedAttributesFactory.get().create(cd);
-    }
 
     if (!pluginInfos.isEmpty()) {
-      if (out.plugins == null) {
-        out.plugins = pluginInfos;
-      } else {
-        out.plugins = new ArrayList<>(out.plugins);
-        out.plugins.addAll(pluginInfos);
-      }
+      out.plugins = pluginInfos;
     }
     out.revertOf = cd.change().getRevertOf() != null ? cd.change().getRevertOf().get() : null;
     out.submissionId = cd.change().getSubmissionId();
diff --git a/java/com/google/gerrit/server/change/ChangeKeyAdapter.java b/java/com/google/gerrit/server/change/ChangeKeyAdapter.java
deleted file mode 100644
index 0db4cea..0000000
--- a/java/com/google/gerrit/server/change/ChangeKeyAdapter.java
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.change;
-
-import com.google.gerrit.entities.Change;
-import com.google.gson.JsonDeserializationContext;
-import com.google.gson.JsonDeserializer;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
-import com.google.gson.JsonParseException;
-import com.google.gson.JsonSerializationContext;
-import com.google.gson.JsonSerializer;
-import java.lang.reflect.Type;
-
-/**
- * Adapter that serializes {@link com.google.gerrit.entities.Change.Key}'s {@code key} field as
- * {@code id}, for backwards compatibility in stream-events.
- */
-// TODO(dborowitz): auto-value-gson should support this directly using @SerializedName on the
-// AutoValue method.
-public class ChangeKeyAdapter implements JsonSerializer<Change.Key>, JsonDeserializer<Change.Key> {
-  @Override
-  public JsonElement serialize(Change.Key src, Type typeOfSrc, JsonSerializationContext context) {
-    JsonObject obj = new JsonObject();
-    obj.addProperty("id", src.get());
-    return obj;
-  }
-
-  @Override
-  public Change.Key deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
-      throws JsonParseException {
-    JsonElement keyJson = json.getAsJsonObject().get("id");
-    if (keyJson == null || !keyJson.isJsonPrimitive() || !keyJson.getAsJsonPrimitive().isString()) {
-      throw new JsonParseException("Key is not a string: " + keyJson);
-    }
-    String key = keyJson.getAsJsonPrimitive().getAsString();
-    return Change.key(key);
-  }
-}
diff --git a/java/com/google/gerrit/server/change/DeleteReviewerOp.java b/java/com/google/gerrit/server/change/DeleteReviewerOp.java
index 07cb04f..bf00d27 100644
--- a/java/com/google/gerrit/server/change/DeleteReviewerOp.java
+++ b/java/com/google/gerrit/server/change/DeleteReviewerOp.java
@@ -40,6 +40,7 @@
 import com.google.gerrit.server.mail.send.DeleteReviewerSender;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
 import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.notedb.ReviewerStateInternal;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.RemoveReviewerControl;
@@ -132,9 +133,15 @@
     for (LabelType lt : labelTypes.getLabelTypes()) {
       newApprovals.put(lt.getName(), (short) 0);
     }
-
+    String ccOrReviewer =
+        approvalsUtil
+                .getReviewers(ctx.getNotes())
+                .byState(ReviewerStateInternal.CC)
+                .contains(reviewerId)
+            ? "cc"
+            : "reviewer";
     StringBuilder msg = new StringBuilder();
-    msg.append("Removed reviewer " + reviewer.account().fullName());
+    msg.append(String.format("Removed %s %s", ccOrReviewer, reviewer.account().fullName()));
     StringBuilder removedVotesMsg = new StringBuilder();
     removedVotesMsg.append(" with the following votes:\n\n");
     boolean votesRemoved = false;
diff --git a/java/com/google/gerrit/server/change/LabelsJson.java b/java/com/google/gerrit/server/change/LabelsJson.java
index b1d154c..76992e8 100644
--- a/java/com/google/gerrit/server/change/LabelsJson.java
+++ b/java/com/google/gerrit/server/change/LabelsJson.java
@@ -42,17 +42,15 @@
 import com.google.gerrit.extensions.common.ApprovalInfo;
 import com.google.gerrit.extensions.common.LabelInfo;
 import com.google.gerrit.extensions.common.VotingRangeInfo;
-import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.account.AccountLoader;
-import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.ReviewerStateInternal;
 import com.google.gerrit.server.permissions.LabelPermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
+import com.google.inject.Singleton;
 import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -68,28 +66,15 @@
 /**
  * Produces label-related entities, like {@link LabelInfo}s, which is serialized to JSON afterwards.
  */
+@Singleton
 public class LabelsJson {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  public interface Factory {
-    LabelsJson create(Iterable<ListChangesOption> options);
-  }
-
-  private final ApprovalsUtil approvalsUtil;
-  private final ChangeNotes.Factory notesFactory;
   private final PermissionBackend permissionBackend;
-  private final boolean lazyLoad;
 
   @Inject
-  LabelsJson(
-      ApprovalsUtil approvalsUtil,
-      ChangeNotes.Factory notesFactory,
-      PermissionBackend permissionBackend,
-      @Assisted Iterable<ListChangesOption> options) {
-    this.approvalsUtil = approvalsUtil;
-    this.notesFactory = notesFactory;
+  LabelsJson(PermissionBackend permissionBackend) {
     this.permissionBackend = permissionBackend;
-    this.lazyLoad = containsAnyOf(Sets.immutableEnumSet(options), ChangeJson.REQUIRE_LAZY_LOAD);
   }
 
   /**
@@ -253,14 +238,10 @@
 
   private Map<String, Short> currentLabels(Account.Id accountId, ChangeData cd) {
     Map<String, Short> result = new HashMap<>();
-    for (PatchSetApproval psa :
-        approvalsUtil.byPatchSetUser(
-            lazyLoad ? cd.notes() : notesFactory.createFromIndexedChange(cd.change()),
-            cd.change().currentPatchSetId(),
-            accountId,
-            null,
-            null)) {
-      result.put(psa.label(), psa.value());
+    for (PatchSetApproval psa : cd.currentApprovals()) {
+      if (psa.accountId().equals(accountId)) {
+        result.put(psa.label(), psa.value());
+      }
     }
     return result;
   }
diff --git a/java/com/google/gerrit/server/change/PluginDefinedAttributesFactories.java b/java/com/google/gerrit/server/change/PluginDefinedAttributesFactories.java
index b474dab..db21f11 100644
--- a/java/com/google/gerrit/server/change/PluginDefinedAttributesFactories.java
+++ b/java/com/google/gerrit/server/change/PluginDefinedAttributesFactories.java
@@ -14,55 +14,22 @@
 
 package com.google.gerrit.server.change;
 
-import static com.google.common.collect.ImmutableList.toImmutableList;
 import static java.util.concurrent.TimeUnit.MINUTES;
 
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.common.PluginDefinedInfo;
 import com.google.gerrit.extensions.registration.Extension;
 import com.google.gerrit.server.DynamicOptions.BeanProvider;
 import com.google.gerrit.server.query.change.ChangeData;
 import java.util.Collection;
-import java.util.Objects;
 import java.util.stream.Stream;
 
-/** Static helpers for use by {@link PluginDefinedAttributesFactory} implementations. */
+/** Static helpers for use by {@link PluginDefinedInfosFactory} implementations. */
 public class PluginDefinedAttributesFactories {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  @Nullable
-  public static ImmutableList<PluginDefinedInfo> createAll(
-      ChangeData cd,
-      BeanProvider beanProvider,
-      Stream<Extension<ChangeAttributeFactory>> attrFactories) {
-    ImmutableList<PluginDefinedInfo> result =
-        attrFactories
-            .map(e -> tryCreate(cd, beanProvider, e.getPluginName(), e.get()))
-            .filter(Objects::nonNull)
-            .collect(toImmutableList());
-    return !result.isEmpty() ? result : null;
-  }
-
-  @Nullable
-  private static PluginDefinedInfo tryCreate(
-      ChangeData cd, BeanProvider beanProvider, String plugin, ChangeAttributeFactory attrFactory) {
-    PluginDefinedInfo pdi = null;
-    try {
-      pdi = attrFactory.create(cd, beanProvider, plugin);
-    } catch (RuntimeException ex) {
-      logger.atWarning().atMostEvery(1, MINUTES).withCause(ex).log(
-          "error populating attribute on change %s from plugin %s", cd.getId(), plugin);
-    }
-    if (pdi != null) {
-      pdi.name = plugin;
-    }
-    return pdi;
-  }
-
   public static ImmutableListMultimap<Change.Id, PluginDefinedInfo> createAll(
       Collection<ChangeData> cds,
       BeanProvider beanProvider,
diff --git a/java/com/google/gerrit/server/change/PluginDefinedAttributesFactory.java b/java/com/google/gerrit/server/change/PluginDefinedAttributesFactory.java
deleted file mode 100644
index 08d6ce7..0000000
--- a/java/com/google/gerrit/server/change/PluginDefinedAttributesFactory.java
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.change;
-
-import com.google.gerrit.extensions.common.PluginDefinedInfo;
-import com.google.gerrit.server.query.change.ChangeData;
-import java.util.List;
-
-public interface PluginDefinedAttributesFactory {
-  List<PluginDefinedInfo> create(ChangeData cd);
-}
diff --git a/java/com/google/gerrit/server/change/ResetCherryPickOp.java b/java/com/google/gerrit/server/change/ResetCherryPickOp.java
new file mode 100644
index 0000000..d1177d4
--- /dev/null
+++ b/java/com/google/gerrit/server/change/ResetCherryPickOp.java
@@ -0,0 +1,37 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.change;
+
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.update.BatchUpdateOp;
+import com.google.gerrit.server.update.ChangeContext;
+
+/** Reset cherryPickOf to an empty value. */
+public class ResetCherryPickOp implements BatchUpdateOp {
+
+  @Override
+  public boolean updateChange(ChangeContext ctx) throws RestApiException {
+    Change change = ctx.getChange();
+    if (change.getCherryPickOf() == null) {
+      return false;
+    }
+
+    ChangeUpdate update = ctx.getUpdate(change.currentPatchSetId());
+    update.resetCherryPickOf();
+    return true;
+  }
+}
diff --git a/java/com/google/gerrit/server/change/ReviewerAdder.java b/java/com/google/gerrit/server/change/ReviewerAdder.java
index 3d986d2..5d55b4d 100644
--- a/java/com/google/gerrit/server/change/ReviewerAdder.java
+++ b/java/com/google/gerrit/server/change/ReviewerAdder.java
@@ -19,7 +19,6 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.gerrit.extensions.client.ReviewerState.CC;
-import static com.google.gerrit.extensions.client.ReviewerState.REVIEWER;
 import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Comparator.comparing;
 import static java.util.Objects.requireNonNull;
@@ -140,12 +139,12 @@
     }
 
     logger.atFine().log(
-        "Adding account %d from author/committer identity of commit %s as reviewer to change %d",
+        "Adding account %d from author/committer identity of commit %s as cc to change %d",
         accountId.get(), commitId.name(), change.getChangeId());
 
     InternalAddReviewerInput in = new InternalAddReviewerInput();
     in.reviewer = accountId.toString();
-    in.state = REVIEWER;
+    in.state = CC;
     in.notify = notify;
     in.otherFailureBehavior = FailureBehavior.IGNORE;
     return Optional.of(in);
diff --git a/java/com/google/gerrit/server/change/RevisionJson.java b/java/com/google/gerrit/server/change/RevisionJson.java
index 414107f..c1c0cfc 100644
--- a/java/com/google/gerrit/server/change/RevisionJson.java
+++ b/java/com/google/gerrit/server/change/RevisionJson.java
@@ -164,7 +164,12 @@
    * RevWalk and assumes it is backed by an open repository.
    */
   public CommitInfo getCommitInfo(
-      Project.NameKey project, RevWalk rw, RevCommit commit, boolean addLinks, boolean fillCommit)
+      Project.NameKey project,
+      RevWalk rw,
+      RevCommit commit,
+      boolean addLinks,
+      boolean fillCommit,
+      String branchName)
       throws IOException {
     CommitInfo info = new CommitInfo();
     if (fillCommit) {
@@ -177,7 +182,8 @@
     info.message = commit.getFullMessage();
 
     if (addLinks) {
-      ImmutableList<WebLinkInfo> links = webLinks.getPatchSetLinks(project, commit.name());
+      ImmutableList<WebLinkInfo> links =
+          webLinks.getPatchSetLinks(project, commit.name(), commit.getFullMessage(), branchName);
       info.webLinks = links.isEmpty() ? null : links;
     }
 
@@ -187,7 +193,8 @@
       i.commit = parent.name();
       i.subject = parent.getShortMessage();
       if (addLinks) {
-        ImmutableList<WebLinkInfo> parentLinks = webLinks.getParentLinks(project, parent.name());
+        ImmutableList<WebLinkInfo> parentLinks =
+            webLinks.getParentLinks(project, parent.name(), parent.getFullMessage(), branchName);
         i.webLinks = parentLinks.isEmpty() ? null : parentLinks;
       }
       info.parents.add(i);
@@ -288,11 +295,12 @@
       String rev = in.commitId().name();
       RevCommit commit = rw.parseCommit(ObjectId.fromString(rev));
       rw.parseBody(commit);
+      String branchName = cd.change().getDest().branch();
       if (setCommit) {
-        out.commit = getCommitInfo(project, rw, commit, has(WEB_LINKS), fillCommit);
+        out.commit = getCommitInfo(project, rw, commit, has(WEB_LINKS), fillCommit, branchName);
       }
       if (addFooters) {
-        Ref ref = repo.exactRef(cd.change().getDest().branch());
+        Ref ref = repo.exactRef(branchName);
         RevCommit mergeTip = null;
         if (ref != null) {
           mergeTip = rw.parseCommit(ref.getObjectId());
diff --git a/java/com/google/gerrit/server/restapi/change/SetTopicOp.java b/java/com/google/gerrit/server/change/SetTopicOp.java
similarity index 88%
rename from java/com/google/gerrit/server/restapi/change/SetTopicOp.java
rename to java/com/google/gerrit/server/change/SetTopicOp.java
index 9eff5c1..c4a49b0 100644
--- a/java/com/google/gerrit/server/restapi/change/SetTopicOp.java
+++ b/java/com/google/gerrit/server/change/SetTopicOp.java
@@ -12,12 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.gerrit.server.restapi.change;
+package com.google.gerrit.server.change;
 
 import com.google.common.base.Strings;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.ChangeMessage;
-import com.google.gerrit.extensions.api.changes.TopicInput;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.extensions.events.TopicEdited;
@@ -31,10 +31,10 @@
 
 public class SetTopicOp implements BatchUpdateOp {
   public interface Factory {
-    SetTopicOp create(TopicInput input);
+    SetTopicOp create(@Nullable String topic);
   }
 
-  private final TopicInput input;
+  private final String topic;
   private final TopicEdited topicEdited;
   private final ChangeMessagesUtil cmUtil;
 
@@ -44,8 +44,8 @@
 
   @Inject
   public SetTopicOp(
-      TopicEdited topicEdited, ChangeMessagesUtil cmUtil, @Assisted TopicInput input) {
-    this.input = input;
+      TopicEdited topicEdited, ChangeMessagesUtil cmUtil, @Nullable @Assisted String topic) {
+    this.topic = topic;
     this.topicEdited = topicEdited;
     this.cmUtil = cmUtil;
   }
@@ -54,7 +54,7 @@
   public boolean updateChange(ChangeContext ctx) throws BadRequestException {
     change = ctx.getChange();
     ChangeUpdate update = ctx.getUpdate(change.currentPatchSetId());
-    newTopicName = Strings.nullToEmpty(input.topic);
+    newTopicName = Strings.nullToEmpty(topic);
     oldTopicName = Strings.nullToEmpty(change.getTopic());
     if (oldTopicName.equals(newTopicName)) {
       return false;
diff --git a/java/com/google/gerrit/server/comment/CommentContextCache.java b/java/com/google/gerrit/server/comment/CommentContextCache.java
new file mode 100644
index 0000000..8c40763
--- /dev/null
+++ b/java/com/google/gerrit/server/comment/CommentContextCache.java
@@ -0,0 +1,42 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License
+
+package com.google.gerrit.server.comment;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.entities.CommentContext;
+
+/**
+ * Caches the context lines of comments (source file content surrounding and including the lines
+ * where the comment was written)
+ */
+public interface CommentContextCache {
+
+  /**
+   * Returns the context lines for a single comment.
+   *
+   * @param key a key representing a subset of fields for a comment that serves as an identifier.
+   * @return a {@link CommentContext} object containing all line numbers and text of the context.
+   */
+  CommentContext get(CommentContextKey key);
+
+  /**
+   * Returns the context lines for multiple comments - identified by their {@code keys}.
+   *
+   * @param keys list of keys, where each key represents a single comment through its project,
+   *     change ID, patchset, path and ID. The keys can belong to different projects and changes.
+   * @return {@code Map} of {@code CommentContext} containing the context for all comments.
+   */
+  ImmutableMap<CommentContextKey, CommentContext> getAll(Iterable<CommentContextKey> keys);
+}
diff --git a/java/com/google/gerrit/server/comment/CommentContextCacheImpl.java b/java/com/google/gerrit/server/comment/CommentContextCacheImpl.java
new file mode 100644
index 0000000..c4e29d8
--- /dev/null
+++ b/java/com/google/gerrit/server/comment/CommentContextCacheImpl.java
@@ -0,0 +1,256 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License
+
+package com.google.gerrit.server.comment;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.cache.Weigher;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Streams;
+import com.google.common.hash.Hashing;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.Comment;
+import com.google.gerrit.entities.CommentContext;
+import com.google.gerrit.entities.HumanComment;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.CommentContextLoader;
+import com.google.gerrit.server.CommentsUtil;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.cache.proto.Cache.AllCommentContextProto;
+import com.google.gerrit.server.cache.proto.Cache.AllCommentContextProto.CommentContextProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.name.Named;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/** Implementation of {@link CommentContextCache}. */
+public class CommentContextCacheImpl implements CommentContextCache {
+  private static final String CACHE_NAME = "comment_context";
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        persist(CACHE_NAME, CommentContextKey.class, CommentContext.class)
+            .version(1)
+            .diskLimit(1 << 30) // limit the total cache size to 1 GB
+            .maximumWeight(1 << 23) // Limit the size of the in-memory cache to 8 MB
+            .weigher(CommentContextWeigher.class)
+            .keySerializer(CommentContextKey.Serializer.INSTANCE)
+            .valueSerializer(CommentContextSerializer.INSTANCE)
+            .loader(Loader.class);
+
+        bind(CommentContextCache.class).to(CommentContextCacheImpl.class);
+      }
+    };
+  }
+
+  private final LoadingCache<CommentContextKey, CommentContext> contextCache;
+
+  @Inject
+  CommentContextCacheImpl(
+      @Named(CACHE_NAME) LoadingCache<CommentContextKey, CommentContext> contextCache) {
+    this.contextCache = contextCache;
+  }
+
+  @Override
+  public CommentContext get(CommentContextKey comment) {
+    return getAll(ImmutableList.of(comment)).get(comment);
+  }
+
+  @Override
+  public ImmutableMap<CommentContextKey, CommentContext> getAll(
+      Iterable<CommentContextKey> inputKeys) {
+    ImmutableMap.Builder<CommentContextKey, CommentContext> result = ImmutableMap.builder();
+
+    // Convert the input keys to the same keys but with their file paths hashed
+    Map<CommentContextKey, CommentContextKey> keysToCacheKeys =
+        Streams.stream(inputKeys)
+            .collect(
+                Collectors.toMap(
+                    Function.identity(),
+                    k -> k.toBuilder().path(Loader.hashPath(k.path())).build()));
+
+    try {
+      ImmutableMap<CommentContextKey, CommentContext> allContext =
+          contextCache.getAll(keysToCacheKeys.values());
+
+      for (CommentContextKey inputKey : inputKeys) {
+        CommentContextKey cacheKey = keysToCacheKeys.get(inputKey);
+        result.put(inputKey, allContext.get(cacheKey));
+      }
+      return result.build();
+    } catch (ExecutionException e) {
+      throw new StorageException("Failed to retrieve comments' context", e);
+    }
+  }
+
+  public enum CommentContextSerializer implements CacheSerializer<CommentContext> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(CommentContext commentContext) {
+      AllCommentContextProto.Builder allBuilder = AllCommentContextProto.newBuilder();
+
+      commentContext
+          .lines()
+          .entrySet()
+          .forEach(
+              c ->
+                  allBuilder.addContext(
+                      CommentContextProto.newBuilder()
+                          .setLineNumber(c.getKey())
+                          .setContextLine(c.getValue())));
+      return Protos.toByteArray(allBuilder.build());
+    }
+
+    @Override
+    public CommentContext deserialize(byte[] in) {
+      ImmutableMap.Builder<Integer, String> contextLinesMap = ImmutableMap.builder();
+      Protos.parseUnchecked(AllCommentContextProto.parser(), in).getContextList().stream()
+          .forEach(c -> contextLinesMap.put(c.getLineNumber(), c.getContextLine()));
+      return CommentContext.create(contextLinesMap.build());
+    }
+  }
+
+  static class Loader extends CacheLoader<CommentContextKey, CommentContext> {
+    private final ChangeNotes.Factory notesFactory;
+    private final CommentsUtil commentsUtil;
+    private final CommentContextLoader.Factory factory;
+
+    @Inject
+    Loader(
+        CommentsUtil commentsUtil,
+        ChangeNotes.Factory notesFactory,
+        CommentContextLoader.Factory factory) {
+      this.commentsUtil = commentsUtil;
+      this.notesFactory = notesFactory;
+      this.factory = factory;
+    }
+
+    @Override
+    public CommentContext load(CommentContextKey key) {
+      return loadAll(ImmutableList.of(key)).get(key);
+    }
+
+    @Override
+    public Map<CommentContextKey, CommentContext> loadAll(
+        Iterable<? extends CommentContextKey> keys) {
+      ImmutableMap.Builder<CommentContextKey, CommentContext> result =
+          ImmutableMap.builderWithExpectedSize(Iterables.size(keys));
+
+      Map<Project.NameKey, Map<Change.Id, List<CommentContextKey>>> groupedKeys =
+          Streams.stream(keys)
+              .distinct()
+              .map(k -> (CommentContextKey) k)
+              .collect(
+                  Collectors.groupingBy(
+                      CommentContextKey::project,
+                      Collectors.groupingBy(CommentContextKey::changeId)));
+
+      for (Map.Entry<Project.NameKey, Map<Change.Id, List<CommentContextKey>>> perProject :
+          groupedKeys.entrySet()) {
+        Map<Change.Id, List<CommentContextKey>> keysPerProject = perProject.getValue();
+
+        for (Map.Entry<Change.Id, List<CommentContextKey>> perChange : keysPerProject.entrySet()) {
+          Map<CommentContextKey, CommentContext> context =
+              loadForSameChange(perChange.getValue(), perProject.getKey(), perChange.getKey());
+          result.putAll(context);
+        }
+      }
+      return result.build();
+    }
+
+    /**
+     * Load the comment context for comments of the same project and change ID.
+     *
+     * @param keys a list of keys corresponding to some comments
+     * @param project a gerrit project/repository
+     * @param changeId an identifier for a change
+     * @return a map of the input keys to their corresponding {@link CommentContext}
+     */
+    private Map<CommentContextKey, CommentContext> loadForSameChange(
+        List<CommentContextKey> keys, Project.NameKey project, Change.Id changeId) {
+      ChangeNotes notes = notesFactory.createChecked(project, changeId);
+      List<HumanComment> humanComments = commentsUtil.publishedHumanCommentsByChange(notes);
+      CommentContextLoader loader = factory.create(project);
+      Map<Comment, CommentContextKey> commentsToKeys = new HashMap<>();
+      for (CommentContextKey key : keys) {
+        commentsToKeys.put(getCommentForKey(humanComments, key), key);
+      }
+      Map<Comment, CommentContext> allContext = loader.getContext(commentsToKeys.keySet());
+      return allContext.entrySet().stream()
+          .collect(Collectors.toMap(e -> commentsToKeys.get(e.getKey()), Map.Entry::getValue));
+    }
+
+    /**
+     * Return the single comment from the {@code allComments} input list corresponding to the key
+     * parameter.
+     *
+     * @param allComments a list of comments.
+     * @param key a key representing a single comment.
+     * @return the single comment corresponding to the key parameter.
+     */
+    private Comment getCommentForKey(List<HumanComment> allComments, CommentContextKey key) {
+      return allComments.stream()
+          .filter(
+              c ->
+                  key.id().equals(c.key.uuid)
+                      && key.patchset() == c.key.patchSetId
+                      && key.path().equals(hashPath(c.key.filename)))
+          .findFirst()
+          .orElseThrow(() -> new IllegalArgumentException("Unable to find comment for key " + key));
+    }
+
+    /**
+     * Hash an input String using the general {@link Hashing#murmur3_128()} hash.
+     *
+     * @param input the input String
+     * @return a hashed representation of the input String
+     */
+    static String hashPath(String input) {
+      return Hashing.murmur3_128().hashString(input, UTF_8).toString();
+    }
+  }
+
+  private static class CommentContextWeigher implements Weigher<CommentContextKey, CommentContext> {
+    @Override
+    public int weigh(CommentContextKey key, CommentContext commentContext) {
+      int size = 0;
+      size += key.id().length();
+      size += key.path().length();
+      size += key.project().get().length();
+      size += 4;
+      for (String line : commentContext.lines().values()) {
+        size += 4; // line number
+        size += line.length(); // number of characters in the context line
+      }
+      return size;
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/comment/CommentContextKey.java b/java/com/google/gerrit/server/comment/CommentContextKey.java
new file mode 100644
index 0000000..ccd50b7
--- /dev/null
+++ b/java/com/google/gerrit/server/comment/CommentContextKey.java
@@ -0,0 +1,81 @@
+package com.google.gerrit.server.comment;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+
+/**
+ * An identifier of a comment that should be used to load the comment context using {@link
+ * CommentContextCache#get(CommentContextKey)}, or {@link CommentContextCache#getAll(Iterable)}.
+ *
+ * <p>The {@link CommentContextCacheImpl} implementation uses this class as the cache key, while
+ * replacing the {@link #path()} field with the hashed path.
+ */
+@AutoValue
+public abstract class CommentContextKey {
+  abstract Project.NameKey project();
+
+  abstract Change.Id changeId();
+
+  /** The unique comment ID. */
+  abstract String id();
+
+  /** File path at which the comment was written. */
+  abstract String path();
+
+  abstract Integer patchset();
+
+  abstract Builder toBuilder();
+
+  public static Builder builder() {
+    return new AutoValue_CommentContextKey.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder project(Project.NameKey nameKey);
+
+    public abstract Builder changeId(Change.Id changeId);
+
+    public abstract Builder id(String id);
+
+    public abstract Builder path(String path);
+
+    public abstract Builder patchset(Integer patchset);
+
+    public abstract CommentContextKey build();
+  }
+
+  public enum Serializer implements CacheSerializer<CommentContextKey> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(CommentContextKey key) {
+      return Protos.toByteArray(
+          Cache.CommentContextKeyProto.newBuilder()
+              .setProject(key.project().get())
+              .setChangeId(key.changeId().toString())
+              .setPatchset(key.patchset())
+              .setPathHash(key.path())
+              .setCommentId(key.id())
+              .build());
+    }
+
+    @Override
+    public CommentContextKey deserialize(byte[] in) {
+      Cache.CommentContextKeyProto proto =
+          Protos.parseUnchecked(Cache.CommentContextKeyProto.parser(), in);
+      return CommentContextKey.builder()
+          .project(Project.NameKey.parse(proto.getProject()))
+          .changeId(Change.Id.tryParse(proto.getChangeId()).get())
+          .patchset(proto.getPatchset())
+          .id(proto.getCommentId())
+          .path(proto.getPathHash())
+          .build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/config/ConfigUtil.java b/java/com/google/gerrit/server/config/ConfigUtil.java
index 43c05e0..27ded63 100644
--- a/java/com/google/gerrit/server/config/ConfigUtil.java
+++ b/java/com/google/gerrit/server/config/ConfigUtil.java
@@ -16,6 +16,7 @@
 
 import static java.util.Objects.requireNonNull;
 
+import com.google.common.flogger.FluentLogger;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Modifier;
@@ -30,6 +31,8 @@
 import org.eclipse.jgit.lib.Config;
 
 public class ConfigUtil {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   @SuppressWarnings("unchecked")
   private static <T> T[] allValuesOf(T defaultValue) {
     try {
@@ -138,7 +141,12 @@
     } else {
       for (String string : values) {
         if (string != null) {
-          list.add(getEnum(section, subsection, setting, string, all));
+          try {
+            list.add(getEnum(section, subsection, setting, string, all));
+          } catch (IllegalArgumentException ex) {
+            // It's better to ignore a wrongly configured enum, rather than fail to load Gerrit.
+            logger.atWarning().log(ex.getMessage());
+          }
         }
       }
     }
diff --git a/java/com/google/gerrit/server/config/GerritGlobalModule.java b/java/com/google/gerrit/server/config/GerritGlobalModule.java
index 78dd38c..9308662 100644
--- a/java/com/google/gerrit/server/config/GerritGlobalModule.java
+++ b/java/com/google/gerrit/server/config/GerritGlobalModule.java
@@ -81,6 +81,7 @@
 import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.ExceptionHook;
 import com.google.gerrit.server.ExceptionHookImpl;
+import com.google.gerrit.server.ExternalUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.RequestListener;
 import com.google.gerrit.server.TraceRequestListener;
@@ -105,16 +106,15 @@
 import com.google.gerrit.server.cache.CacheRemovalListener;
 import com.google.gerrit.server.change.AbandonOp;
 import com.google.gerrit.server.change.AccountPatchReviewStore;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangeETagComputation;
 import com.google.gerrit.server.change.ChangeFinder;
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangeKindCacheImpl;
 import com.google.gerrit.server.change.ChangePluginDefinedInfoFactory;
-import com.google.gerrit.server.change.LabelsJson;
 import com.google.gerrit.server.change.MergeabilityCacheImpl;
 import com.google.gerrit.server.change.ReviewerSuggestion;
 import com.google.gerrit.server.change.RevisionJson;
+import com.google.gerrit.server.comment.CommentContextCacheImpl;
 import com.google.gerrit.server.events.EventFactory;
 import com.google.gerrit.server.events.EventListener;
 import com.google.gerrit.server.events.EventsMetrics;
@@ -180,6 +180,7 @@
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
 import com.google.gerrit.server.query.change.ConflictsCacheImpl;
 import com.google.gerrit.server.quota.QuotaEnforcer;
+import com.google.gerrit.server.restapi.change.OnPostReview;
 import com.google.gerrit.server.restapi.change.SuggestReviewers;
 import com.google.gerrit.server.restapi.group.GroupModule;
 import com.google.gerrit.server.rules.DefaultSubmitRule;
@@ -251,6 +252,7 @@
     install(TagCache.module());
     install(OAuthTokenCache.module());
     install(PureRevertCache.module());
+    install(CommentContextCacheImpl.module());
 
     install(new AccessControlModule());
     install(new CmdLineParserModule());
@@ -271,13 +273,13 @@
     factory(ChangeData.AssistedFactory.class);
     factory(ChangeJson.AssistedFactory.class);
     factory(ChangeIsVisibleToPredicate.Factory.class);
-    factory(LabelsJson.Factory.class);
     factory(MergeUtil.Factory.class);
     factory(PatchScriptFactory.Factory.class);
     factory(PatchScriptFactoryForAutoFix.Factory.class);
     factory(ProjectState.Factory.class);
     factory(RevisionJson.Factory.class);
     factory(InboundEmailRejectionSender.Factory.class);
+    factory(ExternalUser.Factory.class);
     bind(PermissionCollection.Factory.class);
     bind(AccountVisibility.class).toProvider(AccountVisibilityProvider.class).in(SINGLETON);
     AccountDefaultDisplayName accountDefaultDisplayName =
@@ -413,6 +415,7 @@
     DynamicSet.setOf(binder(), ExceptionHook.class);
     DynamicSet.bind(binder(), ExceptionHook.class).to(ExceptionHookImpl.class);
     DynamicSet.setOf(binder(), MailSoyTemplateProvider.class);
+    DynamicSet.setOf(binder(), OnPostReview.class);
 
     DynamicMap.mapOf(binder(), MailFilter.class);
     bind(MailFilter.class).annotatedWith(Exports.named("ListMailFilter")).to(ListMailFilter.class);
@@ -437,7 +440,6 @@
     DynamicMap.mapOf(binder(), ChangeQueryBuilder.ChangeOperatorFactory.class);
     DynamicMap.mapOf(binder(), ChangeQueryBuilder.ChangeHasOperandFactory.class);
     DynamicMap.mapOf(binder(), ChangeQueryBuilder.ChangeIsOperandFactory.class);
-    DynamicSet.setOf(binder(), ChangeAttributeFactory.class);
     DynamicSet.setOf(binder(), ChangePluginDefinedInfoFactory.class);
 
     install(new GitwebConfig.LegacyModule(cfg));
diff --git a/java/com/google/gerrit/server/config/GitwebConfig.java b/java/com/google/gerrit/server/config/GitwebConfig.java
index b5f09fd..8214f03 100644
--- a/java/com/google/gerrit/server/config/GitwebConfig.java
+++ b/java/com/google/gerrit/server/config/GitwebConfig.java
@@ -327,8 +327,10 @@
     }
 
     @Override
-    public WebLinkInfo getPatchSetWebLink(String projectName, String commit) {
+    public WebLinkInfo getPatchSetWebLink(
+        String projectName, String commit, String commitMessage, String branchName) {
       if (revision != null) {
+        // commitMessage and branchName are not needed, hence not used.
         return link(
             revision
                 .replace("project", encode(projectName))
@@ -339,9 +341,10 @@
     }
 
     @Override
-    public WebLinkInfo getParentWebLink(String projectName, String commit) {
+    public WebLinkInfo getParentWebLink(
+        String projectName, String commit, String commitMessage, String branchName) {
       // For Gitweb treat parent revision links the same as patch set links
-      return getPatchSetWebLink(projectName, commit);
+      return getPatchSetWebLink(projectName, commit, commitMessage, branchName);
     }
 
     @Override
diff --git a/java/com/google/gerrit/server/events/EventGsonProvider.java b/java/com/google/gerrit/server/events/EventGsonProvider.java
index 688507b..72cf7be3 100644
--- a/java/com/google/gerrit/server/events/EventGsonProvider.java
+++ b/java/com/google/gerrit/server/events/EventGsonProvider.java
@@ -15,9 +15,8 @@
 package com.google.gerrit.server.events;
 
 import com.google.common.base.Supplier;
-import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.EntitiesAdapterFactory;
 import com.google.gerrit.entities.Project;
-import com.google.gerrit.server.change.ChangeKeyAdapter;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.inject.Provider;
@@ -29,8 +28,8 @@
         .registerTypeAdapter(Event.class, new EventDeserializer())
         .registerTypeAdapter(Supplier.class, new SupplierSerializer())
         .registerTypeAdapter(Supplier.class, new SupplierDeserializer())
-        .registerTypeAdapter(Change.Key.class, new ChangeKeyAdapter())
         .registerTypeAdapter(Project.NameKey.class, new ProjectNameKeyAdapter())
+        .registerTypeAdapterFactory(EntitiesAdapterFactory.create())
         .create();
   }
 }
diff --git a/java/com/google/gerrit/server/git/GroupCollector.java b/java/com/google/gerrit/server/git/GroupCollector.java
index 9e0f2ee..5bbe5e2 100644
--- a/java/com/google/gerrit/server/git/GroupCollector.java
+++ b/java/com/google/gerrit/server/git/GroupCollector.java
@@ -29,7 +29,6 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Project;
-import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.change.RevisionResource;
 import com.google.gerrit.server.git.receive.ReceivePackRefCache;
@@ -43,7 +42,6 @@
 import java.util.Set;
 import java.util.TreeSet;
 import org.eclipse.jgit.lib.ObjectId;
-import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.revwalk.RevCommit;
 
 /**
@@ -231,7 +229,7 @@
 
   private boolean isGroupFromExistingPatchSet(RevCommit commit, String group) throws IOException {
     ObjectId id = parseGroup(commit, group);
-    return id != null && !receivePackRefCache.tipsFromObjectId(id, RefNames.REFS_CHANGES).isEmpty();
+    return id != null && !receivePackRefCache.patchSetIdsFromObjectId(id).isEmpty();
   }
 
   private Set<String> resolveGroups(ObjectId forCommit, Collection<String> candidates)
@@ -273,17 +271,13 @@
   private Iterable<String> resolveGroup(ObjectId forCommit, String group) throws IOException {
     ObjectId id = parseGroup(forCommit, group);
     if (id != null) {
-      Ref ref =
-          Iterables.getFirst(receivePackRefCache.tipsFromObjectId(id, RefNames.REFS_CHANGES), null);
-      if (ref != null) {
-        PatchSet.Id psId = PatchSet.Id.fromRef(ref.getName());
-        if (psId != null) {
-          List<String> groups = groupLookup.lookup(psId);
-          // Group for existing patch set may be missing, e.g. if group has not
-          // been migrated yet.
-          if (groups != null && !groups.isEmpty()) {
-            return groups;
-          }
+      PatchSet.Id psId = Iterables.getFirst(receivePackRefCache.patchSetIdsFromObjectId(id), null);
+      if (psId != null) {
+        List<String> groups = groupLookup.lookup(psId);
+        // Group for existing patch set may be missing, e.g. if group has not
+        // been migrated yet.
+        if (groups != null && !groups.isEmpty()) {
+          return groups;
         }
       }
     }
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index 8d92347..4c90ef9 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -21,6 +21,7 @@
 import static com.google.common.flogger.LazyArgs.lazy;
 import static com.google.gerrit.entities.RefNames.REFS_CHANGES;
 import static com.google.gerrit.entities.RefNames.isConfigRef;
+import static com.google.gerrit.entities.RefNames.isRefsUsersSelf;
 import static com.google.gerrit.git.ObjectIds.abbreviateName;
 import static com.google.gerrit.server.change.HashtagsUtil.cleanupHashtag;
 import static com.google.gerrit.server.git.MultiProgressMonitor.UNKNOWN;
@@ -112,6 +113,7 @@
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.change.SetHashtagsOp;
 import com.google.gerrit.server.change.SetPrivateOp;
+import com.google.gerrit.server.change.SetTopicOp;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.PluginConfig;
@@ -179,7 +181,6 @@
 import com.google.gerrit.server.util.MagicBranch;
 import com.google.gerrit.server.util.RequestScopePropagator;
 import com.google.gerrit.server.util.time.TimeUtil;
-import com.google.gerrit.server.validators.ValidationException;
 import com.google.gerrit.util.cli.CmdLineParser;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -344,7 +345,8 @@
   private final RequestScopePropagator requestScopePropagator;
   private final Sequences seq;
   private final SetHashtagsOp.Factory hashtagsFactory;
-  private final SubmissionListener superprojectUpdateSubmissionListener;
+  private final SetTopicOp.Factory setTopicFactory;
+  private final ImmutableList<SubmissionListener> superprojectUpdateSubmissionListeners;
   private final TagCache tagCache;
   private final ProjectConfig.Factory projectConfigFactory;
   private final SetPrivateOp.Factory setPrivateOpFactory;
@@ -426,7 +428,9 @@
       RequestScopePropagator requestScopePropagator,
       Sequences seq,
       SetHashtagsOp.Factory hashtagsFactory,
-      @SuperprojectUpdateOnSubmission SubmissionListener superprojectUpdateSubmissionListener,
+      SetTopicOp.Factory setTopicFactory,
+      @SuperprojectUpdateOnSubmission
+          ImmutableList<SubmissionListener> superprojectUpdateSubmissionListeners,
       TagCache tagCache,
       SetPrivateOp.Factory setPrivateOpFactory,
       ReplyAttentionSetUpdates replyAttentionSetUpdates,
@@ -452,6 +456,7 @@
     this.createGroupPermissionSyncer = createGroupPermissionSyncer;
     this.editUtil = editUtil;
     this.hashtagsFactory = hashtagsFactory;
+    this.setTopicFactory = setTopicFactory;
     this.indexer = indexer;
     this.initializers = initializers;
     this.mergeOpProvider = mergeOpProvider;
@@ -474,7 +479,7 @@
     this.retryHelper = retryHelper;
     this.requestScopePropagator = requestScopePropagator;
     this.seq = seq;
-    this.superprojectUpdateSubmissionListener = superprojectUpdateSubmissionListener;
+    this.superprojectUpdateSubmissionListeners = superprojectUpdateSubmissionListeners;
     this.tagCache = tagCache;
     this.projectConfigFactory = projectConfigFactory;
     this.setPrivateOpFactory = setPrivateOpFactory;
@@ -624,7 +629,7 @@
   private void processCommandsUnsafe(
       Collection<ReceiveCommand> commands, MultiProgressMonitor progress) {
     logger.atFine().log("Calling user: %s", user.getLoggableName());
-    logger.atFine().log("Groups: %s", user.getEffectiveGroups().getKnownGroups());
+    logger.atFine().log("Groups: %s", lazy(() -> user.getEffectiveGroups().getKnownGroups()));
 
     if (!projectState.getProject().getState().permitsWrite()) {
       for (ReceiveCommand cmd : commands) {
@@ -742,7 +747,7 @@
         logger.atFine().log("Added %d additional ref updates", added);
 
         SubmissionExecutor submissionExecutor =
-            new SubmissionExecutor(false, superprojectUpdateSubmissionListener);
+            new SubmissionExecutor(false, superprojectUpdateSubmissionListeners);
 
         submissionExecutor.execute(ImmutableList.of(bu));
 
@@ -1076,7 +1081,7 @@
   private ReceiveCommand wrapReceiveCommand(ReceiveCommand cmd, Task progress) {
     String refname = cmd.getRefName();
 
-    if (projectState.isAllUsers() && RefNames.REFS_USERS_SELF.equals(cmd.getRefName())) {
+    if (isRefsUsersSelf(cmd.getRefName(), projectState.isAllUsers())) {
       refname = RefNames.refsUsers(user.getAccountId());
       logger.atFine().log("Swapping out command for %s to %s", RefNames.REFS_USERS_SELF, refname);
     }
@@ -2145,15 +2150,15 @@
           receivePack.getRevWalk().parseBody(c);
           String name = c.name();
           groupCollector.visit(c);
-          Collection<Ref> existingRefs =
-              receivePackRefCache.tipsFromObjectId(c, RefNames.REFS_CHANGES);
+          Collection<PatchSet.Id> existingPatchSets =
+              receivePackRefCache.patchSetIdsFromObjectId(c);
 
           if (rejectImplicitMerges) {
             Collections.addAll(mergedParents, c.getParents());
             mergedParents.remove(c);
           }
 
-          boolean commitAlreadyTracked = !existingRefs.isEmpty();
+          boolean commitAlreadyTracked = !existingPatchSets.isEmpty();
           if (commitAlreadyTracked) {
             alreadyTracked++;
             // Corner cases where an existing commit might need a new group:
@@ -2169,9 +2174,7 @@
             //      A's group.
             // C) Commit is a PatchSet of a pre-existing change uploaded with a
             //    different target branch.
-            existingRefs.stream()
-                .map(r -> PatchSet.Id.fromRef(r.getName()))
-                .filter(Objects::nonNull)
+            existingPatchSets.stream()
                 .forEach(i -> updateGroups.add(new UpdateGroupsRequest(i, c)));
             if (!(newChangeForAllNotInTarget || magicBranch.base != null)) {
               continue;
@@ -2312,8 +2315,7 @@
 
             // In case the change look up from the index failed,
             // double check against the existing refs
-            if (foundInExistingRef(
-                receivePackRefCache.tipsFromObjectId(p.commit, RefNames.REFS_CHANGES))) {
+            if (foundInExistingPatchSets(receivePackRefCache.patchSetIdsFromObjectId(p.commit))) {
               if (pending.size() == 1) {
                 reject(magicBranch.cmd, "commit(s) already exists (as current patchset)");
                 return Collections.emptyList();
@@ -2361,11 +2363,10 @@
     }
   }
 
-  private boolean foundInExistingRef(Collection<Ref> existingRefs) {
-    try (TraceTimer traceTimer = newTimer("foundInExistingRef")) {
-      for (Ref ref : existingRefs) {
-        ChangeNotes notes =
-            notesFactory.create(project.getNameKey(), Change.Id.fromRef(ref.getName()));
+  private boolean foundInExistingPatchSets(Collection<PatchSet.Id> existingPatchSets) {
+    try (TraceTimer traceTimer = newTimer("foundInExistingPatchSet")) {
+      for (PatchSet.Id psId : existingPatchSets) {
+        ChangeNotes notes = notesFactory.create(project.getNameKey(), psId.changeId());
         Change change = notes.getChange();
         if (change.getDest().equals(magicBranch.dest)) {
           logger.atFine().log("Found change %s from existing refs.", change.getKey());
@@ -2598,7 +2599,7 @@
                     .setFireEvent(false));
           }
           if (!Strings.isNullOrEmpty(magicBranch.topic)) {
-            bu.addOp(changeId, new SetTopicOp(magicBranch.topic));
+            bu.addOp(changeId, setTopicFactory.create(magicBranch.topic));
           }
           bu.addOp(
               changeId,
@@ -2837,15 +2838,15 @@
           return false;
         }
 
-        List<Ref> existingChangesWithSameCommit =
-            receivePackRefCache.tipsFromObjectId(newCommit, RefNames.REFS_CHANGES);
-        if (!existingChangesWithSameCommit.isEmpty()) {
+        List<PatchSet.Id> existingPatchSetsWithSameCommit =
+            receivePackRefCache.patchSetIdsFromObjectId(newCommit);
+        if (!existingPatchSetsWithSameCommit.isEmpty()) {
           // TODO(hiesel, hanwen): Remove this check entirely when Gerrit requires change IDs
           //  without the option to turn that off.
           reject(
               inputCommand,
               "commit already exists (in the project): "
-                  + existingChangesWithSameCommit.get(0).getName());
+                  + existingPatchSetsWithSameCommit.get(0).toRefName());
           return false;
         }
 
@@ -3224,7 +3225,7 @@
                     "more than %d commits, and %s not set", limit, PUSH_OPTION_SKIP_VALIDATION));
             return;
           }
-          if (!receivePackRefCache.tipsFromObjectId(c, RefNames.REFS_CHANGES).isEmpty()) {
+          if (!receivePackRefCache.patchSetIdsFromObjectId(c).isEmpty()) {
             continue;
           }
 
@@ -3293,12 +3294,8 @@
 
                       // Check if change refs point to this commit. Usually there are 0-1 change
                       // refs pointing to this commit.
-                      for (Ref ref :
-                          receivePackRefCache.tipsFromObjectId(c.copy(), RefNames.REFS_CHANGES)) {
-                        if (!PatchSet.isChangeRef(ref.getName())) {
-                          continue;
-                        }
-                        PatchSet.Id psId = PatchSet.Id.fromRef(ref.getName());
+                      for (PatchSet.Id psId :
+                          receivePackRefCache.patchSetIdsFromObjectId(c.copy())) {
                         Optional<ChangeNotes> notes = getChangeNotes(psId.changeId());
                         if (notes.isPresent() && notes.get().getChange().getDest().equals(branch)) {
                           if (submissionId == null) {
@@ -3474,19 +3471,4 @@
     b.append(")\n");
     return b.toString();
   }
-
-  private static class SetTopicOp implements BatchUpdateOp {
-
-    private final String topic;
-
-    public SetTopicOp(String topic) {
-      this.topic = topic;
-    }
-
-    @Override
-    public boolean updateChange(ChangeContext ctx) throws ValidationException {
-      ctx.getUpdate(ctx.getChange().currentPatchSetId()).setTopic(topic);
-      return true;
-    }
-  }
 }
diff --git a/java/com/google/gerrit/server/git/receive/ReceivePackRefCache.java b/java/com/google/gerrit/server/git/receive/ReceivePackRefCache.java
index 376ab2d..8568810 100644
--- a/java/com/google/gerrit/server/git/receive/ReceivePackRefCache.java
+++ b/java/com/google/gerrit/server/git/receive/ReceivePackRefCache.java
@@ -21,9 +21,11 @@
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.MultimapBuilder;
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.RefNames;
 import java.io.IOException;
 import java.util.Map;
+import java.util.Objects;
 import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
@@ -58,8 +60,8 @@
     return new WithAdvertisedRefs(allRefsSupplier);
   }
 
-  /** Returns a list of refs whose name starts with {@code prefix} that point to {@code id}. */
-  ImmutableList<Ref> tipsFromObjectId(ObjectId id, @Nullable String prefix) throws IOException;
+  /** Returns a list of {@link com.google.gerrit.entities.PatchSet.Id}s that point to {@code id}. */
+  ImmutableList<PatchSet.Id> patchSetIdsFromObjectId(ObjectId id) throws IOException;
 
   /** Returns all refs whose name starts with {@code prefix}. */
   ImmutableList<Ref> byPrefix(String prefix) throws IOException;
@@ -76,10 +78,10 @@
     }
 
     @Override
-    public ImmutableList<Ref> tipsFromObjectId(ObjectId id, @Nullable String prefix)
-        throws IOException {
+    public ImmutableList<PatchSet.Id> patchSetIdsFromObjectId(ObjectId id) throws IOException {
       return delegate.getTipsWithSha1(id).stream()
-          .filter(r -> prefix == null || r.getName().startsWith(prefix))
+          .map(r -> PatchSet.Id.fromRef(r.getName()))
+          .filter(Objects::nonNull)
           .collect(toImmutableList());
     }
 
@@ -113,10 +115,11 @@
     }
 
     @Override
-    public ImmutableList<Ref> tipsFromObjectId(ObjectId id, String prefix) {
+    public ImmutableList<PatchSet.Id> patchSetIdsFromObjectId(ObjectId id) {
       lazilyInitRefMaps();
       return refsByObjectId.get(id).stream()
-          .filter(r -> prefix == null || r.getName().startsWith(prefix))
+          .map(r -> PatchSet.Id.fromRef(r.getName()))
+          .filter(Objects::nonNull)
           .collect(toImmutableList());
     }
 
diff --git a/java/com/google/gerrit/server/group/SystemGroupBackend.java b/java/com/google/gerrit/server/group/SystemGroupBackend.java
index b5ccb18..5d50d22 100644
--- a/java/com/google/gerrit/server/group/SystemGroupBackend.java
+++ b/java/com/google/gerrit/server/group/SystemGroupBackend.java
@@ -24,6 +24,8 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.ExternalUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.StartupCheck;
 import com.google.gerrit.server.StartupException;
@@ -90,6 +92,7 @@
   private final SortedMap<String, GroupReference> namesToGroups;
   private final ImmutableSet<String> names;
   private final ImmutableMap<AccountGroup.UUID, GroupReference> uuids;
+  private final ImmutableSet<AccountGroup.UUID> externalUserMemberships;
 
   @Inject
   @VisibleForTesting
@@ -114,6 +117,10 @@
         ImmutableSet.copyOf(
             namesToGroups.values().stream().map(GroupReference::getName).collect(toSet()));
     uuids = u.build();
+    externalUserMemberships =
+        cfg.getBoolean("groups", null, "includeExternalUsersInRegisteredUsersGroup", true)
+            ? ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS)
+            : ImmutableSet.of(ANONYMOUS_USERS);
   }
 
   public GroupReference getGroup(AccountGroup.UUID uuid) {
@@ -182,8 +189,14 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
-    return new ListGroupMembership(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS));
+  public GroupMembership membershipsOf(CurrentUser user) {
+    if (user instanceof ExternalUser) {
+      return new ListGroupMembership(externalUserMemberships);
+    }
+    if (user instanceof IdentifiedUser) {
+      return new ListGroupMembership(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS));
+    }
+    return new ListGroupMembership(ImmutableSet.of(ANONYMOUS_USERS));
   }
 
   public static class NameCheck implements StartupCheck {
diff --git a/java/com/google/gerrit/server/group/testing/TestGroupBackend.java b/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
index 35f18a2..601ac59 100644
--- a/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
+++ b/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
@@ -22,7 +22,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupDescription;
 import com.google.gerrit.entities.GroupReference;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.project.ProjectState;
@@ -122,7 +122,10 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
+  public GroupMembership membershipsOf(CurrentUser user) {
+    if (!user.isIdentifiedUser()) {
+      return GroupMembership.EMPTY;
+    }
     return memberships.getOrDefault(user.getAccountId(), GroupMembership.EMPTY);
   }
 
diff --git a/java/com/google/gerrit/server/index/IndexUtils.java b/java/com/google/gerrit/server/index/IndexUtils.java
index 9e3d91c..ee8dfc8 100644
--- a/java/com/google/gerrit/server/index/IndexUtils.java
+++ b/java/com/google/gerrit/server/index/IndexUtils.java
@@ -30,7 +30,7 @@
 import com.google.gerrit.server.index.account.AccountField;
 import com.google.gerrit.server.index.group.GroupField;
 import com.google.gerrit.server.query.change.ChangeData;
-import com.google.gerrit.server.query.change.SingleGroupUser;
+import com.google.gerrit.server.query.change.GroupBackedUser;
 import java.io.IOException;
 import java.util.Set;
 import org.eclipse.jgit.errors.ConfigInvalidException;
@@ -107,7 +107,7 @@
     if (user.isIdentifiedUser()) {
       return user.getAccountId().toString();
     }
-    if (user instanceof SingleGroupUser) {
+    if (user instanceof GroupBackedUser) {
       return "group:" + user.getEffectiveGroups().getKnownGroups().iterator().next().toString();
     }
     return user.toString();
diff --git a/java/com/google/gerrit/server/index/change/ChangeField.java b/java/com/google/gerrit/server/index/change/ChangeField.java
index ef538cb..5f2525e 100644
--- a/java/com/google/gerrit/server/index/change/ChangeField.java
+++ b/java/com/google/gerrit/server/index/change/ChangeField.java
@@ -152,6 +152,12 @@
   public static final FieldDef<ChangeData, Timestamp> UPDATED =
       timestamp("updated2").stored().build(changeGetter(Change::getLastUpdatedOn));
 
+  /** When this change was merged, time since January 1, 1970. */
+  public static final FieldDef<ChangeData, Timestamp> MERGED_ON =
+      timestamp(ChangeQueryBuilder.FIELD_MERGED_ON)
+          .stored()
+          .build(cd -> cd.getMergedOn().orElse(null));
+
   /** List of full file paths modified in the current patch set. */
   public static final FieldDef<ChangeData, Iterable<String>> PATH =
       // Named for backwards compatibility.
diff --git a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
index 928f21c..969b071 100644
--- a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
@@ -130,9 +130,14 @@
           .build();
 
   /** Added new fields {@link ChangeField#MERGE} */
+  @Deprecated
   static final Schema<ChangeData> V60 =
       new Schema.Builder<ChangeData>().add(V59).add(ChangeField.MERGE).build();
 
+  /** Added new field {@link ChangeField#MERGED_ON} */
+  static final Schema<ChangeData> V61 =
+      new Schema.Builder<ChangeData>().add(V60).add(ChangeField.MERGED_ON).build();
+
   /**
    * Name of the change index to be used when contacting index backends or loading configurations.
    */
diff --git a/java/com/google/gerrit/server/logging/LoggingContext.java b/java/com/google/gerrit/server/logging/LoggingContext.java
index 671c224..a1b807d 100644
--- a/java/com/google/gerrit/server/logging/LoggingContext.java
+++ b/java/com/google/gerrit/server/logging/LoggingContext.java
@@ -42,11 +42,12 @@
   private static final ThreadLocal<MutableTags> tags = new ThreadLocal<>();
   private static final ThreadLocal<Boolean> forceLogging = new ThreadLocal<>();
   private static final ThreadLocal<Boolean> performanceLogging = new ThreadLocal<>();
+  private static final ThreadLocal<Boolean> aclLogging = new ThreadLocal<>();
 
   /**
-   * When copying the logging context to a new thread we need to ensure that the performance log
-   * records that are added in the new thread are added to the same {@link
-   * MutablePerformanceLogRecords} instance (see {@link LoggingContextAwareRunnable} and {@link
+   * When copying the logging context to a new thread we need to ensure that the mutable log records
+   * (performance logs and ACL logs) that are added in the new thread are added to the same multable
+   * log records instance (see {@link LoggingContextAwareRunnable} and {@link
    * LoggingContextAwareCallable}). This is important since performance log records are processed
    * only at the end of the request and performance log records that are created in another thread
    * should not get lost.
@@ -54,6 +55,8 @@
   private static final ThreadLocal<MutablePerformanceLogRecords> performanceLogRecords =
       new ThreadLocal<>();
 
+  private static final ThreadLocal<MutableAclLogRecords> aclLogRecords = new ThreadLocal<>();
+
   private LoggingContext() {}
 
   /** This method is expected to be called via reflection (and might otherwise be unused). */
@@ -67,7 +70,9 @@
     }
 
     return new LoggingContextAwareRunnable(
-        runnable, getInstance().getMutablePerformanceLogRecords());
+        runnable,
+        getInstance().getMutablePerformanceLogRecords(),
+        getInstance().getMutableAclRecords());
   }
 
   public static <T> Callable<T> copy(Callable<T> callable) {
@@ -76,14 +81,18 @@
     }
 
     return new LoggingContextAwareCallable<>(
-        callable, getInstance().getMutablePerformanceLogRecords());
+        callable,
+        getInstance().getMutablePerformanceLogRecords(),
+        getInstance().getMutableAclRecords());
   }
 
   public boolean isEmpty() {
     return tags.get() == null
         && forceLogging.get() == null
         && performanceLogging.get() == null
-        && performanceLogRecords.get() == null;
+        && performanceLogRecords.get() == null
+        && aclLogging.get() == null
+        && aclLogRecords.get() == null;
   }
 
   public void clear() {
@@ -91,6 +100,8 @@
     forceLogging.remove();
     performanceLogging.remove();
     performanceLogRecords.remove();
+    aclLogging.remove();
+    aclLogRecords.remove();
   }
 
   @Override
@@ -250,6 +261,101 @@
     return records;
   }
 
+  public boolean isAclLogging() {
+    Boolean isAclLogging = aclLogging.get();
+    return isAclLogging != null ? isAclLogging : false;
+  }
+
+  /**
+   * Enables ACL logging.
+   *
+   * <p>It's important to enable ACL logging only in a context that ensures to consume the captured
+   * ACL log records. Otherwise captured ACL log records might leak into other requests that are
+   * executed by the same thread (if a thread pool is used to process requests).
+   *
+   * @param enable whether ACL logging should be enabled.
+   * @return whether ACL logging was be enabled before invoking this method (old value).
+   */
+  boolean aclLogging(boolean enable) {
+    Boolean oldValue = aclLogging.get();
+    if (enable) {
+      aclLogging.set(true);
+    } else {
+      aclLogging.remove();
+    }
+    return oldValue != null ? oldValue : false;
+  }
+
+  /**
+   * Adds an ACL log record.
+   *
+   * @param aclLogRecord ACL log record
+   */
+  public void addAclLogRecord(String aclLogRecord) {
+    if (!isAclLogging()) {
+      return;
+    }
+
+    getMutableAclRecords().add(aclLogRecord);
+  }
+
+  ImmutableList<String> getAclLogRecords() {
+    MutableAclLogRecords records = aclLogRecords.get();
+    if (records != null) {
+      return records.list();
+    }
+    return ImmutableList.of();
+  }
+
+  void clearAclLogEntries() {
+    aclLogRecords.remove();
+  }
+
+  /**
+   * Set the ACL log records in this logging context. Existing log records are overwritten.
+   *
+   * <p>This method makes a defensive copy of the passed in list.
+   *
+   * @param newAclLogRecords ACL log records that should be set
+   */
+  void setAclLogRecords(List<String> newAclLogRecords) {
+    if (newAclLogRecords.isEmpty()) {
+      aclLogRecords.remove();
+      return;
+    }
+
+    getMutableAclRecords().set(newAclLogRecords);
+  }
+
+  /**
+   * Sets a {@link MutableAclLogRecords} instance for storing ACL log records.
+   *
+   * <p><strong>Attention:</strong> The passed in {@link MutableAclLogRecords} instance is directly
+   * stored in the logging context.
+   *
+   * <p>This method is intended to be only used when the logging context is copied to a new thread
+   * to ensure that the ACL log records that are added in the new thread are added to the same
+   * {@link MutableAclLogRecords} instance (see {@link LoggingContextAwareRunnable} and {@link
+   * LoggingContextAwareCallable}). This is important since ACL log records are processed only at
+   * the end of the request and ACL log records that are created in another thread should not get
+   * lost.
+   *
+   * @param mutableAclLogRecords the {@link MutableAclLogRecords} instance in which ACL log records
+   *     should be stored
+   */
+  void setMutableAclLogRecords(MutableAclLogRecords mutableAclLogRecords) {
+    aclLogRecords.set(requireNonNull(mutableAclLogRecords));
+  }
+
+  private MutableAclLogRecords getMutableAclRecords() {
+    MutableAclLogRecords records = aclLogRecords.get();
+    if (records == null) {
+      records = new MutableAclLogRecords();
+      aclLogRecords.set(records);
+    }
+    return records;
+  }
+
   @Override
   public String toString() {
     return MoreObjects.toStringHelper(this)
@@ -257,6 +363,8 @@
         .add("forceLogging", forceLogging.get())
         .add("performanceLogging", performanceLogging.get())
         .add("performanceLogRecords", performanceLogRecords.get())
+        .add("aclLogging", aclLogging.get())
+        .add("aclLogRecords", aclLogRecords.get())
         .toString();
   }
 }
diff --git a/java/com/google/gerrit/server/logging/LoggingContextAwareCallable.java b/java/com/google/gerrit/server/logging/LoggingContextAwareCallable.java
index 1adee1b..ab5db02 100644
--- a/java/com/google/gerrit/server/logging/LoggingContextAwareCallable.java
+++ b/java/com/google/gerrit/server/logging/LoggingContextAwareCallable.java
@@ -40,6 +40,8 @@
   private final boolean forceLogging;
   private final boolean performanceLogging;
   private final MutablePerformanceLogRecords mutablePerformanceLogRecords;
+  private final boolean aclLogging;
+  private final MutableAclLogRecords mutableAclLogRecords;
 
   /**
    * Creates a LoggingContextAwareCallable that wraps the given {@link Callable}.
@@ -47,15 +49,21 @@
    * @param callable Callable that should be wrapped.
    * @param mutablePerformanceLogRecords instance of {@link MutablePerformanceLogRecords} to which
    *     performance log records that are created from the runnable are added
+   * @param mutableAclLogRecords instance of {@link MutableAclLogRecords} to which ACL log records
+   *     that are created from the runnable are added
    */
   LoggingContextAwareCallable(
-      Callable<T> callable, MutablePerformanceLogRecords mutablePerformanceLogRecords) {
+      Callable<T> callable,
+      MutablePerformanceLogRecords mutablePerformanceLogRecords,
+      MutableAclLogRecords mutableAclLogRecords) {
     this.callable = callable;
     this.callingThread = Thread.currentThread();
     this.tags = LoggingContext.getInstance().getTagsAsMap();
     this.forceLogging = LoggingContext.getInstance().isLoggingForced();
     this.performanceLogging = LoggingContext.getInstance().isPerformanceLogging();
     this.mutablePerformanceLogRecords = mutablePerformanceLogRecords;
+    this.aclLogging = LoggingContext.getInstance().isAclLogging();
+    this.mutableAclLogRecords = mutableAclLogRecords;
   }
 
   @Override
@@ -76,6 +84,8 @@
     loggingCtx.forceLogging(forceLogging);
     loggingCtx.performanceLogging(performanceLogging);
     loggingCtx.setMutablePerformanceLogRecords(mutablePerformanceLogRecords);
+    loggingCtx.aclLogging(aclLogging);
+    loggingCtx.setMutableAclLogRecords(mutableAclLogRecords);
     try {
       return callable.call();
     } finally {
diff --git a/java/com/google/gerrit/server/logging/LoggingContextAwareRunnable.java b/java/com/google/gerrit/server/logging/LoggingContextAwareRunnable.java
index d0559cc..3c4c563 100644
--- a/java/com/google/gerrit/server/logging/LoggingContextAwareRunnable.java
+++ b/java/com/google/gerrit/server/logging/LoggingContextAwareRunnable.java
@@ -58,6 +58,8 @@
   private final boolean forceLogging;
   private final boolean performanceLogging;
   private final MutablePerformanceLogRecords mutablePerformanceLogRecords;
+  private final boolean aclLogging;
+  private final MutableAclLogRecords mutableAclLogRecords;
 
   /**
    * Creates a LoggingContextAwareRunnable that wraps the given {@link Runnable}.
@@ -65,15 +67,21 @@
    * @param runnable Runnable that should be wrapped.
    * @param mutablePerformanceLogRecords instance of {@link MutablePerformanceLogRecords} to which
    *     performance log records that are created from the runnable are added
+   * @param mutableAclLogRecords instance of {@link MutableAclLogRecords} to which ACL log records
+   *     that are created from the runnable are added
    */
   LoggingContextAwareRunnable(
-      Runnable runnable, MutablePerformanceLogRecords mutablePerformanceLogRecords) {
+      Runnable runnable,
+      MutablePerformanceLogRecords mutablePerformanceLogRecords,
+      MutableAclLogRecords mutableAclLogRecords) {
     this.runnable = runnable;
     this.callingThread = Thread.currentThread();
     this.tags = LoggingContext.getInstance().getTagsAsMap();
     this.forceLogging = LoggingContext.getInstance().isLoggingForced();
     this.performanceLogging = LoggingContext.getInstance().isPerformanceLogging();
     this.mutablePerformanceLogRecords = mutablePerformanceLogRecords;
+    this.aclLogging = LoggingContext.getInstance().isAclLogging();
+    this.mutableAclLogRecords = mutableAclLogRecords;
   }
 
   public Runnable unwrap() {
@@ -99,6 +107,8 @@
     loggingCtx.forceLogging(forceLogging);
     loggingCtx.performanceLogging(performanceLogging);
     loggingCtx.setMutablePerformanceLogRecords(mutablePerformanceLogRecords);
+    loggingCtx.aclLogging(aclLogging);
+    loggingCtx.setMutableAclLogRecords(mutableAclLogRecords);
     try {
       runnable.run();
     } finally {
diff --git a/java/com/google/gerrit/server/logging/MutableAclLogRecords.java b/java/com/google/gerrit/server/logging/MutableAclLogRecords.java
new file mode 100644
index 0000000..baa9b1f
--- /dev/null
+++ b/java/com/google/gerrit/server/logging/MutableAclLogRecords.java
@@ -0,0 +1,52 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.logging;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.collect.ImmutableList;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Thread-safe store for ACL log records.
+ *
+ * <p>This class is intended to keep track of user ACL records in {@link LoggingContext}. It needs
+ * to be thread-safe because it gets shared between threads when the logging context is copied to
+ * another thread (see {@link LoggingContextAwareRunnable} and {@link LoggingContextAwareCallable}.
+ * In this case the logging contexts of both threads share the same instance of this class. This is
+ * important since ACL log records are processed only at the end of a request and user ACL records
+ * that are created in another thread should not get lost.
+ */
+public class MutableAclLogRecords {
+  private final ArrayList<String> aclLogRecords = new ArrayList<>();
+
+  public synchronized void add(String record) {
+    aclLogRecords.add(record);
+  }
+
+  public synchronized void set(List<String> records) {
+    aclLogRecords.clear();
+    aclLogRecords.addAll(records);
+  }
+
+  public synchronized ImmutableList<String> list() {
+    return ImmutableList.copyOf(aclLogRecords);
+  }
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this).add("aclLogRecords", aclLogRecords).toString();
+  }
+}
diff --git a/java/com/google/gerrit/server/logging/TraceContext.java b/java/com/google/gerrit/server/logging/TraceContext.java
index 21a4ce6..2fc19b5 100644
--- a/java/com/google/gerrit/server/logging/TraceContext.java
+++ b/java/com/google/gerrit/server/logging/TraceContext.java
@@ -19,6 +19,7 @@
 import com.google.common.base.Stopwatch;
 import com.google.common.base.Strings;
 import com.google.common.collect.HashBasedTable;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Table;
 import com.google.common.flogger.FluentLogger;
@@ -222,9 +223,17 @@
   // Table<TAG_NAME, TAG_VALUE, REMOVE_ON_CLOSE>
   private final Table<String, String, Boolean> tags = HashBasedTable.create();
 
-  private boolean stopForceLoggingOnClose;
+  private final boolean oldAclLogging;
+  private final ImmutableList<String> oldAclLogRecords;
 
-  private TraceContext() {}
+  private boolean stopForceLoggingOnClose;
+  private boolean stopAclLoggingOnClose;
+
+  private TraceContext() {
+    // Just in case remember the old state and reset ACL log entries.
+    this.oldAclLogging = LoggingContext.getInstance().isAclLogging();
+    this.oldAclLogRecords = LoggingContext.getInstance().getAclLogRecords();
+  }
 
   public TraceContext addTag(RequestId.Type requestId, Object tagValue) {
     return addTag(requireNonNull(requestId, "request ID is required").name(), tagValue);
@@ -265,6 +274,23 @@
         .findFirst();
   }
 
+  public TraceContext enableAclLogging() {
+    if (stopAclLoggingOnClose) {
+      return this;
+    }
+
+    stopAclLoggingOnClose = !LoggingContext.getInstance().aclLogging(true);
+    return this;
+  }
+
+  public boolean isAclLoggingEnabled() {
+    return LoggingContext.getInstance().isAclLogging();
+  }
+
+  public ImmutableList<String> getAclLogRecords() {
+    return LoggingContext.getInstance().getAclLogRecords();
+  }
+
   @Override
   public void close() {
     for (Table.Cell<String, String, Boolean> cell : tags.cellSet()) {
@@ -275,5 +301,10 @@
     if (stopForceLoggingOnClose) {
       LoggingContext.getInstance().forceLogging(false);
     }
+
+    if (stopAclLoggingOnClose) {
+      LoggingContext.getInstance().aclLogging(oldAclLogging);
+      LoggingContext.getInstance().setAclLogRecords(oldAclLogRecords);
+    }
   }
 }
diff --git a/java/com/google/gerrit/server/mail/send/ChangeEmail.java b/java/com/google/gerrit/server/mail/send/ChangeEmail.java
index 8d76e23..a10021a 100644
--- a/java/com/google/gerrit/server/mail/send/ChangeEmail.java
+++ b/java/com/google/gerrit/server/mail/send/ChangeEmail.java
@@ -91,12 +91,14 @@
   protected ProjectState projectState;
   protected Set<Account.Id> authors;
   protected boolean emailOnlyAuthors;
+  protected boolean emailOnlyAttentionSetIfEnabled;
 
   protected ChangeEmail(EmailArguments args, String messageClass, ChangeData changeData) {
     super(args, messageClass, changeData.change().getDest());
     this.changeData = changeData;
     this.change = changeData.change();
     this.emailOnlyAuthors = false;
+    this.emailOnlyAttentionSetIfEnabled = true;
     this.currentAttentionSet = getAttentionSet();
   }
 
@@ -401,7 +403,8 @@
     if (!accountState.isPresent()) {
       return;
     }
-    if (accountState.get().generalPreferences().getEmailStrategy()
+    if (emailOnlyAttentionSetIfEnabled
+        && accountState.get().generalPreferences().getEmailStrategy()
             == EmailStrategy.ATTENTION_SET_ONLY
         && !currentAttentionSet.contains(to)) {
       return;
diff --git a/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java b/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java
index d5863a6..0de0dbe 100644
--- a/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java
+++ b/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java
@@ -61,7 +61,7 @@
     bccStarredBy();
     ccExistingReviewers();
     includeWatchers(NotifyType.ALL_COMMENTS);
-    add(RecipientType.TO, reviewers);
+    reviewers.stream().forEach(r -> add(RecipientType.TO, r));
     addByEmail(RecipientType.TO, reviewersByEmail);
     removeUsersThatIgnoredTheChange();
   }
diff --git a/java/com/google/gerrit/server/mail/send/MergedSender.java b/java/com/google/gerrit/server/mail/send/MergedSender.java
index 928bdc3..9c2d6ff 100644
--- a/java/com/google/gerrit/server/mail/send/MergedSender.java
+++ b/java/com/google/gerrit/server/mail/send/MergedSender.java
@@ -46,6 +46,9 @@
 
   @Override
   protected void init() throws EmailException {
+    // We want to send the submit email even if the "send only when in attention set" is enabled.
+    emailOnlyAttentionSetIfEnabled = false;
+
     super.init();
 
     ccAllApprovals();
diff --git a/java/com/google/gerrit/server/mail/send/NewChangeSender.java b/java/com/google/gerrit/server/mail/send/NewChangeSender.java
index 0e97f7e..ee9a328 100644
--- a/java/com/google/gerrit/server/mail/send/NewChangeSender.java
+++ b/java/com/google/gerrit/server/mail/send/NewChangeSender.java
@@ -65,11 +65,11 @@
         break;
       case ALL:
       default:
-        add(RecipientType.CC, extraCC);
+        extraCC.stream().forEach(cc -> add(RecipientType.CC, cc));
         extraCCByEmail.stream().forEach(cc -> add(RecipientType.CC, cc));
         // $FALL-THROUGH$
       case OWNER_REVIEWERS:
-        add(RecipientType.TO, reviewers, true);
+        reviewers.stream().forEach(r -> add(RecipientType.TO, r, true));
         addByEmail(RecipientType.TO, reviewersByEmail, true);
         break;
     }
diff --git a/java/com/google/gerrit/server/mail/send/OutgoingEmail.java b/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
index bef5317..44453d5 100644
--- a/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
+++ b/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
@@ -25,7 +25,6 @@
 import com.google.gerrit.entities.Address;
 import com.google.gerrit.entities.EmailHeader;
 import com.google.gerrit.entities.EmailHeader.AddressList;
-import com.google.gerrit.entities.UserIdentity;
 import com.google.gerrit.exceptions.EmailException;
 import com.google.gerrit.extensions.api.changes.RecipientType;
 import com.google.gerrit.extensions.client.GeneralPreferencesInfo;
@@ -284,7 +283,7 @@
     setHeader(MailHeader.AUTO_SUBMITTED.fieldName(), "auto-generated");
 
     for (RecipientType recipientType : notify.accounts().keySet()) {
-      add(recipientType, notify.accounts().get(recipientType));
+      notify.accounts().get(recipientType).stream().forEach(a -> add(recipientType, a));
     }
 
     setHeader(MailHeader.MESSAGE_TYPE.fieldName(), messageClass);
@@ -471,40 +470,18 @@
     return true;
   }
 
-  /** Schedule this message for delivery to the listed accounts. */
-  protected void add(RecipientType rt, Collection<Account.Id> list) {
-    add(rt, list, false);
-  }
-
-  /** Schedule this message for delivery to the listed accounts. */
-  protected void add(RecipientType rt, Collection<Account.Id> list, boolean override) {
-    for (final Account.Id id : list) {
-      add(rt, id, override);
-    }
-  }
-
   /** Schedule this message for delivery to the listed address. */
-  protected void addByEmail(RecipientType rt, Collection<Address> list) {
+  protected final void addByEmail(RecipientType rt, Collection<Address> list) {
     addByEmail(rt, list, false);
   }
 
   /** Schedule this message for delivery to the listed address. */
-  protected void addByEmail(RecipientType rt, Collection<Address> list, boolean override) {
+  protected final void addByEmail(RecipientType rt, Collection<Address> list, boolean override) {
     for (final Address id : list) {
       add(rt, id, override);
     }
   }
 
-  protected void add(RecipientType rt, UserIdentity who) {
-    add(rt, who, false);
-  }
-
-  protected void add(RecipientType rt, UserIdentity who, boolean override) {
-    if (who != null && who.getAccount() != null) {
-      add(rt, who.getAccount(), override);
-    }
-  }
-
   /** Schedule delivery of this message to the given account. */
   protected void add(RecipientType rt, Account.Id to) {
     add(rt, to, false);
@@ -531,11 +508,11 @@
   }
 
   /** Schedule delivery of this message to the given account. */
-  protected void add(RecipientType rt, Address addr) {
+  protected final void add(RecipientType rt, Address addr) {
     add(rt, addr, false);
   }
 
-  protected void add(RecipientType rt, Address addr, boolean override) {
+  protected final void add(RecipientType rt, Address addr, boolean override) {
     if (addr != null && addr.email() != null && addr.email().length() > 0) {
       if (!args.validator.isValid(addr.email())) {
         logger.atWarning().log("Not emailing %s (invalid email address)", addr.email());
diff --git a/java/com/google/gerrit/server/mail/send/ProjectWatch.java b/java/com/google/gerrit/server/mail/send/ProjectWatch.java
index 0514337..173b121 100644
--- a/java/com/google/gerrit/server/mail/send/ProjectWatch.java
+++ b/java/com/google/gerrit/server/mail/send/ProjectWatch.java
@@ -33,7 +33,7 @@
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
-import com.google.gerrit.server.query.change.SingleGroupUser;
+import com.google.gerrit.server.query.change.GroupBackedUser;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -150,7 +150,7 @@
       throws QueryParseException {
     logger.atFine().log("Checking watchers for notify config %s from project %s", nc, projectName);
     for (GroupReference groupRef : nc.getGroups()) {
-      CurrentUser user = new SingleGroupUser(groupRef.getUUID());
+      CurrentUser user = new GroupBackedUser(ImmutableSet.of(groupRef.getUUID()));
       if (filterMatch(user, nc.getFilter())) {
         deliverToMembers(matching.list(nc.getHeader()), groupRef.getUUID());
         logger.atFine().log("Added watchers for group %s", groupRef);
diff --git a/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java b/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java
index 5caac37..9516b9f 100644
--- a/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java
+++ b/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java
@@ -64,8 +64,8 @@
     if (args.settings.sendNewPatchsetEmails) {
       if (notify.handling() == NotifyHandling.ALL
           || notify.handling() == NotifyHandling.OWNER_REVIEWERS) {
-        add(RecipientType.TO, reviewers);
-        add(RecipientType.CC, extraCC);
+        reviewers.stream().forEach(r -> add(RecipientType.TO, r));
+        extraCC.stream().forEach(cc -> add(RecipientType.CC, cc));
       }
       rcptToAuthors(RecipientType.CC);
     }
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotes.java b/java/com/google/gerrit/server/notedb/ChangeNotes.java
index c35d815..b816264 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotes.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotes.java
@@ -64,6 +64,7 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -77,6 +78,9 @@
 import org.eclipse.jgit.lib.Repository;
 
 /** View of a single {@link Change} based on the log of its notes branch. */
+// TODO(paiking): This class should be refactored to get rid of potentially duplicate or unneeded
+// variables, such as allAttentionSetUpdates, reviewerUpdates, and others.
+
 public class ChangeNotes extends AbstractChangeNotes<ChangeNotes> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
@@ -125,17 +129,6 @@
       return new ChangeNotes(args, newChange(project, changeId), true, null).load();
     }
 
-    /**
-     * Create change notes for a change that was loaded from index. This method should only be used
-     * when database access is harmful and potentially stale data from the index is acceptable.
-     *
-     * @param change change loaded from secondary index
-     * @return change notes
-     */
-    public ChangeNotes createFromIndexedChange(Change change) {
-      return new ChangeNotes(args, change, true, null);
-    }
-
     public ChangeNotes createForBatchUpdate(Change change, boolean shouldExist) {
       return new ChangeNotes(args, change, shouldExist, null).load();
     }
@@ -400,6 +393,11 @@
     return state.attentionSet();
   }
 
+  /** Returns all updates for the attention set. */
+  public ImmutableList<AttentionSetUpdate> getAttentionSetUpdates() {
+    return state.allAttentionSetUpdates();
+  }
+
   /**
    * @return an ImmutableSet of Account.Ids of all users that have been assigned to this change. The
    *     order of the set is the order in which they were assigned.
@@ -463,6 +461,11 @@
     return state.updateCount();
   }
 
+  /** @return {@link Optional} value of time when the change was merged. */
+  public Optional<Timestamp> getMergedOn() {
+    return Optional.ofNullable(state.mergedOn());
+  }
+
   public ImmutableListMultimap<ObjectId, HumanComment> getDraftComments(Account.Id author) {
     return getDraftComments(author, null);
   }
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotesCache.java b/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
index 7fde297..c554ca5 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
@@ -121,12 +121,18 @@
     // Single Timestamp overhead.
     private static final int T = O + 8;
 
+    /**
+     * {@inheritDoc}
+     *
+     * <p>Take all columns and all collection sizes into account, but use estimated average element
+     * sizes rather than iterating over collections. Numbers are largely hand-wavy based on
+     * http://stackoverflow.com/questions/258120/what-is-the-memory-consumption-of-an-object-in-java
+     *
+     * <p>Should be kept up to date with {@link ChangeNotesState}. Please, keep weights listed in
+     * the same order as fields.
+     */
     @Override
     public int weigh(Key key, ChangeNotesState state) {
-      // Take all columns and all collection sizes into account, but use
-      // estimated average element sizes rather than iterating over collections.
-      // Numbers are largely hand-wavy based on
-      // http://stackoverflow.com/questions/258120/what-is-the-memory-consumption-of-an-object-in-java
       return P
           + O
           + 20 // metaId
@@ -138,6 +144,7 @@
           + K // owner
           + P
           + str(state.columns().branch())
+          + P // status
           + P
           + patchSetId() // currentPatchSetId
           + P
@@ -148,9 +155,16 @@
           + str(state.columns().originalSubject())
           + P
           + str(state.columns().submissionId())
-          + P // status
+          + 1 // isPrivate
+          + 1 // workInProgress
+          + 1 // reviewStarted
+          + P
+          + K // revertOf
+          + P
+          + patchSetId() // cherryPickOf
           + P
           + set(state.hashtags(), str(10))
+          + str(state.serverId()) // serverId
           + P
           + list(state.patchSets(), patchSet())
           + P
@@ -168,15 +182,17 @@
           + P
           + list(state.assigneeUpdates(), 4 * O + K + K)
           + P
+          + set(state.attentionSet(), 4 * O + K + I + str(15))
+          + P
+          + list(state.allAttentionSetUpdates(), 4 * O + K + I + str(15))
+          + P
           + list(state.submitRecords(), P + list(2, str(4) + P + K) + P)
           + P
           + list(state.changeMessages(), changeMessage())
           + P
           + map(state.publishedComments().asMap(), comment())
-          + 1 // isPrivate
-          + 1 // workInProgress
-          + 1 // reviewStarted
-          + I; // updateCount
+          + I // updateCount
+          + T; // mergedOn
     }
 
     private static int str(String s) {
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotesParser.java b/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
index c92d236..846d4b8 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
@@ -55,6 +55,7 @@
 import com.google.common.collect.Tables;
 import com.google.common.flogger.FluentLogger;
 import com.google.common.primitives.Ints;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.Address;
 import com.google.gerrit.entities.AttentionSetUpdate;
@@ -118,6 +119,8 @@
   private final List<ReviewerStatusUpdate> reviewerUpdates;
   /** Holds only the most recent update per user. Older updates are discarded. */
   private final Map<Account.Id, AttentionSetUpdate> latestAttentionStatus;
+  /** Holds all updates to attention set. */
+  private final List<AttentionSetUpdate> allAttentionSetUpdates;
 
   private final List<AssigneeStatusUpdate> assigneeUpdates;
   private final List<SubmitRecord> submitRecords;
@@ -153,7 +156,11 @@
   private ReviewerByEmailSet pendingReviewersByEmail;
   private Change.Id revertOf;
   private int updateCount;
-  private PatchSet.Id cherryPickOf;
+  // Null indicates that the field was not parsed (yet).
+  // We only set the value once, based on the latest update (the actual value or Optional.empty() if
+  // the latest record unsets the field).
+  private Optional<PatchSet.Id> cherryPickOf;
+  private Timestamp mergedOn;
 
   ChangeNotesParser(
       Change.Id changeId,
@@ -175,6 +182,7 @@
     allPastReviewers = new ArrayList<>();
     reviewerUpdates = new ArrayList<>();
     latestAttentionStatus = new HashMap<>();
+    allAttentionSetUpdates = new ArrayList<>();
     assigneeUpdates = new ArrayList<>();
     submitRecords = Lists.newArrayListWithExpectedSize(1);
     allChangeMessages = new ArrayList<>();
@@ -246,6 +254,7 @@
         allPastReviewers,
         buildReviewerUpdates(),
         ImmutableSet.copyOf(latestAttentionStatus.values()),
+        allAttentionSetUpdates,
         assigneeUpdates,
         submitRecords,
         buildAllMessages(),
@@ -254,8 +263,9 @@
         firstNonNull(workInProgress, false),
         firstNonNull(hasReviewStarted, true),
         revertOf,
-        cherryPickOf,
-        updateCount);
+        cherryPickOf != null ? cherryPickOf.orElse(null) : null,
+        updateCount,
+        mergedOn);
   }
 
   private Map<PatchSet.Id, PatchSet> buildPatchSets() throws ConfigInvalidException {
@@ -318,9 +328,9 @@
 
   private void parse(ChangeNotesCommit commit) throws ConfigInvalidException {
     updateCount++;
-    Timestamp ts = new Timestamp(commit.getCommitterIdent().getWhen().getTime());
+    Timestamp commitTimestamp = getCommitTimestamp(commit);
 
-    createdOn = ts;
+    createdOn = commitTimestamp;
     parseTag(commit);
 
     if (branch == null) {
@@ -360,21 +370,19 @@
       originalSubject = currSubject;
     }
 
-    parseChangeMessage(psId, accountId, realAccountId, commit, ts);
+    parseChangeMessage(psId, accountId, realAccountId, commit, commitTimestamp);
     if (topic == null) {
       topic = parseTopic(commit);
     }
 
     parseHashtags(commit);
     parseAttentionSetUpdates(commit);
-    parseAssigneeUpdates(ts, commit);
+    parseAssigneeUpdates(commitTimestamp, commit);
 
-    if (submissionId == null) {
-      submissionId = parseSubmissionId(commit);
-    }
+    parseSubmission(commit, commitTimestamp);
 
-    if (lastUpdatedOn == null || ts.after(lastUpdatedOn)) {
-      lastUpdatedOn = ts;
+    if (lastUpdatedOn == null || commitTimestamp.after(lastUpdatedOn)) {
+      lastUpdatedOn = commitTimestamp;
     }
 
     if (deletedPatchSets.contains(psId)) {
@@ -388,16 +396,10 @@
 
     ObjectId currRev = parseRevision(commit);
     if (currRev != null) {
-      parsePatchSet(psId, currRev, accountId, ts);
+      parsePatchSet(psId, currRev, accountId, commitTimestamp);
     }
     parseCurrentPatchSet(psId, commit);
 
-    if (submitRecords.isEmpty()) {
-      // Only parse the most recent set of submit records; any older ones are
-      // still there, but not currently used.
-      parseSubmitRecords(commit.getFooterLineValues(FOOTER_SUBMITTED_WITH));
-    }
-
     if (status == null) {
       status = parseStatus(commit);
     }
@@ -405,15 +407,15 @@
     // Parse approvals after status to treat approvals in the same commit as
     // "Status: merged" as non-post-submit.
     for (String line : commit.getFooterLineValues(FOOTER_LABEL)) {
-      parseApproval(psId, accountId, realAccountId, ts, line);
+      parseApproval(psId, accountId, realAccountId, commitTimestamp, line);
     }
 
     for (ReviewerStateInternal state : ReviewerStateInternal.values()) {
       for (String line : commit.getFooterLineValues(state.getFooterKey())) {
-        parseReviewer(ts, state, line);
+        parseReviewer(commitTimestamp, state, line);
       }
       for (String line : commit.getFooterLineValues(state.getByEmailFooterKey())) {
-        parseReviewerByEmail(ts, state, line);
+        parseReviewerByEmail(commitTimestamp, state, line);
       }
       // Don't update timestamp when a reviewer was added, matching RevewDb
       // behavior.
@@ -435,6 +437,24 @@
     parseWorkInProgress(commit);
   }
 
+  private void parseSubmission(ChangeNotesCommit commit, Timestamp commitTimestamp)
+      throws ConfigInvalidException {
+    // Only parse the most recent sumbit commit (there should be exactly one).
+    if (submissionId == null) {
+      submissionId = parseSubmissionId(commit);
+    }
+
+    if (submissionId != null && mergedOn == null) {
+      mergedOn = commitTimestamp;
+    }
+
+    if (submitRecords.isEmpty()) {
+      // Only parse the most recent set of submit records; any older ones are
+      // still there, but not currently used.
+      parseSubmitRecords(commit.getFooterLineValues(FOOTER_SUBMITTED_WITH));
+    }
+  }
+
   private String parseSubmissionId(ChangeNotesCommit commit) throws ConfigInvalidException {
     return parseOneFooter(commit, FOOTER_SUBMISSION_ID);
   }
@@ -589,6 +609,9 @@
       }
       // Processing is in reverse chronological order. Keep only the latest update.
       latestAttentionStatus.putIfAbsent(attentionStatus.get().account(), attentionStatus.get());
+
+      // Keep all updates as well.
+      allAttentionSetUpdates.add(attentionStatus.get());
     }
   }
 
@@ -997,16 +1020,49 @@
     return Change.id(revertOf);
   }
 
-  private PatchSet.Id parseCherryPickOf(ChangeNotesCommit commit) throws ConfigInvalidException {
-    String cherryPickOf = parseOneFooter(commit, FOOTER_CHERRY_PICK_OF);
-    if (cherryPickOf == null) {
+  /**
+   * Parses {@link ChangeNoteUtil#FOOTER_CHERRY_PICK_OF} of the commit.
+   *
+   * @param commit the commit to parse.
+   * @return {@link Optional} value of the parsed footer or {@code null} if the footer is missing in
+   *     this commit.
+   * @throws ConfigInvalidException if the footer value could not be parsed as a valid {@link
+   *     PatchSet.Id}.
+   */
+  @Nullable
+  private Optional<PatchSet.Id> parseCherryPickOf(ChangeNotesCommit commit)
+      throws ConfigInvalidException {
+    String footer = parseOneFooter(commit, FOOTER_CHERRY_PICK_OF);
+    if (footer == null) {
+      // The footer is missing, nothing to parse.
       return null;
+    } else if (footer.equals("")) {
+      // Empty footer value, cherryPickOf was unset at this commit.
+      return Optional.empty();
+    } else {
+      try {
+        return Optional.of(PatchSet.Id.parse(footer));
+      } catch (IllegalArgumentException e) {
+        throw new ConfigInvalidException("\"" + footer + "\" is not a valid patchset", e);
+      }
     }
-    try {
-      return PatchSet.Id.parse(cherryPickOf);
-    } catch (IllegalArgumentException e) {
-      throw new ConfigInvalidException("\"" + cherryPickOf + "\" is not a valid patchset", e);
-    }
+  }
+
+  /**
+   * Returns the {@link Timestamp} when the commit was applied.
+   *
+   * <p>The author's date only notes when the commit was originally made. Thus, use the commiter's
+   * date as it accounts for the rebase, cherry-pick, commit --amend and other commands that rewrite
+   * the history of the branch.
+   *
+   * <p>Don't use {@link org.eclipse.jgit.revwalk.RevCommit#getCommitTime} directly because it
+   * returns int and would overflow.
+   *
+   * @param commit the commit to return commit time.
+   * @return the timestamp when the commit was applied.
+   */
+  private Timestamp getCommitTimestamp(ChangeNotesCommit commit) {
+    return new Timestamp(commit.getCommitterIdent().getWhen().getTime());
   }
 
   private void pruneReviewers() {
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotesState.java b/java/com/google/gerrit/server/notedb/ChangeNotesState.java
index 76c4678..af8c8c8 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotesState.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotesState.java
@@ -81,9 +81,15 @@
  * <p>One instance is the output of a single {@link ChangeNotesParser}, and contains types required
  * to support public methods on {@link ChangeNotes}. It is intended to be cached in-process.
  *
+ * <p>When new fields are added to the {@link ChangeNotesState}, {@link
+ * ChangeNotesCache.Weigher#weigh} should be updated.
+ *
  * <p>Note that {@link ChangeNotes} contains more than just a single {@code ChangeNoteState}, such
  * as per-draft information, so that class is not cached directly.
  */
+// TODO(paiking): This class should be refactored to get rid of potentially duplicate or unneeded
+// variables, such as allAttentionSetUpdates, reviewerUpdates, and others.
+
 @AutoValue
 public abstract class ChangeNotesState {
 
@@ -120,6 +126,7 @@
       List<Account.Id> allPastReviewers,
       List<ReviewerStatusUpdate> reviewerUpdates,
       Set<AttentionSetUpdate> attentionSetUpdates,
+      List<AttentionSetUpdate> allAttentionSetUpdates,
       List<AssigneeStatusUpdate> assigneeUpdates,
       List<SubmitRecord> submitRecords,
       List<ChangeMessage> changeMessages,
@@ -129,7 +136,8 @@
       boolean reviewStarted,
       @Nullable Change.Id revertOf,
       @Nullable PatchSet.Id cherryPickOf,
-      int updateCount) {
+      int updateCount,
+      @Nullable Timestamp mergedOn) {
     requireNonNull(
         metaId,
         () ->
@@ -171,11 +179,13 @@
         .allPastReviewers(allPastReviewers)
         .reviewerUpdates(reviewerUpdates)
         .attentionSet(attentionSetUpdates)
+        .allAttentionSetUpdates(allAttentionSetUpdates)
         .assigneeUpdates(assigneeUpdates)
         .submitRecords(submitRecords)
         .changeMessages(changeMessages)
         .publishedComments(publishedComments)
         .updateCount(updateCount)
+        .mergedOn(mergedOn)
         .build();
   }
 
@@ -305,9 +315,12 @@
 
   abstract ImmutableList<ReviewerStatusUpdate> reviewerUpdates();
 
-  /** Returns the most recent update (i.e. current status status) per user. */
+  /** Returns the most recent update (i.e. current status) per user. */
   abstract ImmutableSet<AttentionSetUpdate> attentionSet();
 
+  /** Returns all attention set updates. */
+  abstract ImmutableList<AttentionSetUpdate> allAttentionSetUpdates();
+
   abstract ImmutableList<AssigneeStatusUpdate> assigneeUpdates();
 
   abstract ImmutableList<SubmitRecord> submitRecords();
@@ -318,6 +331,9 @@
 
   abstract int updateCount();
 
+  @Nullable
+  abstract Timestamp mergedOn();
+
   Change newChange(Project.NameKey project) {
     ChangeColumns c = requireNonNull(columns(), "columns are required");
     Change change =
@@ -386,6 +402,7 @@
           .allPastReviewers(ImmutableList.of())
           .reviewerUpdates(ImmutableList.of())
           .attentionSet(ImmutableSet.of())
+          .allAttentionSetUpdates(ImmutableList.of())
           .assigneeUpdates(ImmutableList.of())
           .submitRecords(ImmutableList.of())
           .changeMessages(ImmutableList.of())
@@ -421,6 +438,8 @@
 
     abstract Builder attentionSet(Set<AttentionSetUpdate> attentionSetUpdates);
 
+    abstract Builder allAttentionSetUpdates(List<AttentionSetUpdate> attentionSetUpdates);
+
     abstract Builder assigneeUpdates(List<AssigneeStatusUpdate> assigneeUpdates);
 
     abstract Builder submitRecords(List<SubmitRecord> submitRecords);
@@ -431,6 +450,8 @@
 
     abstract Builder updateCount(int updateCount);
 
+    abstract Builder mergedOn(Timestamp mergedOn);
+
     abstract ChangeNotesState build();
   }
 
@@ -489,6 +510,9 @@
       object.allPastReviewers().forEach(a -> b.addPastReviewer(a.get()));
       object.reviewerUpdates().forEach(u -> b.addReviewerUpdate(toReviewerStatusUpdateProto(u)));
       object.attentionSet().forEach(u -> b.addAttentionSetUpdate(toAttentionSetUpdateProto(u)));
+      object
+          .allAttentionSetUpdates()
+          .forEach(u -> b.addAllAttentionSetUpdate(toAttentionSetUpdateProto(u)));
       object.assigneeUpdates().forEach(u -> b.addAssigneeUpdate(toAssigneeStatusUpdateProto(u)));
       object
           .submitRecords()
@@ -498,6 +522,10 @@
           .forEach(m -> b.addChangeMessage(toByteString(m, ChangeMessageProtoConverter.INSTANCE)));
       object.publishedComments().values().forEach(c -> b.addPublishedComment(GSON.toJson(c)));
       b.setUpdateCount(object.updateCount());
+      if (object.mergedOn() != null) {
+        b.setMergedOnMillis(object.mergedOn().getTime());
+        b.setHasMergedOn(true);
+      }
 
       return Protos.toByteArray(b.build());
     }
@@ -623,6 +651,8 @@
                   proto.getPastReviewerList().stream().map(Account::id).collect(toImmutableList()))
               .reviewerUpdates(toReviewerStatusUpdateList(proto.getReviewerUpdateList()))
               .attentionSet(toAttentionSetUpdates(proto.getAttentionSetUpdateList()))
+              .allAttentionSetUpdates(
+                  toAllAttentionSetUpdates(proto.getAllAttentionSetUpdateList()))
               .assigneeUpdates(toAssigneeStatusUpdateList(proto.getAssigneeUpdateList()))
               .submitRecords(
                   proto.getSubmitRecordList().stream()
@@ -636,7 +666,8 @@
                   proto.getPublishedCommentList().stream()
                       .map(r -> GSON.fromJson(r, HumanComment.class))
                       .collect(toImmutableListMultimap(HumanComment::getCommitId, c -> c)))
-              .updateCount(proto.getUpdateCount());
+              .updateCount(proto.getUpdateCount())
+              .mergedOn(proto.getHasMergedOn() ? new Timestamp(proto.getMergedOnMillis()) : null);
       return b.build();
     }
 
@@ -735,6 +766,20 @@
       return b.build();
     }
 
+    private static ImmutableList<AttentionSetUpdate> toAllAttentionSetUpdates(
+        List<AttentionSetUpdateProto> protos) {
+      ImmutableList.Builder<AttentionSetUpdate> b = ImmutableList.builder();
+      for (AttentionSetUpdateProto proto : protos) {
+        b.add(
+            AttentionSetUpdate.createFromRead(
+                Instant.ofEpochMilli(proto.getTimestampMillis()),
+                Account.id(proto.getAccount()),
+                AttentionSetUpdate.Operation.valueOf(proto.getOperation()),
+                proto.getReason()));
+      }
+      return b.build();
+    }
+
     private static ImmutableList<AssigneeStatusUpdate> toAssigneeStatusUpdateList(
         List<AssigneeStatusUpdateProto> protos) {
       ImmutableList.Builder<AssigneeStatusUpdate> b = ImmutableList.builder();
diff --git a/java/com/google/gerrit/server/notedb/ChangeUpdate.java b/java/com/google/gerrit/server/notedb/ChangeUpdate.java
index c3b0e79..9d23137 100644
--- a/java/com/google/gerrit/server/notedb/ChangeUpdate.java
+++ b/java/com/google/gerrit/server/notedb/ChangeUpdate.java
@@ -65,6 +65,7 @@
 import com.google.gerrit.entities.SubmissionId;
 import com.google.gerrit.entities.SubmitRecord;
 import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.extensions.client.ReviewerState;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.account.ServiceUserClassifier;
@@ -87,6 +88,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.CommitBuilder;
 import org.eclipse.jgit.lib.ObjectId;
@@ -152,7 +154,9 @@
   private Boolean isPrivate;
   private Boolean workInProgress;
   private Integer revertOf;
-  private String cherryPickOf;
+  // If null, the update does not modify the field. Otherwise, it updates the field with the
+  // new value or resets if cherryPickOf == Optional.empty().
+  private Optional<String> cherryPickOf;
 
   private ChangeDraftUpdate draftUpdate;
   private RobotCommentUpdate robotCommentUpdate;
@@ -473,7 +477,12 @@
   }
 
   public void setCherryPickOf(String cherryPickOf) {
-    this.cherryPickOf = cherryPickOf;
+    checkArgument(cherryPickOf != null, "use resetCherryPickOf");
+    this.cherryPickOf = Optional.of(cherryPickOf);
+  }
+
+  public void resetCherryPickOf() {
+    this.cherryPickOf = Optional.empty();
   }
 
   /** @return the tree id for the updated tree */
@@ -736,7 +745,12 @@
     }
 
     if (cherryPickOf != null) {
-      addFooter(msg, FOOTER_CHERRY_PICK_OF, cherryPickOf);
+      if (cherryPickOf.isPresent()) {
+        addFooter(msg, FOOTER_CHERRY_PICK_OF, cherryPickOf.get());
+      } else {
+        // Update cherryPickOf with an empty value.
+        addFooter(msg, FOOTER_CHERRY_PICK_OF).append('\n');
+      }
     }
 
     if (plannedAttentionSetUpdates != null) {
@@ -780,21 +794,25 @@
         getNotes().getReviewers().byState(ReviewerStateInternal.REVIEWER);
     Set<AttentionSetUpdate> updates = new HashSet<>();
     for (Map.Entry<Account.Id, ReviewerStateInternal> reviewer : reviewers.entrySet()) {
-      // Only add new reviewers to the attention set.
-      if (reviewer.getValue().equals(ReviewerStateInternal.REVIEWER)
-          && !currentReviewers.contains(reviewer.getKey())) {
+      Account.Id reviewerId = reviewer.getKey();
+      ReviewerStateInternal reviewerState = reviewer.getValue();
+      // Only add new reviewers to the attention set. Also, don't add the owner because the owner
+      // can only be a "dummy" reviewer for legacy reasons.
+      if (reviewerState.equals(ReviewerStateInternal.REVIEWER)
+          && !currentReviewers.contains(reviewerId)
+          && !reviewerId.equals(getChange().getOwner())) {
         updates.add(
             AttentionSetUpdate.createForWrite(
-                reviewer.getKey(), AttentionSetUpdate.Operation.ADD, "Reviewer was added"));
+                reviewerId, AttentionSetUpdate.Operation.ADD, "Reviewer was added"));
       }
       boolean reviewerRemoved =
-          !reviewer.getValue().equals(ReviewerStateInternal.REVIEWER)
-              && currentReviewers.contains(reviewer.getKey());
-      boolean ccRemoved = reviewer.getValue().equals(ReviewerStateInternal.REMOVED);
+          !reviewerState.equals(ReviewerStateInternal.REVIEWER)
+              && currentReviewers.contains(reviewerId);
+      boolean ccRemoved = reviewerState.equals(ReviewerStateInternal.REMOVED);
       if (reviewerRemoved || ccRemoved) {
         updates.add(
             AttentionSetUpdate.createForWrite(
-                reviewer.getKey(), AttentionSetUpdate.Operation.REMOVE, "Reviewer/Cc was removed"));
+                reviewerId, AttentionSetUpdate.Operation.REMOVE, "Reviewer/Cc was removed"));
       }
     }
     addToPlannedAttentionSetUpdates(updates);
@@ -821,6 +839,22 @@
         AttentionSetUtil.additionsOnly(getNotes().getAttentionSet()).stream()
             .map(AttentionSetUpdate::account)
             .collect(Collectors.toSet());
+
+    // Current reviewers/ccs are the reviewers/ccs before the update + the new reviewers/ccs - the
+    // deleted reviewers/ccs.
+    Set<Account.Id> currentReviewers =
+        Stream.concat(
+                getNotes().getReviewers().all().stream(),
+                reviewers.entrySet().stream()
+                    .filter(r -> r.getValue().asReviewerState() != ReviewerState.REMOVED)
+                    .map(r -> r.getKey()))
+            .collect(Collectors.toSet());
+    currentReviewers.removeAll(
+        reviewers.entrySet().stream()
+            .filter(r -> r.getValue().asReviewerState() == ReviewerState.REMOVED)
+            .map(r -> r.getKey())
+            .collect(ImmutableSet.toImmutableSet()));
+
     for (AttentionSetUpdate attentionSetUpdate : plannedAttentionSetUpdates.values()) {
       if (attentionSetUpdate.operation() == AttentionSetUpdate.Operation.ADD
           && currentUsersInAttentionSet.contains(attentionSetUpdate.account())) {
@@ -848,11 +882,27 @@
         continue;
       }
 
+      // Don't add accounts that are not active in the change to the attention set.
+      if (attentionSetUpdate.operation() == AttentionSetUpdate.Operation.ADD
+          && !isActiveOnChange(currentReviewers, attentionSetUpdate.account())) {
+        continue;
+      }
+
       addFooter(msg, FOOTER_ATTENTION, noteUtil.attentionSetUpdateToJson(attentionSetUpdate));
     }
   }
 
   /**
+   * Returns whether {@code accountId} is active on a change based on the {@code currentReviewers}.
+   * Activity is defined as being a part of the reviewers, an uploader, or an owner of a change.
+   */
+  private boolean isActiveOnChange(Set<Account.Id> currentReviewers, Account.Id accountId) {
+    return currentReviewers.contains(accountId)
+        || getChange().getOwner().equals(accountId)
+        || getNotes().getCurrentPatchSet().uploader().equals(accountId);
+  }
+
+  /**
    * When set, default attention set rules are ignored (E.g, adding reviewers -> adds to attention
    * set, etc).
    */
diff --git a/java/com/google/gerrit/server/patch/DiffExecutor.java b/java/com/google/gerrit/server/patch/DiffExecutor.java
index 072c2da..63d5c50 100644
--- a/java/com/google/gerrit/server/patch/DiffExecutor.java
+++ b/java/com/google/gerrit/server/patch/DiffExecutor.java
@@ -16,6 +16,7 @@
 
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
+import com.google.gerrit.server.patch.filediff.PatchListLoader;
 import com.google.inject.BindingAnnotation;
 import java.lang.annotation.Retention;
 import java.util.concurrent.ExecutorService;
diff --git a/java/com/google/gerrit/server/patch/DiffMappings.java b/java/com/google/gerrit/server/patch/DiffMappings.java
index 921d66e..57132f8 100644
--- a/java/com/google/gerrit/server/patch/DiffMappings.java
+++ b/java/com/google/gerrit/server/patch/DiffMappings.java
@@ -15,12 +15,17 @@
 package com.google.gerrit.server.patch;
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static java.util.stream.Collectors.toList;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.entities.Patch;
 import com.google.gerrit.server.patch.GitPositionTransformer.FileMapping;
 import com.google.gerrit.server.patch.GitPositionTransformer.Mapping;
 import com.google.gerrit.server.patch.GitPositionTransformer.Range;
 import com.google.gerrit.server.patch.GitPositionTransformer.RangeMapping;
+import com.google.gerrit.server.patch.filediff.Edit;
+import com.google.gerrit.server.patch.filediff.FileEdits;
+import java.util.List;
 
 /** Mappings derived from diffs. */
 public class DiffMappings {
@@ -33,31 +38,47 @@
     return Mapping.create(fileMapping, rangeMappings);
   }
 
-  private static FileMapping toFileMapping(PatchListEntry patchListEntry) {
-    switch (patchListEntry.getChangeType()) {
+  public static Mapping toMapping(FileEdits fileEdits) {
+    FileMapping fileMapping = FileMapping.forFile(fileEdits.oldPath(), fileEdits.newPath());
+    ImmutableSet<RangeMapping> rangeMappings = toRangeMappings(fileEdits.edits());
+    return Mapping.create(fileMapping, rangeMappings);
+  }
+
+  private static FileMapping toFileMapping(PatchListEntry ple) {
+    return toFileMapping(ple.getChangeType(), ple.getOldName(), ple.getNewName());
+  }
+
+  private static FileMapping toFileMapping(
+      Patch.ChangeType changeType, String oldName, String newName) {
+    switch (changeType) {
       case ADDED:
-        return FileMapping.forAddedFile(patchListEntry.getNewName());
+        return FileMapping.forAddedFile(newName);
       case MODIFIED:
       case REWRITE:
-        return FileMapping.forModifiedFile(patchListEntry.getNewName());
+        return FileMapping.forModifiedFile(newName);
       case DELETED:
         // Name of deleted file is mentioned as newName.
-        return FileMapping.forDeletedFile(patchListEntry.getNewName());
+        return FileMapping.forDeletedFile(newName);
       case RENAMED:
       case COPIED:
-        return FileMapping.forRenamedFile(patchListEntry.getOldName(), patchListEntry.getNewName());
+        return FileMapping.forRenamedFile(oldName, newName);
       default:
-        throw new IllegalStateException("Unmapped diff type: " + patchListEntry.getChangeType());
+        throw new IllegalStateException("Unmapped diff type: " + changeType);
     }
   }
 
   private static ImmutableSet<RangeMapping> toRangeMappings(PatchListEntry patchListEntry) {
-    return patchListEntry.getEdits().stream()
+    return toRangeMappings(
+        patchListEntry.getEdits().stream().map(Edit::fromJGitEdit).collect(toList()));
+  }
+
+  private static ImmutableSet<RangeMapping> toRangeMappings(List<Edit> edits) {
+    return edits.stream()
         .map(
             edit ->
                 RangeMapping.create(
-                    Range.create(edit.getBeginA(), edit.getEndA()),
-                    Range.create(edit.getBeginB(), edit.getEndB())))
+                    Range.create(edit.beginA(), edit.endA()),
+                    Range.create(edit.beginB(), edit.endB())))
         .collect(toImmutableSet());
   }
 }
diff --git a/java/com/google/gerrit/server/patch/DiffNotAvailableException.java b/java/com/google/gerrit/server/patch/DiffNotAvailableException.java
new file mode 100644
index 0000000..e75adec
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/DiffNotAvailableException.java
@@ -0,0 +1,32 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch;
+
+import com.google.gerrit.server.patch.diff.ModifiedFilesCache;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCache;
+
+/**
+ * Thrown by the diff caches - the {@link GitModifiedFilesCache} and the {@link ModifiedFilesCache},
+ * if the implementations failed to retrieve the modified files between the 2 commits.
+ */
+public class DiffNotAvailableException extends Exception {
+  public DiffNotAvailableException(Throwable cause) {
+    super(cause);
+  }
+
+  public DiffNotAvailableException(String message) {
+    super(message);
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/DiffUtil.java b/java/com/google/gerrit/server/patch/DiffUtil.java
new file mode 100644
index 0000000..1e88f9f
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/DiffUtil.java
@@ -0,0 +1,89 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+package com.google.gerrit.server.patch;
+
+import com.google.gerrit.server.patch.diff.ModifiedFilesCache;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCache;
+import java.io.IOException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * A utility class used by the diff cache interfaces {@link GitModifiedFilesCache} and {@link
+ * ModifiedFilesCache}.
+ */
+public class DiffUtil {
+
+  /**
+   * Returns the Git tree object ID pointed to by the commitId parameter.
+   *
+   * @param rw a {@link RevWalk} of an opened repository that is used to walk the commit graph.
+   * @param commitId 20 bytes commitId SHA-1 hash.
+   * @return Git tree object ID pointed to by the commitId.
+   */
+  public static ObjectId getTreeId(RevWalk rw, ObjectId commitId) throws IOException {
+    RevCommit current = rw.parseCommit(commitId);
+    return current.getTree().getId();
+  }
+
+  /**
+   * Returns the RevCommit object given the 20 bytes commitId SHA-1 hash.
+   *
+   * @param rw a {@link RevWalk} of an opened repository that is used to walk the commit graph.
+   * @param commitId 20 bytes commitId SHA-1 hash
+   * @return The RevCommit representing the commit in Git
+   * @throws IOException a pack file or loose object could not be read while parsing the commits.
+   */
+  public static RevCommit getRevCommit(RevWalk rw, ObjectId commitId) throws IOException {
+    return rw.parseCommit(commitId);
+  }
+
+  /**
+   * Returns true if the commitA and commitB parameters are parent/child, if they have a common
+   * parent, or if any of them is a root or merge commit.
+   */
+  public static boolean areRelated(RevCommit commitA, RevCommit commitB) {
+    return commitA == null
+        || isRootOrMergeCommit(commitA)
+        || isRootOrMergeCommit(commitB)
+        || areParentAndChild(commitA, commitB)
+        || haveCommonParent(commitA, commitB);
+  }
+
+  public static int stringSize(String str) {
+    if (str != null) {
+      // each character in the string occupies 2 bytes. Ignoring the fixed overhead for the string
+      // (length, offset and hash code) since they are negligible and do not affect the comparison
+      // of 2 strings.
+      return str.length() * 2;
+    }
+    return 0;
+  }
+
+  private static boolean isRootOrMergeCommit(RevCommit commit) {
+    return commit.getParentCount() != 1;
+  }
+
+  private static boolean areParentAndChild(RevCommit commitA, RevCommit commitB) {
+    return ObjectId.isEqual(commitA.getParent(0), commitB)
+        || ObjectId.isEqual(commitB.getParent(0), commitA);
+  }
+
+  private static boolean haveCommonParent(RevCommit commitA, RevCommit commitB) {
+    return ObjectId.isEqual(commitA.getParent(0), commitB.getParent(0));
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/GitPositionTransformer.java b/java/com/google/gerrit/server/patch/GitPositionTransformer.java
index d890bc2..f00f909 100644
--- a/java/com/google/gerrit/server/patch/GitPositionTransformer.java
+++ b/java/com/google/gerrit/server/patch/GitPositionTransformer.java
@@ -330,6 +330,11 @@
       return new AutoValue_GitPositionTransformer_FileMapping(
           Optional.of(oldPath), Optional.of(newPath));
     }
+
+    /** Creates a {@link FileMapping} using the old and new paths. */
+    public static FileMapping forFile(Optional<String> oldPath, Optional<String> newPath) {
+      return new AutoValue_GitPositionTransformer_FileMapping(oldPath, newPath);
+    }
   }
 
   /**
diff --git a/java/com/google/gerrit/server/patch/PatchListCacheImpl.java b/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
index b663b9d..a3e9a54 100644
--- a/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
+++ b/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
@@ -25,6 +25,7 @@
 import com.google.gerrit.server.cache.CacheBackend;
 import com.google.gerrit.server.cache.CacheModule;
 import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.patch.filediff.PatchListLoader;
 import com.google.inject.Inject;
 import com.google.inject.Module;
 import com.google.inject.Singleton;
@@ -37,7 +38,7 @@
 /** Provides a cached list of {@link PatchListEntry}. */
 @Singleton
 public class PatchListCacheImpl implements PatchListCache {
-  static final String FILE_NAME = "diff";
+  public static final String FILE_NAME = "diff";
   static final String INTRA_NAME = "diff_intraline";
   static final String DIFF_SUMMARY = "diff_summary";
 
diff --git a/java/com/google/gerrit/server/patch/PatchListEntry.java b/java/com/google/gerrit/server/patch/PatchListEntry.java
index c91355a..1d1d0ea 100644
--- a/java/com/google/gerrit/server/patch/PatchListEntry.java
+++ b/java/com/google/gerrit/server/patch/PatchListEntry.java
@@ -77,7 +77,7 @@
   // Note: When adding new fields, the serialVersionUID in PatchListKey must be
   // incremented so that entries from the cache are automatically invalidated.
 
-  PatchListEntry(
+  public PatchListEntry(
       FileHeader hdr, List<Edit> editList, Set<Edit> editsDueToRebase, long size, long sizeDelta) {
     changeType = toChangeType(hdr);
     patchType = toPatchType(hdr);
diff --git a/java/com/google/gerrit/server/patch/diff/ModifiedFilesCache.java b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCache.java
new file mode 100644
index 0000000..bcae238
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCache.java
@@ -0,0 +1,45 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.diff;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCache;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheImpl;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheKey;
+import com.google.gerrit.server.patch.gitdiff.ModifiedFile;
+
+/**
+ * A cache for the list of Git modified files between 2 commits (patchsets) with extra Gerrit logic.
+ *
+ * <p>The loader uses the underlying {@link GitModifiedFilesCacheImpl} to retrieve the git modified
+ * files.
+ *
+ * <p>If the {@link ModifiedFilesCacheKey#aCommit()} is equal to {@link
+ * org.eclipse.jgit.lib.Constants#EMPTY_TREE_ID}, the diff will be evaluated against the empty tree,
+ * and the result will be exactly the same as the caller can get from {@link
+ * GitModifiedFilesCache#get(GitModifiedFilesCacheKey)}
+ */
+public interface ModifiedFilesCache {
+
+  /**
+   * @param key used to identify two git commits and contains other attributes to control the diff
+   *     calculation.
+   * @return the list of {@link ModifiedFile}s between the 2 git commits identified by the key.
+   * @throws DiffNotAvailableException the supplied commits IDs of the key do no exist, are not IDs
+   *     of a commit, or an exception occurred while reading a pack file.
+   */
+  ImmutableList<ModifiedFile> get(ModifiedFilesCacheKey key) throws DiffNotAvailableException;
+}
diff --git a/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheImpl.java b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheImpl.java
new file mode 100644
index 0000000..6023c0e
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheImpl.java
@@ -0,0 +1,206 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.diff;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static org.eclipse.jgit.lib.Constants.EMPTY_TREE_ID;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import com.google.common.collect.Streams;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.gerrit.server.patch.DiffUtil;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCache;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheImpl;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheKey;
+import com.google.gerrit.server.patch.gitdiff.ModifiedFile;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.TypeLiteral;
+import com.google.inject.name.Named;
+import java.io.IOException;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Stream;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * A cache for the list of Git modified files between 2 commits (patchsets) with extra Gerrit logic.
+ *
+ * <p>The loader of this cache wraps a {@link GitModifiedFilesCache} to retrieve the git modified
+ * files.
+ *
+ * <p>If the {@link ModifiedFilesCacheKey#aCommit()} is equal to {@link
+ * org.eclipse.jgit.lib.Constants#EMPTY_TREE_ID}, the diff will be evaluated against the empty tree,
+ * and the result will be exactly the same as the caller can get from {@link
+ * GitModifiedFilesCache#get(GitModifiedFilesCacheKey)}
+ */
+public class ModifiedFilesCacheImpl implements ModifiedFilesCache {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private static final String MODIFIED_FILES = "modified_files";
+
+  private final LoadingCache<ModifiedFilesCacheKey, ImmutableList<ModifiedFile>> cache;
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        bind(ModifiedFilesCache.class).to(ModifiedFilesCacheImpl.class);
+
+        // The documentation has some defaults and recommendations for setting the cache
+        // attributes:
+        // https://gerrit-review.googlesource.com/Documentation/config-gerrit.html#cache.
+        // The cache is using the default disk limit as per section cache.<name>.diskLimit
+        // in the cache documentation link.
+        persist(
+                ModifiedFilesCacheImpl.MODIFIED_FILES,
+                ModifiedFilesCacheKey.class,
+                new TypeLiteral<ImmutableList<ModifiedFile>>() {})
+            .keySerializer(ModifiedFilesCacheKey.Serializer.INSTANCE)
+            .valueSerializer(GitModifiedFilesCacheImpl.ValueSerializer.INSTANCE)
+            .maximumWeight(10 << 20)
+            .weigher(ModifiedFilesWeigher.class)
+            .version(1)
+            .loader(ModifiedFilesLoader.class);
+      }
+    };
+  }
+
+  @Inject
+  public ModifiedFilesCacheImpl(
+      @Named(ModifiedFilesCacheImpl.MODIFIED_FILES)
+          LoadingCache<ModifiedFilesCacheKey, ImmutableList<ModifiedFile>> cache) {
+    this.cache = cache;
+  }
+
+  @Override
+  public ImmutableList<ModifiedFile> get(ModifiedFilesCacheKey key)
+      throws DiffNotAvailableException {
+    try {
+      return cache.get(key);
+    } catch (Exception e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  static class ModifiedFilesLoader
+      extends CacheLoader<ModifiedFilesCacheKey, ImmutableList<ModifiedFile>> {
+    private final GitModifiedFilesCache gitCache;
+    private final GitRepositoryManager repoManager;
+
+    @Inject
+    ModifiedFilesLoader(GitModifiedFilesCache gitCache, GitRepositoryManager repoManager) {
+      this.gitCache = gitCache;
+      this.repoManager = repoManager;
+    }
+
+    @Override
+    public ImmutableList<ModifiedFile> load(ModifiedFilesCacheKey key)
+        throws IOException, DiffNotAvailableException {
+      try (Repository repo = repoManager.openRepository(key.project());
+          RevWalk rw = new RevWalk(repo.newObjectReader())) {
+        return loadModifiedFiles(key, rw);
+      }
+    }
+
+    private ImmutableList<ModifiedFile> loadModifiedFiles(ModifiedFilesCacheKey key, RevWalk rw)
+        throws IOException, DiffNotAvailableException {
+      ObjectId aTree =
+          key.aCommit().equals(EMPTY_TREE_ID)
+              ? key.aCommit()
+              : DiffUtil.getTreeId(rw, key.aCommit());
+      ObjectId bTree = DiffUtil.getTreeId(rw, key.bCommit());
+      GitModifiedFilesCacheKey gitKey =
+          GitModifiedFilesCacheKey.builder()
+              .project(key.project())
+              .aTree(aTree)
+              .bTree(bTree)
+              .renameScore(key.renameScore())
+              .build();
+      List<ModifiedFile> modifiedFiles = gitCache.get(gitKey);
+      if (key.aCommit().equals(EMPTY_TREE_ID)) {
+        return ImmutableList.copyOf(modifiedFiles);
+      }
+      RevCommit revCommitA = DiffUtil.getRevCommit(rw, key.aCommit());
+      RevCommit revCommitB = DiffUtil.getRevCommit(rw, key.bCommit());
+      if (DiffUtil.areRelated(revCommitA, revCommitB)) {
+        return ImmutableList.copyOf(modifiedFiles);
+      }
+      Set<String> touchedFiles =
+          getTouchedFilesWithParents(
+              key, revCommitA.getParent(0).getId(), revCommitB.getParent(0).getId(), rw);
+      return modifiedFiles.stream()
+          .filter(f -> isTouched(touchedFiles, f))
+          .collect(toImmutableList());
+    }
+
+    /**
+     * Returns the paths of files that were modified between the old and new commits versus their
+     * parents (i.e. old commit vs. its parent, and new commit vs. its parent).
+     *
+     * @param key the {@link ModifiedFilesCacheKey} representing the commits we are diffing
+     * @param rw a {@link RevWalk} for the repository
+     * @return The list of modified files between the old/new commits and their parents
+     */
+    private Set<String> getTouchedFilesWithParents(
+        ModifiedFilesCacheKey key, ObjectId parentOfA, ObjectId parentOfB, RevWalk rw)
+        throws IOException {
+      try {
+        // TODO(ghareeb): as an enhancement: the 3 calls of the underlying git cache can be combined
+        GitModifiedFilesCacheKey oldVsBaseKey =
+            GitModifiedFilesCacheKey.create(
+                key.project(), parentOfA, key.aCommit(), key.renameScore(), rw);
+        List<ModifiedFile> oldVsBase = gitCache.get(oldVsBaseKey);
+
+        GitModifiedFilesCacheKey newVsBaseKey =
+            GitModifiedFilesCacheKey.create(
+                key.project(), parentOfB, key.bCommit(), key.renameScore(), rw);
+        List<ModifiedFile> newVsBase = gitCache.get(newVsBaseKey);
+
+        return Sets.union(getOldAndNewPaths(oldVsBase), getOldAndNewPaths(newVsBase));
+      } catch (DiffNotAvailableException e) {
+        logger.atWarning().log(
+            "Failed to retrieve the touched files' commits (%s, %s) and parents (%s, %s): %s",
+            key.aCommit(), key.bCommit(), parentOfA, parentOfB, e.getMessage());
+        return ImmutableSet.of();
+      }
+    }
+
+    private ImmutableSet<String> getOldAndNewPaths(List<ModifiedFile> files) {
+      return files.stream()
+          .flatMap(
+              file -> Stream.concat(Streams.stream(file.oldPath()), Streams.stream(file.newPath())))
+          .collect(ImmutableSet.toImmutableSet());
+    }
+
+    private static boolean isTouched(Set<String> touchedFilePaths, ModifiedFile modifiedFile) {
+      String oldFilePath = modifiedFile.oldPath().orElse(null);
+      String newFilePath = modifiedFile.newPath().orElse(null);
+      // One of the above file paths could be /dev/null but we need not explicitly check for this
+      // value as the set of file paths shouldn't contain it.
+      return touchedFilePaths.contains(oldFilePath) || touchedFilePaths.contains(newFilePath);
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheKey.java b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheKey.java
new file mode 100644
index 0000000..2ac3f5e
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/diff/ModifiedFilesCacheKey.java
@@ -0,0 +1,108 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.diff;
+
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.Project.NameKey;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.ModifiedFilesKeyProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import org.eclipse.jgit.lib.ObjectId;
+
+/** Cache key for the {@link com.google.gerrit.server.patch.diff.ModifiedFilesCache} */
+@AutoValue
+public abstract class ModifiedFilesCacheKey {
+
+  /** A specific git project / repository. */
+  public abstract Project.NameKey project();
+
+  /** @return the old commit ID used in the git tree diff */
+  public abstract ObjectId aCommit();
+
+  /** @return the new commit ID used in the git tree diff */
+  public abstract ObjectId bCommit();
+
+  /**
+   * Percentage score used to identify a file as a "rename". A special value of -1 means that the
+   * computation will ignore renames and rename detection will be disabled.
+   */
+  public abstract int renameScore();
+
+  public boolean renameDetectionEnabled() {
+    return renameScore() != -1;
+  }
+
+  /** Returns the size of the object in bytes */
+  public int weight() {
+    return stringSize(project().get()) // project
+        + 20 * 2 // aCommit and bCommit
+        + 4; // renameScore
+  }
+
+  public static ModifiedFilesCacheKey.Builder builder() {
+    return new AutoValue_ModifiedFilesCacheKey.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract ModifiedFilesCacheKey.Builder project(NameKey value);
+
+    public abstract ModifiedFilesCacheKey.Builder aCommit(ObjectId value);
+
+    public abstract ModifiedFilesCacheKey.Builder bCommit(ObjectId value);
+
+    public ModifiedFilesCacheKey.Builder disableRenameDetection() {
+      renameScore(-1);
+      return this;
+    }
+
+    public abstract ModifiedFilesCacheKey.Builder renameScore(int value);
+
+    public abstract ModifiedFilesCacheKey build();
+  }
+
+  public enum Serializer implements CacheSerializer<ModifiedFilesCacheKey> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(ModifiedFilesCacheKey key) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return Protos.toByteArray(
+          ModifiedFilesKeyProto.newBuilder()
+              .setProject(key.project().get())
+              .setACommit(idConverter.toByteString(key.aCommit()))
+              .setBCommit(idConverter.toByteString(key.bCommit()))
+              .setRenameScore(key.renameScore())
+              .build());
+    }
+
+    @Override
+    public ModifiedFilesCacheKey deserialize(byte[] in) {
+      ModifiedFilesKeyProto proto = Protos.parseUnchecked(ModifiedFilesKeyProto.parser(), in);
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return ModifiedFilesCacheKey.builder()
+          .project(NameKey.parse(proto.getProject()))
+          .aCommit(idConverter.fromByteString(proto.getACommit()))
+          .bCommit(idConverter.fromByteString(proto.getBCommit()))
+          .renameScore(proto.getRenameScore())
+          .build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/diff/ModifiedFilesWeigher.java b/java/com/google/gerrit/server/patch/diff/ModifiedFilesWeigher.java
new file mode 100644
index 0000000..512da6f
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/diff/ModifiedFilesWeigher.java
@@ -0,0 +1,31 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.diff;
+
+import com.google.common.cache.Weigher;
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.server.patch.gitdiff.ModifiedFile;
+
+public class ModifiedFilesWeigher
+    implements Weigher<ModifiedFilesCacheKey, ImmutableList<ModifiedFile>> {
+  @Override
+  public int weigh(ModifiedFilesCacheKey key, ImmutableList<ModifiedFile> modifiedFiles) {
+    int weight = key.weight();
+    for (ModifiedFile modifiedFile : modifiedFiles) {
+      weight += modifiedFile.weight();
+    }
+    return weight;
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/AllDiffsEvaluator.java b/java/com/google/gerrit/server/patch/filediff/AllDiffsEvaluator.java
new file mode 100644
index 0000000..12decc3
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/AllDiffsEvaluator.java
@@ -0,0 +1,218 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static org.eclipse.jgit.lib.Constants.EMPTY_TREE_ID;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.gerrit.server.patch.DiffUtil;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiff;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCache;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheKey;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * A helper class that computes the four {@link GitFileDiff}s for a list of {@link
+ * FileDiffCacheKey}s:
+ *
+ * <ul>
+ *   <li>old commit vs. new commit
+ *   <li>old parent vs. old commit
+ *   <li>new parent vs. new commit
+ *   <li>old parent vs. new parent
+ * </ul>
+ *
+ * The four {@link GitFileDiff} are stored in the entity class {@link AllFileGitDiffs}. We use these
+ * diffs to identify the edits due to rebase using the {@link EditTransformer} class.
+ */
+class AllDiffsEvaluator {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private final RevWalk rw;
+  private final GitFileDiffCache gitCache;
+
+  interface Factory {
+    AllDiffsEvaluator create(RevWalk rw);
+  }
+
+  @Inject
+  private AllDiffsEvaluator(GitFileDiffCache gitCache, @Assisted RevWalk rw) {
+    this.gitCache = gitCache;
+    this.rw = rw;
+  }
+
+  Map<AugmentedFileDiffCacheKey, AllFileGitDiffs> execute(
+      List<AugmentedFileDiffCacheKey> augmentedKeys) throws DiffNotAvailableException {
+    ImmutableMap.Builder<AugmentedFileDiffCacheKey, AllFileGitDiffs> keyToAllDiffs =
+        ImmutableMap.builderWithExpectedSize(augmentedKeys.size());
+
+    List<AugmentedFileDiffCacheKey> keysWithRebaseEdits =
+        augmentedKeys.stream().filter(k -> !k.ignoreRebase()).collect(Collectors.toList());
+
+    // TODO(ghareeb): as an enhancement, you can batch these calls as follows.
+    // First batch: "old commit vs. new commit" and "new parent vs. new commit"
+    // Second batch: "old parent vs. old commit" and "old parent vs. new parent"
+
+    Map<FileDiffCacheKey, GitDiffEntity> mainDiffs =
+        computeGitFileDiffs(
+            createGitKeys(
+                augmentedKeys,
+                k -> k.key().oldCommit(),
+                k -> k.key().newCommit(),
+                k -> k.key().newFilePath()));
+
+    Map<FileDiffCacheKey, GitDiffEntity> oldVsParentDiffs =
+        computeGitFileDiffs(
+            createGitKeys(
+                keysWithRebaseEdits,
+                k -> k.oldParentId().get(), // oldParent is set for keysWithRebaseEdits
+                k -> k.key().oldCommit(),
+                k -> mainDiffs.get(k.key()).gitDiff().oldPath().orElse(null)));
+
+    Map<FileDiffCacheKey, GitDiffEntity> newVsParentDiffs =
+        computeGitFileDiffs(
+            createGitKeys(
+                keysWithRebaseEdits,
+                k -> k.newParentId().get(), // newParent is set for keysWithRebaseEdits
+                k -> k.key().newCommit(),
+                k -> k.key().newFilePath()));
+
+    Map<FileDiffCacheKey, GitDiffEntity> parentsDiffs =
+        computeGitFileDiffs(
+            createGitKeys(
+                keysWithRebaseEdits,
+                k -> k.oldParentId().get(),
+                k -> k.newParentId().get(),
+                k -> {
+                  GitFileDiff newVsParDiff = newVsParentDiffs.get(k.key()).gitDiff();
+                  // TODO(ghareeb): Follow up on replacing key.newFilePath as a fallback.
+                  // If the file was added between newParent and newCommit, we actually wouldn't
+                  // need to have to determine the oldParent vs. newParent diff as nothing in
+                  // that file could be an edit due to rebase anymore. Only if the returned diff
+                  // is empty, the oldParent vs. newParent diff becomes relevant again (e.g. to
+                  // identify a file deletion which was due to rebase. Check if the structure
+                  // can be improved to make this clearer. Can we maybe even skip the diff in
+                  // the first situation described?
+                  return newVsParDiff.oldPath().orElse(k.key().newFilePath());
+                }));
+
+    for (AugmentedFileDiffCacheKey augmentedKey : augmentedKeys) {
+      FileDiffCacheKey key = augmentedKey.key();
+      AllFileGitDiffs.Builder builder =
+          AllFileGitDiffs.builder().augmentedKey(augmentedKey).mainDiff(mainDiffs.get(key));
+
+      if (augmentedKey.ignoreRebase()) {
+        keyToAllDiffs.put(augmentedKey, builder.build());
+        continue;
+      }
+
+      if (oldVsParentDiffs.containsKey(key) && !oldVsParentDiffs.get(key).gitDiff().isEmpty()) {
+        builder.oldVsParentDiff(Optional.of(oldVsParentDiffs.get(key)));
+      }
+
+      if (newVsParentDiffs.containsKey(key) && !newVsParentDiffs.get(key).gitDiff().isEmpty()) {
+        builder.newVsParentDiff(Optional.of(newVsParentDiffs.get(key)));
+      }
+
+      if (parentsDiffs.containsKey(key) && !parentsDiffs.get(key).gitDiff().isEmpty()) {
+        builder.parentVsParentDiff(Optional.of(parentsDiffs.get(key)));
+      }
+
+      keyToAllDiffs.put(augmentedKey, builder.build());
+    }
+    return keyToAllDiffs.build();
+  }
+
+  /**
+   * Computes the git diff for the git keys of the input map {@code keys} parameter. The computation
+   * uses the underlying {@link GitFileDiffCache}.
+   */
+  private Map<FileDiffCacheKey, GitDiffEntity> computeGitFileDiffs(
+      Map<FileDiffCacheKey, GitFileDiffCacheKey> keys) throws DiffNotAvailableException {
+    ImmutableMap.Builder<FileDiffCacheKey, GitDiffEntity> result =
+        ImmutableMap.builderWithExpectedSize(keys.size());
+    ImmutableMap<GitFileDiffCacheKey, GitFileDiff> gitDiffs = gitCache.getAll(keys.values());
+    for (FileDiffCacheKey key : keys.keySet()) {
+      GitFileDiffCacheKey gitKey = keys.get(key);
+      GitFileDiff gitFileDiff = gitDiffs.get(gitKey);
+      result.put(key, GitDiffEntity.create(gitKey, gitFileDiff));
+    }
+    return result.build();
+  }
+
+  /**
+   * Convert a list of {@link AugmentedFileDiffCacheKey} to their corresponding {@link
+   * GitFileDiffCacheKey} which can be used to call the underlying {@link GitFileDiffCache}.
+   *
+   * @param keys a list of input {@link AugmentedFileDiffCacheKey}s.
+   * @param aCommitFn a function to compute the aCommit that will be used in the git diff.
+   * @param bCommitFn a function to compute the bCommit that will be used in the git diff.
+   * @param newPathFn a function to compute the new path of the git key.
+   * @return a map of the input {@link FileDiffCacheKey} to the {@link GitFileDiffCacheKey}.
+   */
+  private Map<FileDiffCacheKey, GitFileDiffCacheKey> createGitKeys(
+      List<AugmentedFileDiffCacheKey> keys,
+      Function<AugmentedFileDiffCacheKey, ObjectId> aCommitFn,
+      Function<AugmentedFileDiffCacheKey, ObjectId> bCommitFn,
+      Function<AugmentedFileDiffCacheKey, String> newPathFn) {
+    Map<FileDiffCacheKey, GitFileDiffCacheKey> result = new HashMap<>();
+    for (AugmentedFileDiffCacheKey key : keys) {
+      try {
+        String path = newPathFn.apply(key);
+        if (path != null) {
+          result.put(
+              key.key(),
+              createGitKey(key.key(), aCommitFn.apply(key), bCommitFn.apply(key), path, rw));
+        }
+      } catch (IOException e) {
+        // TODO(ghareeb): This implies that the output keys may not have the same size as the input.
+        // Check the caller's code path about the correctness of the computation in this case. If
+        // errors are rare, it may be better to throw an exception and fail the whole computation.
+        logger.atWarning().log("Failed to compute the git key for key %s: %s", key, e.getMessage());
+      }
+    }
+    return result;
+  }
+
+  /** Returns the {@link GitFileDiffCacheKey} for the {@code key} input parameter. */
+  private GitFileDiffCacheKey createGitKey(
+      FileDiffCacheKey key, ObjectId aCommit, ObjectId bCommit, String pathNew, RevWalk rw)
+      throws IOException {
+    ObjectId oldTreeId =
+        aCommit.equals(EMPTY_TREE_ID) ? EMPTY_TREE_ID : DiffUtil.getTreeId(rw, aCommit);
+    ObjectId newTreeId = DiffUtil.getTreeId(rw, bCommit);
+    return GitFileDiffCacheKey.builder()
+        .project(key.project())
+        .oldTree(oldTreeId)
+        .newTree(newTreeId)
+        .newFilePath(pathNew == null ? key.newFilePath() : pathNew)
+        .renameScore(key.renameScore())
+        .diffAlgorithm(key.diffAlgorithm())
+        .whitespace(key.whitespace())
+        .build();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/AllFileGitDiffs.java b/java/com/google/gerrit/server/patch/filediff/AllFileGitDiffs.java
new file mode 100644
index 0000000..3b1886f
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/AllFileGitDiffs.java
@@ -0,0 +1,61 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.auto.value.AutoValue;
+import java.util.Optional;
+
+/**
+ * An entity containing the four git diffs for a {@link FileDiffCacheKey}:
+ *
+ * <ol>
+ *   <li>The old vs. new commit
+ *   <li>The old commit vs. the old parent
+ *   <li>The new commit vs. the new parent
+ *   <li>The old parent vs. the new parent
+ * </ol>
+ */
+@AutoValue
+abstract class AllFileGitDiffs {
+  abstract AugmentedFileDiffCacheKey augmentedKey();
+
+  abstract GitDiffEntity mainDiff();
+
+  abstract Optional<GitDiffEntity> oldVsParentDiff();
+
+  abstract Optional<GitDiffEntity> newVsParentDiff();
+
+  abstract Optional<GitDiffEntity> parentVsParentDiff();
+
+  static AllFileGitDiffs.Builder builder() {
+    return new AutoValue_AllFileGitDiffs.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder augmentedKey(AugmentedFileDiffCacheKey value);
+
+    public abstract Builder mainDiff(GitDiffEntity value);
+
+    public abstract Builder oldVsParentDiff(Optional<GitDiffEntity> value);
+
+    public abstract Builder newVsParentDiff(Optional<GitDiffEntity> value);
+
+    public abstract Builder parentVsParentDiff(Optional<GitDiffEntity> value);
+
+    public abstract AllFileGitDiffs build();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/AugmentedFileDiffCacheKey.java b/java/com/google/gerrit/server/patch/filediff/AugmentedFileDiffCacheKey.java
new file mode 100644
index 0000000..8e40452
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/AugmentedFileDiffCacheKey.java
@@ -0,0 +1,52 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.auto.value.AutoValue;
+import java.util.Optional;
+import org.eclipse.jgit.lib.ObjectId;
+
+/**
+ * A wrapper entity to the {@link FileDiffCacheKey} that also includes the old parent commit ID, the
+ * new parent commit ID and if we should ignore computing the rebase edits for that key.
+ */
+@AutoValue
+abstract class AugmentedFileDiffCacheKey {
+  abstract FileDiffCacheKey key();
+
+  abstract boolean ignoreRebase();
+
+  abstract Optional<ObjectId> oldParentId();
+
+  abstract Optional<ObjectId> newParentId();
+
+  static Builder builder() {
+    return new AutoValue_AugmentedFileDiffCacheKey.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder oldParentId(Optional<ObjectId> value);
+
+    public abstract Builder newParentId(Optional<ObjectId> value);
+
+    public abstract Builder ignoreRebase(boolean value);
+
+    public abstract Builder key(FileDiffCacheKey value);
+
+    public abstract AugmentedFileDiffCacheKey build();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/Edit.java b/java/com/google/gerrit/server/patch/filediff/Edit.java
new file mode 100644
index 0000000..4a698a4
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/Edit.java
@@ -0,0 +1,54 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.auto.value.AutoValue;
+
+/**
+ * A modified region between 2 versions of the same content. This is the Gerrit entity class
+ * corresponding to {@link org.eclipse.jgit.diff.Edit} and is needed to ensure immutability when
+ * included as fields of the diff persisted caches.
+ */
+@AutoValue
+public abstract class Edit {
+  public static Edit create(int beginA, int endA, int beginB, int endB) {
+    return new AutoValue_Edit(beginA, endA, beginB, endB);
+  }
+
+  public static Edit fromJGitEdit(org.eclipse.jgit.diff.Edit jgitEdit) {
+    return create(
+        jgitEdit.getBeginA(), jgitEdit.getEndA(), jgitEdit.getBeginB(), jgitEdit.getEndB());
+  }
+
+  public static org.eclipse.jgit.diff.Edit toJGitEdit(Edit e) {
+    return new org.eclipse.jgit.diff.Edit(e.beginA(), e.endA(), e.beginB(), e.endB());
+  }
+
+  public org.eclipse.jgit.diff.Edit asJGitEdit() {
+    return new org.eclipse.jgit.diff.Edit(beginA(), endA(), beginB(), endB());
+  }
+
+  /** Start of a region in sequence A. */
+  public abstract int beginA();
+
+  /** End of a region in sequence A. */
+  public abstract int endA();
+
+  /** Start of a region in sequence B. */
+  public abstract int beginB();
+
+  /** End of a region in sequence B. */
+  public abstract int endB();
+}
diff --git a/java/com/google/gerrit/server/patch/EditTransformer.java b/java/com/google/gerrit/server/patch/filediff/EditTransformer.java
similarity index 62%
rename from java/com/google/gerrit/server/patch/EditTransformer.java
rename to java/com/google/gerrit/server/patch/filediff/EditTransformer.java
index 6288270..55568e4 100644
--- a/java/com/google/gerrit/server/patch/EditTransformer.java
+++ b/java/com/google/gerrit/server/patch/filediff/EditTransformer.java
@@ -12,20 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.gerrit.server.patch;
+package com.google.gerrit.server.patch.filediff;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.Multimaps.toMultimap;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.MoreObjects;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Multimap;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Patch;
+import com.google.gerrit.server.patch.DiffMappings;
+import com.google.gerrit.server.patch.GitPositionTransformer;
 import com.google.gerrit.server.patch.GitPositionTransformer.Mapping;
 import com.google.gerrit.server.patch.GitPositionTransformer.OmitPositionOnConflict;
 import com.google.gerrit.server.patch.GitPositionTransformer.Position;
@@ -36,7 +37,6 @@
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.stream.Stream;
-import org.eclipse.jgit.diff.Edit;
 
 /**
  * Transformer of edits regarding their base trees. An edit describes a difference between {@code
@@ -54,40 +54,42 @@
 
   /**
    * Creates a new {@code EditTransformer} for the edits contained in the specified {@code
-   * PatchListEntry}s.
+   * FileEdits}s.
    *
-   * @param patchListEntries a list of {@code PatchListEntry}s containing the edits
+   * @param fileEdits a list of {@code FileEdits}s containing the edits
    */
-  public EditTransformer(List<PatchListEntry> patchListEntries) {
-    edits = patchListEntries.stream().flatMap(EditTransformer::toEdits).collect(toImmutableList());
+  public EditTransformer(List<FileEdits> fileEdits) {
+    // TODO(ghareeb): Can we replace FileEdits with another entity from the new refactored
+    // diff cache implementation? e.g. one of the GitFileDiffCache entities
+    edits = fileEdits.stream().flatMap(EditTransformer::toEdits).collect(toImmutableList());
   }
 
   /**
    * Transforms the references of side A of the edits. If the edits describe differences between
-   * {@code treeA} and {@code treeB} and the specified {@code PatchListEntry}s define a
-   * transformation from {@code treeA} to {@code treeA'}, the resulting edits will be defined as
-   * differences between {@code treeA'} and {@code treeB}. Edits which can't be transformed due to
-   * conflicts with the transformation are omitted.
+   * {@code treeA} and {@code treeB} and the specified {@code FileEdits}s define a transformation
+   * from {@code treeA} to {@code treeA'}, the resulting edits will be defined as differences
+   * between {@code treeA'} and {@code treeB}. Edits which can't be transformed due to conflicts
+   * with the transformation are omitted.
    *
-   * @param transformationEntries a list of {@code PatchListEntry}s defining the transformation of
-   *     {@code treeA} to {@code treeA'}
+   * @param transformingEntries a list of {@code FileEdits}s defining the transformation of {@code
+   *     treeA} to {@code treeA'}
    */
-  public void transformReferencesOfSideA(List<PatchListEntry> transformationEntries) {
-    transformEdits(transformationEntries, SideAStrategy.INSTANCE);
+  public void transformReferencesOfSideA(ImmutableList<FileEdits> transformingEntries) {
+    transformEdits(transformingEntries, SideAStrategy.INSTANCE);
   }
 
   /**
    * Transforms the references of side B of the edits. If the edits describe differences between
-   * {@code treeA} and {@code treeB} and the specified {@code PatchListEntry}s define a
-   * transformation from {@code treeB} to {@code treeB'}, the resulting edits will be defined as
-   * differences between {@code treeA} and {@code treeB'}. Edits which can't be transformed due to
-   * conflicts with the transformation are omitted.
+   * {@code treeA} and {@code treeB} and the specified {@code FileEdits}s define a transformation
+   * from {@code treeB} to {@code treeB'}, the resulting edits will be defined as differences
+   * between {@code treeA} and {@code treeB'}. Edits which can't be transformed due to conflicts
+   * with the transformation are omitted.
    *
-   * @param transformationEntries a list of {@code PatchListEntry}s defining the transformation of
+   * @param transformingEntries a list of {@code PatchListEntry}s defining the transformation of
    *     {@code treeB} to {@code treeB'}
    */
-  public void transformReferencesOfSideB(List<PatchListEntry> transformationEntries) {
-    transformEdits(transformationEntries, SideBStrategy.INSTANCE);
+  public void transformReferencesOfSideB(ImmutableList<FileEdits> transformingEntries) {
+    transformEdits(transformingEntries, SideBStrategy.INSTANCE);
   }
 
   /**
@@ -99,25 +101,33 @@
     return edits.stream()
         .collect(
             toMultimap(
-                ContextAwareEdit::getNewFilePath, Function.identity(), ArrayListMultimap::create));
+                c -> {
+                  String path =
+                      c.getNewFilePath().isPresent()
+                          ? c.getNewFilePath().get()
+                          : c.getOldFilePath().get();
+                  return path;
+                },
+                Function.identity(),
+                ArrayListMultimap::create));
   }
 
-  public static Stream<ContextAwareEdit> toEdits(PatchListEntry patchListEntry) {
-    ImmutableList<Edit> edits = patchListEntry.getEdits();
+  public static Stream<ContextAwareEdit> toEdits(FileEdits in) {
+    List<Edit> edits = in.edits();
     if (edits.isEmpty()) {
-      return Stream.of(ContextAwareEdit.createForNoContentEdit(patchListEntry));
+      return Stream.of(ContextAwareEdit.createForNoContentEdit(in.oldPath(), in.newPath()));
     }
 
-    return edits.stream().map(edit -> ContextAwareEdit.create(patchListEntry, edit));
+    return edits.stream().map(edit -> ContextAwareEdit.create(in.oldPath(), in.newPath(), edit));
   }
 
-  private void transformEdits(List<PatchListEntry> transformingEntries, SideStrategy sideStrategy) {
+  private void transformEdits(List<FileEdits> inputs, SideStrategy sideStrategy) {
     ImmutableList<PositionedEntity<ContextAwareEdit>> positionedEdits =
         edits.stream()
             .map(edit -> toPositionedEntity(edit, sideStrategy))
             .collect(toImmutableList());
     ImmutableSet<Mapping> mappings =
-        transformingEntries.stream().map(DiffMappings::toMapping).collect(toImmutableSet());
+        inputs.stream().map(DiffMappings::toMapping).collect(toImmutableSet());
 
     edits =
         positionTransformer.transform(positionedEdits, mappings).stream()
@@ -133,41 +143,41 @@
 
   @AutoValue
   abstract static class ContextAwareEdit {
-    static ContextAwareEdit create(PatchListEntry patchListEntry, Edit edit) {
+    static ContextAwareEdit create(Optional<String> oldPath, Optional<String> newPath, Edit edit) {
+      // TODO(ghareeb): Look if the new FileEdits class is capable of representing renames/copies
+      // and in this case we can get rid of the ContextAwareEdit class.
       return create(
-          patchListEntry.getOldName(),
-          patchListEntry.getNewName(),
-          edit.getBeginA(),
-          edit.getEndA(),
-          edit.getBeginB(),
-          edit.getEndB(),
-          false);
+          oldPath, newPath, edit.beginA(), edit.endA(), edit.beginB(), edit.endB(), false);
     }
 
-    static ContextAwareEdit createForNoContentEdit(PatchListEntry patchListEntry) {
+    static ContextAwareEdit createForNoContentEdit(
+        Optional<String> oldPath, Optional<String> newPath) {
       // Remove the warning in createEditAtNewPosition() if we switch to an empty range instead of
       // (-1:-1, -1:-1) in the future.
-      return create(
-          patchListEntry.getOldName(), patchListEntry.getNewName(), -1, -1, -1, -1, false);
+      return create(oldPath, newPath, -1, -1, -1, -1, false);
     }
 
     static ContextAwareEdit create(
-        String oldFilePath,
-        String newFilePath,
+        Optional<String> oldFilePath,
+        Optional<String> newFilePath,
         int beginA,
         int endA,
         int beginB,
         int endB,
         boolean filePathAdjusted) {
-      String adjustedOldFilePath = MoreObjects.firstNonNull(oldFilePath, newFilePath);
-      boolean implicitRename = !Objects.equals(oldFilePath, newFilePath) && filePathAdjusted;
+      Optional<String> adjustedFilePath = oldFilePath.isPresent() ? oldFilePath : newFilePath;
+      boolean implicitRename =
+          newFilePath.isPresent()
+              && oldFilePath.isPresent()
+              && !Objects.equals(oldFilePath.get(), newFilePath.get())
+              && filePathAdjusted;
       return new AutoValue_EditTransformer_ContextAwareEdit(
-          adjustedOldFilePath, newFilePath, beginA, endA, beginB, endB, implicitRename);
+          adjustedFilePath, newFilePath, beginA, endA, beginB, endB, implicitRename);
     }
 
-    public abstract String getOldFilePath();
+    public abstract Optional<String> getOldFilePath();
 
-    public abstract String getNewFilePath();
+    public abstract Optional<String> getNewFilePath();
 
     public abstract int getBeginA();
 
@@ -180,12 +190,13 @@
     // Used for equals(), for which this value is important.
     public abstract boolean isImplicitRename();
 
-    public Optional<Edit> toEdit() {
+    public Optional<org.eclipse.jgit.diff.Edit> toEdit() {
       if (getBeginA() < 0) {
         return Optional.empty();
       }
 
-      return Optional.of(new Edit(getBeginA(), getEndA(), getBeginB(), getEndB()));
+      return Optional.of(
+          new org.eclipse.jgit.diff.Edit(getBeginA(), getEndA(), getBeginB(), getEndB()));
     }
   }
 
@@ -200,8 +211,12 @@
 
     @Override
     public Position extractPosition(ContextAwareEdit edit) {
+      String filePath =
+          edit.getOldFilePath().isPresent()
+              ? edit.getOldFilePath().get()
+              : edit.getNewFilePath().get();
       return Position.builder()
-          .filePath(edit.getOldFilePath())
+          .filePath(filePath)
           .lineRange(Range.create(edit.getBeginA(), edit.getEndA()))
           .build();
     }
@@ -227,13 +242,13 @@
             newPosition);
       }
       return ContextAwareEdit.create(
-          updatedFilePath,
+          Optional.of(updatedFilePath),
           edit.getNewFilePath(),
           updatedRange.start(),
           updatedRange.end(),
           edit.getBeginB(),
           edit.getEndB(),
-          !Objects.equals(edit.getOldFilePath(), updatedFilePath));
+          !Objects.equals(edit.getOldFilePath(), Optional.of(updatedFilePath)));
     }
   }
 
@@ -242,8 +257,12 @@
 
     @Override
     public Position extractPosition(ContextAwareEdit edit) {
+      String filePath =
+          edit.getNewFilePath().isPresent()
+              ? edit.getNewFilePath().get()
+              : edit.getOldFilePath().get();
       return Position.builder()
-          .filePath(edit.getNewFilePath())
+          .filePath(filePath)
           .lineRange(Range.create(edit.getBeginB(), edit.getEndB()))
           .build();
     }
@@ -255,7 +274,8 @@
       // in the future.
       Range updatedRange = newPosition.lineRange().orElseGet(() -> Range.create(-1, -1));
       // Same as far the range above. PATCHSET_LEVEL is a safe fallback.
-      String updatedFilePath = newPosition.filePath().orElse(Patch.PATCHSET_LEVEL);
+      Optional<String> updatedFilePath =
+          Optional.of(newPosition.filePath().orElse(Patch.PATCHSET_LEVEL));
       return ContextAwareEdit.create(
           edit.getOldFilePath(),
           updatedFilePath,
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffCache.java b/java/com/google/gerrit/server/patch/filediff/FileDiffCache.java
new file mode 100644
index 0000000..a9bcf03
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffCache.java
@@ -0,0 +1,45 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+
+/**
+ * This cache computes the git diff for a single file path and adds some extra logic, e.g. for
+ * identifying edits that are due to rebase.
+ */
+public interface FileDiffCache {
+  /**
+   * Returns the file diff for a single file path identified by its key.
+   *
+   * @param key identifies two git commits, a specific file path and other diff parameters.
+   * @return the file diff for a single file path identified by its key.
+   * @throws DiffNotAvailableException if the commit IDs of the key are invalid for this project or
+   *     if file contents could not be read.
+   */
+  FileDiffOutput get(FileDiffCacheKey key) throws DiffNotAvailableException;
+
+  /**
+   * Returns the file diff for a collection of file paths identified by their keys.
+   *
+   * @param keys identifying different file paths of different projects.
+   * @return a map of the input keys to their corresponding git file diffs.
+   * @throws DiffNotAvailableException if the diff failed to be evaluated for one or more of the
+   *     input keys due to invalid commit IDs or if file contents could not be read.
+   */
+  ImmutableMap<FileDiffCacheKey, FileDiffOutput> getAll(Iterable<FileDiffCacheKey> keys)
+      throws DiffNotAvailableException;
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
new file mode 100644
index 0000000..091b02c
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
@@ -0,0 +1,509 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.eclipse.jgit.lib.Constants.EMPTY_TREE_ID;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Streams;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.patch.ComparisonType;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.gerrit.server.patch.DiffUtil;
+import com.google.gerrit.server.patch.Text;
+import com.google.gerrit.server.patch.filediff.EditTransformer.ContextAwareEdit;
+import com.google.gerrit.server.patch.gitfilediff.FileHeaderUtil;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiff;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithmFactory;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.name.Named;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.stream.Collectors;
+import org.eclipse.jgit.diff.EditList;
+import org.eclipse.jgit.diff.RawText;
+import org.eclipse.jgit.diff.RawTextComparator;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.patch.FileHeader;
+import org.eclipse.jgit.patch.FileHeader.PatchType;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * Cache for the single file diff between two commits for a single file path. This cache adds extra
+ * Gerrit logic such as identifying edits due to rebase.
+ *
+ * <p>If the {@link FileDiffCacheKey#oldCommit()} is equal to {@link
+ * org.eclipse.jgit.lib.Constants#EMPTY_TREE_ID}, the git diff will be evaluated against the empty
+ * tree.
+ */
+public class FileDiffCacheImpl implements FileDiffCache {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private static final String DIFF = "gerrit_file_diff";
+
+  private final LoadingCache<FileDiffCacheKey, FileDiffOutput> cache;
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        bind(FileDiffCache.class).to(FileDiffCacheImpl.class);
+
+        factory(AllDiffsEvaluator.Factory.class);
+
+        persist(DIFF, FileDiffCacheKey.class, FileDiffOutput.class)
+            .maximumWeight(10 << 20)
+            .weigher(FileDiffWeigher.class)
+            .keySerializer(FileDiffCacheKey.Serializer.INSTANCE)
+            .valueSerializer(FileDiffOutput.Serializer.INSTANCE)
+            .loader(FileDiffLoader.class);
+      }
+    };
+  }
+
+  private enum MagicPath {
+    COMMIT,
+    MERGE_LIST
+  }
+
+  @Inject
+  public FileDiffCacheImpl(@Named(DIFF) LoadingCache<FileDiffCacheKey, FileDiffOutput> cache) {
+    this.cache = cache;
+  }
+
+  @Override
+  public FileDiffOutput get(FileDiffCacheKey key) throws DiffNotAvailableException {
+    try {
+      return cache.get(key);
+    } catch (ExecutionException e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  @Override
+  public ImmutableMap<FileDiffCacheKey, FileDiffOutput> getAll(Iterable<FileDiffCacheKey> keys)
+      throws DiffNotAvailableException {
+    try {
+      ImmutableMap<FileDiffCacheKey, FileDiffOutput> result = cache.getAll(keys);
+      if (result.size() != Iterables.size(keys)) {
+        throw new DiffNotAvailableException(
+            String.format(
+                "Failed to load the value for all %d keys. Returned "
+                    + "map contains only %d values",
+                Iterables.size(keys), result.size()));
+      }
+      return result;
+    } catch (ExecutionException e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  static class FileDiffLoader extends CacheLoader<FileDiffCacheKey, FileDiffOutput> {
+    private final GitRepositoryManager repoManager;
+    private final AllDiffsEvaluator.Factory allDiffsEvaluatorFactory;
+
+    @Inject
+    FileDiffLoader(
+        AllDiffsEvaluator.Factory allDiffsEvaluatorFactory, GitRepositoryManager manager) {
+      this.allDiffsEvaluatorFactory = allDiffsEvaluatorFactory;
+      this.repoManager = manager;
+    }
+
+    @Override
+    public FileDiffOutput load(FileDiffCacheKey key) throws IOException, DiffNotAvailableException {
+      return loadAll(ImmutableList.of(key)).get(key);
+    }
+
+    @Override
+    public Map<FileDiffCacheKey, FileDiffOutput> loadAll(Iterable<? extends FileDiffCacheKey> keys)
+        throws DiffNotAvailableException {
+      ImmutableMap.Builder<FileDiffCacheKey, FileDiffOutput> result = ImmutableMap.builder();
+
+      Map<Project.NameKey, List<FileDiffCacheKey>> keysByProject =
+          Streams.stream(keys).distinct().collect(Collectors.groupingBy(FileDiffCacheKey::project));
+
+      for (Project.NameKey project : keysByProject.keySet()) {
+        List<FileDiffCacheKey> fileKeys = new ArrayList<>();
+
+        try (Repository repo = repoManager.openRepository(project);
+            ObjectReader reader = repo.newObjectReader();
+            RevWalk rw = new RevWalk(reader)) {
+
+          for (FileDiffCacheKey key : keysByProject.get(project)) {
+            if (key.newFilePath().equals(Patch.COMMIT_MSG)) {
+              result.put(key, createMagicPathEntry(key, reader, rw, MagicPath.COMMIT));
+            } else if (key.newFilePath().equals(Patch.MERGE_LIST)) {
+              result.put(key, createMagicPathEntry(key, reader, rw, MagicPath.MERGE_LIST));
+            } else {
+              fileKeys.add(key);
+            }
+          }
+          result.putAll(createFileEntries(reader, fileKeys, rw));
+        } catch (IOException e) {
+          logger.atWarning().log("Failed to open the repository %s: %s", project, e.getMessage());
+        }
+      }
+      return result.build();
+    }
+
+    private ComparisonType getComparisonType(RevWalk rw, ObjectId oldCommitId, ObjectId newCommitId)
+        throws IOException {
+      RevCommit oldCommit = DiffUtil.getRevCommit(rw, oldCommitId);
+      RevCommit newCommit = DiffUtil.getRevCommit(rw, newCommitId);
+      for (int i = 0; i < newCommit.getParentCount(); i++) {
+        if (newCommit.getParent(i).equals(oldCommit)) {
+          return ComparisonType.againstParent(i + 1);
+        }
+      }
+      if (newCommit.getParentCount() > 0) {
+        return ComparisonType.againstAutoMerge();
+      }
+      return ComparisonType.againstOtherPatchSet();
+    }
+
+    /**
+     * Creates a {@link FileDiffOutput} entry for the "Commit message" and "Merge list" file paths.
+     */
+    private FileDiffOutput createMagicPathEntry(
+        FileDiffCacheKey key, ObjectReader reader, RevWalk rw, MagicPath magicPath) {
+      try {
+        RawTextComparator cmp = comparatorFor(key.whitespace());
+        ComparisonType comparisonType = getComparisonType(rw, key.oldCommit(), key.newCommit());
+        RevCommit aCommit =
+            comparisonType.isAgainstParentOrAutoMerge()
+                ? null
+                : DiffUtil.getRevCommit(rw, key.oldCommit());
+        RevCommit bCommit = DiffUtil.getRevCommit(rw, key.newCommit());
+        return magicPath == MagicPath.COMMIT
+            ? createCommitEntry(reader, aCommit, bCommit, cmp, key.diffAlgorithm())
+            : createMergeListEntry(
+                reader, aCommit, bCommit, comparisonType, cmp, key.diffAlgorithm());
+      } catch (IOException e) {
+        logger.atWarning().log("Failed to compute commit entry for key " + key);
+      }
+      return FileDiffOutput.empty(key.newFilePath());
+    }
+
+    private static RawTextComparator comparatorFor(Whitespace ws) {
+      switch (ws) {
+        case IGNORE_ALL:
+          return RawTextComparator.WS_IGNORE_ALL;
+
+        case IGNORE_TRAILING:
+          return RawTextComparator.WS_IGNORE_TRAILING;
+
+        case IGNORE_LEADING_AND_TRAILING:
+          return RawTextComparator.WS_IGNORE_CHANGE;
+
+        case IGNORE_NONE:
+        default:
+          return RawTextComparator.DEFAULT;
+      }
+    }
+
+    private FileDiffOutput createCommitEntry(
+        ObjectReader reader,
+        RevCommit oldCommit,
+        RevCommit newCommit,
+        RawTextComparator rawTextComparator,
+        GitFileDiffCacheImpl.DiffAlgorithm diffAlgorithm)
+        throws IOException {
+      Text aText = newCommit != null ? Text.forCommit(reader, newCommit) : Text.EMPTY;
+      Text bText = Text.forCommit(reader, newCommit);
+      return createMagicFileDiffOutput(
+          rawTextComparator, oldCommit, aText, bText, Patch.COMMIT_MSG, diffAlgorithm);
+    }
+
+    private FileDiffOutput createMergeListEntry(
+        ObjectReader reader,
+        RevCommit oldCommit,
+        RevCommit newCommit,
+        ComparisonType comparisonType,
+        RawTextComparator rawTextComparator,
+        GitFileDiffCacheImpl.DiffAlgorithm diffAlgorithm)
+        throws IOException {
+      Text aText =
+          oldCommit != null ? Text.forMergeList(comparisonType, reader, oldCommit) : Text.EMPTY;
+      Text bText = Text.forMergeList(comparisonType, reader, newCommit);
+      return createMagicFileDiffOutput(
+          rawTextComparator, oldCommit, aText, bText, Patch.MERGE_LIST, diffAlgorithm);
+    }
+
+    private static FileDiffOutput createMagicFileDiffOutput(
+        RawTextComparator rawTextComparator,
+        RevCommit aCommit,
+        Text aText,
+        Text bText,
+        String fileName,
+        GitFileDiffCacheImpl.DiffAlgorithm diffAlgorithm) {
+      byte[] rawHdr = getRawHeader(aCommit != null, fileName);
+      byte[] aContent = aText.getContent();
+      byte[] bContent = bText.getContent();
+      long size = bContent.length;
+      long sizeDelta = size - aContent.length;
+      RawText aRawText = new RawText(aContent);
+      RawText bRawText = new RawText(bContent);
+      EditList edits =
+          DiffAlgorithmFactory.create(diffAlgorithm).diff(rawTextComparator, aRawText, bRawText);
+      FileHeader fileHeader = new FileHeader(rawHdr, edits, PatchType.UNIFIED);
+      Patch.ChangeType changeType = FileHeaderUtil.getChangeType(fileHeader);
+      return FileDiffOutput.builder()
+          .oldPath(FileHeaderUtil.getOldPath(fileHeader))
+          .newPath(FileHeaderUtil.getNewPath(fileHeader))
+          .changeType(Optional.of(changeType))
+          .patchType(Optional.of(FileHeaderUtil.getPatchType(fileHeader)))
+          .headerLines(FileHeaderUtil.getHeaderLines(fileHeader))
+          .edits(
+              asTaggedEdits(
+                  edits.stream().map(Edit::fromJGitEdit).collect(Collectors.toList()),
+                  ImmutableList.of()))
+          .size(size)
+          .sizeDelta(sizeDelta)
+          .build();
+    }
+
+    private static byte[] getRawHeader(boolean hasA, String fileName) {
+      StringBuilder hdr = new StringBuilder();
+      hdr.append("diff --git");
+      if (hasA) {
+        hdr.append(" a/").append(fileName);
+      } else {
+        hdr.append(" ").append(FileHeader.DEV_NULL);
+      }
+      hdr.append(" b/").append(fileName);
+      hdr.append("\n");
+
+      if (hasA) {
+        hdr.append("--- a/").append(fileName).append("\n");
+      } else {
+        hdr.append("--- ").append(FileHeader.DEV_NULL).append("\n");
+      }
+      hdr.append("+++ b/").append(fileName).append("\n");
+      return hdr.toString().getBytes(UTF_8);
+    }
+
+    private Map<FileDiffCacheKey, FileDiffOutput> createFileEntries(
+        ObjectReader reader, List<FileDiffCacheKey> keys, RevWalk rw)
+        throws DiffNotAvailableException, IOException {
+      Map<AugmentedFileDiffCacheKey, AllFileGitDiffs> allFileDiffs =
+          allDiffsEvaluatorFactory.create(rw).execute(wrapKeys(keys, rw));
+
+      Map<FileDiffCacheKey, FileDiffOutput> result = new HashMap<>();
+
+      for (AugmentedFileDiffCacheKey augmentedKey : allFileDiffs.keySet()) {
+        AllFileGitDiffs allDiffs = allFileDiffs.get(augmentedKey);
+
+        FileEdits rebaseFileEdits = FileEdits.empty();
+        if (!augmentedKey.ignoreRebase()) {
+          rebaseFileEdits = computeRebaseEdits(allDiffs);
+        }
+        List<Edit> rebaseEdits = rebaseFileEdits.edits();
+
+        RevTree aTree = rw.parseTree(allDiffs.mainDiff().gitKey().oldTree());
+        RevTree bTree = rw.parseTree(allDiffs.mainDiff().gitKey().newTree());
+        GitFileDiff mainGitDiff = allDiffs.mainDiff().gitDiff();
+
+        Long oldSize =
+            mainGitDiff.oldPath().isPresent()
+                ? new FileSizeEvaluator(reader, aTree)
+                    .compute(
+                        mainGitDiff.oldId(),
+                        mainGitDiff.oldMode().get(),
+                        mainGitDiff.oldPath().get())
+                : 0;
+        Long newSize =
+            mainGitDiff.newPath().isPresent()
+                ? new FileSizeEvaluator(reader, bTree)
+                    .compute(
+                        mainGitDiff.newId(),
+                        mainGitDiff.newMode().get(),
+                        mainGitDiff.newPath().get())
+                : 0;
+
+        FileDiffOutput fileDiff =
+            FileDiffOutput.builder()
+                .changeType(mainGitDiff.changeType())
+                .patchType(mainGitDiff.patchType())
+                .oldPath(mainGitDiff.oldPath())
+                .newPath(mainGitDiff.newPath())
+                .headerLines(FileHeaderUtil.getHeaderLines(mainGitDiff.fileHeader()))
+                .edits(asTaggedEdits(mainGitDiff.edits(), rebaseEdits))
+                .size(newSize)
+                .sizeDelta(newSize - oldSize)
+                .build();
+
+        result.put(augmentedKey.key(), fileDiff);
+      }
+
+      return result;
+    }
+
+    /**
+     * Convert the list of input keys {@link FileDiffCacheKey} to a list of {@link
+     * AugmentedFileDiffCacheKey} that also include the old and new parent commit IDs, and a boolean
+     * that indicates whether we should include the rebase edits for each key.
+     *
+     * <p>The output list is expected to have the same size of the input list, i.e. we map all keys.
+     */
+    private List<AugmentedFileDiffCacheKey> wrapKeys(List<FileDiffCacheKey> keys, RevWalk rw) {
+      List<AugmentedFileDiffCacheKey> result = new ArrayList<>();
+      for (FileDiffCacheKey key : keys) {
+        if (key.oldCommit().equals(EMPTY_TREE_ID)) {
+          result.add(AugmentedFileDiffCacheKey.builder().key(key).ignoreRebase(true).build());
+          continue;
+        }
+        try {
+          RevCommit oldRevCommit = DiffUtil.getRevCommit(rw, key.oldCommit());
+          RevCommit newRevCommit = DiffUtil.getRevCommit(rw, key.newCommit());
+          if (!DiffUtil.areRelated(oldRevCommit, newRevCommit)) {
+            result.add(
+                AugmentedFileDiffCacheKey.builder()
+                    .key(key)
+                    .oldParentId(Optional.of(oldRevCommit.getParent(0).getId()))
+                    .newParentId(Optional.of(newRevCommit.getParent(0).getId()))
+                    .ignoreRebase(false)
+                    .build());
+          } else {
+            result.add(AugmentedFileDiffCacheKey.builder().key(key).ignoreRebase(true).build());
+          }
+        } catch (IOException e) {
+          logger.atWarning().log(
+              "Failed to evaluate commits relation for key "
+                  + key
+                  + ". Skipping this key: "
+                  + e.getMessage(),
+              e);
+          result.add(AugmentedFileDiffCacheKey.builder().key(key).ignoreRebase(true).build());
+        }
+      }
+      return result;
+    }
+
+    private static ImmutableList<TaggedEdit> asTaggedEdits(
+        List<Edit> normalEdits, List<Edit> rebaseEdits) {
+      Set<Edit> rebaseEditsSet = new HashSet(rebaseEdits);
+      ImmutableList.Builder<TaggedEdit> result =
+          ImmutableList.builderWithExpectedSize(normalEdits.size());
+      for (Edit e : normalEdits) {
+        result.add(TaggedEdit.create(e, rebaseEditsSet.contains(e)));
+      }
+      return result.build();
+    }
+
+    /**
+     * Computes the subset of edits that are due to rebase between 2 commits.
+     *
+     * <p>The input parameter {@link AllFileGitDiffs#mainDiff} contains all the edits in
+     * consideration. Of those, we identify the edits due to rebase as a function of:
+     *
+     * <ol>
+     *   <li>The edits between the old commit and its parent {@link
+     *       AllFileGitDiffs#oldVsParentDiff}.
+     *   <li>The edits between the new commit and its parent {@link
+     *       AllFileGitDiffs#newVsParentDiff}.
+     *   <li>The edits between the parents of the old commit and new commits {@link
+     *       AllFileGitDiffs#parentVsParentDiff}.
+     * </ol>
+     *
+     * @param diffs an entity containing 4 sets of edits: those between the old and new commit,
+     *     between the old and new commits vs. their parents, and between the old and new parents.
+     * @return the list of edits that are due to rebase.
+     */
+    private FileEdits computeRebaseEdits(AllFileGitDiffs diffs) {
+      if (!diffs.parentVsParentDiff().isPresent()) {
+        return FileEdits.empty();
+      }
+
+      GitFileDiff parentVsParentDiff = diffs.parentVsParentDiff().get().gitDiff();
+
+      EditTransformer editTransformer =
+          new EditTransformer(
+              ImmutableList.of(
+                  FileEdits.create(
+                      parentVsParentDiff.edits().stream()
+                          .map(Edit::toJGitEdit)
+                          .collect(Collectors.toList()),
+                      parentVsParentDiff.oldPath(),
+                      parentVsParentDiff.newPath())));
+
+      if (diffs.oldVsParentDiff().isPresent()) {
+        GitFileDiff oldVsParDiff = diffs.oldVsParentDiff().get().gitDiff();
+        editTransformer.transformReferencesOfSideA(
+            ImmutableList.of(
+                FileEdits.create(
+                    oldVsParDiff.edits().stream()
+                        .map(Edit::toJGitEdit)
+                        .collect(Collectors.toList()),
+                    oldVsParDiff.oldPath(),
+                    oldVsParDiff.newPath())));
+      }
+
+      if (diffs.newVsParentDiff().isPresent()) {
+        GitFileDiff newVsParDiff = diffs.newVsParentDiff().get().gitDiff();
+        editTransformer.transformReferencesOfSideB(
+            ImmutableList.of(
+                FileEdits.create(
+                    newVsParDiff.edits().stream()
+                        .map(Edit::toJGitEdit)
+                        .collect(Collectors.toList()),
+                    newVsParDiff.oldPath(),
+                    newVsParDiff.newPath())));
+      }
+
+      Multimap<String, ContextAwareEdit> editsPerFilePath = editTransformer.getEditsPerFilePath();
+
+      if (editsPerFilePath.isEmpty()) {
+        return FileEdits.empty();
+      }
+
+      // editsPerFilePath is expected to have a single item representing the file
+      String filePath = editsPerFilePath.keys().iterator().next();
+      Collection<ContextAwareEdit> edits = editsPerFilePath.get(filePath);
+      return FileEdits.create(
+          Streams.stream(edits)
+              .map(ContextAwareEdit::toEdit)
+              .filter(Optional::isPresent)
+              .map(Optional::get)
+              .collect(Collectors.toList()),
+          edits.iterator().next().getOldFilePath(),
+          edits.iterator().next().getNewFilePath());
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheKey.java b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheKey.java
new file mode 100644
index 0000000..a478fcf
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheKey.java
@@ -0,0 +1,130 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.Project.NameKey;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.FileDiffKeyProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithm;
+import org.eclipse.jgit.lib.ObjectId;
+
+/** Cache key for the {@link FileDiffCache}. */
+@AutoValue
+public abstract class FileDiffCacheKey {
+
+  /** A specific git project / repository. */
+  public abstract Project.NameKey project();
+
+  /** The 20 bytes SHA-1 commit ID of the old commit used in the diff. */
+  public abstract ObjectId oldCommit();
+
+  /** The 20 bytes SHA-1 commit ID of the new commit used in the diff. */
+  public abstract ObjectId newCommit();
+
+  /** File path identified by its name. */
+  public abstract String newFilePath();
+
+  /**
+   * Percentage score used to identify a file as a "rename". A special value of -1 means that the
+   * computation will ignore renames and rename detection will be disabled.
+   */
+  public abstract int renameScore();
+
+  /** The diff algorithm that should be used in the computation. */
+  public abstract DiffAlgorithm diffAlgorithm();
+
+  public abstract DiffPreferencesInfo.Whitespace whitespace();
+
+  /** Number of bytes that this entity occupies. */
+  public int weight() {
+    return stringSize(project().get())
+        + 20 * 2 // old and new commits
+        + stringSize(newFilePath())
+        + 4 // renameScore
+        + 4 // diffAlgorithm
+        + 4; // whitespace
+  }
+
+  public static FileDiffCacheKey.Builder builder() {
+    return new AutoValue_FileDiffCacheKey.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract FileDiffCacheKey.Builder project(NameKey value);
+
+    public abstract FileDiffCacheKey.Builder oldCommit(ObjectId value);
+
+    public abstract FileDiffCacheKey.Builder newCommit(ObjectId value);
+
+    public abstract FileDiffCacheKey.Builder newFilePath(String value);
+
+    public abstract FileDiffCacheKey.Builder renameScore(int value);
+
+    public FileDiffCacheKey.Builder disableRenameDetection() {
+      renameScore(-1);
+      return this;
+    }
+
+    public abstract FileDiffCacheKey.Builder diffAlgorithm(DiffAlgorithm value);
+
+    public abstract FileDiffCacheKey.Builder whitespace(Whitespace value);
+
+    public abstract FileDiffCacheKey build();
+  }
+
+  public enum Serializer implements CacheSerializer<FileDiffCacheKey> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(FileDiffCacheKey key) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return Protos.toByteArray(
+          FileDiffKeyProto.newBuilder()
+              .setProject(key.project().get())
+              .setOldCommit(idConverter.toByteString(key.oldCommit()))
+              .setNewCommit(idConverter.toByteString(key.newCommit()))
+              .setFilePath(key.newFilePath())
+              .setRenameScore(key.renameScore())
+              .setDiffAlgorithm(key.diffAlgorithm().name())
+              .setWhitespace(key.whitespace().name())
+              .build());
+    }
+
+    @Override
+    public FileDiffCacheKey deserialize(byte[] in) {
+      FileDiffKeyProto proto = Protos.parseUnchecked(FileDiffKeyProto.parser(), in);
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return FileDiffCacheKey.builder()
+          .project(Project.nameKey(proto.getProject()))
+          .oldCommit(idConverter.fromByteString(proto.getOldCommit()))
+          .newCommit(idConverter.fromByteString(proto.getNewCommit()))
+          .newFilePath(proto.getFilePath())
+          .renameScore(proto.getRenameScore())
+          .diffAlgorithm(DiffAlgorithm.valueOf(proto.getDiffAlgorithm()))
+          .whitespace(Whitespace.valueOf(proto.getWhitespace()))
+          .build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
new file mode 100644
index 0000000..e89f148
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
@@ -0,0 +1,255 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.entities.Patch.PatchType;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.FileDiffOutputProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import java.io.Serializable;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+/** File diff for a single file path. Produced as output of the {@link FileDiffCache}. */
+@AutoValue
+public abstract class FileDiffOutput implements Serializable {
+
+  /**
+   * The file path at the old commit. Returns an empty Optional if {@link #changeType()} is equal to
+   * {@link ChangeType#ADDED}.
+   */
+  public abstract Optional<String> oldPath();
+
+  /**
+   * The file path at the new commit. Returns an empty optional if {@link #changeType()} is equal to
+   * {@link ChangeType#DELETED}.
+   */
+  public abstract Optional<String> newPath();
+
+  /** The change type of the underlying file, e.g. added, deleted, renamed, etc... */
+  public abstract Optional<Patch.ChangeType> changeType();
+
+  /** The patch type of the underlying file, e.g. unified, binary , etc... */
+  public abstract Optional<Patch.PatchType> patchType();
+
+  /**
+   * A list of strings representation of the header lines of the {@link
+   * org.eclipse.jgit.patch.FileHeader} that is produced as output of the diff.
+   */
+  public abstract ImmutableList<String> headerLines();
+
+  /** The list of edits resulting from the diff hunks of the file. */
+  public abstract ImmutableList<TaggedEdit> edits();
+
+  /** The file size at the new commit. */
+  public abstract long size();
+
+  /** Difference in file size between the old and new commits. */
+  public abstract long sizeDelta();
+
+  /** A boolean indicating if all underlying edits of the file diff are due to rebase. */
+  public boolean allEditsDueToRebase() {
+    return !edits().isEmpty() && edits().stream().allMatch(TaggedEdit::dueToRebase);
+  }
+
+  /** Returns the number of inserted lines for the file diff. */
+  public int insertions() {
+    int ins = 0;
+    for (TaggedEdit e : edits()) {
+      if (!e.dueToRebase()) {
+        ins += e.edit().endB() - e.edit().beginB();
+      }
+    }
+    return ins;
+  }
+
+  /** Returns the number of deleted lines for the file diff. */
+  public int deletions() {
+    int del = 0;
+    for (TaggedEdit e : edits()) {
+      if (!e.dueToRebase()) {
+        del += e.edit().endA() - e.edit().beginA();
+      }
+    }
+    return del;
+  }
+
+  /** Returns an entity representing an unchanged file between two commits. */
+  static FileDiffOutput empty(String filePath) {
+    return builder()
+        .oldPath(Optional.empty())
+        .newPath(Optional.of(filePath))
+        .headerLines(ImmutableList.of())
+        .edits(ImmutableList.of())
+        .size(0)
+        .sizeDelta(0)
+        .build();
+  }
+
+  /** Returns true if this entity represents an unchanged file between two commits. */
+  public boolean isEmpty() {
+    return headerLines().isEmpty() && edits().isEmpty();
+  }
+
+  public static Builder builder() {
+    return new AutoValue_FileDiffOutput.Builder();
+  }
+
+  public int weight() {
+    int result = 0;
+    if (oldPath().isPresent()) {
+      result += stringSize(oldPath().get());
+    }
+    if (newPath().isPresent()) {
+      result += stringSize(newPath().get());
+    }
+    if (changeType().isPresent()) {
+      result += 4;
+    }
+    if (patchType().isPresent()) {
+      result += 4;
+    }
+    result += 4 + 4; // insertions and deletions
+    result += 4 + 4; // size and size delta
+    result += 20 * edits().size(); // each edit is 4 Integers + boolean = 4 * 4 + 4 = 20
+    for (String s : headerLines()) {
+      s += stringSize(s);
+    }
+    return result;
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder oldPath(Optional<String> value);
+
+    public abstract Builder newPath(Optional<String> value);
+
+    public abstract Builder changeType(Optional<ChangeType> value);
+
+    public abstract Builder patchType(Optional<PatchType> value);
+
+    public abstract Builder headerLines(ImmutableList<String> value);
+
+    public abstract Builder edits(ImmutableList<TaggedEdit> value);
+
+    public abstract Builder size(long value);
+
+    public abstract Builder sizeDelta(long value);
+
+    public abstract FileDiffOutput build();
+  }
+
+  public enum Serializer implements CacheSerializer<FileDiffOutput> {
+    INSTANCE;
+
+    private static final FieldDescriptor OLD_PATH_DESCRIPTOR =
+        FileDiffOutputProto.getDescriptor().findFieldByNumber(1);
+
+    private static final FieldDescriptor NEW_PATH_DESCRIPTOR =
+        FileDiffOutputProto.getDescriptor().findFieldByNumber(2);
+
+    private static final FieldDescriptor CHANGE_TYPE_DESCRIPTOR =
+        FileDiffOutputProto.getDescriptor().findFieldByNumber(3);
+
+    private static final FieldDescriptor PATCH_TYPE_DESCRIPTOR =
+        FileDiffOutputProto.getDescriptor().findFieldByNumber(4);
+
+    @Override
+    public byte[] serialize(FileDiffOutput fileDiff) {
+      FileDiffOutputProto.Builder builder =
+          FileDiffOutputProto.newBuilder()
+              .setSize(fileDiff.size())
+              .setSizeDelta(fileDiff.sizeDelta())
+              .addAllHeaderLines(fileDiff.headerLines())
+              .addAllEdits(
+                  fileDiff.edits().stream()
+                      .map(
+                          e ->
+                              FileDiffOutputProto.TaggedEdit.newBuilder()
+                                  .setEdit(
+                                      FileDiffOutputProto.Edit.newBuilder()
+                                          .setBeginA(e.edit().beginA())
+                                          .setEndA(e.edit().endA())
+                                          .setBeginB(e.edit().beginB())
+                                          .setEndB(e.edit().endB())
+                                          .build())
+                                  .setDueToRebase(e.dueToRebase())
+                                  .build())
+                      .collect(Collectors.toList()));
+
+      if (fileDiff.oldPath().isPresent()) {
+        builder.setOldPath(fileDiff.oldPath().get());
+      }
+
+      if (fileDiff.newPath().isPresent()) {
+        builder.setNewPath(fileDiff.newPath().get());
+      }
+
+      if (fileDiff.changeType().isPresent()) {
+        builder.setChangeType(fileDiff.changeType().get().name());
+      }
+
+      if (fileDiff.patchType().isPresent()) {
+        builder.setPatchType(fileDiff.patchType().get().name());
+      }
+
+      return Protos.toByteArray(builder.build());
+    }
+
+    @Override
+    public FileDiffOutput deserialize(byte[] in) {
+      FileDiffOutputProto proto = Protos.parseUnchecked(FileDiffOutputProto.parser(), in);
+      FileDiffOutput.Builder builder = FileDiffOutput.builder();
+      builder
+          .size(proto.getSize())
+          .sizeDelta(proto.getSizeDelta())
+          .headerLines(proto.getHeaderLinesList().stream().collect(ImmutableList.toImmutableList()))
+          .edits(
+              proto.getEditsList().stream()
+                  .map(
+                      e ->
+                          TaggedEdit.create(
+                              Edit.create(
+                                  e.getEdit().getBeginA(),
+                                  e.getEdit().getEndA(),
+                                  e.getEdit().getBeginB(),
+                                  e.getEdit().getEndB()),
+                              e.getDueToRebase()))
+                  .collect(ImmutableList.toImmutableList()));
+
+      if (proto.hasField(OLD_PATH_DESCRIPTOR)) {
+        builder.oldPath(Optional.of(proto.getOldPath()));
+      }
+      if (proto.hasField(NEW_PATH_DESCRIPTOR)) {
+        builder.newPath(Optional.of(proto.getNewPath()));
+      }
+      if (proto.hasField(CHANGE_TYPE_DESCRIPTOR)) {
+        builder.changeType(Optional.of(Patch.ChangeType.valueOf(proto.getChangeType())));
+      }
+      if (proto.hasField(PATCH_TYPE_DESCRIPTOR)) {
+        builder.patchType(Optional.of(Patch.PatchType.valueOf(proto.getPatchType())));
+      }
+      return builder.build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffWeigher.java b/java/com/google/gerrit/server/patch/filediff/FileDiffWeigher.java
new file mode 100644
index 0000000..8eda234
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffWeigher.java
@@ -0,0 +1,29 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.common.cache.Weigher;
+
+/**
+ * A weigher for the {@link FileDiffCache} key and value. This is used by the cache backend to
+ * assign weights for cache entries and is used for evictions.
+ */
+public class FileDiffWeigher implements Weigher<FileDiffCacheKey, FileDiffOutput> {
+
+  @Override
+  public int weigh(FileDiffCacheKey key, FileDiffOutput fileDiffOutput) {
+    return key.weight() + fileDiffOutput.weight();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileEdits.java b/java/com/google/gerrit/server/patch/filediff/FileEdits.java
new file mode 100644
index 0000000..376bbc2
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileEdits.java
@@ -0,0 +1,48 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * An entity class containing the list of edits between two commits for a file, and the old and new
+ * paths.
+ */
+@AutoValue
+public abstract class FileEdits {
+  public static FileEdits create(
+      List<org.eclipse.jgit.diff.Edit> jgitEdits,
+      Optional<String> oldPath,
+      Optional<String> newPath) {
+    ImmutableList<Edit> edits =
+        jgitEdits.stream().map(Edit::fromJGitEdit).collect(toImmutableList());
+    return new AutoValue_FileEdits(edits, oldPath, newPath);
+  }
+
+  public abstract ImmutableList<Edit> edits();
+
+  public abstract Optional<String> oldPath();
+
+  public abstract Optional<String> newPath();
+
+  public static FileEdits empty() {
+    return new AutoValue_FileEdits(ImmutableList.of(), Optional.empty(), Optional.empty());
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/FileSizeEvaluator.java b/java/com/google/gerrit/server/patch/filediff/FileSizeEvaluator.java
new file mode 100644
index 0000000..97b55dc
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/FileSizeEvaluator.java
@@ -0,0 +1,95 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.entities.Patch.FileMode;
+import com.google.gerrit.exceptions.StorageException;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Optional;
+import org.eclipse.jgit.lib.AbbreviatedObjectId;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.treewalk.TreeWalk;
+
+/** Helper class for computing the size of a file in a given git tree. */
+class FileSizeEvaluator {
+  private final ObjectReader reader;
+  private final RevTree tree;
+
+  FileSizeEvaluator(ObjectReader reader, RevTree tree) {
+    this.reader = reader;
+    this.tree = tree;
+  }
+
+  /**
+   * Computes the file size identified by the {@code path} parameter at the given git tree
+   * identified by {@code gitTreeId}.
+   */
+  long compute(AbbreviatedObjectId gitTreeId, Patch.FileMode mode, String path) throws IOException {
+    if (!isBlob(mode)) {
+      return 0;
+    }
+    ObjectId fileId =
+        toObjectId(reader, gitTreeId).orElseGet(() -> lookupObjectId(reader, path, tree));
+    if (ObjectId.zeroId().equals(fileId)) {
+      return 0;
+    }
+    return reader.getObjectSize(fileId, OBJ_BLOB);
+  }
+
+  private static ObjectId lookupObjectId(ObjectReader reader, String path, RevTree tree) {
+    // This variant is very expensive.
+    try (TreeWalk treeWalk = TreeWalk.forPath(reader, path, tree)) {
+      return treeWalk != null ? treeWalk.getObjectId(0) : ObjectId.zeroId();
+    } catch (IOException e) {
+      throw new StorageException(e);
+    }
+  }
+
+  private static Optional<ObjectId> toObjectId(
+      ObjectReader reader, @Nullable AbbreviatedObjectId abbreviatedId) throws IOException {
+    if (abbreviatedId == null) {
+      // In theory, DiffEntry#getOldId or DiffEntry#getNewId can be null for pure renames or pure
+      // mode changes (e.g. DiffEntry#modify doesn't set the IDs). However, the method we call for
+      // diffs (DiffFormatter#scan) seems to always produce DiffEntries with set IDs, even for pure
+      // renames.
+      return Optional.empty();
+    }
+    if (abbreviatedId.isComplete()) {
+      // With the current JGit version and the method we call for diffs (DiffFormatter#scan),
+      // this
+      // is the only code path taken right now.
+      return Optional.ofNullable(abbreviatedId.toObjectId());
+    }
+    Collection<ObjectId> objectIds = reader.resolve(abbreviatedId);
+    // It seems very unlikely that an ObjectId which was just abbreviated by the diff
+    // computation
+    // now can't be resolved to exactly one ObjectId. The API allows this possibility, though.
+    return objectIds.size() == 1
+        ? Optional.of(Iterables.getOnlyElement(objectIds))
+        : Optional.empty();
+  }
+
+  private static boolean isBlob(Patch.FileMode mode) {
+    return mode.equals(FileMode.REGULAR_FILE) || mode.equals(FileMode.SYMLINK);
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/filediff/GitDiffEntity.java b/java/com/google/gerrit/server/patch/filediff/GitDiffEntity.java
new file mode 100644
index 0000000..2ca8fa6
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/GitDiffEntity.java
@@ -0,0 +1,31 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiff;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheKey;
+
+/** An entity containing a {@link GitFileDiffCacheKey} and its loaded value {@link GitFileDiff}. */
+@AutoValue
+abstract class GitDiffEntity {
+  public static GitDiffEntity create(GitFileDiffCacheKey gitKey, GitFileDiff gitDiff) {
+    return new AutoValue_GitDiffEntity(gitKey, gitDiff);
+  }
+
+  abstract GitFileDiffCacheKey gitKey();
+
+  abstract GitFileDiff gitDiff();
+}
diff --git a/java/com/google/gerrit/server/patch/PatchListLoader.java b/java/com/google/gerrit/server/patch/filediff/PatchListLoader.java
similarity index 89%
rename from java/com/google/gerrit/server/patch/PatchListLoader.java
rename to java/com/google/gerrit/server/patch/filediff/PatchListLoader.java
index be0895b..5b7eddb 100644
--- a/java/com/google/gerrit/server/patch/PatchListLoader.java
+++ b/java/com/google/gerrit/server/patch/filediff/PatchListLoader.java
@@ -1,19 +1,21 @@
-// Copyright (C) 2009 The Android Open Source Project
+//  Copyright (C) 2020 The Android Open Source Project
 //
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
 //
-// http://www.apache.org/licenses/LICENSE-2.0
+//  http://www.apache.org/licenses/LICENSE-2.0
 //
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+//
 //
 
-package com.google.gerrit.server.patch;
+package com.google.gerrit.server.patch.filediff;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableList.toImmutableList;
@@ -38,7 +40,17 @@
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.InMemoryInserter;
 import com.google.gerrit.server.git.MergeUtil;
-import com.google.gerrit.server.patch.EditTransformer.ContextAwareEdit;
+import com.google.gerrit.server.patch.AutoMerger;
+import com.google.gerrit.server.patch.ComparisonType;
+import com.google.gerrit.server.patch.DiffExecutor;
+import com.google.gerrit.server.patch.PatchList;
+import com.google.gerrit.server.patch.PatchListCache;
+import com.google.gerrit.server.patch.PatchListCacheImpl;
+import com.google.gerrit.server.patch.PatchListEntry;
+import com.google.gerrit.server.patch.PatchListKey;
+import com.google.gerrit.server.patch.PatchListNotAvailableException;
+import com.google.gerrit.server.patch.Text;
+import com.google.gerrit.server.patch.filediff.EditTransformer.ContextAwareEdit;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
 import java.io.IOException;
@@ -81,7 +93,7 @@
 import org.eclipse.jgit.util.io.DisabledOutputStream;
 
 public class PatchListLoader implements Callable<PatchList> {
-  static final FluentLogger logger = FluentLogger.forEnclosingClass();
+  public static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   public interface Factory {
     PatchListLoader create(PatchListKey key, Project.NameKey project);
@@ -306,13 +318,39 @@
         getRelevantPatchListEntries(
             parentDiffEntries, parentCommitA, parentCommitB, touchedFilePaths, df);
 
-    EditTransformer editTransformer = new EditTransformer(parentPatchListEntries);
-    editTransformer.transformReferencesOfSideA(oldPatches);
-    editTransformer.transformReferencesOfSideB(newPatches);
+    EditTransformer editTransformer = new EditTransformer(toFileEditsList(parentPatchListEntries));
+    editTransformer.transformReferencesOfSideA(toFileEditsList(oldPatches));
+    editTransformer.transformReferencesOfSideB(toFileEditsList(newPatches));
     return EditsDueToRebaseResult.create(
         relevantDiffEntries, editTransformer.getEditsPerFilePath());
   }
 
+  private ImmutableList<FileEdits> toFileEditsList(List<PatchListEntry> entries) {
+    return entries.stream().map(PatchListLoader::toFileEdits).collect(toImmutableList());
+  }
+
+  private static FileEdits toFileEdits(PatchListEntry patchListEntry) {
+    Optional<String> oldName = Optional.empty();
+    Optional<String> newName = Optional.empty();
+    switch (patchListEntry.getChangeType()) {
+      case DELETED:
+        oldName = Optional.of(patchListEntry.getNewName());
+        break;
+      case ADDED:
+      case MODIFIED:
+      case REWRITE:
+        newName = Optional.of(patchListEntry.getNewName());
+        break;
+
+      case COPIED:
+      case RENAMED:
+        oldName = Optional.of(patchListEntry.getOldName());
+        newName = Optional.of(patchListEntry.getNewName());
+        break;
+    }
+    return FileEdits.create(patchListEntry.getEdits(), oldName, newName);
+  }
+
   private static boolean isRootOrMergeCommit(RevCommit commit) {
     return commit.getParentCount() != 1;
   }
@@ -405,7 +443,7 @@
     PatchListEntry patchListEntry =
         newEntry(treeA, fileHeader, contentEditsDueToRebase, newSize, newSize - oldSize);
     // All edits in a file are due to rebase -> exclude the file from the diff.
-    if (EditTransformer.toEdits(patchListEntry).allMatch(editsDueToRebase::contains)) {
+    if (EditTransformer.toEdits(toFileEdits(patchListEntry)).allMatch(editsDueToRebase::contains)) {
       return Optional.empty();
     }
     return Optional.of(patchListEntry);
@@ -611,15 +649,16 @@
           rw.parseBody(r);
           return r;
         }
-      case 2:
+      default:
         if (key.getParentNum() != null) {
           RevCommit r = b.getParent(key.getParentNum() - 1);
           rw.parseBody(r);
           return r;
         }
-        return autoMerger.merge(repo, rw, ins, b, mergeStrategy);
-      default:
-        // TODO(sop) handle an octopus merge.
+        // Only support auto-merge for 2 parents, not octopus merges
+        if (b.getParentCount() == 2) {
+          return autoMerger.merge(repo, rw, ins, b, mergeStrategy);
+        }
         return null;
     }
   }
diff --git a/java/com/google/gerrit/server/patch/filediff/TaggedEdit.java b/java/com/google/gerrit/server/patch/filediff/TaggedEdit.java
new file mode 100644
index 0000000..aef2f63
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/filediff/TaggedEdit.java
@@ -0,0 +1,33 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.filediff;
+
+import com.google.auto.value.AutoValue;
+
+/**
+ * An entity class encapsulating a JGit {@link Edit} along with extra attributes (e.g. identifying a
+ * rebase edit).
+ */
+@AutoValue
+public abstract class TaggedEdit {
+
+  public static TaggedEdit create(Edit edit, boolean dueToRebase) {
+    return new AutoValue_TaggedEdit(edit, dueToRebase);
+  }
+
+  abstract Edit edit();
+
+  abstract boolean dueToRebase();
+}
diff --git a/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCache.java b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCache.java
new file mode 100644
index 0000000..d178f22
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCache.java
@@ -0,0 +1,40 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitdiff;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.gerrit.server.patch.diff.ModifiedFilesCache;
+
+/**
+ * A cache interface for identifying the list of Git modified files between 2 different git trees.
+ * This cache does not read the actual file contents, nor does it include the edits (modified
+ * regions) of the file.
+ *
+ * <p>The other {@link ModifiedFilesCache} is similar to this cache, and includes other extra Gerrit
+ * logic that we need to add with the list of modified files.
+ */
+public interface GitModifiedFilesCache {
+
+  /**
+   * Computes the list of of {@link ModifiedFile}s between the 2 git trees.
+   *
+   * @param key used to identify two git trees and contains other attributes to control the diff
+   *     calculation.
+   * @return the list of {@link ModifiedFile}s between the 2 git trees identified by the key.
+   * @throws DiffNotAvailableException trees cannot be read or file contents cannot be read.
+   */
+  ImmutableList<ModifiedFile> get(GitModifiedFilesCacheKey key) throws DiffNotAvailableException;
+}
diff --git a/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheImpl.java b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheImpl.java
new file mode 100644
index 0000000..b3b82bb
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheImpl.java
@@ -0,0 +1,177 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitdiff;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.cache.proto.Cache.ModifiedFilesProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.TypeLiteral;
+import com.google.inject.name.Named;
+import java.io.IOException;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.ExecutionException;
+import org.eclipse.jgit.diff.DiffEntry;
+import org.eclipse.jgit.diff.DiffEntry.ChangeType;
+import org.eclipse.jgit.diff.DiffFormatter;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.util.io.DisabledOutputStream;
+
+/** Implementation of the {@link GitModifiedFilesCache} */
+public class GitModifiedFilesCacheImpl implements GitModifiedFilesCache {
+  private static final String GIT_MODIFIED_FILES = "git_modified_files";
+  private static final ImmutableMap<ChangeType, Patch.ChangeType> changeTypeMap =
+      ImmutableMap.of(
+          DiffEntry.ChangeType.ADD,
+          Patch.ChangeType.ADDED,
+          DiffEntry.ChangeType.MODIFY,
+          Patch.ChangeType.MODIFIED,
+          DiffEntry.ChangeType.DELETE,
+          Patch.ChangeType.DELETED,
+          DiffEntry.ChangeType.RENAME,
+          Patch.ChangeType.RENAMED,
+          DiffEntry.ChangeType.COPY,
+          Patch.ChangeType.COPIED);
+
+  private LoadingCache<GitModifiedFilesCacheKey, ImmutableList<ModifiedFile>> cache;
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        bind(GitModifiedFilesCache.class).to(GitModifiedFilesCacheImpl.class);
+
+        persist(
+                GIT_MODIFIED_FILES,
+                GitModifiedFilesCacheKey.class,
+                new TypeLiteral<ImmutableList<ModifiedFile>>() {})
+            .keySerializer(GitModifiedFilesCacheKey.Serializer.INSTANCE)
+            .valueSerializer(ValueSerializer.INSTANCE)
+            // The documentation has some defaults and recommendations for setting the cache
+            // attributes:
+            // https://gerrit-review.googlesource.com/Documentation/config-gerrit.html#cache.
+            .maximumWeight(10 << 20)
+            .weigher(GitModifiedFilesWeigher.class)
+            // The cache is using the default disk limit as per section cache.<name>.diskLimit
+            // in the cache documentation link.
+            .version(1)
+            .loader(GitModifiedFilesCacheImpl.Loader.class);
+      }
+    };
+  }
+
+  @Inject
+  public GitModifiedFilesCacheImpl(
+      @Named(GIT_MODIFIED_FILES)
+          LoadingCache<GitModifiedFilesCacheKey, ImmutableList<ModifiedFile>> cache) {
+    this.cache = cache;
+  }
+
+  @Override
+  public ImmutableList<ModifiedFile> get(GitModifiedFilesCacheKey key)
+      throws DiffNotAvailableException {
+    try {
+      return cache.get(key);
+    } catch (ExecutionException e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  static class Loader extends CacheLoader<GitModifiedFilesCacheKey, ImmutableList<ModifiedFile>> {
+    private final GitRepositoryManager repoManager;
+
+    @Inject
+    Loader(GitRepositoryManager repoManager) {
+      this.repoManager = repoManager;
+    }
+
+    @Override
+    public ImmutableList<ModifiedFile> load(GitModifiedFilesCacheKey key) throws IOException {
+      try (Repository repo = repoManager.openRepository(key.project());
+          ObjectReader reader = repo.newObjectReader()) {
+        List<DiffEntry> entries = getGitTreeDiff(repo, reader, key);
+
+        return entries.stream().map(Loader::toModifiedFile).collect(toImmutableList());
+      }
+    }
+
+    private List<DiffEntry> getGitTreeDiff(
+        Repository repo, ObjectReader reader, GitModifiedFilesCacheKey key) throws IOException {
+      try (DiffFormatter df = new DiffFormatter(DisabledOutputStream.INSTANCE)) {
+        df.setReader(reader, repo.getConfig());
+        if (key.renameDetection()) {
+          df.setDetectRenames(true);
+          df.getRenameDetector().setRenameScore(key.renameScore());
+        }
+        // The scan method only returns the file paths that are different. Callers may choose to
+        // format these paths themselves.
+        return df.scan(key.aTree(), key.bTree());
+      }
+    }
+
+    private static ModifiedFile toModifiedFile(DiffEntry entry) {
+      String oldPath = entry.getOldPath();
+      String newPath = entry.getNewPath();
+      return ModifiedFile.builder()
+          .changeType(toChangeType(entry.getChangeType()))
+          .oldPath(oldPath.equals(DiffEntry.DEV_NULL) ? Optional.empty() : Optional.of(oldPath))
+          .newPath(newPath.equals(DiffEntry.DEV_NULL) ? Optional.empty() : Optional.of(newPath))
+          .build();
+    }
+
+    private static Patch.ChangeType toChangeType(DiffEntry.ChangeType changeType) {
+      if (!changeTypeMap.containsKey(changeType)) {
+        throw new IllegalArgumentException("Unsupported type " + changeType);
+      }
+      return changeTypeMap.get(changeType);
+    }
+  }
+
+  public enum ValueSerializer implements CacheSerializer<ImmutableList<ModifiedFile>> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(ImmutableList<ModifiedFile> modifiedFiles) {
+      ModifiedFilesProto.Builder builder = ModifiedFilesProto.newBuilder();
+      modifiedFiles.forEach(
+          f -> builder.addModifiedFile(ModifiedFile.Serializer.INSTANCE.toProto(f)));
+      return Protos.toByteArray(builder.build());
+    }
+
+    @Override
+    public ImmutableList<ModifiedFile> deserialize(byte[] in) {
+      ImmutableList.Builder<ModifiedFile> modifiedFiles = ImmutableList.builder();
+      ModifiedFilesProto modifiedFilesProto =
+          Protos.parseUnchecked(ModifiedFilesProto.parser(), in);
+      modifiedFilesProto
+          .getModifiedFileList()
+          .forEach(f -> modifiedFiles.add(ModifiedFile.Serializer.INSTANCE.fromProto(f)));
+      return modifiedFiles.build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheKey.java b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheKey.java
new file mode 100644
index 0000000..fb8fce1
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesCacheKey.java
@@ -0,0 +1,129 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.gitdiff;
+
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.Project.NameKey;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.GitModifiedFilesKeyProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import com.google.gerrit.server.patch.DiffUtil;
+import java.io.IOException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/** Cache key for the {@link GitModifiedFilesCache}. */
+@AutoValue
+public abstract class GitModifiedFilesCacheKey {
+
+  /** A specific git project / repository. */
+  public abstract Project.NameKey project();
+
+  /**
+   * The git SHA-1 {@link ObjectId} of the first git tree object for which the diff should be
+   * computed.
+   */
+  public abstract ObjectId aTree();
+
+  /**
+   * The git SHA-1 {@link ObjectId} of the second git tree object for which the diff should be
+   * computed.
+   */
+  public abstract ObjectId bTree();
+
+  /**
+   * Percentage score used to identify a file as a rename. This value is only available if {@link
+   * #renameDetection()} is true. Otherwise, this method will return -1.
+   *
+   * <p>This value will be used to set the rename score of {@link
+   * org.eclipse.jgit.diff.DiffFormatter#getRenameDetector()}.
+   */
+  public abstract int renameScore();
+
+  /** Returns true if rename detection was set for this key. */
+  public boolean renameDetection() {
+    return renameScore() != -1;
+  }
+
+  public static GitModifiedFilesCacheKey create(
+      Project.NameKey project, ObjectId aCommit, ObjectId bCommit, int renameScore, RevWalk rw)
+      throws IOException {
+    ObjectId aTree = DiffUtil.getTreeId(rw, aCommit);
+    ObjectId bTree = DiffUtil.getTreeId(rw, bCommit);
+    return builder().project(project).aTree(aTree).bTree(bTree).renameScore(renameScore).build();
+  }
+
+  public static Builder builder() {
+    return new AutoValue_GitModifiedFilesCacheKey.Builder();
+  }
+
+  /** Returns the size of the object in bytes */
+  public int weight() {
+    return stringSize(project().get())
+        + 20 * 2 // old and new tree IDs
+        + 4; // rename score
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder project(NameKey value);
+
+    public abstract Builder aTree(ObjectId value);
+
+    public abstract Builder bTree(ObjectId value);
+
+    public abstract Builder renameScore(int value);
+
+    public Builder disableRenameDetection() {
+      renameScore(-1);
+      return this;
+    }
+
+    public abstract GitModifiedFilesCacheKey build();
+  }
+
+  public enum Serializer implements CacheSerializer<GitModifiedFilesCacheKey> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(GitModifiedFilesCacheKey key) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return Protos.toByteArray(
+          GitModifiedFilesKeyProto.newBuilder()
+              .setProject(key.project().get())
+              .setATree(idConverter.toByteString(key.aTree()))
+              .setBTree(idConverter.toByteString(key.bTree()))
+              .setRenameScore(key.renameScore())
+              .build());
+    }
+
+    @Override
+    public GitModifiedFilesCacheKey deserialize(byte[] in) {
+      GitModifiedFilesKeyProto proto = Protos.parseUnchecked(GitModifiedFilesKeyProto.parser(), in);
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return GitModifiedFilesCacheKey.builder()
+          .project(NameKey.parse(proto.getProject()))
+          .aTree(idConverter.fromByteString(proto.getATree()))
+          .bTree(idConverter.fromByteString(proto.getBTree()))
+          .renameScore(proto.getRenameScore())
+          .build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesWeigher.java b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesWeigher.java
new file mode 100644
index 0000000..a678379
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitdiff/GitModifiedFilesWeigher.java
@@ -0,0 +1,26 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitdiff;
+
+import com.google.common.cache.Weigher;
+import com.google.common.collect.ImmutableList;
+
+public class GitModifiedFilesWeigher
+    implements Weigher<GitModifiedFilesCacheKey, ImmutableList<ModifiedFile>> {
+  @Override
+  public int weigh(GitModifiedFilesCacheKey key, ImmutableList<ModifiedFile> modifiedFiles) {
+    return key.weight() + modifiedFiles.stream().mapToInt(ModifiedFile::weight).sum();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitdiff/ModifiedFile.java b/java/com/google/gerrit/server/patch/gitdiff/ModifiedFile.java
new file mode 100644
index 0000000..9512094
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitdiff/ModifiedFile.java
@@ -0,0 +1,123 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitdiff;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.ModifiedFileProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import java.util.Optional;
+
+/**
+ * An entity representing a Modified file due to a diff between 2 git trees. This entity contains
+ * the change type and the old & new paths, but does not include any actual content diff of the
+ * file.
+ */
+@AutoValue
+public abstract class ModifiedFile {
+  /**
+   * Returns the change type (i.e. add, delete, modify, rename, etc...) associated with this
+   * modified file.
+   */
+  public abstract ChangeType changeType();
+
+  /**
+   * Returns the old name associated with this file. An empty optional is returned if {@link
+   * #changeType()} is equal to {@link ChangeType#ADDED}.
+   */
+  public abstract Optional<String> oldPath();
+
+  /**
+   * Returns the new name associated with this file. An empty optional is returned if {@link
+   * #changeType()} is equal to {@link ChangeType#DELETED}
+   */
+  public abstract Optional<String> newPath();
+
+  public static Builder builder() {
+    return new AutoValue_ModifiedFile.Builder();
+  }
+
+  /** Computes this object's weight, which is its size in bytes. */
+  public int weight() {
+    int weight = 1; // the changeType field
+    if (oldPath().isPresent()) {
+      weight += oldPath().get().length();
+    }
+    if (newPath().isPresent()) {
+      weight += newPath().get().length();
+    }
+    return weight;
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder changeType(ChangeType value);
+
+    public abstract Builder oldPath(Optional<String> value);
+
+    public abstract Builder newPath(Optional<String> value);
+
+    public abstract ModifiedFile build();
+  }
+
+  enum Serializer implements CacheSerializer<ModifiedFile> {
+    INSTANCE;
+
+    private static final FieldDescriptor oldPathDescriptor =
+        ModifiedFileProto.getDescriptor().findFieldByNumber(2);
+
+    private static final FieldDescriptor newPathDescriptor =
+        ModifiedFileProto.getDescriptor().findFieldByNumber(3);
+
+    @Override
+    public byte[] serialize(ModifiedFile modifiedFile) {
+      return Protos.toByteArray(toProto(modifiedFile));
+    }
+
+    public ModifiedFileProto toProto(ModifiedFile modifiedFile) {
+      ModifiedFileProto.Builder builder = ModifiedFileProto.newBuilder();
+      builder.setChangeType(modifiedFile.changeType().toString());
+      if (modifiedFile.oldPath().isPresent()) {
+        builder.setOldPath(modifiedFile.oldPath().get());
+      }
+      if (modifiedFile.newPath().isPresent()) {
+        builder.setNewPath(modifiedFile.newPath().get());
+      }
+      return builder.build();
+    }
+
+    @Override
+    public ModifiedFile deserialize(byte[] in) {
+      ModifiedFileProto modifiedFileProto = Protos.parseUnchecked(ModifiedFileProto.parser(), in);
+      return fromProto(modifiedFileProto);
+    }
+
+    public ModifiedFile fromProto(ModifiedFileProto modifiedFileProto) {
+      ModifiedFile.Builder builder = ModifiedFile.builder();
+      builder.changeType(ChangeType.valueOf(modifiedFileProto.getChangeType()));
+
+      if (modifiedFileProto.hasField(oldPathDescriptor)) {
+        builder.oldPath(Optional.of(modifiedFileProto.getOldPath()));
+      }
+      if (modifiedFileProto.hasField(newPathDescriptor)) {
+        builder.newPath(Optional.of(modifiedFileProto.getNewPath()));
+      }
+      return builder.build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/FileHeaderUtil.java b/java/com/google/gerrit/server/patch/gitfilediff/FileHeaderUtil.java
new file mode 100644
index 0000000..7454f81
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/FileHeaderUtil.java
@@ -0,0 +1,198 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.entities.Patch.PatchType;
+import java.util.Optional;
+import org.eclipse.jgit.patch.CombinedFileHeader;
+import org.eclipse.jgit.patch.FileHeader;
+import org.eclipse.jgit.util.IntList;
+import org.eclipse.jgit.util.RawParseUtils;
+
+/** A utility class for the {@link FileHeader} JGit object */
+public class FileHeaderUtil {
+  private static final Byte NUL = '\0';
+
+  /**
+   * The maximum number of characters to lookup in the binary file {@link FileHeader}. This is used
+   * to scan the file header for the occurrence of the {@link #NUL} character.
+   *
+   * <p>This limit assumes a uniform distribution of all characters, hence the probability of the
+   * occurrence of each character = (1 / 256). We want to find the limit that makes the prob. of
+   * finding {@link #NUL} > 0.999. 1 - (255 / 256) ^ N > 0.999 yields N = 1766. We set the limit to
+   * this value multiplied by 10 for more confidence.
+   */
+  private static final int BIN_FILE_MAX_SCAN_LIMIT = 20000;
+
+  /** Converts the {@link FileHeader} parameter to a String representation. */
+  static String toString(FileHeader header) {
+    return new String(FileHeaderUtil.toByteArray(header), UTF_8);
+  }
+
+  /** Converts the {@link FileHeader} parameter to a byte array. */
+  static byte[] toByteArray(FileHeader header) {
+    int end = getEndOffset(header);
+    if (header.getStartOffset() == 0 && end == header.getBuffer().length) {
+      return header.getBuffer();
+    }
+
+    final byte[] buf = new byte[end - header.getStartOffset()];
+    System.arraycopy(header.getBuffer(), header.getStartOffset(), buf, 0, buf.length);
+    return buf;
+  }
+
+  /** Splits the {@code FileHeader} string to a list of strings, one string per header line. */
+  public static ImmutableList<String> getHeaderLines(FileHeader fileHeader) {
+    String fileHeaderString = toString(fileHeader);
+    return getHeaderLines(fileHeaderString);
+  }
+
+  public static ImmutableList<String> getHeaderLines(String header) {
+    return getHeaderLines(header.getBytes(UTF_8));
+  }
+
+  static ImmutableList<String> getHeaderLines(byte[] header) {
+    final IntList lineStartOffsets = RawParseUtils.lineMap(header, 0, header.length);
+    final ImmutableList.Builder<String> headerLines =
+        ImmutableList.builderWithExpectedSize(lineStartOffsets.size() - 1);
+    for (int i = 1; i < lineStartOffsets.size() - 1; i++) {
+      final int b = lineStartOffsets.get(i);
+      int e = lineStartOffsets.get(i + 1);
+      if (header[e - 1] == '\n') {
+        e--;
+      }
+      headerLines.add(RawParseUtils.decode(UTF_8, header, b, e));
+    }
+    return headerLines.build();
+  }
+
+  /**
+   * Returns the old file path associated with the {@link FileHeader}, or empty if the file is
+   * {@link com.google.gerrit.entities.Patch.ChangeType#ADDED} or {@link
+   * com.google.gerrit.entities.Patch.ChangeType#REWRITE}.
+   */
+  public static Optional<String> getOldPath(FileHeader header) {
+    Patch.ChangeType changeType = getChangeType(header);
+    switch (changeType) {
+      case DELETED:
+      case COPIED:
+      case RENAMED:
+      case MODIFIED:
+        return Optional.of(header.getOldPath());
+
+      case ADDED:
+      case REWRITE:
+        return Optional.empty();
+    }
+    return Optional.empty();
+  }
+
+  /**
+   * Returns the new file path associated with the {@link FileHeader}, or empty if the file is
+   * {@link com.google.gerrit.entities.Patch.ChangeType#DELETED}.
+   */
+  public static Optional<String> getNewPath(FileHeader header) {
+    Patch.ChangeType changeType = getChangeType(header);
+    switch (changeType) {
+      case DELETED:
+        return Optional.empty();
+
+      case ADDED:
+      case MODIFIED:
+      case REWRITE:
+      case COPIED:
+      case RENAMED:
+        return Optional.of(header.getNewPath());
+    }
+    return Optional.empty();
+  }
+
+  /** Returns the change type associated with the file header. */
+  public static Patch.ChangeType getChangeType(FileHeader header) {
+    // In Gerrit, we define our own entities  of the JGit entities, so that we have full control
+    // over their behaviors (e.g. making sure that these entities are immutable so that we can add
+    // them as fields of keys / values of persisted caches).
+
+    // TODO(ghareeb): remove the dead code of the value REWRITE and all its handling
+    switch (header.getChangeType()) {
+      case ADD:
+        return Patch.ChangeType.ADDED;
+      case MODIFY:
+        return Patch.ChangeType.MODIFIED;
+      case DELETE:
+        return Patch.ChangeType.DELETED;
+      case RENAME:
+        return Patch.ChangeType.RENAMED;
+      case COPY:
+        return Patch.ChangeType.COPIED;
+      default:
+        throw new IllegalArgumentException("Unsupported type " + header.getChangeType());
+    }
+  }
+
+  public static PatchType getPatchType(FileHeader header) {
+    PatchType patchType;
+
+    switch (header.getPatchType()) {
+      case UNIFIED:
+        patchType = Patch.PatchType.UNIFIED;
+        break;
+      case GIT_BINARY:
+      case BINARY:
+        patchType = Patch.PatchType.BINARY;
+        break;
+      default:
+        throw new IllegalArgumentException("Unsupported type " + header.getPatchType());
+    }
+
+    if (patchType != PatchType.BINARY) {
+      byte[] buf = header.getBuffer();
+      // TODO(ghareeb): should we adjust the max limit threshold?
+      // JGit sometimes misses the detection of binary files. In this case we look into the file
+      // header for the occurrence of NUL characters, which is a definite signal that the file is
+      // binary. We limit the number of characters to lookup to avoid performance bottlenecks.
+      for (int ptr = header.getStartOffset();
+          ptr < Math.min(header.getEndOffset(), BIN_FILE_MAX_SCAN_LIMIT);
+          ptr++) {
+        if (buf[ptr] == NUL) {
+          // It's really binary, but Git couldn't see the nul early enough to realize its binary,
+          // and instead produced the diff.
+          //
+          // Force it to be a binary; it really should have been that.
+          return PatchType.BINARY;
+        }
+      }
+    }
+    return patchType;
+  }
+
+  /**
+   * Returns the end offset of the diff header line of the {@code FileHeader parameter} before the
+   * appearance of any file edits (diff hunks).
+   */
+  private static int getEndOffset(FileHeader fileHeader) {
+    if (fileHeader instanceof CombinedFileHeader) {
+      return fileHeader.getEndOffset();
+    }
+    if (!fileHeader.getHunks().isEmpty()) {
+      return fileHeader.getHunks().get(0).getStartOffset();
+    }
+    return fileHeader.getEndOffset();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java
new file mode 100644
index 0000000..6d63243
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java
@@ -0,0 +1,296 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.entities.Patch;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.entities.Patch.PatchType;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.GitFileDiffProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import com.google.gerrit.server.patch.filediff.Edit;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import java.io.IOException;
+import java.util.Map;
+import java.util.Optional;
+import org.eclipse.jgit.diff.DiffEntry;
+import org.eclipse.jgit.diff.DiffFormatter;
+import org.eclipse.jgit.lib.AbbreviatedObjectId;
+import org.eclipse.jgit.lib.FileMode;
+import org.eclipse.jgit.patch.FileHeader;
+
+/**
+ * Entity representing a modified file (added, deleted, modified, renamed, etc...) between two
+ * different git commits.
+ */
+@AutoValue
+public abstract class GitFileDiff {
+  private static final Map<FileMode, Patch.FileMode> fileModeMap =
+      ImmutableMap.of(
+          FileMode.TREE,
+          Patch.FileMode.TREE,
+          FileMode.SYMLINK,
+          Patch.FileMode.SYMLINK,
+          FileMode.REGULAR_FILE,
+          Patch.FileMode.REGULAR_FILE,
+          FileMode.EXECUTABLE_FILE,
+          Patch.FileMode.EXECUTABLE_FILE,
+          FileMode.MISSING,
+          Patch.FileMode.MISSING);
+
+  private static Patch.FileMode mapFileMode(FileMode jgitFileMode) {
+    if (!fileModeMap.containsKey(jgitFileMode)) {
+      throw new IllegalArgumentException("Unsupported type " + jgitFileMode);
+    }
+    return fileModeMap.get(jgitFileMode);
+  }
+
+  /**
+   * Creates a {@link GitFileDiff} using the {@code diffEntry} and the {@code diffFormatter}
+   * parameters.
+   */
+  static GitFileDiff create(DiffEntry diffEntry, DiffFormatter diffFormatter) throws IOException {
+    FileHeader fileHeader = diffFormatter.toFileHeader(diffEntry);
+    ImmutableList<Edit> edits =
+        fileHeader.toEditList().stream().map(Edit::fromJGitEdit).collect(toImmutableList());
+
+    return builder()
+        .edits(edits)
+        .oldId(diffEntry.getOldId())
+        .newId(diffEntry.getNewId())
+        .fileHeader(FileHeaderUtil.toString(fileHeader))
+        .oldPath(FileHeaderUtil.getOldPath(fileHeader))
+        .newPath(FileHeaderUtil.getNewPath(fileHeader))
+        .changeType(Optional.of(FileHeaderUtil.getChangeType(fileHeader)))
+        .patchType(Optional.of(FileHeaderUtil.getPatchType(fileHeader)))
+        .oldMode(Optional.of(mapFileMode(diffEntry.getOldMode())))
+        .newMode(Optional.of(mapFileMode(diffEntry.getNewMode())))
+        .build();
+  }
+
+  /**
+   * Represents an empty file diff, which means that the file was not modified between the two git
+   * trees identified by {@link #oldId()} and {@link #newId()}.
+   *
+   * @param newFilePath the file name at the {@link #newId()} git tree.
+   */
+  static GitFileDiff empty(
+      AbbreviatedObjectId oldId, AbbreviatedObjectId newId, String newFilePath) {
+    return builder()
+        .oldId(oldId)
+        .newId(newId)
+        .newPath(Optional.of(newFilePath))
+        .edits(ImmutableList.of())
+        .fileHeader("")
+        .build();
+  }
+
+  /** An {@link ImmutableList} of the modified regions in the file. */
+  public abstract ImmutableList<Edit> edits();
+
+  /** A string representation of the {@link org.eclipse.jgit.patch.FileHeader}. */
+  public abstract String fileHeader();
+
+  /** The file name at the old git tree identified by {@link #oldId()} */
+  public abstract Optional<String> oldPath();
+
+  /** The file name at the new git tree identified by {@link #newId()} */
+  public abstract Optional<String> newPath();
+
+  /** The 20 bytes SHA-1 object ID of the old git tree of the diff. */
+  public abstract AbbreviatedObjectId oldId();
+
+  /** The 20 bytes SHA-1 object ID of the new git tree of the diff. */
+  public abstract AbbreviatedObjectId newId();
+
+  /** The file mode of the old file at the old git tree diff identified by {@link #oldId()}. */
+  public abstract Optional<Patch.FileMode> oldMode();
+
+  /** The file mode of the new file at the new git tree diff identified by {@link #newId()}. */
+  public abstract Optional<Patch.FileMode> newMode();
+
+  /** The change type associated with the file. */
+  public abstract Optional<ChangeType> changeType();
+
+  /** The patch type associated with the file. */
+  public abstract Optional<PatchType> patchType();
+
+  /**
+   * Returns true if the object was created using the {@link #empty(AbbreviatedObjectId,
+   * AbbreviatedObjectId, String)} method.
+   */
+  public boolean isEmpty() {
+    return edits().isEmpty();
+  }
+
+  /** Returns the size of the object in bytes. */
+  public int weight() {
+    int result = 20 * 2; // oldId and newId
+    result += 16 * edits().size(); // each edit contains 4 integers (hence 16 bytes)
+    result += stringSize(fileHeader());
+    if (oldPath().isPresent()) {
+      result += stringSize(oldPath().get());
+    }
+    if (newPath().isPresent()) {
+      result += stringSize(newPath().get());
+    }
+    if (changeType().isPresent()) {
+      result += 4;
+    }
+    if (patchType().isPresent()) {
+      result += 4;
+    }
+    if (oldMode().isPresent()) {
+      result += 4;
+    }
+    if (newMode().isPresent()) {
+      result += 4;
+    }
+    return result;
+  }
+
+  public static Builder builder() {
+    return new AutoValue_GitFileDiff.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder edits(ImmutableList<Edit> value);
+
+    public abstract Builder fileHeader(String value);
+
+    public abstract Builder oldPath(Optional<String> value);
+
+    public abstract Builder newPath(Optional<String> value);
+
+    public abstract Builder oldId(AbbreviatedObjectId value);
+
+    public abstract Builder newId(AbbreviatedObjectId value);
+
+    public abstract Builder oldMode(Optional<Patch.FileMode> value);
+
+    public abstract Builder newMode(Optional<Patch.FileMode> value);
+
+    public abstract Builder changeType(Optional<ChangeType> value);
+
+    public abstract Builder patchType(Optional<PatchType> value);
+
+    public abstract GitFileDiff build();
+  }
+
+  public enum Serializer implements CacheSerializer<GitFileDiff> {
+    INSTANCE;
+
+    private static final FieldDescriptor OLD_PATH_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(3);
+
+    private static final FieldDescriptor NEW_PATH_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(4);
+
+    private static final FieldDescriptor OLD_MODE_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(7);
+
+    private static final FieldDescriptor NEW_MODE_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(8);
+
+    private static final FieldDescriptor CHANGE_TYPE_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(9);
+
+    private static final FieldDescriptor PATCH_TYPE_DESCRIPTOR =
+        GitFileDiffProto.getDescriptor().findFieldByNumber(10);
+
+    @Override
+    public byte[] serialize(GitFileDiff gitFileDiff) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      GitFileDiffProto.Builder builder =
+          GitFileDiffProto.newBuilder()
+              .setFileHeader(gitFileDiff.fileHeader())
+              .setOldId(idConverter.toByteString(gitFileDiff.oldId().toObjectId()))
+              .setNewId(idConverter.toByteString(gitFileDiff.newId().toObjectId()));
+      gitFileDiff
+          .edits()
+          .forEach(
+              e ->
+                  builder.addEdits(
+                      GitFileDiffProto.Edit.newBuilder()
+                          .setBeginA(e.beginA())
+                          .setEndA(e.endA())
+                          .setBeginB(e.beginB())
+                          .setEndB(e.endB())));
+      if (gitFileDiff.oldPath().isPresent()) {
+        builder.setOldPath(gitFileDiff.oldPath().get());
+      }
+      if (gitFileDiff.newPath().isPresent()) {
+        builder.setNewPath(gitFileDiff.newPath().get());
+      }
+      if (gitFileDiff.oldMode().isPresent()) {
+        builder.setOldMode(gitFileDiff.oldMode().get().name());
+      }
+      if (gitFileDiff.newMode().isPresent()) {
+        builder.setNewMode(gitFileDiff.newMode().get().name());
+      }
+      if (gitFileDiff.changeType().isPresent()) {
+        builder.setChangeType(gitFileDiff.changeType().get().name());
+      }
+      if (gitFileDiff.patchType().isPresent()) {
+        builder.setPatchType(gitFileDiff.patchType().get().name());
+      }
+      return Protos.toByteArray(builder.build());
+    }
+
+    @Override
+    public GitFileDiff deserialize(byte[] in) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      GitFileDiffProto proto = Protos.parseUnchecked(GitFileDiffProto.parser(), in);
+      GitFileDiff.Builder builder = GitFileDiff.builder();
+      builder
+          .edits(
+              proto.getEditsList().stream()
+                  .map(e -> Edit.create(e.getBeginA(), e.getEndA(), e.getBeginB(), e.getEndB()))
+                  .collect(toImmutableList()))
+          .fileHeader(proto.getFileHeader())
+          .oldId(AbbreviatedObjectId.fromObjectId(idConverter.fromByteString(proto.getOldId())))
+          .newId(AbbreviatedObjectId.fromObjectId(idConverter.fromByteString(proto.getNewId())));
+
+      if (proto.hasField(OLD_PATH_DESCRIPTOR)) {
+        builder.oldPath(Optional.of(proto.getOldPath()));
+      }
+      if (proto.hasField(NEW_PATH_DESCRIPTOR)) {
+        builder.newPath(Optional.of(proto.getNewPath()));
+      }
+      if (proto.hasField(OLD_MODE_DESCRIPTOR)) {
+        builder.oldMode(Optional.of(Patch.FileMode.valueOf(proto.getOldMode())));
+      }
+      if (proto.hasField(NEW_MODE_DESCRIPTOR)) {
+        builder.newMode(Optional.of(Patch.FileMode.valueOf(proto.getNewMode())));
+      }
+      if (proto.hasField(CHANGE_TYPE_DESCRIPTOR)) {
+        builder.changeType(Optional.of(Patch.ChangeType.valueOf(proto.getChangeType())));
+      }
+      if (proto.hasField(PATCH_TYPE_DESCRIPTOR)) {
+        builder.patchType(Optional.of(Patch.PatchType.valueOf(proto.getPatchType())));
+      }
+      return builder.build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCache.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCache.java
new file mode 100644
index 0000000..2516761
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCache.java
@@ -0,0 +1,43 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+
+/** This cache computes pure git diff for a single file path according to a git tree diff. */
+public interface GitFileDiffCache {
+
+  /**
+   * Returns the git file diff for a single file path identified by its key.
+   *
+   * @param key identifies two git trees, a specific file path and other diff parameters.
+   * @return the file diff for a single file path identified by its key.
+   * @throws DiffNotAvailableException if the tree IDs of the key are invalid for this project or if
+   *     file contents could not be read.
+   */
+  GitFileDiff get(GitFileDiffCacheKey key) throws DiffNotAvailableException;
+
+  /**
+   * Returns the file diff for a collection of file paths identified by their keys.
+   *
+   * @param keys identifying different file paths of different projects.
+   * @return a map of the input keys to their corresponding git file diffs.
+   * @throws DiffNotAvailableException if the diff failed to be evaluated for one or more of the
+   *     input keys due to invalid tree IDs or if file contents could not be read.
+   */
+  ImmutableMap<GitFileDiffCacheKey, GitFileDiff> getAll(Iterable<GitFileDiffCacheKey> keys)
+      throws DiffNotAvailableException;
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheImpl.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheImpl.java
new file mode 100644
index 0000000..97cf37d32
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheImpl.java
@@ -0,0 +1,273 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import static java.util.function.Function.identity;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Streams;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.patch.DiffNotAvailableException;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.name.Named;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import org.eclipse.jgit.diff.DiffEntry;
+import org.eclipse.jgit.diff.DiffEntry.ChangeType;
+import org.eclipse.jgit.diff.DiffFormatter;
+import org.eclipse.jgit.diff.HistogramDiff;
+import org.eclipse.jgit.diff.RawTextComparator;
+import org.eclipse.jgit.lib.AbbreviatedObjectId;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.util.io.DisabledOutputStream;
+
+/** Implementation of the {@link GitFileDiffCache} */
+public class GitFileDiffCacheImpl implements GitFileDiffCache {
+  private static final String GIT_DIFF = "git_file_diff";
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        bind(GitFileDiffCache.class).to(GitFileDiffCacheImpl.class);
+        persist(GIT_DIFF, GitFileDiffCacheKey.class, GitFileDiff.class)
+            .maximumWeight(10 << 20)
+            .weigher(GitFileDiffWeigher.class)
+            .keySerializer(GitFileDiffCacheKey.Serializer.INSTANCE)
+            .valueSerializer(GitFileDiff.Serializer.INSTANCE)
+            .loader(GitFileDiffCacheImpl.Loader.class);
+      }
+    };
+  }
+
+  /** Enum for the supported diff algorithms for the file diff computation. */
+  public enum DiffAlgorithm {
+    HISTOGRAM,
+    HISTOGRAM_WITHOUT_MYERS_FALLBACK
+  }
+
+  /** Creates a new JGit diff algorithm instance using the Gerrit's {@link DiffAlgorithm} enum. */
+  public static class DiffAlgorithmFactory {
+    public static org.eclipse.jgit.diff.DiffAlgorithm create(DiffAlgorithm diffAlgorithm) {
+      HistogramDiff result = new HistogramDiff();
+      if (diffAlgorithm.equals(DiffAlgorithm.HISTOGRAM_WITHOUT_MYERS_FALLBACK)) {
+        result.setFallbackAlgorithm(null);
+      }
+      return result;
+    }
+  }
+
+  private final LoadingCache<GitFileDiffCacheKey, GitFileDiff> cache;
+
+  @Inject
+  public GitFileDiffCacheImpl(
+      @Named(GIT_DIFF) LoadingCache<GitFileDiffCacheKey, GitFileDiff> cache) {
+    this.cache = cache;
+  }
+
+  @Override
+  public GitFileDiff get(GitFileDiffCacheKey key) throws DiffNotAvailableException {
+    try {
+      return cache.get(key);
+    } catch (ExecutionException e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  @Override
+  public ImmutableMap<GitFileDiffCacheKey, GitFileDiff> getAll(Iterable<GitFileDiffCacheKey> keys)
+      throws DiffNotAvailableException {
+    try {
+      return cache.getAll(keys);
+    } catch (ExecutionException e) {
+      throw new DiffNotAvailableException(e);
+    }
+  }
+
+  static class Loader extends CacheLoader<GitFileDiffCacheKey, GitFileDiff> {
+    /**
+     * Extractor for the file path from a {@link DiffEntry}. Returns the old file path if the entry
+     * corresponds to a deleted file, otherwise it returns the new file path.
+     */
+    private static final Function<DiffEntry, String> pathExtractor =
+        (DiffEntry entry) ->
+            entry.getChangeType().equals(ChangeType.DELETE)
+                ? entry.getOldPath()
+                : entry.getNewPath();
+
+    private final GitRepositoryManager repoManager;
+
+    @Inject
+    public Loader(GitRepositoryManager repoManager) {
+      this.repoManager = repoManager;
+    }
+
+    @Override
+    public GitFileDiff load(GitFileDiffCacheKey key) throws IOException {
+      return loadAll(ImmutableList.of(key)).get(key);
+    }
+
+    @Override
+    public Map<GitFileDiffCacheKey, GitFileDiff> loadAll(
+        Iterable<? extends GitFileDiffCacheKey> keys) throws IOException {
+      ImmutableMap.Builder<GitFileDiffCacheKey, GitFileDiff> result =
+          ImmutableMap.builderWithExpectedSize(Iterables.size(keys));
+
+      Map<Project.NameKey, List<GitFileDiffCacheKey>> byProject =
+          Streams.stream(keys)
+              .distinct()
+              .collect(Collectors.groupingBy(GitFileDiffCacheKey::project));
+
+      for (Map.Entry<Project.NameKey, List<GitFileDiffCacheKey>> entry : byProject.entrySet()) {
+        try (Repository repo = repoManager.openRepository(entry.getKey());
+            ObjectReader reader = repo.newObjectReader()) {
+
+          // Grouping keys by diff options because each group of keys will be processed with a
+          // separate call to JGit using the DiffFormatter object.
+          Map<DiffOptions, List<GitFileDiffCacheKey>> optionsGroups =
+              entry.getValue().stream().collect(Collectors.groupingBy(DiffOptions::fromKey));
+
+          for (Map.Entry<DiffOptions, List<GitFileDiffCacheKey>> group : optionsGroups.entrySet()) {
+            result.putAll(loadAllImpl(repo, reader, group.getKey(), group.getValue()));
+          }
+        }
+      }
+      return result.build();
+    }
+
+    /**
+     * Loads the git file diffs for all keys of the same repository, and having the same diff {@code
+     * options}.
+     *
+     * @return The git file diffs for all input keys.
+     */
+    private Map<GitFileDiffCacheKey, GitFileDiff> loadAllImpl(
+        Repository repo, ObjectReader reader, DiffOptions options, List<GitFileDiffCacheKey> keys)
+        throws IOException {
+      ImmutableMap.Builder<GitFileDiffCacheKey, GitFileDiff> result =
+          ImmutableMap.builderWithExpectedSize(keys.size());
+      Map<GitFileDiffCacheKey, String> filePaths =
+          keys.stream().collect(Collectors.toMap(identity(), GitFileDiffCacheKey::newFilePath));
+      DiffFormatter formatter = createDiffFormatter(options, repo, reader);
+      Map<String, DiffEntry> diffEntries = loadDiffEntries(formatter, options, filePaths.values());
+      for (GitFileDiffCacheKey key : filePaths.keySet()) {
+        String newFilePath = filePaths.get(key);
+        if (diffEntries.containsKey(newFilePath)) {
+          result.put(key, GitFileDiff.create(diffEntries.get(newFilePath), formatter));
+          continue;
+        }
+        result.put(
+            key,
+            GitFileDiff.empty(
+                AbbreviatedObjectId.fromObjectId(key.oldTree()),
+                AbbreviatedObjectId.fromObjectId(key.newTree()),
+                newFilePath));
+      }
+      return result.build();
+    }
+
+    private static Map<String, DiffEntry> loadDiffEntries(
+        DiffFormatter diffFormatter, DiffOptions diffOptions, Collection<String> filePaths)
+        throws IOException {
+      Set<String> filePathsSet = ImmutableSet.copyOf(filePaths);
+      List<DiffEntry> diffEntries =
+          diffFormatter.scan(diffOptions.oldTree(), diffOptions.newTree());
+
+      return diffEntries.stream()
+          .filter(d -> filePathsSet.contains(pathExtractor.apply(d)))
+          .collect(Collectors.toMap(d -> pathExtractor.apply(d), identity()));
+    }
+
+    private static DiffFormatter createDiffFormatter(
+        DiffOptions diffOptions, Repository repo, ObjectReader reader) {
+      try (DiffFormatter diffFormatter = new DiffFormatter(DisabledOutputStream.INSTANCE)) {
+        diffFormatter.setReader(reader, repo.getConfig());
+        RawTextComparator cmp = comparatorFor(diffOptions.whitespace());
+        diffFormatter.setDiffComparator(cmp);
+        if (diffOptions.renameScore() != -1) {
+          diffFormatter.setDetectRenames(true);
+          diffFormatter.getRenameDetector().setRenameScore(diffOptions.renameScore());
+        }
+        diffFormatter.setDiffAlgorithm(DiffAlgorithmFactory.create(diffOptions.diffAlgorithm()));
+        return diffFormatter;
+      }
+    }
+
+    private static RawTextComparator comparatorFor(Whitespace ws) {
+      switch (ws) {
+        case IGNORE_ALL:
+          return RawTextComparator.WS_IGNORE_ALL;
+
+        case IGNORE_TRAILING:
+          return RawTextComparator.WS_IGNORE_TRAILING;
+
+        case IGNORE_LEADING_AND_TRAILING:
+          return RawTextComparator.WS_IGNORE_CHANGE;
+
+        case IGNORE_NONE:
+        default:
+          return RawTextComparator.DEFAULT;
+      }
+    }
+  }
+
+  /** An entity representing the options affecting the diff computation. */
+  @AutoValue
+  abstract static class DiffOptions {
+    /** Convert a {@link GitFileDiffCacheKey} input to a {@link DiffOptions}. */
+    static DiffOptions fromKey(GitFileDiffCacheKey key) {
+      return create(
+          key.oldTree(), key.newTree(), key.renameScore(), key.whitespace(), key.diffAlgorithm());
+    }
+
+    private static DiffOptions create(
+        ObjectId oldTree,
+        ObjectId newTree,
+        Integer renameScore,
+        Whitespace whitespace,
+        DiffAlgorithm diffAlgorithm) {
+      return new AutoValue_GitFileDiffCacheImpl_DiffOptions(
+          oldTree, newTree, renameScore, whitespace, diffAlgorithm);
+    }
+
+    abstract ObjectId oldTree();
+
+    abstract ObjectId newTree();
+
+    abstract Integer renameScore();
+
+    abstract Whitespace whitespace();
+
+    abstract DiffAlgorithm diffAlgorithm();
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheKey.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheKey.java
new file mode 100644
index 0000000..f104388
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffCacheKey.java
@@ -0,0 +1,127 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import static com.google.gerrit.server.patch.DiffUtil.stringSize;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.Project.NameKey;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.proto.Protos;
+import com.google.gerrit.server.cache.proto.Cache.GitFileDiffKeyProto;
+import com.google.gerrit.server.cache.serialize.CacheSerializer;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithm;
+import org.eclipse.jgit.lib.ObjectId;
+
+@AutoValue
+public abstract class GitFileDiffCacheKey {
+
+  /** A specific git project / repository. */
+  public abstract Project.NameKey project();
+
+  /** The old 20 bytes SHA-1 git tree ID used in the git tree diff */
+  public abstract ObjectId oldTree();
+
+  /** The new 20 bytes SHA-1 git tree ID used in the git tree diff */
+  public abstract ObjectId newTree();
+
+  /** File name in the tree identified by {@link #newTree()} */
+  public abstract String newFilePath();
+
+  /**
+   * Percentage score used to identify a file as a "rename". A special value of -1 means that the
+   * computation will ignore renames and rename detection will be disabled.
+   */
+  public abstract int renameScore();
+
+  public abstract DiffAlgorithm diffAlgorithm();
+
+  public abstract DiffPreferencesInfo.Whitespace whitespace();
+
+  public int weight() {
+    return stringSize(project().get())
+        + 20 * 2 // oldTree and newTree
+        + stringSize(newFilePath())
+        + 4 // renameScore
+        + 4 // diffAlgorithm
+        + 4; // whitespace
+  }
+
+  public static Builder builder() {
+    return new AutoValue_GitFileDiffCacheKey.Builder();
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    public abstract Builder project(NameKey value);
+
+    public abstract Builder oldTree(ObjectId value);
+
+    public abstract Builder newTree(ObjectId value);
+
+    public abstract Builder newFilePath(String value);
+
+    public abstract Builder renameScore(Integer value);
+
+    public Builder disableRenameDetection() {
+      renameScore(-1);
+      return this;
+    }
+
+    public abstract Builder diffAlgorithm(DiffAlgorithm value);
+
+    public abstract Builder whitespace(Whitespace value);
+
+    public abstract GitFileDiffCacheKey build();
+  }
+
+  public enum Serializer implements CacheSerializer<GitFileDiffCacheKey> {
+    INSTANCE;
+
+    @Override
+    public byte[] serialize(GitFileDiffCacheKey key) {
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return Protos.toByteArray(
+          GitFileDiffKeyProto.newBuilder()
+              .setProject(key.project().get())
+              .setATree(idConverter.toByteString(key.oldTree()))
+              .setBTree(idConverter.toByteString(key.newTree()))
+              .setFilePath(key.newFilePath())
+              .setRenameScore(key.renameScore())
+              .setDiffAlgorithm(key.diffAlgorithm().name())
+              .setWhitepsace(key.whitespace().name())
+              .build());
+    }
+
+    @Override
+    public GitFileDiffCacheKey deserialize(byte[] in) {
+      GitFileDiffKeyProto proto = Protos.parseUnchecked(GitFileDiffKeyProto.parser(), in);
+      ObjectIdConverter idConverter = ObjectIdConverter.create();
+      return GitFileDiffCacheKey.builder()
+          .project(Project.nameKey(proto.getProject()))
+          .oldTree(idConverter.fromByteString(proto.getATree()))
+          .newTree(idConverter.fromByteString(proto.getBTree()))
+          .newFilePath(proto.getFilePath())
+          .renameScore(proto.getRenameScore())
+          .diffAlgorithm(DiffAlgorithm.valueOf(proto.getDiffAlgorithm()))
+          .whitespace(Whitespace.valueOf(proto.getWhitepsace()))
+          .build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffWeigher.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffWeigher.java
new file mode 100644
index 0000000..47f7791
--- /dev/null
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiffWeigher.java
@@ -0,0 +1,25 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.patch.gitfilediff;
+
+import com.google.common.cache.Weigher;
+
+public class GitFileDiffWeigher implements Weigher<GitFileDiffCacheKey, GitFileDiff> {
+
+  @Override
+  public int weigh(GitFileDiffCacheKey key, GitFileDiff gitFileDiff) {
+    return key.weight() + gitFileDiff.weight();
+  }
+}
diff --git a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
index cf6a184..66299a8 100644
--- a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
@@ -49,8 +49,6 @@
 public class DefaultPermissionBackend extends PermissionBackend {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  private static final CurrentUser.PropertyKey<Boolean> IS_ADMIN = CurrentUser.PropertyKey.create();
-
   private final Provider<CurrentUser> currentUser;
   private final ProjectCache projectCache;
   private final ProjectControl.Factory projectControlFactory;
@@ -84,8 +82,15 @@
 
   @Override
   public WithUser absentUser(Account.Id id) {
-    IdentifiedUser identifiedUser = identifiedUserFactory.create(requireNonNull(id, "user"));
-    return new WithUserImpl(identifiedUser);
+    requireNonNull(id, "user");
+    Optional<Account.Id> user = getAccountIdOfIdentifiedUser();
+    if (user.isPresent() && id.equals(user.get())) {
+      // What looked liked an absent user is actually the current caller. Use the per-request
+      // singleton IdentifiedUser instead of constructing a new object to leverage caching in member
+      // variables of IdentifiedUser.
+      return new WithUserImpl(currentUser.get().asIdentifiedUser());
+    }
+    return new WithUserImpl(identifiedUserFactory.create(requireNonNull(id, "user")));
   }
 
   @Override
@@ -93,6 +98,21 @@
     return true;
   }
 
+  /**
+   * Returns the {@link com.google.gerrit.entities.Account.Id} of the current user if a user is
+   * signed in. Catches exceptions so that background jobs don't get impacted.
+   */
+  private Optional<Account.Id> getAccountIdOfIdentifiedUser() {
+    try {
+      return currentUser.get().isIdentifiedUser()
+          ? Optional.of(currentUser.get().getAccountId())
+          : Optional.empty();
+    } catch (Exception e) {
+      logger.atFine().withCause(e).log("Unable to get current user");
+      return Optional.empty();
+    }
+  }
+
   class WithUserImpl extends WithUser {
     private final CurrentUser user;
     private Boolean admin;
@@ -202,21 +222,13 @@
     }
 
     private Boolean computeAdmin() {
-      Optional<Boolean> r = user.get(IS_ADMIN);
-      if (r.isPresent()) {
-        return r.get();
-      }
-
-      boolean isAdmin;
       if (user.isImpersonating()) {
-        isAdmin = false;
-      } else if (user instanceof PeerDaemonUser) {
-        isAdmin = true;
-      } else {
-        isAdmin = allow(capabilities().administrateServer);
+        return false;
       }
-      user.put(IS_ADMIN, isAdmin);
-      return isAdmin;
+      if (user instanceof PeerDaemonUser) {
+        return true;
+      }
+      return allow(capabilities().administrateServer);
     }
 
     private boolean canEmailReviewers() {
diff --git a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
index eca30b6..edd3cb1 100644
--- a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
+++ b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.flogger.LazyArgs.lazy;
 import static com.google.gerrit.entities.RefNames.REFS_CONFIG;
 import static java.util.stream.Collectors.toCollection;
 
@@ -126,7 +127,7 @@
         "Filter refs for repository %s by visibility (options = %s, refs = %s)",
         projectState.getNameKey(), opts, refs);
     logger.atFinest().log("Calling user: %s", user.getLoggableName());
-    logger.atFinest().log("Groups: %s", user.getEffectiveGroups().getKnownGroups());
+    logger.atFinest().log("Groups: %s", lazy(() -> user.getEffectiveGroups().getKnownGroups()));
     logger.atFinest().log(
         "auth.skipFullRefEvaluationIfAllRefsAreVisible = %s",
         skipFullRefEvaluationIfAllRefsAreVisible);
diff --git a/java/com/google/gerrit/server/permissions/GlobalPermission.java b/java/com/google/gerrit/server/permissions/GlobalPermission.java
index 07c9e84..d4f22e6 100644
--- a/java/com/google/gerrit/server/permissions/GlobalPermission.java
+++ b/java/com/google/gerrit/server/permissions/GlobalPermission.java
@@ -18,6 +18,7 @@
 
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.common.data.GlobalCapability;
 import com.google.gerrit.extensions.annotations.CapabilityScope;
 import com.google.gerrit.extensions.annotations.RequiresAnyCapability;
 import com.google.gerrit.extensions.annotations.RequiresCapability;
@@ -31,7 +32,12 @@
 import java.util.Optional;
 import java.util.Set;
 
-/** Global server permissions built into Gerrit. */
+/**
+ * Global server permissions built into Gerrit.
+ *
+ * <p>See also {@link GlobalCapability} which lists the equivalent strings used in the
+ * refs/meta/config settings in All-Projects.
+ */
 public enum GlobalPermission implements GlobalOrPluginPermission {
   ACCESS_DATABASE,
   ADMINISTRATE_SERVER,
diff --git a/java/com/google/gerrit/server/permissions/PermissionBackend.java b/java/com/google/gerrit/server/permissions/PermissionBackend.java
index eceb970..27c6793 100644
--- a/java/com/google/gerrit/server/permissions/PermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/PermissionBackend.java
@@ -60,9 +60,9 @@
  * <p>{@code PermissionBackend} is a singleton for the server, acting as a factory for lightweight
  * request instances. Implementation classes may cache supporting data inside of {@link WithUser},
  * {@link ForProject}, {@link ForRef}, and {@link ForChange} instances, in addition to storing
- * within {@link CurrentUser} using a {@link com.google.gerrit.server.CurrentUser.PropertyKey}.
- * {@link GlobalPermission} caching for {@link WithUser} may best cached inside {@link CurrentUser}
- * as {@link WithUser} instances are frequently created.
+ * within {@link CurrentUser} using a {@link com.google.gerrit.server.PropertyMap.Key}. {@link
+ * GlobalPermission} caching for {@link WithUser} may best cached inside {@link CurrentUser} as
+ * {@link WithUser} instances are frequently created.
  *
  * <p>Example use:
  *
diff --git a/java/com/google/gerrit/server/permissions/RefControl.java b/java/com/google/gerrit/server/permissions/RefControl.java
index fd82559..dd00dca 100644
--- a/java/com/google/gerrit/server/permissions/RefControl.java
+++ b/java/com/google/gerrit/server/permissions/RefControl.java
@@ -31,6 +31,7 @@
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.logging.CallerFinder;
+import com.google.gerrit.server.logging.LoggingContext;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.permissions.PermissionBackend.ForChange;
 import com.google.gerrit.server.permissions.PermissionBackend.ForRef;
@@ -425,40 +426,52 @@
   /** True if the user has this permission. */
   private boolean canPerform(String permissionName, boolean isChangeOwner, boolean withForce) {
     if (isBlocked(permissionName, isChangeOwner, withForce)) {
-      logger.atFine().log(
-          "'%s' cannot perform '%s' with force=%s on project '%s' for ref '%s'"
-              + " because this permission is blocked (caller: %s)",
-          getUser().getLoggableName(),
-          permissionName,
-          withForce,
-          projectControl.getProject().getName(),
-          refName,
-          callerFinder.findCallerLazy());
+      if (logger.atFine().isEnabled() || LoggingContext.getInstance().isAclLogging()) {
+        String logMessage =
+            String.format(
+                "'%s' cannot perform '%s' with force=%s on project '%s' for ref '%s'"
+                    + " because this permission is blocked",
+                getUser().getLoggableName(),
+                permissionName,
+                withForce,
+                projectControl.getProject().getName(),
+                refName);
+        LoggingContext.getInstance().addAclLogRecord(logMessage);
+        logger.atFine().log("%s (caller: %s)", logMessage, callerFinder.findCallerLazy());
+      }
       return false;
     }
 
     for (PermissionRule pr : relevant.getAllowRules(permissionName)) {
       if (isAllow(pr, withForce) && projectControl.match(pr, isChangeOwner)) {
-        logger.atFine().log(
-            "'%s' can perform '%s' with force=%s on project '%s' for ref '%s' (caller: %s)",
-            getUser().getLoggableName(),
-            permissionName,
-            withForce,
-            projectControl.getProject().getName(),
-            refName,
-            callerFinder.findCallerLazy());
+        if (logger.atFine().isEnabled() || LoggingContext.getInstance().isAclLogging()) {
+          String logMessage =
+              String.format(
+                  "'%s' can perform '%s' with force=%s on project '%s' for ref '%s'",
+                  getUser().getLoggableName(),
+                  permissionName,
+                  withForce,
+                  projectControl.getProject().getName(),
+                  refName);
+          LoggingContext.getInstance().addAclLogRecord(logMessage);
+          logger.atFine().log("%s (caller: %s)", logMessage, callerFinder.findCallerLazy());
+        }
         return true;
       }
     }
 
-    logger.atFine().log(
-        "'%s' cannot perform '%s' with force=%s on project '%s' for ref '%s' (caller: %s)",
-        getUser().getLoggableName(),
-        permissionName,
-        withForce,
-        projectControl.getProject().getName(),
-        refName,
-        callerFinder.findCallerLazy());
+    if (logger.atFine().isEnabled() || LoggingContext.getInstance().isAclLogging()) {
+      String logMessage =
+          String.format(
+              "'%s' cannot perform '%s' with force=%s on project '%s' for ref '%s'",
+              getUser().getLoggableName(),
+              permissionName,
+              withForce,
+              projectControl.getProject().getName(),
+              refName);
+      LoggingContext.getInstance().addAclLogRecord(logMessage);
+      logger.atFine().log("%s (caller: %s)", logMessage, callerFinder.findCallerLazy());
+    }
     return false;
   }
 
diff --git a/java/com/google/gerrit/server/permissions/RefVisibilityControl.java b/java/com/google/gerrit/server/permissions/RefVisibilityControl.java
index 4744037..cc6387b 100644
--- a/java/com/google/gerrit/server/permissions/RefVisibilityControl.java
+++ b/java/com/google/gerrit/server/permissions/RefVisibilityControl.java
@@ -118,9 +118,14 @@
     Account.Id accountId;
     if ((accountId = Account.Id.fromRef(refName)) != null) {
       // Account ref is visible only to the corresponding account.
-      if (accountId.equals(currentUserAccountId)
-          && projectControl.controlForRef(refName).hasReadPermissionOnRef(true)) {
-        return true;
+      if (accountId.equals(currentUserAccountId)) {
+        // Always allow visibility to refs/draft-comments and refs/starred-changes. For all other
+        // refs, check if the user has read permissions.
+        if (RefNames.isRefsDraftsComments(refName)
+            || RefNames.isRefsStarredChanges(refName)
+            || projectControl.controlForRef(refName).hasReadPermissionOnRef(true)) {
+          return true;
+        }
       }
       return false;
     }
diff --git a/java/com/google/gerrit/server/project/ProjectConfig.java b/java/com/google/gerrit/server/project/ProjectConfig.java
index 89038e2..a1c48bc 100644
--- a/java/com/google/gerrit/server/project/ProjectConfig.java
+++ b/java/com/google/gerrit/server/project/ProjectConfig.java
@@ -385,6 +385,7 @@
     this.accountsSection = accountsSection;
   }
 
+  /** Returns an access section, {@code name} typically is a ref pattern. */
   public AccessSection getAccessSection(String name) {
     return accessSections.get(name);
   }
diff --git a/java/com/google/gerrit/server/project/ProjectState.java b/java/com/google/gerrit/server/project/ProjectState.java
index eecf1fe..8c024ef 100644
--- a/java/com/google/gerrit/server/project/ProjectState.java
+++ b/java/com/google/gerrit/server/project/ProjectState.java
@@ -14,7 +14,9 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.gerrit.entities.PermissionRule.Action.ALLOW;
+import static java.util.Comparator.comparing;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.FluentIterable;
@@ -264,7 +266,10 @@
   List<SectionMatcher> getLocalAccessSections() {
     List<SectionMatcher> sm = localAccessSections;
     if (sm == null) {
-      Collection<AccessSection> fromConfig = cachedConfig.getAccessSections().values();
+      ImmutableList<AccessSection> fromConfig =
+          cachedConfig.getAccessSections().values().stream()
+              .sorted(comparing(AccessSection::getName))
+              .collect(toImmutableList());
       sm = new ArrayList<>(fromConfig.size());
       for (AccessSection section : fromConfig) {
         if (isAllProjects) {
diff --git a/java/com/google/gerrit/server/project/RefUtil.java b/java/com/google/gerrit/server/project/RefUtil.java
index dc8cdc7..797756b 100644
--- a/java/com/google/gerrit/server/project/RefUtil.java
+++ b/java/com/google/gerrit/server/project/RefUtil.java
@@ -102,6 +102,7 @@
     return Constants.R_HEADS;
   }
 
+  /** Fully qualifies a tag name to refs/tags/TAG-NAME */
   public static String normalizeTagRef(String tag) throws BadRequestException {
     String result = tag;
     while (result.startsWith("/")) {
diff --git a/java/com/google/gerrit/server/query/change/AfterPredicate.java b/java/com/google/gerrit/server/query/change/AfterPredicate.java
index df5a71d..8f92d9a 100644
--- a/java/com/google/gerrit/server/query/change/AfterPredicate.java
+++ b/java/com/google/gerrit/server/query/change/AfterPredicate.java
@@ -14,15 +14,21 @@
 
 package com.google.gerrit.server.query.change;
 
+import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.query.QueryParseException;
-import com.google.gerrit.server.index.change.ChangeField;
+import java.sql.Timestamp;
 import java.util.Date;
 
+/**
+ * Predicate that matches a {@link Timestamp} field from the index in a range from the passed {@code
+ * String} representation of the Timestamp value to the maximum supported time.
+ */
 public class AfterPredicate extends TimestampRangeChangePredicate {
   protected final Date cut;
 
-  public AfterPredicate(String value) throws QueryParseException {
-    super(ChangeField.UPDATED, ChangeQueryBuilder.FIELD_BEFORE, value);
+  public AfterPredicate(FieldDef<ChangeData, Timestamp> def, String name, String value)
+      throws QueryParseException {
+    super(def, name, value);
     cut = parse(value);
   }
 
@@ -38,6 +44,10 @@
 
   @Override
   public boolean match(ChangeData cd) {
-    return cd.change().getLastUpdatedOn().getTime() >= cut.getTime();
+    Timestamp valueTimestamp = this.getValueTimestamp(cd);
+    if (valueTimestamp == null) {
+      return false;
+    }
+    return valueTimestamp.getTime() >= cut.getTime();
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/AgePredicate.java b/java/com/google/gerrit/server/query/change/AgePredicate.java
index 36eb5b7..d38789f 100644
--- a/java/com/google/gerrit/server/query/change/AgePredicate.java
+++ b/java/com/google/gerrit/server/query/change/AgePredicate.java
@@ -17,7 +17,6 @@
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.SECONDS;
 
-import com.google.gerrit.entities.Change;
 import com.google.gerrit.server.config.ConfigUtil;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.util.time.TimeUtil;
@@ -46,7 +45,10 @@
 
   @Override
   public boolean match(ChangeData object) {
-    Change change = object.change();
-    return change != null && change.getLastUpdatedOn().getTime() <= cut;
+    Timestamp valueTimestamp = this.getValueTimestamp(object);
+    if (valueTimestamp == null) {
+      return false;
+    }
+    return valueTimestamp.getTime() <= cut;
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/BeforePredicate.java b/java/com/google/gerrit/server/query/change/BeforePredicate.java
index dacabc0..6e28ce6 100644
--- a/java/com/google/gerrit/server/query/change/BeforePredicate.java
+++ b/java/com/google/gerrit/server/query/change/BeforePredicate.java
@@ -14,15 +14,21 @@
 
 package com.google.gerrit.server.query.change;
 
+import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.query.QueryParseException;
-import com.google.gerrit.server.index.change.ChangeField;
+import java.sql.Timestamp;
 import java.util.Date;
 
+/**
+ * Predicate that matches a {@link Timestamp} field from the index in a range from the the epoch to
+ * the passed {@code String} representation of the Timestamp value.
+ */
 public class BeforePredicate extends TimestampRangeChangePredicate {
   protected final Date cut;
 
-  public BeforePredicate(String value) throws QueryParseException {
-    super(ChangeField.UPDATED, ChangeQueryBuilder.FIELD_BEFORE, value);
+  public BeforePredicate(FieldDef<ChangeData, Timestamp> def, String name, String value)
+      throws QueryParseException {
+    super(def, name, value);
     cut = parse(value);
   }
 
@@ -38,6 +44,10 @@
 
   @Override
   public boolean match(ChangeData cd) {
-    return cd.change().getLastUpdatedOn().getTime() <= cut.getTime();
+    Timestamp valueTimestamp = this.getValueTimestamp(cd);
+    if (valueTimestamp == null) {
+      return false;
+    }
+    return valueTimestamp.getTime() <= cut.getTime();
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 432b48a..6de263e 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -307,7 +307,7 @@
   private Integer unresolvedCommentCount;
   private Integer totalCommentCount;
   private LabelTypes labelTypes;
-
+  private Optional<Timestamp> mergedOn;
   private ImmutableList<byte[]> refStates;
   private ImmutableList<byte[]> refStatePatterns;
 
@@ -616,6 +616,29 @@
   }
 
   /**
+   * Returns the {@link Optional} value of time when the change was merged.
+   *
+   * <p>The value can be set from index field, see {@link ChangeData#setMergedOn} or loaded from the
+   * database (available in {@link ChangeNotes})
+   *
+   * @return {@link Optional} value of time when the change was merged.
+   * @throws StorageException if {@code lazyLoad} is off, {@link ChangeNotes} can not be loaded
+   *     because we do not expect to call the database.
+   */
+  public Optional<Timestamp> getMergedOn() throws StorageException {
+    if (mergedOn == null) {
+      // The value was not loaded yet, try to get from the database.
+      mergedOn = notes().getMergedOn();
+    }
+    return mergedOn;
+  }
+
+  /** Sets the value e.g. when loading from index. */
+  public void setMergedOn(@Nullable Timestamp mergedOn) {
+    this.mergedOn = Optional.ofNullable(mergedOn);
+  }
+
+  /**
    * Sets the specified attention set. If two or more entries refer to the same user, throws an
    * {@link IllegalStateException}.
    */
@@ -670,7 +693,9 @@
     return allApprovals;
   }
 
-  /** @return The submit ('SUBM') approval label */
+  /* @return legacy submit ('SUBM') approval label */
+  // TODO(mariasavtchouk): Deprecate legacy submit label,
+  // see com.google.gerrit.entities.LabelId.LEGACY_SUBMIT_NAME
   public Optional<PatchSetApproval> getSubmitApproval() {
     return currentApprovals().stream().filter(PatchSetApproval::isLegacySubmit).findFirst();
   }
diff --git a/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java b/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
index c6bcd60..a66c43ae 100644
--- a/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
@@ -88,7 +88,7 @@
             ? permissionBackend.absentUser(user.getAccountId())
             : permissionBackend.user(
                 Optional.of(user)
-                    .filter(u -> u instanceof SingleGroupUser || u instanceof InternalUser)
+                    .filter(u -> u instanceof GroupBackedUser || u instanceof InternalUser)
                     .orElseGet(anonymousUserProvider::get));
     try {
       withUser.change(cd).check(ChangePermission.READ);
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index 2021b2b..68a90d2 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -142,7 +142,7 @@
   public static final String FIELD_ASSIGNEE = "assignee";
   public static final String FIELD_AUTHOR = "author";
   public static final String FIELD_EXACTAUTHOR = "exactauthor";
-  public static final String FIELD_BEFORE = "before";
+
   public static final String FIELD_CHANGE = "change";
   public static final String FIELD_CHANGE_ID = "change_id";
   public static final String FIELD_COMMENT = "comment";
@@ -169,6 +169,7 @@
   public static final String FIELD_LIMIT = "limit";
   public static final String FIELD_MERGE = "merge";
   public static final String FIELD_MERGEABLE = "mergeable2";
+  public static final String FIELD_MERGED_ON = "mergedon";
   public static final String FIELD_MESSAGE = "message";
   public static final String FIELD_OWNER = "owner";
   public static final String FIELD_OWNERIN = "ownerin";
@@ -199,11 +200,19 @@
   public static final String FIELD_CHERRY_PICK_OF_CHANGE = "cherrypickofchange";
   public static final String FIELD_CHERRY_PICK_OF_PATCHSET = "cherrypickofpatchset";
 
+  public static final String ARG_ID_NAME = "name";
   public static final String ARG_ID_USER = "user";
   public static final String ARG_ID_GROUP = "group";
   public static final String ARG_ID_OWNER = "owner";
   public static final Account.Id OWNER_ACCOUNT_ID = Account.id(0);
 
+  public static final String OPERATOR_MERGED_BEFORE = "mergedbefore";
+  public static final String OPERATOR_MERGED_AFTER = "mergedafter";
+
+  // Operators to match on the last time the change was updated. Naming for legacy reasons.
+  public static final String OPERATOR_BEFORE = "before";
+  public static final String OPERATOR_AFTER = "after";
+
   private static final QueryBuilder.Definition<ChangeData, ChangeQueryBuilder> mydef =
       new QueryBuilder.Definition<>(ChangeQueryBuilder.class);
 
@@ -470,7 +479,7 @@
 
   @Operator
   public Predicate<ChangeData> before(String value) throws QueryParseException {
-    return new BeforePredicate(value);
+    return new BeforePredicate(ChangeField.UPDATED, ChangeQueryBuilder.OPERATOR_BEFORE, value);
   }
 
   @Operator
@@ -480,7 +489,7 @@
 
   @Operator
   public Predicate<ChangeData> after(String value) throws QueryParseException {
-    return new AfterPredicate(value);
+    return new AfterPredicate(ChangeField.UPDATED, ChangeQueryBuilder.OPERATOR_AFTER, value);
   }
 
   @Operator
@@ -489,6 +498,28 @@
   }
 
   @Operator
+  public Predicate<ChangeData> mergedBefore(String value) throws QueryParseException {
+    if (!args.index.getSchema().hasField(ChangeField.MERGED_ON)) {
+      throw new QueryParseException(
+          String.format(
+              "'%s' operator is not supported by change index version", OPERATOR_MERGED_BEFORE));
+    }
+    return new BeforePredicate(
+        ChangeField.MERGED_ON, ChangeQueryBuilder.OPERATOR_MERGED_BEFORE, value);
+  }
+
+  @Operator
+  public Predicate<ChangeData> mergedAfter(String value) throws QueryParseException {
+    if (!args.index.getSchema().hasField(ChangeField.MERGED_ON)) {
+      throw new QueryParseException(
+          String.format(
+              "'%s' operator is not supported by change index version", OPERATOR_MERGED_AFTER));
+    }
+    return new AfterPredicate(
+        ChangeField.MERGED_ON, ChangeQueryBuilder.OPERATOR_MERGED_AFTER, value);
+  }
+
+  @Operator
   public Predicate<ChangeData> change(String query) throws QueryParseException {
     Optional<ChangeTriplet> triplet = ChangeTriplet.parse(query);
     if (triplet.isPresent()) {
@@ -1034,7 +1065,7 @@
       for (GroupReference ref : suggestions) {
         ids.add(ref.getUUID());
       }
-      return visibleto(new SingleGroupUser(ids));
+      return visibleto(new GroupBackedUser(ids));
     }
 
     throw error("No user or group matches \"" + who + "\".");
@@ -1232,9 +1263,36 @@
   }
 
   @Operator
-  public Predicate<ChangeData> query(String name) throws QueryParseException {
+  public Predicate<ChangeData> query(String value) throws QueryParseException {
+    // [name=]<name>[,user=<user>] || [user=<user>,][name=]<name>
+    PredicateArgs inputArgs = new PredicateArgs(value);
+    String name = null;
+    Account.Id account = null;
+
     try (Repository git = args.repoManager.openRepository(args.allUsersName)) {
-      VersionedAccountQueries q = VersionedAccountQueries.forUser(self());
+      // [name=]<name>
+      if (inputArgs.keyValue.containsKey(ARG_ID_NAME)) {
+        name = inputArgs.keyValue.get(ARG_ID_NAME);
+      } else if (inputArgs.positional.size() == 1) {
+        name = Iterables.getOnlyElement(inputArgs.positional);
+      } else if (inputArgs.positional.size() > 1) {
+        throw new QueryParseException("Error parsing named query: " + value);
+      }
+
+      // [,user=<user>]
+      if (inputArgs.keyValue.containsKey(ARG_ID_USER)) {
+        Set<Account.Id> accounts = parseAccount(inputArgs.keyValue.get(ARG_ID_USER));
+        if (accounts != null && accounts.size() > 1) {
+          throw error(
+              String.format(
+                  "\"%s\" resolves to multiple accounts", inputArgs.keyValue.get(ARG_ID_USER)));
+        }
+        account = (accounts == null ? self() : Iterables.getOnlyElement(accounts));
+      } else {
+        account = self();
+      }
+
+      VersionedAccountQueries q = VersionedAccountQueries.forUser(account);
       q.load(args.allUsersName, git);
       String query = q.getQueryList().getQuery(name);
       if (query != null) {
@@ -1244,7 +1302,7 @@
       throw new QueryParseException(
           "Unknown named query (no " + args.allUsersName + " repo): " + name, e);
     } catch (IOException | ConfigInvalidException e) {
-      throw new QueryParseException("Error parsing named query: " + name, e);
+      throw new QueryParseException("Error parsing named query: " + value, e);
     }
     throw new QueryParseException("Unknown named query: " + name);
   }
@@ -1256,19 +1314,46 @@
   }
 
   @Operator
-  public Predicate<ChangeData> destination(String name) throws QueryParseException {
+  public Predicate<ChangeData> destination(String value) throws QueryParseException {
+    // [name=]<name>[,user=<user>] || [user=<user>,][name=]<name>
+    PredicateArgs inputArgs = new PredicateArgs(value);
+    String name = null;
+    Account.Id account = null;
+
     try (Repository git = args.repoManager.openRepository(args.allUsersName)) {
-      VersionedAccountDestinations d = VersionedAccountDestinations.forUser(self());
+      // [name=]<name>
+      if (inputArgs.keyValue.containsKey(ARG_ID_NAME)) {
+        name = inputArgs.keyValue.get(ARG_ID_NAME);
+      } else if (inputArgs.positional.size() == 1) {
+        name = Iterables.getOnlyElement(inputArgs.positional);
+      } else if (inputArgs.positional.size() > 1) {
+        throw new QueryParseException("Error parsing named destination: " + value);
+      }
+
+      // [,user=<user>]
+      if (inputArgs.keyValue.containsKey(ARG_ID_USER)) {
+        Set<Account.Id> accounts = parseAccount(inputArgs.keyValue.get(ARG_ID_USER));
+        if (accounts != null && accounts.size() > 1) {
+          throw error(
+              String.format(
+                  "\"%s\" resolves to multiple accounts", inputArgs.keyValue.get(ARG_ID_USER)));
+        }
+        account = (accounts == null ? self() : Iterables.getOnlyElement(accounts));
+      } else {
+        account = self();
+      }
+
+      VersionedAccountDestinations d = VersionedAccountDestinations.forUser(account);
       d.load(args.allUsersName, git);
       Set<BranchNameKey> destinations = d.getDestinationList().getDestinations(name);
       if (destinations != null && !destinations.isEmpty()) {
-        return new DestinationPredicate(destinations, name);
+        return new DestinationPredicate(destinations, value);
       }
     } catch (RepositoryNotFoundException e) {
       throw new QueryParseException(
           "Unknown named destination (no " + args.allUsersName + " repo): " + name, e);
     } catch (IOException | ConfigInvalidException e) {
-      throw new QueryParseException("Error parsing named destination: " + name, e);
+      throw new QueryParseException("Error parsing named destination: " + value, e);
     }
     throw new QueryParseException("Unknown named destination: " + name);
   }
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java b/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
index 370bc75..ed1f2f1 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
@@ -17,7 +17,6 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.query.change.ChangeQueryBuilder.FIELD_LIMIT;
 
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.common.PluginDefinedInfo;
@@ -33,10 +32,8 @@
 import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.DynamicOptions.DynamicBean;
 import com.google.gerrit.server.account.AccountLimits;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangePluginDefinedInfoFactory;
 import com.google.gerrit.server.change.PluginDefinedAttributesFactories;
-import com.google.gerrit.server.change.PluginDefinedAttributesFactory;
 import com.google.gerrit.server.change.PluginDefinedInfosFactory;
 import com.google.gerrit.server.index.change.ChangeIndexCollection;
 import com.google.gerrit.server.index.change.ChangeIndexRewriter;
@@ -60,7 +57,6 @@
 public class ChangeQueryProcessor extends QueryProcessor<ChangeData>
     implements DynamicOptions.BeanReceiver, DynamicOptions.BeanProvider, PluginDefinedInfosFactory {
   private final Provider<CurrentUser> userProvider;
-  private final ImmutableListMultimap<String, ChangeAttributeFactory> attributeFactoriesByPlugin;
   private final ChangeIsVisibleToPredicate.Factory changeIsVisibleToPredicateFactory;
   private final Map<String, DynamicBean> dynamicBeans = new HashMap<>();
   private final List<Extension<ChangePluginDefinedInfoFactory>>
@@ -81,7 +77,6 @@
       IndexConfig indexConfig,
       ChangeIndexCollection indexes,
       ChangeIndexRewriter rewriter,
-      DynamicSet<ChangeAttributeFactory> attributeFactories,
       ChangeIsVisibleToPredicate.Factory changeIsVisibleToPredicateFactory,
       DynamicSet<ChangePluginDefinedInfoFactory> changePluginDefinedInfoFactories) {
     super(
@@ -95,14 +90,6 @@
     this.userProvider = userProvider;
     this.changeIsVisibleToPredicateFactory = changeIsVisibleToPredicateFactory;
 
-    ImmutableListMultimap.Builder<String, ChangeAttributeFactory> factoriesBuilder =
-        ImmutableListMultimap.builder();
-    ImmutableListMultimap.Builder<String, ChangePluginDefinedInfoFactory> infosFactoriesBuilder =
-        ImmutableListMultimap.builder();
-    // Eagerly call Extension#get() rather than storing Extensions, since that method invokes the
-    // Provider on every call, which could be expensive if we invoke it once for every change.
-    attributeFactories.entries().forEach(e -> factoriesBuilder.put(e.getPluginName(), e.get()));
-    attributeFactoriesByPlugin = factoriesBuilder.build();
     changePluginDefinedInfoFactories
         .entries()
         .forEach(e -> changePluginDefinedInfoFactoriesByPlugin.add(e));
@@ -130,18 +117,6 @@
     return dynamicBeans.get(plugin);
   }
 
-  public PluginDefinedAttributesFactory getAttributesFactory() {
-    return this::buildPluginInfo;
-  }
-
-  private ImmutableList<PluginDefinedInfo> buildPluginInfo(ChangeData cd) {
-    return PluginDefinedAttributesFactories.createAll(
-        cd,
-        this,
-        attributeFactoriesByPlugin.entries().stream()
-            .map(e -> new Extension<>(e.getKey(), e::getValue)));
-  }
-
   public PluginDefinedInfosFactory getInfosFactory() {
     return this::createPluginDefinedInfos;
   }
diff --git a/java/com/google/gerrit/server/query/change/GroupBackedUser.java b/java/com/google/gerrit/server/query/change/GroupBackedUser.java
new file mode 100644
index 0000000..d0d5735
--- /dev/null
+++ b/java/com/google/gerrit/server/query/change/GroupBackedUser.java
@@ -0,0 +1,64 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.account.GroupMembership;
+import com.google.gerrit.server.account.ListGroupMembership;
+import java.util.Set;
+
+/**
+ * Representation of a user that does not have a Gerrit account.
+ *
+ * <p>This user representation is intended to be used to check permissions for groups:
+ *
+ * <p>There are occasions where we need to check if a resource - such as a change - is accessible by
+ * a group. Our entire {@link com.google.gerrit.server.permissions.PermissionBackend} works solely
+ * with {@link CurrentUser}. This class can be used to check permissions on a synthetic user with
+ * the given group memberships. Any real Gerrit user with the same group memberships would receive
+ * the same permission check results.
+ */
+public final class GroupBackedUser extends CurrentUser {
+  private final GroupMembership groups;
+
+  /**
+   * Creates a new instance
+   *
+   * @param groups this set has to include all parent groups the user is contained in through
+   *     subgroup membership. Given a set of groups that contains the user directly, callers can use
+   *     {@link
+   *     com.google.gerrit.server.account.GroupIncludeCache#parentGroupsOf(AccountGroup.UUID)} to
+   *     resolve parent groups.
+   */
+  public GroupBackedUser(Set<AccountGroup.UUID> groups) {
+    this.groups = new ListGroupMembership(groups);
+  }
+
+  @Override
+  public GroupMembership getEffectiveGroups() {
+    return groups;
+  }
+
+  @Override
+  public String getLoggableName() {
+    return "GroupBackedUser with memberships: " + groups.getKnownGroups();
+  }
+
+  @Override
+  public Object getCacheKey() {
+    return groups.getKnownGroups();
+  }
+}
diff --git a/java/com/google/gerrit/server/query/change/OutputStreamQuery.java b/java/com/google/gerrit/server/query/change/OutputStreamQuery.java
index b931457..4922b57 100644
--- a/java/com/google/gerrit/server/query/change/OutputStreamQuery.java
+++ b/java/com/google/gerrit/server/query/change/OutputStreamQuery.java
@@ -330,15 +330,9 @@
       eventFactory.addDependencies(rw, c, d.change(), d.currentPatchSet());
     }
 
-    c.plugins = queryProcessor.getAttributesFactory().create(d);
     List<PluginDefinedInfo> pluginInfos = pluginInfosByChange.get(d.getId());
     if (!pluginInfos.isEmpty()) {
-      if (c.plugins == null) {
-        c.plugins = pluginInfos;
-      } else {
-        c.plugins = new ArrayList<>(c.plugins);
-        c.plugins.addAll(pluginInfos);
-      }
+      c.plugins = pluginInfos;
     }
     return c;
   }
diff --git a/java/com/google/gerrit/server/query/change/SingleGroupUser.java b/java/com/google/gerrit/server/query/change/SingleGroupUser.java
deleted file mode 100644
index c451d46..0000000
--- a/java/com/google/gerrit/server/query/change/SingleGroupUser.java
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (C) 2009 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.common.collect.ImmutableSet;
-import com.google.gerrit.entities.AccountGroup;
-import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.account.GroupMembership;
-import com.google.gerrit.server.account.ListGroupMembership;
-import java.util.Set;
-
-public final class SingleGroupUser extends CurrentUser {
-  private final GroupMembership groups;
-
-  public SingleGroupUser(AccountGroup.UUID groupId) {
-    this(ImmutableSet.of(groupId));
-  }
-
-  public SingleGroupUser(Set<AccountGroup.UUID> groups) {
-    this.groups = new ListGroupMembership(groups);
-  }
-
-  @Override
-  public GroupMembership getEffectiveGroups() {
-    return groups;
-  }
-
-  @Override
-  public Object getCacheKey() {
-    return groups.getKnownGroups();
-  }
-}
diff --git a/java/com/google/gerrit/server/restapi/account/AccountsCollection.java b/java/com/google/gerrit/server/restapi/account/AccountsCollection.java
index 119e2e4..61ff6b8 100644
--- a/java/com/google/gerrit/server/restapi/account/AccountsCollection.java
+++ b/java/com/google/gerrit/server/restapi/account/AccountsCollection.java
@@ -53,6 +53,7 @@
       return new AccountResource(accountResolver.resolve(id.get()).asUniqueUser());
     } catch (UnresolvableAccountException e) {
       if (e.isSelf()) {
+        // Must be authenticated to use 'me' or 'self'.
         throw new AuthException(e.getMessage(), e);
       }
       throw new ResourceNotFoundException(e.getMessage(), e);
diff --git a/java/com/google/gerrit/server/restapi/account/GetSshKeys.java b/java/com/google/gerrit/server/restapi/account/GetSshKeys.java
index 6df6c3c..9952987 100644
--- a/java/com/google/gerrit/server/restapi/account/GetSshKeys.java
+++ b/java/com/google/gerrit/server/restapi/account/GetSshKeys.java
@@ -60,8 +60,7 @@
 
   @Override
   public Response<List<SshKeyInfo>> apply(AccountResource rsrc)
-      throws AuthException, RepositoryNotFoundException, IOException, ConfigInvalidException,
-          PermissionBackendException {
+      throws AuthException, IOException, ConfigInvalidException, PermissionBackendException {
     if (!self.get().hasSameAccountId(rsrc.getUser())) {
       permissionBackend.currentUser().check(GlobalPermission.MODIFY_ACCOUNT);
     }
diff --git a/java/com/google/gerrit/server/restapi/account/PostWatchedProjects.java b/java/com/google/gerrit/server/restapi/account/PostWatchedProjects.java
index c80bf57..5979b2a 100644
--- a/java/com/google/gerrit/server/restapi/account/PostWatchedProjects.java
+++ b/java/com/google/gerrit/server/restapi/account/PostWatchedProjects.java
@@ -91,7 +91,7 @@
       throws RestApiException, IOException, PermissionBackendException {
     Map<ProjectWatchKey, Set<NotifyType>> m = new HashMap<>();
     for (ProjectWatchInfo info : input) {
-      if (info.project == null) {
+      if (info.project == null || info.project.trim().isEmpty()) {
         throw new BadRequestException("project name must be specified");
       }
 
diff --git a/java/com/google/gerrit/server/restapi/account/PutActive.java b/java/com/google/gerrit/server/restapi/account/PutActive.java
index a80ab3f..3b431db 100644
--- a/java/com/google/gerrit/server/restapi/account/PutActive.java
+++ b/java/com/google/gerrit/server/restapi/account/PutActive.java
@@ -32,7 +32,7 @@
  *
  * <p>This REST endpoint handles {@code PUT /accounts/<account-identifier>/active} requests.
  *
- * <p>Only active accounts can login into Gerrit.
+ * <p>Only active accounts can login into Gerrit, or are suggested as reviewers.
  *
  * <p>Marking an account as inactive is handled by {@link DeleteActive}.
  */
diff --git a/java/com/google/gerrit/server/restapi/account/Stars.java b/java/com/google/gerrit/server/restapi/account/Stars.java
index c27bdd8..cc362f2 100644
--- a/java/com/google/gerrit/server/restapi/account/Stars.java
+++ b/java/com/google/gerrit/server/restapi/account/Stars.java
@@ -46,6 +46,12 @@
 import java.util.Set;
 import java.util.SortedSet;
 
+/**
+ * Implements adding label stars to changes.
+ *
+ * <p>This handles {@code POST} and {@code GET} for {@code
+ * /accounts/<account-identifier>/stars.changes/<change ID>}.
+ */
 @Singleton
 public class Stars implements ChildCollection<AccountResource, AccountResource.Star> {
 
@@ -70,6 +76,7 @@
   public Star parse(AccountResource parent, IdString id)
       throws RestApiException, PermissionBackendException, IOException {
     IdentifiedUser user = parent.getUser();
+    // This enforces visibility of the change.
     ChangeResource change = changes.parse(TopLevelResource.INSTANCE, id);
     Set<String> labels = starredChangesUtil.getLabels(user.getAccountId(), change.getId());
     return new AccountResource.Star(user, change, labels);
@@ -87,6 +94,7 @@
 
   @Singleton
   public static class ListStarredChanges implements RestReadView<AccountResource> {
+
     private final Provider<CurrentUser> self;
     private final ChangesCollection changes;
 
@@ -121,6 +129,7 @@
 
   @Singleton
   public static class Get implements RestReadView<AccountResource.Star> {
+
     private final Provider<CurrentUser> self;
     private final StarredChangesUtil starredChangesUtil;
 
@@ -142,6 +151,7 @@
 
   @Singleton
   public static class Post implements RestModifyView<AccountResource.Star, StarsInput> {
+
     private final Provider<CurrentUser> self;
     private final StarredChangesUtil starredChangesUtil;
 
diff --git a/java/com/google/gerrit/server/restapi/change/AddToAttentionSet.java b/java/com/google/gerrit/server/restapi/change/AddToAttentionSet.java
index a5be14f..cb1256c 100644
--- a/java/com/google/gerrit/server/restapi/change/AddToAttentionSet.java
+++ b/java/com/google/gerrit/server/restapi/change/AddToAttentionSet.java
@@ -42,6 +42,7 @@
 public class AddToAttentionSet
     implements RestCollectionModifyView<
         ChangeResource, AttentionSetEntryResource, AttentionSetInput> {
+
   private final BatchUpdate.Factory updateFactory;
   private final AccountResolver accountResolver;
   private final AddToAttentionSetOp.Factory opFactory;
@@ -72,8 +73,9 @@
   public Response<AccountInfo> apply(ChangeResource changeResource, AttentionSetInput input)
       throws Exception {
     AttentionSetUtil.validateInput(input);
+    Account.Id attentionUserId =
+        AttentionSetUtil.resolveAccount(accountResolver, changeResource.getNotes(), input.user);
 
-    Account.Id attentionUserId = accountResolver.resolve(input.user).asUnique().account().id();
     if (serviceUserClassifier.isServiceUser(attentionUserId)) {
       throw new BadRequestException(
           String.format(
diff --git a/java/com/google/gerrit/server/restapi/change/AttentionSet.java b/java/com/google/gerrit/server/restapi/change/AttentionSet.java
index 45d78dc..f72fe64ec 100644
--- a/java/com/google/gerrit/server/restapi/change/AttentionSet.java
+++ b/java/com/google/gerrit/server/restapi/change/AttentionSet.java
@@ -17,14 +17,15 @@
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.server.account.AccountResolver;
-import com.google.gerrit.server.account.AccountResolver.UnresolvableAccountException;
 import com.google.gerrit.server.change.AttentionSetEntryResource;
 import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.util.AttentionSetUtil;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.io.IOException;
@@ -58,12 +59,10 @@
 
   @Override
   public AttentionSetEntryResource parse(ChangeResource changeResource, IdString idString)
-      throws ResourceNotFoundException, AuthException, IOException, ConfigInvalidException {
-    try {
-      Account.Id accountId = accountResolver.resolve(idString.get()).asUnique().account().id();
-      return new AttentionSetEntryResource(changeResource, accountId);
-    } catch (UnresolvableAccountException e) {
-      throw new ResourceNotFoundException(idString, e);
-    }
+      throws ResourceNotFoundException, AuthException, IOException, ConfigInvalidException,
+          BadRequestException {
+    Account.Id accountId =
+        AttentionSetUtil.resolveAccount(accountResolver, changeResource.getNotes(), idString.get());
+    return new AttentionSetEntryResource(changeResource, accountId);
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/change/CherryPickChange.java b/java/com/google/gerrit/server/restapi/change/CherryPickChange.java
index fdac552..5753874 100644
--- a/java/com/google/gerrit/server/restapi/change/CherryPickChange.java
+++ b/java/com/google/gerrit/server/restapi/change/CherryPickChange.java
@@ -42,6 +42,7 @@
 import com.google.gerrit.server.change.ChangeInserter;
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.change.PatchSetInserter;
+import com.google.gerrit.server.change.ResetCherryPickOp;
 import com.google.gerrit.server.change.SetCherryPickOp;
 import com.google.gerrit.server.config.UrlFormatter;
 import com.google.gerrit.server.git.CodeReviewCommit;
@@ -281,20 +282,36 @@
                 input.parent, commitToCherryPick.getParentCount()));
       }
 
-      String message = Strings.nullToEmpty(input.message).trim();
-      message = message.isEmpty() ? commitToCherryPick.getFullMessage() : message;
+      // If the commit message is not set, the commit message of the source commit will be used.
+      String commitMessage = Strings.nullToEmpty(input.message);
+      commitMessage = commitMessage.isEmpty() ? commitToCherryPick.getFullMessage() : commitMessage;
 
-      PersonIdent committerIdent = identifiedUser.newCommitterIdent(timestamp, serverTimeZone);
+      String destChangeId = getDestinationChangeId(commitMessage, changeIdForNewChange);
 
-      final ObjectId generatedChangeId =
-          changeIdForNewChange != null
-              ? changeIdForNewChange
-              : CommitMessageUtil.generateChangeId();
-      String commitMessage = ChangeIdUtil.insertId(message, generatedChangeId).trim() + '\n';
+      ChangeData destChange = null;
+      if (destChangeId != null) {
+        // If "idForNewChange" is not null we must fail, since we are not expecting an already
+        // existing change.
+        destChange = getDestChangeWithVerification(destChangeId, dest, idForNewChange != null);
+      }
+
+      if (changeIdForNewChange != null) {
+        // If Change-Id was explicitly provided for the new change, override the value in commit
+        // message.
+        commitMessage = ChangeIdUtil.insertId(commitMessage, changeIdForNewChange, true);
+      } else if (destChangeId == null) {
+        // If commit message did not specify Change-Id, generate a new one and insert to the
+        // message.
+        commitMessage =
+            ChangeIdUtil.insertId(commitMessage, CommitMessageUtil.generateChangeId(), true);
+      }
+      commitMessage = CommitMessageUtil.checkAndSanitizeCommitMessage(commitMessage);
 
       CodeReviewCommit cherryPickCommit;
       ProjectState projectState =
           projectCache.get(dest.project()).orElseThrow(noSuchProject(dest.project()));
+      PersonIdent committerIdent = identifiedUser.newCommitterIdent(timestamp, serverTimeZone);
+
       try {
         MergeUtil mergeUtil;
         if (input.allowConflicts) {
@@ -316,87 +333,55 @@
                 input.parent - 1,
                 input.allowEmpty,
                 input.allowConflicts);
-
-        Change.Key changeKey;
-        final List<String> idList =
-            ChangeUtil.getChangeIdsFromFooter(cherryPickCommit, urlFormatter.get());
-        if (!idList.isEmpty()) {
-          final String idStr = idList.get(idList.size() - 1).trim();
-          changeKey = Change.key(idStr);
-        } else {
-          changeKey = Change.key("I" + generatedChangeId.name());
-        }
-
-        BranchNameKey newDest = BranchNameKey.create(project, destRef.getName());
-        List<ChangeData> destChanges =
-            queryProvider.get().setLimit(2).byBranchKey(newDest, changeKey);
-        if (destChanges.size() > 1) {
-          throw new InvalidChangeOperationException(
-              "Several changes with key "
-                  + changeKey
-                  + " reside on the same branch. "
-                  + "Cannot create a new patch set.");
-        }
-        try (BatchUpdate bu = batchUpdateFactory.create(project, identifiedUser, timestamp)) {
-          bu.setRepository(git, revWalk, oi);
-          bu.setNotify(resolveNotify(input));
-          Change.Id changeId;
-          String newTopic = null;
-          if (input.topic != null) {
-            newTopic = Strings.emptyToNull(input.topic.trim());
-          }
-          if (newTopic == null
-              && sourceChange != null
-              && !Strings.isNullOrEmpty(sourceChange.getTopic())) {
-            newTopic = sourceChange.getTopic() + "-" + newDest.shortName();
-          }
-          if (destChanges.size() == 1) {
-            // The change key exists on the destination branch. The cherry pick
-            // will be added as a new patch set. If "idForNewChange" is not null we must fail,
-            // since we are not expecting an already existing change.
-            if (idForNewChange != null) {
-              throw new InvalidChangeOperationException(
-                  String.format(
-                      "Expected that cherry-pick of commit %s with Change-Id %s to branch %s"
-                          + "in project %s creates a new change, but found existing change %d",
-                      sourceCommit.getName(),
-                      changeKey,
-                      dest.branch(),
-                      dest.project(),
-                      destChanges.get(0).getId().get()));
-            }
-            changeId =
-                insertPatchSet(
-                    bu,
-                    git,
-                    destChanges.get(0).notes(),
-                    cherryPickCommit,
-                    sourceChange.currentPatchSetId(),
-                    newTopic,
-                    workInProgress);
-          } else {
-            // Change key not found on destination branch. We can create a new
-            // change.
-            changeId =
-                createNewChange(
-                    bu,
-                    cherryPickCommit,
-                    dest.branch(),
-                    newTopic,
-                    project,
-                    sourceChange,
-                    sourceCommit,
-                    input,
-                    revertedChange,
-                    idForNewChange,
-                    workInProgress);
-          }
-          bu.execute();
-          return Result.create(changeId, cherryPickCommit.getFilesWithGitConflicts());
-        }
       } catch (MergeIdenticalTreeException | MergeConflictException e) {
         throw new IntegrationConflictException("Cherry pick failed: " + e.getMessage());
       }
+
+      try (BatchUpdate bu = batchUpdateFactory.create(project, identifiedUser, timestamp)) {
+        bu.setRepository(git, revWalk, oi);
+        bu.setNotify(resolveNotify(input));
+        Change.Id changeId;
+        String newTopic = null;
+        if (input.topic != null) {
+          newTopic = Strings.emptyToNull(input.topic.trim());
+        }
+        if (newTopic == null
+            && sourceChange != null
+            && !Strings.isNullOrEmpty(sourceChange.getTopic())) {
+          newTopic = sourceChange.getTopic() + "-" + dest.shortName();
+        }
+        if (destChange != null) {
+          // The change key exists on the destination branch. The cherry pick
+          // will be added as a new patch set.
+          changeId =
+              insertPatchSet(
+                  bu,
+                  git,
+                  destChange.notes(),
+                  cherryPickCommit,
+                  sourceChange,
+                  newTopic,
+                  workInProgress);
+        } else {
+          // Change key not found on destination branch. We can create a new
+          // change.
+          changeId =
+              createNewChange(
+                  bu,
+                  cherryPickCommit,
+                  dest.branch(),
+                  newTopic,
+                  project,
+                  sourceChange,
+                  sourceCommit,
+                  input,
+                  revertedChange,
+                  idForNewChange,
+                  workInProgress);
+        }
+        bu.execute();
+        return Result.create(changeId, cherryPickCommit.getFilesWithGitConflicts());
+      }
     }
   }
 
@@ -456,7 +441,7 @@
       Repository git,
       ChangeNotes destNotes,
       CodeReviewCommit cherryPickCommit,
-      PatchSet.Id sourcePatchSetId,
+      @Nullable Change sourceChange,
       String topic,
       @Nullable Boolean workInProgress)
       throws IOException {
@@ -469,7 +454,11 @@
       inserter.setWorkInProgress(workInProgress);
     }
     bu.addOp(destChange.getId(), inserter);
-    if (destChange.getCherryPickOf() == null
+    PatchSet.Id sourcePatchSetId = sourceChange == null ? null : sourceChange.currentPatchSetId();
+    // If sourceChange is not provided, reset cherryPickOf to avoid stale value.
+    if (sourcePatchSetId == null) {
+      bu.addOp(destChange.getId(), new ResetCherryPickOp());
+    } else if (destChange.getCherryPickOf() == null
         || !destChange.getCherryPickOf().equals(sourcePatchSetId)) {
       SetCherryPickOp cherryPickOfUpdater = setCherryPickOfFactory.create(sourcePatchSetId);
       bu.addOp(destChange.getId(), cherryPickOfUpdater);
@@ -571,4 +560,82 @@
 
     return stringBuilder.toString();
   }
+
+  /**
+   * Returns the Change-Id of destination change (as intended by the caller of cherry-pick
+   * operation).
+   *
+   * <p>The Change-Id can be provided in one of the following ways:
+   *
+   * <ul>
+   *   <li>Explicitly provided for the new change.
+   *   <li>Provided in the input commit message.
+   *   <li>Taken from the source commit if commit message was not set.
+   * </ul>
+   *
+   * Otherwise should be generated.
+   *
+   * @param commitMessage the commit message, as intended by the caller of cherry-pick operation.
+   * @param changeIdForNewChange the explicitly provided Change-Id for the new change.
+   * @return The Change-Id of destination change, {@code null} if Change-Id was not provided by the
+   *     caller of cherry-pick operation and should be generated.
+   */
+  @Nullable
+  private String getDestinationChangeId(
+      String commitMessage, @Nullable ObjectId changeIdForNewChange) {
+    if (changeIdForNewChange != null) {
+      return CommitMessageUtil.getChangeIdFromObjectId(changeIdForNewChange);
+    } else {
+      return CommitMessageUtil.getChangeIdFromCommitMessageFooter(commitMessage).orElse(null);
+    }
+  }
+
+  /**
+   * Returns the change from the destination branch, if it exists and is valid for the cherry-pick.
+   *
+   * @param destChangeId the Change-ID of the change in the destination branch.
+   * @param destBranch the branch to search by the Change-ID.
+   * @param verifyIsMissing if {@code true}, verifies that the change should be missing in the
+   *     destination branch.
+   * @return the verified change or {@code null} if the change was not found.
+   * @throws InvalidChangeOperationException if the change was found but failed validation
+   */
+  @Nullable
+  private ChangeData getDestChangeWithVerification(
+      String destChangeId, BranchNameKey destBranch, boolean verifyIsMissing)
+      throws InvalidChangeOperationException {
+    List<ChangeData> destChanges =
+        queryProvider.get().setLimit(2).byBranchKey(destBranch, Change.key(destChangeId));
+    if (destChanges.size() > 1) {
+      throw new InvalidChangeOperationException(
+          "Several changes with key "
+              + destChangeId
+              + " reside on the same branch. "
+              + "Cannot create a new patch set.");
+    }
+    if (destChanges.size() == 1 && verifyIsMissing) {
+      throw new InvalidChangeOperationException(
+          String.format(
+              "Expected that cherry-pick with Change-Id %s to branch %s "
+                  + "in project %s creates a new change, but found existing change %d",
+              destChangeId,
+              destBranch.branch(),
+              destBranch.project().get(),
+              destChanges.get(0).getId().get()));
+    }
+    ChangeData destChange = destChanges.size() == 1 ? destChanges.get(0) : null;
+
+    if (destChange != null && destChange.change().isClosed()) {
+      throw new InvalidChangeOperationException(
+          String.format(
+              "Cherry-pick with Change-Id %s could not update the existing change %d "
+                  + "in destination branch %s of project %s, because the change was closed (%s)",
+              destChangeId,
+              destChange.getId().get(),
+              destBranch.branch(),
+              destBranch.project(),
+              destChange.change().getStatus().name()));
+    }
+    return destChange;
+  }
 }
diff --git a/java/com/google/gerrit/server/restapi/change/CommentJson.java b/java/com/google/gerrit/server/restapi/change/CommentJson.java
index 4de9b63..02f39ab 100644
--- a/java/com/google/gerrit/server/restapi/change/CommentJson.java
+++ b/java/com/google/gerrit/server/restapi/change/CommentJson.java
@@ -20,9 +20,12 @@
 
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Streams;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.Comment;
+import com.google.gerrit.entities.CommentContext;
 import com.google.gerrit.entities.FixReplacement;
 import com.google.gerrit.entities.FixSuggestion;
 import com.google.gerrit.entities.HumanComment;
@@ -31,15 +34,18 @@
 import com.google.gerrit.extensions.client.Comment.Range;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.gerrit.extensions.common.ContextLineInfo;
 import com.google.gerrit.extensions.common.FixReplacementInfo;
 import com.google.gerrit.extensions.common.FixSuggestionInfo;
 import com.google.gerrit.extensions.common.RobotCommentInfo;
 import com.google.gerrit.extensions.restapi.Url;
-import com.google.gerrit.server.CommentContextLoader;
 import com.google.gerrit.server.account.AccountLoader;
+import com.google.gerrit.server.comment.CommentContextCache;
+import com.google.gerrit.server.comment.CommentContextKey;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.inject.Inject;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -47,18 +53,19 @@
 public class CommentJson {
 
   private final AccountLoader.Factory accountLoaderFactory;
+  private final CommentContextCache commentContextCache;
+
+  private Project.NameKey project;
+  private Change.Id changeId;
 
   private boolean fillAccounts = true;
   private boolean fillPatchSet;
-  private CommentContextLoader.Factory commentContextLoaderFactory;
-  private CommentContextLoader commentContextLoader;
+  private boolean fillCommentContext;
 
   @Inject
-  CommentJson(
-      AccountLoader.Factory accountLoaderFactory,
-      CommentContextLoader.Factory commentContextLoaderFactory) {
+  CommentJson(AccountLoader.Factory accountLoaderFactory, CommentContextCache commentContextCache) {
     this.accountLoaderFactory = accountLoaderFactory;
-    this.commentContextLoaderFactory = commentContextLoaderFactory;
+    this.commentContextCache = commentContextCache;
   }
 
   CommentJson setFillAccounts(boolean fillAccounts) {
@@ -71,10 +78,18 @@
     return this;
   }
 
-  CommentJson setEnableContext(boolean enableContext, Project.NameKey project) {
-    if (enableContext) {
-      this.commentContextLoader = commentContextLoaderFactory.create(project);
-    }
+  CommentJson setFillCommentContext(boolean fillCommentContext) {
+    this.fillCommentContext = fillCommentContext;
+    return this;
+  }
+
+  CommentJson setProjectKey(Project.NameKey project) {
+    this.project = project;
+    return this;
+  }
+
+  CommentJson setChangeId(Change.Id changeId) {
+    this.changeId = changeId;
     return this;
   }
 
@@ -93,9 +108,6 @@
       if (loader != null) {
         loader.fill();
       }
-      if (commentContextLoader != null) {
-        commentContextLoader.fill();
-      }
       return info;
     }
 
@@ -111,7 +123,6 @@
           list = new ArrayList<>();
           out.put(o.path, list);
         }
-        o.path = null;
         list.add(o);
       }
 
@@ -120,9 +131,12 @@
       if (loader != null) {
         loader.fill();
       }
-      if (commentContextLoader != null) {
-        commentContextLoader.fill();
+
+      List<T> allComments = out.values().stream().flatMap(Collection::stream).collect(toList());
+      if (fillCommentContext) {
+        addCommentContext(allComments);
       }
+      allComments.forEach(c -> c.path = null); // we don't need path since it exists in the map keys
       return out;
     }
 
@@ -138,12 +152,41 @@
       if (loader != null) {
         loader.fill();
       }
-      if (commentContextLoader != null) {
-        commentContextLoader.fill();
+
+      if (fillCommentContext) {
+        addCommentContext(out);
       }
+
       return out;
     }
 
+    protected void addCommentContext(List<T> allComments) {
+      List<CommentContextKey> keys =
+          allComments.stream().map(this::createCommentContextKey).collect(toList());
+      ImmutableMap<CommentContextKey, CommentContext> allContext = commentContextCache.getAll(keys);
+      for (T c : allComments) {
+        c.contextLines = toContextLineInfoList(allContext.get(createCommentContextKey(c)));
+      }
+    }
+
+    protected List<ContextLineInfo> toContextLineInfoList(CommentContext commentContext) {
+      List<ContextLineInfo> result = new ArrayList<>();
+      for (Map.Entry<Integer, String> e : commentContext.lines().entrySet()) {
+        result.add(new ContextLineInfo(e.getKey(), e.getValue()));
+      }
+      return result;
+    }
+
+    protected CommentContextKey createCommentContextKey(T r) {
+      return CommentContextKey.builder()
+          .project(project)
+          .changeId(changeId)
+          .id(r.id)
+          .path(r.path)
+          .patchset(r.patchSet)
+          .build();
+    }
+
     protected abstract T toInfo(F comment, AccountLoader loader);
 
     protected void fillCommentInfo(Comment c, CommentInfo r, AccountLoader loader) {
@@ -170,9 +213,6 @@
         r.author = loader.get(c.author.getId());
       }
       r.commitId = c.getCommitId().getName();
-      if (commentContextLoader != null) {
-        r.contextLines = commentContextLoader.getContext(r);
-      }
     }
 
     protected Range toRange(Comment.Range commentRange) {
diff --git a/java/com/google/gerrit/server/restapi/change/CreateChange.java b/java/com/google/gerrit/server/restapi/change/CreateChange.java
index 52887e0..c392bd1 100644
--- a/java/com/google/gerrit/server/restapi/change/CreateChange.java
+++ b/java/com/google/gerrit/server/restapi/change/CreateChange.java
@@ -223,6 +223,12 @@
       throw new BadRequestException("branch must be non-empty");
     }
     input.branch = RefNames.fullName(input.branch);
+    if (!isBranchAllowed(input.branch)) {
+      throw new BadRequestException(
+          "Cannot create a change on ref "
+              + input.branch
+              + ". Gerrit internal refs and refs/tags/* are not allowed.");
+    }
 
     String subject = Strings.nullToEmpty(input.subject);
     subject = subject.replaceAll("(?m)^#.*$\n?", "").trim();
@@ -292,6 +298,11 @@
     }
   }
 
+  /** Changes are allowed to be created on any ref that is not Gerrit internal or a tag ref. */
+  private boolean isBranchAllowed(String branch) {
+    return !RefNames.isGerritRef(branch) && !branch.startsWith(RefNames.REFS_TAGS);
+  }
+
   private void checkRequiredPermissions(
       Project.NameKey project, String refName, @Nullable AccountInput author)
       throws ResourceNotFoundException, AuthException, PermissionBackendException {
diff --git a/java/com/google/gerrit/server/restapi/change/GetChange.java b/java/com/google/gerrit/server/restapi/change/GetChange.java
index 1ef3c4b..f28d2b3 100644
--- a/java/com/google/gerrit/server/restapi/change/GetChange.java
+++ b/java/com/google/gerrit/server/restapi/change/GetChange.java
@@ -14,7 +14,6 @@
 
 package com.google.gerrit.server.restapi.change;
 
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.Streams;
 import com.google.gerrit.entities.Change;
@@ -27,7 +26,6 @@
 import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.DynamicOptions.DynamicBean;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangePluginDefinedInfoFactory;
 import com.google.gerrit.server.change.ChangeResource;
@@ -46,7 +44,6 @@
         DynamicOptions.BeanReceiver,
         DynamicOptions.BeanProvider {
   private final ChangeJson.Factory json;
-  private final DynamicSet<ChangeAttributeFactory> attrFactories;
   private final DynamicSet<ChangePluginDefinedInfoFactory> pdiFactories;
   private final EnumSet<ListChangesOption> options = EnumSet.noneOf(ListChangesOption.class);
   private final Map<String, DynamicBean> dynamicBeans = new HashMap<>();
@@ -62,12 +59,8 @@
   }
 
   @Inject
-  GetChange(
-      ChangeJson.Factory json,
-      DynamicSet<ChangeAttributeFactory> attrFactories,
-      DynamicSet<ChangePluginDefinedInfoFactory> pdiFactories) {
+  GetChange(ChangeJson.Factory json, DynamicSet<ChangePluginDefinedInfoFactory> pdiFactories) {
     this.json = json;
-    this.attrFactories = attrFactories;
     this.pdiFactories = pdiFactories;
   }
 
@@ -91,12 +84,7 @@
   }
 
   private ChangeJson newChangeJson() {
-    return json.create(options, this::buildPluginInfo, this::createPluginDefinedInfos);
-  }
-
-  private ImmutableList<PluginDefinedInfo> buildPluginInfo(ChangeData cd) {
-    return PluginDefinedAttributesFactories.createAll(
-        cd, this, Streams.stream(attrFactories.entries()));
+    return json.create(options, this::createPluginDefinedInfos);
   }
 
   private ImmutableListMultimap<Change.Id, PluginDefinedInfo> createPluginDefinedInfos(
diff --git a/java/com/google/gerrit/server/restapi/change/GetCommit.java b/java/com/google/gerrit/server/restapi/change/GetCommit.java
index 21a08dc..d76ce04 100644
--- a/java/com/google/gerrit/server/restapi/change/GetCommit.java
+++ b/java/com/google/gerrit/server/restapi/change/GetCommit.java
@@ -58,7 +58,13 @@
       rw.parseBody(commit);
       CommitInfo info =
           json.create(ImmutableSet.of())
-              .getCommitInfo(rsrc.getProject(), rw, commit, addLinks, true);
+              .getCommitInfo(
+                  rsrc.getProject(),
+                  rw,
+                  commit,
+                  addLinks,
+                  /* fillCommit= */ true,
+                  rsrc.getChange().getDest().branch());
       Response<CommitInfo> r = Response.ok(info);
       if (rsrc.isCacheable()) {
         r.caching(CacheControl.PRIVATE(7, TimeUnit.DAYS));
diff --git a/java/com/google/gerrit/server/restapi/change/GetMergeList.java b/java/com/google/gerrit/server/restapi/change/GetMergeList.java
index 0c67fd6..f0639b5 100644
--- a/java/com/google/gerrit/server/restapi/change/GetMergeList.java
+++ b/java/com/google/gerrit/server/restapi/change/GetMergeList.java
@@ -81,7 +81,14 @@
       List<CommitInfo> result = new ArrayList<>(commits.size());
       RevisionJson changeJson = json.create(ImmutableSet.of());
       for (RevCommit c : commits) {
-        result.add(changeJson.getCommitInfo(rsrc.getProject(), rw, c, addLinks, true));
+        result.add(
+            changeJson.getCommitInfo(
+                rsrc.getProject(),
+                rw,
+                c,
+                addLinks,
+                /* fillCommit= */ true,
+                rsrc.getChange().getDest().branch()));
       }
       return createResponse(rsrc, result);
     }
diff --git a/java/com/google/gerrit/server/restapi/change/ListChangeComments.java b/java/com/google/gerrit/server/restapi/change/ListChangeComments.java
index e3b433c..fa7c1f5 100644
--- a/java/com/google/gerrit/server/restapi/change/ListChangeComments.java
+++ b/java/com/google/gerrit/server/restapi/change/ListChangeComments.java
@@ -19,7 +19,6 @@
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.entities.ChangeMessage;
 import com.google.gerrit.entities.HumanComment;
-import com.google.gerrit.entities.Project;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.ContextLineInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
@@ -84,8 +83,7 @@
 
   private ImmutableList<CommentInfo> getAsList(Iterable<HumanComment> comments, ChangeResource rsrc)
       throws PermissionBackendException {
-    ImmutableList<CommentInfo> commentInfos =
-        getCommentFormatter(rsrc.getProject()).formatAsList(comments);
+    ImmutableList<CommentInfo> commentInfos = getCommentFormatter(rsrc).formatAsList(comments);
     List<ChangeMessage> changeMessages = changeMessagesUtil.byChange(rsrc.getNotes());
     CommentsUtil.linkCommentsToChangeMessages(commentInfos, changeMessages, true);
     return commentInfos;
@@ -93,8 +91,7 @@
 
   private Map<String, List<CommentInfo>> getAsMap(
       Iterable<HumanComment> comments, ChangeResource rsrc) throws PermissionBackendException {
-    Map<String, List<CommentInfo>> commentInfosMap =
-        getCommentFormatter(rsrc.getProject()).format(comments);
+    Map<String, List<CommentInfo>> commentInfosMap = getCommentFormatter(rsrc).format(comments);
     List<CommentInfo> commentInfos =
         commentInfosMap.values().stream().flatMap(List::stream).collect(toList());
     List<ChangeMessage> changeMessages = changeMessagesUtil.byChange(rsrc.getNotes());
@@ -102,12 +99,14 @@
     return commentInfosMap;
   }
 
-  private CommentJson.HumanCommentFormatter getCommentFormatter(Project.NameKey project) {
+  private CommentJson.HumanCommentFormatter getCommentFormatter(ChangeResource rsrc) {
     return commentJson
         .get()
         .setFillAccounts(true)
         .setFillPatchSet(true)
-        .setEnableContext(includeContext, project)
+        .setFillCommentContext(includeContext)
+        .setProjectKey(rsrc.getProject())
+        .setChangeId(rsrc.getId())
         .newHumanCommentFormatter();
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/change/ListPortedDrafts.java b/java/com/google/gerrit/server/restapi/change/ListPortedDrafts.java
index 9b254f1..e92fe5c 100644
--- a/java/com/google/gerrit/server/restapi/change/ListPortedDrafts.java
+++ b/java/com/google/gerrit/server/restapi/change/ListPortedDrafts.java
@@ -18,7 +18,9 @@
 import com.google.gerrit.entities.HumanComment;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.change.RevisionResource;
@@ -46,7 +48,10 @@
 
   @Override
   public Response<Map<String, List<CommentInfo>>> apply(RevisionResource revisionResource)
-      throws PermissionBackendException {
+      throws PermissionBackendException, RestApiException {
+    if (!revisionResource.getUser().isIdentifiedUser()) {
+      throw new AuthException("requires authentication; only authenticated users can have drafts");
+    }
     PatchSet targetPatchset = revisionResource.getPatchSet();
 
     List<HumanComment> draftComments =
diff --git a/java/com/google/gerrit/server/restapi/change/Module.java b/java/com/google/gerrit/server/restapi/change/Module.java
index 69e2788..681534c 100644
--- a/java/com/google/gerrit/server/restapi/change/Module.java
+++ b/java/com/google/gerrit/server/restapi/change/Module.java
@@ -47,6 +47,7 @@
 import com.google.gerrit.server.change.SetCherryPickOp;
 import com.google.gerrit.server.change.SetHashtagsOp;
 import com.google.gerrit.server.change.SetPrivateOp;
+import com.google.gerrit.server.change.SetTopicOp;
 import com.google.gerrit.server.change.WorkInProgressOp;
 import com.google.gerrit.server.restapi.change.Reviewed.DeleteReviewed;
 import com.google.gerrit.server.restapi.change.Reviewed.PutReviewed;
@@ -218,9 +219,9 @@
     factory(SetAssigneeOp.Factory.class);
     factory(SetCherryPickOp.Factory.class);
     factory(SetHashtagsOp.Factory.class);
+    factory(SetTopicOp.Factory.class);
     factory(SetPrivateOp.Factory.class);
     factory(WorkInProgressOp.Factory.class);
-    factory(SetTopicOp.Factory.class);
     factory(AddToAttentionSetOp.Factory.class);
     factory(RemoveFromAttentionSetOp.Factory.class);
     factory(AttentionSetEmail.Factory.class);
diff --git a/java/com/google/gerrit/server/restapi/change/Move.java b/java/com/google/gerrit/server/restapi/change/Move.java
index 577174f..8ec394c 100644
--- a/java/com/google/gerrit/server/restapi/change/Move.java
+++ b/java/com/google/gerrit/server/restapi/change/Move.java
@@ -52,6 +52,7 @@
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.permissions.GlobalPermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
@@ -140,6 +141,18 @@
     // Not allowed to move if the current patch set is locked.
     psUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
+    // Keeping all votes can be confusing in the context of the destination branch, see the
+    // discussion in
+    // https://gerrit-review.googlesource.com/c/gerrit/+/129171
+    // Only administrators are allowed to keep all labels at their own risk.
+    try {
+      if (input.keepAllVotes) {
+        permissionBackend.user(caller).check(GlobalPermission.ADMINISTRATE_SERVER);
+      }
+    } catch (AuthException denied) {
+      throw new AuthException("move is not permitted with keepAllVotes option", denied);
+    }
+
     // Move requires abandoning this change, and creating a new change.
     try {
       rsrc.permissions().check(ABANDON);
@@ -226,7 +239,9 @@
       update.setBranch(newDestKey.branch());
       change.setDest(newDestKey);
 
-      updateApprovals(ctx, update, psId, projectKey);
+      if (!input.keepAllVotes) {
+        updateApprovals(ctx, update, psId, projectKey);
+      }
 
       StringBuilder msgBuf = new StringBuilder();
       msgBuf.append("Change destination moved from ");
diff --git a/java/com/google/gerrit/server/restapi/change/OnPostReview.java b/java/com/google/gerrit/server/restapi/change/OnPostReview.java
new file mode 100644
index 0000000..b179d02
--- /dev/null
+++ b/java/com/google/gerrit/server/restapi/change/OnPostReview.java
@@ -0,0 +1,47 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.restapi.change;
+
+import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.extensions.annotations.ExtensionPoint;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import java.util.Map;
+import java.util.Optional;
+
+/** Extension point that is invoked on post review. */
+@ExtensionPoint
+public interface OnPostReview {
+  /**
+   * Allows implementors to return a message that should be included into the change message that is
+   * posted on post review.
+   *
+   * @param user the user that posts the review
+   * @param changeNotes the change on which post review is performed
+   * @param patchSet the patch set on which post review is performed
+   * @param oldApprovals old approvals that changed as result of post review
+   * @param approvals all current approvals
+   * @return message that should be included into the change message that is posted on post review,
+   *     {@link Optional#empty()} if the change message should not be extended
+   */
+  default Optional<String> getChangeMessageAddOn(
+      IdentifiedUser user,
+      ChangeNotes changeNotes,
+      PatchSet patchSet,
+      Map<String, Short> oldApprovals,
+      Map<String, Short> approvals) {
+    return Optional.empty();
+  }
+}
diff --git a/java/com/google/gerrit/server/restapi/change/PostReview.java b/java/com/google/gerrit/server/restapi/change/PostReview.java
index 575a19d..bf9990c 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReview.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReview.java
@@ -30,6 +30,7 @@
 import static javax.servlet.http.HttpServletResponse.SC_BAD_REQUEST;
 
 import com.google.auto.value.AutoValue;
+import com.google.common.base.Joiner;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
@@ -177,6 +178,7 @@
   private final ProjectCache projectCache;
   private final PermissionBackend permissionBackend;
   private final PluginSetContext<CommentValidator> commentValidators;
+  private final PluginSetContext<OnPostReview> onPostReviews;
   private final ReplyAttentionSetUpdates replyAttentionSetUpdates;
   private final boolean strictLabels;
   private final boolean publishPatchSetLevelComment;
@@ -203,6 +205,7 @@
       ProjectCache projectCache,
       PermissionBackend permissionBackend,
       PluginSetContext<CommentValidator> commentValidators,
+      PluginSetContext<OnPostReview> onPostReviews,
       ReplyAttentionSetUpdates replyAttentionSetUpdates) {
     this.updateFactory = updateFactory;
     this.changeResourceFactory = changeResourceFactory;
@@ -223,6 +226,7 @@
     this.projectCache = projectCache;
     this.permissionBackend = permissionBackend;
     this.commentValidators = commentValidators;
+    this.onPostReviews = onPostReviews;
     this.replyAttentionSetUpdates = replyAttentionSetUpdates;
     this.strictLabels = gerritConfig.getBoolean("change", "strictLabels", false);
     this.publishPatchSetLevelComment =
@@ -1425,6 +1429,23 @@
       } else if (in.ready) {
         buf.append("\n\n" + START_REVIEW_MESSAGE);
       }
+
+      List<String> pluginMessages = new ArrayList<>();
+      onPostReviews.runEach(
+          onPostReview ->
+              onPostReview
+                  .getChangeMessageAddOn(user, ctx.getNotes(), ps, oldApprovals, approvals)
+                  .ifPresent(
+                      pluginMessage ->
+                          pluginMessages.add(
+                              !pluginMessage.endsWith("\n")
+                                  ? pluginMessage + "\n"
+                                  : pluginMessage)));
+      if (!pluginMessages.isEmpty()) {
+        buf.append("\n\n");
+        buf.append(Joiner.on("\n").join(pluginMessages));
+      }
+
       if (buf.length() == 0) {
         return false;
       }
diff --git a/java/com/google/gerrit/server/restapi/change/PreviewSubmit.java b/java/com/google/gerrit/server/restapi/change/PreviewSubmit.java
index ed6c0a5..4acf809 100644
--- a/java/com/google/gerrit/server/restapi/change/PreviewSubmit.java
+++ b/java/com/google/gerrit/server/restapi/change/PreviewSubmit.java
@@ -42,7 +42,6 @@
 import com.google.gerrit.server.update.UpdateException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
-import com.google.inject.Singleton;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Collection;
@@ -56,7 +55,6 @@
 import org.eclipse.jgit.transport.ReceiveCommand;
 import org.kohsuke.args4j.Option;
 
-@Singleton
 public class PreviewSubmit implements RestReadView<RevisionResource> {
   private static final int MAX_DEFAULT_BUNDLE_SIZE = 100 * 1024 * 1024;
 
diff --git a/java/com/google/gerrit/server/restapi/change/PutTopic.java b/java/com/google/gerrit/server/restapi/change/PutTopic.java
index 325b80c..3031781 100644
--- a/java/com/google/gerrit/server/restapi/change/PutTopic.java
+++ b/java/com/google/gerrit/server/restapi/change/PutTopic.java
@@ -23,6 +23,7 @@
 import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.change.SetTopicOp;
 import com.google.gerrit.server.permissions.ChangePermission;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.update.BatchUpdate;
@@ -60,7 +61,7 @@
       sanitizedInput.topic = sanitizedInput.topic.trim();
     }
 
-    SetTopicOp op = topicOpFactory.create(sanitizedInput);
+    SetTopicOp op = topicOpFactory.create(sanitizedInput.topic);
     try (BatchUpdate u =
         updateFactory.create(req.getChange().getProject(), req.getUser(), TimeUtil.nowTs())) {
       u.addOp(req.getId(), op);
diff --git a/java/com/google/gerrit/server/restapi/change/QueryChanges.java b/java/com/google/gerrit/server/restapi/change/QueryChanges.java
index 3c8157b..cf0d4cf 100644
--- a/java/com/google/gerrit/server/restapi/change/QueryChanges.java
+++ b/java/com/google/gerrit/server/restapi/change/QueryChanges.java
@@ -187,9 +187,7 @@
     int cnt = queries.size();
     List<QueryResult<ChangeData>> results = queryProcessor.query(qb.parse(queries));
     List<List<ChangeInfo>> res =
-        json.create(
-                options, queryProcessor.getAttributesFactory(), queryProcessor.getInfosFactory())
-            .format(results);
+        json.create(options, queryProcessor.getInfosFactory()).format(results);
     for (int n = 0; n < cnt; n++) {
       List<ChangeInfo> info = res.get(n);
       if (results.get(n).more() && !info.isEmpty()) {
diff --git a/java/com/google/gerrit/server/restapi/change/RemoveFromAttentionSet.java b/java/com/google/gerrit/server/restapi/change/RemoveFromAttentionSet.java
index c4dd04e..7fe463e 100644
--- a/java/com/google/gerrit/server/restapi/change/RemoveFromAttentionSet.java
+++ b/java/com/google/gerrit/server/restapi/change/RemoveFromAttentionSet.java
@@ -30,6 +30,7 @@
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.UpdateException;
+import com.google.gerrit.server.util.AttentionSetUtil;
 import com.google.gerrit.server.util.time.TimeUtil;
 import com.google.inject.Inject;
 import java.io.IOException;
@@ -69,13 +70,9 @@
     }
     input.user = Strings.nullToEmpty(input.user).trim();
     if (!input.user.isEmpty()) {
-      Account.Id attentionUserId = null;
-      try {
-        attentionUserId = accountResolver.resolve(input.user).asUnique().account().id();
-      } catch (AccountResolver.UnresolvableAccountException ex) {
-        throw new BadRequestException(
-            "The user specified in the input body couldn't be found.", ex);
-      }
+      Account.Id attentionUserId =
+          AttentionSetUtil.resolveAccount(
+              accountResolver, attentionResource.getChangeResource().getNotes(), input.user);
       if (attentionUserId.get() != attentionResource.getAccountId().get()) {
         throw new BadRequestException(
             "The field \"user\" must be empty, or must match the user specified in the URL.");
diff --git a/java/com/google/gerrit/server/restapi/change/ReplyAttentionSetUpdates.java b/java/com/google/gerrit/server/restapi/change/ReplyAttentionSetUpdates.java
index 65c0cda..a1bd678 100644
--- a/java/com/google/gerrit/server/restapi/change/ReplyAttentionSetUpdates.java
+++ b/java/com/google/gerrit/server/restapi/change/ReplyAttentionSetUpdates.java
@@ -312,10 +312,14 @@
       throws BadRequestException, IOException, PermissionBackendException,
           UnprocessableEntityException, ConfigInvalidException {
     AttentionSetUtil.validateInput(add);
-    Account.Id attentionUserId =
-        getAccountIdAndValidateUser(changeNotes, add.user, accountsChangedInCommit);
-
-    addToAttentionSet(bu, changeNotes, attentionUserId, add.reason, false);
+    try {
+      Account.Id attentionUserId =
+          getAccountIdAndValidateUser(changeNotes, add.user, accountsChangedInCommit);
+      addToAttentionSet(bu, changeNotes, attentionUserId, add.reason, false);
+    } catch (AccountResolver.UnresolvableAccountException ex) {
+      // This happens only when the account doesn't exist. Silently ignore it. If we threw an error
+      // message here, then it would be possible to probe whether an account exists.
+    }
   }
 
   private void removeFromAttentionSet(
@@ -326,10 +330,14 @@
       throws BadRequestException, IOException, PermissionBackendException,
           UnprocessableEntityException, ConfigInvalidException {
     AttentionSetUtil.validateInput(remove);
-    Account.Id attentionUserId =
-        getAccountIdAndValidateUser(changeNotes, remove.user, accountsChangedInCommit);
-
-    removeFromAttentionSet(bu, changeNotes, attentionUserId, remove.reason, false);
+    try {
+      Account.Id attentionUserId =
+          getAccountIdAndValidateUser(changeNotes, remove.user, accountsChangedInCommit);
+      removeFromAttentionSet(bu, changeNotes, attentionUserId, remove.reason, false);
+    } catch (AccountResolver.UnresolvableAccountException ex) {
+      // This happens only when the account doesn't exist. Silently ignore it. If we threw an error
+      // message here, then it would be possible to probe whether an account exists.
+    }
   }
 
   private Account.Id getAccountId(ChangeNotes changeNotes, String user)
@@ -356,15 +364,21 @@
       ChangeNotes changeNotes, String user, Set<Account.Id> accountsChangedInCommit)
       throws ConfigInvalidException, IOException, PermissionBackendException,
           UnprocessableEntityException, BadRequestException {
-    Account.Id attentionUserId = getAccountId(changeNotes, user);
-    if (accountsChangedInCommit.contains(attentionUserId)) {
-      throw new BadRequestException(
-          String.format(
-              "%s can not be added/removed twice, and can not be added and "
-                  + "removed at the same time",
-              user));
+    try {
+      Account.Id attentionUserId = getAccountId(changeNotes, user);
+      if (accountsChangedInCommit.contains(attentionUserId)) {
+        throw new BadRequestException(
+            String.format(
+                "%s can not be added/removed twice, and can not be added and "
+                    + "removed at the same time",
+                user));
+      }
+      accountsChangedInCommit.add(attentionUserId);
+      return attentionUserId;
+    } catch (AccountResolver.UnresolvableAccountException ex) {
+      // This can only happen if this user can't see the account or the account doesn't exist.
+      // Silently modify the account's attention set anyway, if the account exists.
+      return accountResolver.resolveIgnoreVisibility(user).asUnique().account().id();
     }
-    accountsChangedInCommit.add(attentionUserId);
-    return attentionUserId;
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/change/Submit.java b/java/com/google/gerrit/server/restapi/change/Submit.java
index e77bfe7..790b2db 100644
--- a/java/com/google/gerrit/server/restapi/change/Submit.java
+++ b/java/com/google/gerrit/server/restapi/change/Submit.java
@@ -30,8 +30,10 @@
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.SubmitTypeRecord;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.api.changes.SubmitInput;
+import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -66,12 +68,14 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
+import java.util.stream.Collectors;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.eclipse.jgit.lib.Config;
@@ -373,8 +377,15 @@
 
   public Collection<ChangeData> unmergeableChanges(ChangeSet cs) throws IOException {
     Set<ChangeData> mergeabilityMap = new HashSet<>();
+    Set<ObjectId> outDatedPatchsets = new HashSet<>();
     for (ChangeData change : cs.changes()) {
       mergeabilityMap.add(change);
+      // Add all the patchsets commit ids except the current patchset.
+      outDatedPatchsets.addAll(
+          change.notes().getPatchSets().values().stream()
+              .map(p -> p.commitId())
+              .collect(Collectors.toSet()));
+      outDatedPatchsets.remove(change.currentPatchSet().commitId());
     }
 
     ListMultimap<BranchNameKey, ChangeData> cbb = cs.changesByBranch();
@@ -388,12 +399,17 @@
           allParents.add(parent.getId());
         }
       }
-
       for (ChangeData change : targetBranch) {
+
         RevCommit commit = commits.get(change.getId());
         boolean isMergeCommit = commit.getParentCount() > 1;
         boolean isLastInChain = !allParents.contains(commit.getId());
-
+        if (Arrays.stream(commit.getParents()).anyMatch(c -> outDatedPatchsets.contains(c.getId()))
+            && !isCherryPickSubmit(change)) {
+          // Found a parent that depends on an outdated patchset and the submit strategy is not
+          // cherry-pick.
+          continue;
+        }
         // Recheck mergeability rather than using value stored in the index,
         // which may be stale.
         // TODO(dborowitz): This is ugly; consider providing a way to not read
@@ -419,6 +435,11 @@
     return mergeabilityMap;
   }
 
+  private boolean isCherryPickSubmit(ChangeData changeData) {
+    SubmitTypeRecord submitTypeRecord = changeData.submitTypeRecord();
+    return submitTypeRecord.isOk() && submitTypeRecord.type == SubmitType.CHERRY_PICK;
+  }
+
   private HashMap<Change.Id, RevCommit> findCommits(
       Collection<ChangeData> changes, Project.NameKey project) throws IOException {
     HashMap<Change.Id, RevCommit> commits = new HashMap<>();
diff --git a/java/com/google/gerrit/server/restapi/group/CreateGroup.java b/java/com/google/gerrit/server/restapi/group/CreateGroup.java
index 74ca721..613c805 100644
--- a/java/com/google/gerrit/server/restapi/group/CreateGroup.java
+++ b/java/com/google/gerrit/server/restapi/group/CreateGroup.java
@@ -54,6 +54,7 @@
 import com.google.gerrit.server.notedb.Sequences;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.plugincontext.PluginSetContext;
+import com.google.gerrit.server.util.time.TimeUtil;
 import com.google.gerrit.server.validators.GroupCreationValidationListener;
 import com.google.gerrit.server.validators.ValidationException;
 import com.google.inject.Inject;
@@ -66,6 +67,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Optional;
+import java.util.TimeZone;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -75,7 +77,7 @@
 public class CreateGroup
     implements RestCollectionCreateView<TopLevelResource, GroupResource, GroupInput> {
   private final Provider<IdentifiedUser> self;
-  private final PersonIdent serverIdent;
+  private final TimeZone serverTimeZone;
   private final Provider<GroupsUpdate> groupsUpdateProvider;
   private final GroupCache groupCache;
   private final GroupResolver groups;
@@ -89,7 +91,7 @@
   @Inject
   CreateGroup(
       Provider<IdentifiedUser> self,
-      @GerritPersonIdent PersonIdent serverIdent,
+      @GerritPersonIdent Provider<PersonIdent> serverIdent,
       @UserInitiated Provider<GroupsUpdate> groupsUpdateProvider,
       GroupCache groupCache,
       GroupResolver groups,
@@ -100,7 +102,7 @@
       @GerritServerConfig Config cfg,
       Sequences sequences) {
     this.self = self;
-    this.serverIdent = serverIdent;
+    this.serverTimeZone = serverIdent.get().getTimeZone();
     this.groupsUpdateProvider = groupsUpdateProvider;
     this.groupCache = groupCache;
     this.groups = groups;
@@ -210,7 +212,7 @@
             createGroupArgs.uuid,
             GroupUuid.make(
                 createGroupArgs.getGroupName(),
-                self.get().newCommitterIdent(serverIdent.getWhen(), serverIdent.getTimeZone())));
+                self.get().newCommitterIdent(TimeUtil.nowTs(), serverTimeZone)));
     InternalGroupCreation groupCreation =
         InternalGroupCreation.builder()
             .setGroupUUID(uuid)
diff --git a/java/com/google/gerrit/server/restapi/project/CheckAccess.java b/java/com/google/gerrit/server/restapi/project/CheckAccess.java
index 037a953..37616cd 100644
--- a/java/com/google/gerrit/server/restapi/project/CheckAccess.java
+++ b/java/com/google/gerrit/server/restapi/project/CheckAccess.java
@@ -1,4 +1,4 @@
-// Copyright (C) 2017 The Android Open Source Project
+// Copyright (C) 2018 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 import static com.google.gerrit.entities.RefNames.REFS_HEADS;
 
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.BranchNameKey;
 import com.google.gerrit.extensions.api.config.AccessCheckInfo;
@@ -25,9 +26,10 @@
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestApiException;
-import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.server.account.AccountResolver;
 import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.logging.TraceContext;
 import com.google.gerrit.server.permissions.DefaultPermissionMappings;
 import com.google.gerrit.server.permissions.GlobalPermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
@@ -36,15 +38,14 @@
 import com.google.gerrit.server.permissions.RefPermission;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
-import com.google.inject.Singleton;
 import java.io.IOException;
 import java.util.Optional;
 import javax.servlet.http.HttpServletResponse;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.Repository;
+import org.kohsuke.args4j.Option;
 
-@Singleton
-public class CheckAccess implements RestModifyView<ProjectResource, AccessCheckInput> {
+public class CheckAccess implements RestReadView<ProjectResource> {
   private final AccountResolver accountResolver;
   private final PermissionBackend permissionBackend;
   private final GitRepositoryManager gitRepositoryManager;
@@ -59,7 +60,15 @@
     this.gitRepositoryManager = gitRepositoryManager;
   }
 
-  @Override
+  @Option(name = "--ref", usage = "ref name to check permission for")
+  String refName;
+
+  @Option(name = "--account", usage = "account to check acccess for")
+  String account;
+
+  @Option(name = "--perm", usage = "permission to check; default: read of any ref.")
+  String permission;
+
   public Response<AccessCheckInfo> apply(ProjectResource rsrc, AccessCheckInput input)
       throws PermissionBackendException, RestApiException, IOException, ConfigInvalidException {
     permissionBackend.user(rsrc.getUser()).check(GlobalPermission.VIEW_ACCESS);
@@ -73,60 +82,90 @@
       throw new BadRequestException("input requires 'account'");
     }
 
-    Account.Id match = accountResolver.resolve(input.account).asUnique().account().id();
+    try (TraceContext traceContext = TraceContext.open()) {
+      traceContext.enableAclLogging();
 
-    AccessCheckInfo info = new AccessCheckInfo();
-    try {
-      permissionBackend
-          .absentUser(match)
-          .project(rsrc.getNameKey())
-          .check(ProjectPermission.ACCESS);
-    } catch (AuthException e) {
-      info.message = String.format("user %s cannot see project %s", match, rsrc.getName());
-      info.status = HttpServletResponse.SC_FORBIDDEN;
-      return Response.ok(info);
-    }
+      Account.Id match = accountResolver.resolve(input.account).asUnique().account().id();
 
-    RefPermission refPerm;
-    if (!Strings.isNullOrEmpty(input.permission)) {
-      if (Strings.isNullOrEmpty(input.ref)) {
-        throw new BadRequestException("must set 'ref' when specifying 'permission'");
-      }
-      Optional<RefPermission> rp = DefaultPermissionMappings.refPermission(input.permission);
-      if (!rp.isPresent()) {
-        throw new BadRequestException(
-            String.format("'%s' is not recognized as ref permission", input.permission));
-      }
-
-      refPerm = rp.get();
-    } else {
-      refPerm = RefPermission.READ;
-    }
-
-    if (!Strings.isNullOrEmpty(input.ref)) {
       try {
         permissionBackend
             .absentUser(match)
-            .ref(BranchNameKey.create(rsrc.getNameKey(), input.ref))
-            .check(refPerm);
+            .project(rsrc.getNameKey())
+            .check(ProjectPermission.ACCESS);
       } catch (AuthException e) {
-        info.status = HttpServletResponse.SC_FORBIDDEN;
-        info.message =
-            String.format(
-                "user %s lacks permission %s for %s in project %s",
-                match, input.permission, input.ref, rsrc.getName());
-        return Response.ok(info);
+        return Response.ok(
+            createInfo(
+                traceContext,
+                HttpServletResponse.SC_FORBIDDEN,
+                String.format("user %s cannot see project %s", match, rsrc.getName())));
       }
-    } else {
-      // We say access is okay if there are no refs, but this warrants a warning,
-      // as access denied looks the same as no branches to the user.
-      try (Repository repo = gitRepositoryManager.openRepository(rsrc.getNameKey())) {
-        if (repo.getRefDatabase().getRefsByPrefix(REFS_HEADS).isEmpty()) {
-          info.message = "access is OK, but repository has no branches under refs/heads/";
+
+      RefPermission refPerm;
+      if (!Strings.isNullOrEmpty(input.permission)) {
+        if (Strings.isNullOrEmpty(input.ref)) {
+          throw new BadRequestException("must set 'ref' when specifying 'permission'");
+        }
+        Optional<RefPermission> rp = DefaultPermissionMappings.refPermission(input.permission);
+        if (!rp.isPresent()) {
+          throw new BadRequestException(
+              String.format("'%s' is not recognized as ref permission", input.permission));
+        }
+
+        refPerm = rp.get();
+      } else {
+        refPerm = RefPermission.READ;
+      }
+
+      String message = null;
+      if (!Strings.isNullOrEmpty(input.ref)) {
+        try {
+          permissionBackend
+              .absentUser(match)
+              .ref(BranchNameKey.create(rsrc.getNameKey(), input.ref))
+              .check(refPerm);
+        } catch (AuthException e) {
+          return Response.ok(
+              createInfo(
+                  traceContext,
+                  HttpServletResponse.SC_FORBIDDEN,
+                  String.format(
+                      "user %s lacks permission %s for %s in project %s",
+                      match, input.permission, input.ref, rsrc.getName())));
+        }
+      } else {
+        // We say access is okay if there are no refs, but this warrants a warning,
+        // as access denied looks the same as no branches to the user.
+        try (Repository repo = gitRepositoryManager.openRepository(rsrc.getNameKey())) {
+          if (repo.getRefDatabase().getRefsByPrefix(REFS_HEADS).isEmpty()) {
+            message = "access is OK, but repository has no branches under refs/heads/";
+          }
         }
       }
+      return Response.ok(createInfo(traceContext, HttpServletResponse.SC_OK, message));
     }
-    info.status = HttpServletResponse.SC_OK;
-    return Response.ok(info);
+  }
+
+  private AccessCheckInfo createInfo(TraceContext traceContext, int statusCode, String message) {
+    AccessCheckInfo info = new AccessCheckInfo();
+    info.status = statusCode;
+    info.message = message;
+    info.debugLogs = traceContext.getAclLogRecords();
+    if (info.debugLogs.isEmpty()) {
+      info.debugLogs =
+          ImmutableList.of("Found no rules that apply, so defaulting to no permission");
+    }
+    return info;
+  }
+
+  @Override
+  public Response<AccessCheckInfo> apply(ProjectResource rsrc)
+      throws PermissionBackendException, RestApiException, IOException, ConfigInvalidException {
+
+    AccessCheckInput input = new AccessCheckInput();
+    input.ref = refName;
+    input.account = account;
+    input.permission = permission;
+
+    return apply(rsrc, input);
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/project/CheckAccessReadView.java b/java/com/google/gerrit/server/restapi/project/CheckAccessReadView.java
deleted file mode 100644
index 6aaa678..0000000
--- a/java/com/google/gerrit/server/restapi/project/CheckAccessReadView.java
+++ /dev/null
@@ -1,62 +0,0 @@
-// Copyright (C) 2018 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.restapi.project;
-
-import com.google.gerrit.extensions.api.config.AccessCheckInfo;
-import com.google.gerrit.extensions.api.config.AccessCheckInput;
-import com.google.gerrit.extensions.restapi.Response;
-import com.google.gerrit.extensions.restapi.RestApiException;
-import com.google.gerrit.extensions.restapi.RestReadView;
-import com.google.gerrit.server.permissions.PermissionBackendException;
-import com.google.gerrit.server.project.ProjectResource;
-import com.google.inject.Inject;
-import java.io.IOException;
-import org.eclipse.jgit.errors.ConfigInvalidException;
-import org.kohsuke.args4j.Option;
-
-public class CheckAccessReadView implements RestReadView<ProjectResource> {
-  String refName;
-  String account;
-  String permission;
-
-  @Inject CheckAccess checkAccess;
-
-  @Option(name = "--ref", usage = "ref name to check permission for")
-  void addOption(String refName) {
-    this.refName = refName;
-  }
-
-  @Option(name = "--account", usage = "account to check acccess for")
-  void setAccount(String account) {
-    this.account = account;
-  }
-
-  @Option(name = "--perm", usage = "permission to check; default: read of any ref.")
-  void setPermission(String perm) {
-    this.permission = perm;
-  }
-
-  @Override
-  public Response<AccessCheckInfo> apply(ProjectResource rsrc)
-      throws PermissionBackendException, RestApiException, IOException, ConfigInvalidException {
-
-    AccessCheckInput input = new AccessCheckInput();
-    input.ref = refName;
-    input.account = account;
-    input.permission = permission;
-
-    return checkAccess.apply(rsrc, input);
-  }
-}
diff --git a/java/com/google/gerrit/server/restapi/project/CommitsCollection.java b/java/com/google/gerrit/server/restapi/project/CommitsCollection.java
index 21d7f0b..9e0661c 100644
--- a/java/com/google/gerrit/server/restapi/project/CommitsCollection.java
+++ b/java/com/google/gerrit/server/restapi/project/CommitsCollection.java
@@ -93,10 +93,12 @@
     try (Repository repo = repoManager.openRepository(parent.getNameKey());
         RevWalk rw = new RevWalk(repo)) {
       RevCommit commit = rw.parseCommit(objectId);
-      rw.parseBody(commit);
       if (!canRead(parent.getProjectState(), repo, commit)) {
         throw new ResourceNotFoundException(id);
       }
+      // GetCommit depends on the body of both the commit and parent being parsed, to get the
+      // subject.
+      rw.parseBody(commit);
       for (int i = 0; i < commit.getParentCount(); i++) {
         rw.parseBody(rw.parseCommit(commit.getParent(i)));
       }
diff --git a/java/com/google/gerrit/server/restapi/project/CreateChange.java b/java/com/google/gerrit/server/restapi/project/CreateChange.java
index dbcd8c9..59efd06 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateChange.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateChange.java
@@ -59,8 +59,8 @@
       throw new AuthException("Authentication required");
     }
 
-    if (!Strings.isNullOrEmpty(input.project)) {
-      throw new BadRequestException("may not specify project");
+    if (!Strings.isNullOrEmpty(input.project) && !rsrc.getName().equals(input.project)) {
+      throw new BadRequestException("project must match URL");
     }
 
     input.project = rsrc.getName();
diff --git a/java/com/google/gerrit/server/restapi/project/CreateDashboard.java b/java/com/google/gerrit/server/restapi/project/CreateDashboard.java
index e9a0d7f..34d6696 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateDashboard.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateDashboard.java
@@ -26,11 +26,9 @@
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
-import com.google.inject.Singleton;
 import java.io.IOException;
 import org.kohsuke.args4j.Option;
 
-@Singleton
 public class CreateDashboard
     implements RestCollectionCreateView<ProjectResource, DashboardResource, SetDashboardInput> {
   private final Provider<SetDefaultDashboard> setDefault;
diff --git a/java/com/google/gerrit/server/restapi/project/DeleteTag.java b/java/com/google/gerrit/server/restapi/project/DeleteTag.java
index 545b752..8d0a3d3 100644
--- a/java/com/google/gerrit/server/restapi/project/DeleteTag.java
+++ b/java/com/google/gerrit/server/restapi/project/DeleteTag.java
@@ -14,10 +14,8 @@
 
 package com.google.gerrit.server.restapi.project;
 
-import static com.google.gerrit.entities.RefNames.isConfigRef;
-
+import com.google.common.base.Preconditions;
 import com.google.gerrit.extensions.common.Input;
-import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
@@ -27,6 +25,7 @@
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import org.eclipse.jgit.lib.Constants;
 
 @Singleton
 public class DeleteTag implements RestModifyView<TagResource, Input> {
@@ -43,10 +42,7 @@
       throws RestApiException, IOException, PermissionBackendException {
     String tag = RefUtil.normalizeTagRef(resource.getTagInfo().ref);
 
-    if (isConfigRef(tag)) {
-      // Never allow to delete the meta config branch.
-      throw new MethodNotAllowedException("not allowed to delete " + tag);
-    }
+    Preconditions.checkState(tag.startsWith(Constants.R_TAGS));
 
     deleteRef.deleteSingleRef(resource.getProjectState(), tag);
     return Response.none();
diff --git a/java/com/google/gerrit/server/restapi/project/FilesInCommitCollection.java b/java/com/google/gerrit/server/restapi/project/FilesInCommitCollection.java
index 0d5ab88..0f408db 100644
--- a/java/com/google/gerrit/server/restapi/project/FilesInCommitCollection.java
+++ b/java/com/google/gerrit/server/restapi/project/FilesInCommitCollection.java
@@ -39,6 +39,10 @@
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.kohsuke.args4j.Option;
 
+/**
+ * like {@link FilesCollection}, but for commits that are specified as hex ID, rather than branch
+ * names.
+ */
 @Singleton
 public class FilesInCommitCollection implements ChildCollection<CommitResource, FileResource> {
   private final DynamicMap<RestView<FileResource>> views;
diff --git a/java/com/google/gerrit/server/restapi/project/ListBranches.java b/java/com/google/gerrit/server/restapi/project/ListBranches.java
index fecdc8e..2c26933 100644
--- a/java/com/google/gerrit/server/restapi/project/ListBranches.java
+++ b/java/com/google/gerrit/server/restapi/project/ListBranches.java
@@ -143,7 +143,11 @@
   BranchInfo toBranchInfo(BranchResource rsrc)
       throws IOException, ResourceNotFoundException, PermissionBackendException {
     try (Repository db = repoManager.openRepository(rsrc.getNameKey())) {
-      Ref r = db.exactRef(rsrc.getRef());
+      String refName = rsrc.getRef();
+      if (RefNames.isRefsUsersSelf(refName, rsrc.getProjectState().isAllUsers())) {
+        refName = RefNames.refsUsers(rsrc.getUser().getAccountId());
+      }
+      Ref r = db.exactRef(refName);
       if (r == null) {
         throw new ResourceNotFoundException();
       }
diff --git a/java/com/google/gerrit/server/restapi/project/ListProjects.java b/java/com/google/gerrit/server/restapi/project/ListProjects.java
index 5418876..04e573c 100644
--- a/java/com/google/gerrit/server/restapi/project/ListProjects.java
+++ b/java/com/google/gerrit/server/restapi/project/ListProjects.java
@@ -90,7 +90,11 @@
 import org.eclipse.jgit.lib.Repository;
 import org.kohsuke.args4j.Option;
 
-/** List projects visible to the calling user. */
+/**
+ * List projects visible to the calling user.
+ *
+ * <p>Implement {@code GET /projects/}, without a {@code query=} parameter.
+ */
 public class ListProjects implements RestReadView<TopLevelResource> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
diff --git a/java/com/google/gerrit/server/restapi/project/Module.java b/java/com/google/gerrit/server/restapi/project/Module.java
index ee3914d..70fb6ea 100644
--- a/java/com/google/gerrit/server/restapi/project/Module.java
+++ b/java/com/google/gerrit/server/restapi/project/Module.java
@@ -57,7 +57,7 @@
     get(PROJECT_KIND, "access").to(GetAccess.class);
     post(PROJECT_KIND, "access").to(SetAccess.class);
     put(PROJECT_KIND, "access:review").to(CreateAccessChange.class);
-    get(PROJECT_KIND, "check.access").to(CheckAccessReadView.class);
+    get(PROJECT_KIND, "check.access").to(CheckAccess.class);
 
     post(PROJECT_KIND, "check").to(Check.class);
 
diff --git a/java/com/google/gerrit/server/restapi/project/QueryProjects.java b/java/com/google/gerrit/server/restapi/project/QueryProjects.java
index e4f7df5..a9d818d 100644
--- a/java/com/google/gerrit/server/restapi/project/QueryProjects.java
+++ b/java/com/google/gerrit/server/restapi/project/QueryProjects.java
@@ -36,6 +36,7 @@
 import java.util.List;
 import org.kohsuke.args4j.Option;
 
+/** Implements the {@code GET /projects/?query=QUERY} endpoint. */
 public class QueryProjects implements RestReadView<TopLevelResource> {
   private final ProjectIndexCollection indexes;
   private final ProjectQueryBuilder queryBuilder;
diff --git a/java/com/google/gerrit/server/schema/AllProjectsCreator.java b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
index 6faaec5..9907b1c 100644
--- a/java/com/google/gerrit/server/schema/AllProjectsCreator.java
+++ b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
@@ -176,14 +176,16 @@
           grant(config, refsFor, Permission.ADD_PATCH_SET, registered);
         });
 
+    config.upsertAccessSection(
+        "refs/meta/version",
+        version -> {
+          grant(config, version, Permission.READ, anonymous);
+        });
+
     grant(config, heads, codeReviewLabel, -1, 1, registered);
     grant(config, heads, Permission.FORGE_AUTHOR, registered);
-
-    config.upsertAccessSection(
-        "refs/*",
-        all -> {
-          grant(config, all, Permission.REVERT, registered);
-        });
+    grant(config, heads, Permission.READ, anonymous);
+    grant(config, heads, Permission.REVERT, registered);
 
     config.upsertAccessSection(
         "refs/for/" + AccessSection.ALL,
@@ -213,7 +215,7 @@
     config.upsertAccessSection(
         AccessSection.ALL,
         all -> {
-          grant(config, all, Permission.READ, adminsGroup, anonymous);
+          grant(config, all, Permission.READ, adminsGroup);
         });
 
     config.upsertAccessSection(
diff --git a/java/com/google/gerrit/server/schema/SchemaCreatorImpl.java b/java/com/google/gerrit/server/schema/SchemaCreatorImpl.java
index afa9d1a..de9374e 100644
--- a/java/com/google/gerrit/server/schema/SchemaCreatorImpl.java
+++ b/java/com/google/gerrit/server/schema/SchemaCreatorImpl.java
@@ -23,6 +23,7 @@
 import com.google.gerrit.metrics.MetricMaker;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.account.GroupUuid;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
@@ -91,7 +92,7 @@
   @Override
   public void create() throws IOException, ConfigInvalidException {
     GroupReference admins = createGroupReference("Administrators");
-    GroupReference serviceUsers = createGroupReference("Service Users");
+    GroupReference serviceUsers = createGroupReference(ServiceUserClassifier.SERVICE_USERS);
 
     AllProjectsInput allProjectsInput =
         AllProjectsInput.builder()
diff --git a/java/com/google/gerrit/server/schema/Schema_184.java b/java/com/google/gerrit/server/schema/Schema_184.java
index d0ca3d0..c14ae8a 100644
--- a/java/com/google/gerrit/server/schema/Schema_184.java
+++ b/java/com/google/gerrit/server/schema/Schema_184.java
@@ -18,6 +18,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupReference;
 import com.google.gerrit.git.RefUpdateUtil;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
@@ -44,7 +45,7 @@
   @Override
   public void upgrade(Arguments args, UpdateUI ui) throws Exception {
     try (Repository allUsersRepo = args.repoManager.openRepository(args.allUsers)) {
-      AccountGroup.NameKey newName = AccountGroup.nameKey("Service Users");
+      AccountGroup.NameKey newName = AccountGroup.nameKey(ServiceUserClassifier.SERVICE_USERS);
       Optional<GroupReference> nonInteractiveUsers =
           GroupNameNotes.loadAllGroups(allUsersRepo).stream()
               .filter(g -> g.getName().equals("Non-Interactive Users"))
diff --git a/java/com/google/gerrit/server/schema/testing/AllProjectsCreatorTestUtil.java b/java/com/google/gerrit/server/schema/testing/AllProjectsCreatorTestUtil.java
index 5485192..39e3a59 100644
--- a/java/com/google/gerrit/server/schema/testing/AllProjectsCreatorTestUtil.java
+++ b/java/com/google/gerrit/server/schema/testing/AllProjectsCreatorTestUtil.java
@@ -54,14 +54,14 @@
       ImmutableList.of(
           "[access \"refs/*\"]",
           "  read = group Administrators",
-          "  read = group Anonymous Users",
-          "  revert = group Registered Users",
           "[access \"refs/for/*\"]",
           "  addPatchSet = group Registered Users",
           "[access \"refs/for/refs/*\"]",
           "  push = group Registered Users",
           "  pushMerge = group Registered Users",
           "[access \"refs/heads/*\"]",
+          "  read = group Anonymous Users",
+          "  revert = group Registered Users",
           "  create = group Administrators",
           "  create = group Project Owners",
           "  editTopicName = +force group Administrators",
@@ -88,6 +88,8 @@
           "  read = group Project Owners",
           "  submit = group Administrators",
           "  submit = group Project Owners",
+          "[access \"refs/meta/version\"]",
+          "  read = group Anonymous Users",
           "[access \"refs/tags/*\"]",
           "  create = group Administrators",
           "  create = group Project Owners",
diff --git a/java/com/google/gerrit/server/submit/MergeOp.java b/java/com/google/gerrit/server/submit/MergeOp.java
index fdf3664..01c7b75 100644
--- a/java/com/google/gerrit/server/submit/MergeOp.java
+++ b/java/com/google/gerrit/server/submit/MergeOp.java
@@ -232,7 +232,7 @@
   private final SubmitStrategyFactory submitStrategyFactory;
   private final SubscriptionGraph.Factory subscriptionGraphFactory;
   private final SubmoduleCommits.Factory submoduleCommitsFactory;
-  private final SubmissionListener superprojectUpdateSubmissionListener;
+  private final ImmutableList<SubmissionListener> superprojectUpdateSubmissionListeners;
   private final Provider<MergeOpRepoManager> ormProvider;
   private final NotifyResolver notifyResolver;
   private final RetryHelper retryHelper;
@@ -264,7 +264,8 @@
       SubmitStrategyFactory submitStrategyFactory,
       SubmoduleCommits.Factory submoduleCommitsFactory,
       SubscriptionGraph.Factory subscriptionGraphFactory,
-      @SuperprojectUpdateOnSubmission SubmissionListener superprojectUpdateSubmissionListener,
+      @SuperprojectUpdateOnSubmission
+          ImmutableList<SubmissionListener> superprojectUpdateSubmissionListeners,
       Provider<MergeOpRepoManager> ormProvider,
       NotifyResolver notifyResolver,
       TopicMetrics topicMetrics,
@@ -279,7 +280,7 @@
     this.submitStrategyFactory = submitStrategyFactory;
     this.submoduleCommitsFactory = submoduleCommitsFactory;
     this.subscriptionGraphFactory = subscriptionGraphFactory;
-    this.superprojectUpdateSubmissionListener = superprojectUpdateSubmissionListener;
+    this.superprojectUpdateSubmissionListeners = superprojectUpdateSubmissionListeners;
     this.ormProvider = ormProvider;
     this.notifyResolver = notifyResolver;
     this.retryHelper = retryHelper;
@@ -502,7 +503,7 @@
         }
 
         SubmissionExecutor submissionExecutor =
-            new SubmissionExecutor(dryrun, superprojectUpdateSubmissionListener);
+            new SubmissionExecutor(dryrun, superprojectUpdateSubmissionListeners);
         RetryTracker retryTracker = new RetryTracker();
         retryHelper
             .changeUpdate(
diff --git a/java/com/google/gerrit/server/submit/MergeSuperSet.java b/java/com/google/gerrit/server/submit/MergeSuperSet.java
index 93c78a8..67f2907 100644
--- a/java/com/google/gerrit/server/submit/MergeSuperSet.java
+++ b/java/com/google/gerrit/server/submit/MergeSuperSet.java
@@ -18,19 +18,16 @@
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.base.Strings;
-import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.logging.TraceContext;
-import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.permissions.ChangePermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.plugincontext.PluginContext;
-import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.ChangeData;
@@ -55,8 +52,6 @@
  * included.
  */
 public class MergeSuperSet {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
   private final ChangeData.Factory changeDataFactory;
   private final Provider<InternalChangeQuery> queryProvider;
   private final Provider<MergeOpRepoManager> repoManagerProvider;
@@ -64,7 +59,6 @@
   private final PermissionBackend permissionBackend;
   private final Config cfg;
   private final ProjectCache projectCache;
-  private final ChangeNotes.Factory notesFactory;
 
   private MergeOpRepoManager orm;
   private boolean closeOrm;
@@ -77,8 +71,7 @@
       Provider<MergeOpRepoManager> repoManagerProvider,
       DynamicItem<MergeSuperSetComputation> mergeSuperSetComputation,
       PermissionBackend permissionBackend,
-      ProjectCache projectCache,
-      ChangeNotes.Factory notesFactory) {
+      ProjectCache projectCache) {
     this.cfg = cfg;
     this.changeDataFactory = changeDataFactory;
     this.queryProvider = queryProvider;
@@ -86,7 +79,6 @@
     this.mergeSuperSetComputation = mergeSuperSetComputation;
     this.permissionBackend = permissionBackend;
     this.projectCache = projectCache;
-    this.notesFactory = notesFactory;
   }
 
   public static boolean wholeTopicEnabled(Config config) {
@@ -212,24 +204,8 @@
     if (!projectCache.get(cd.project()).map(ProjectState::statePermitsRead).orElse(false)) {
       return false;
     }
-
-    ChangeNotes notes;
     try {
-      notes = cd.notes();
-    } catch (NoSuchChangeException e) {
-      // The change was found in the index but is missing in NoteDb.
-      // This can happen in systems with multiple primary nodes when the replication of the index
-      // documents is faster than the replication of the Git data.
-      // Instead of failing, create the change notes from the index data so that the read permission
-      // check can be performed successfully.
-      logger.atWarning().log(
-          "Got change %d of project %s from index, but couldn't find it in NoteDb",
-          cd.getId().get(), cd.project().get());
-      notes = notesFactory.createFromIndexedChange(cd.change());
-    }
-
-    try {
-      permissionBackend.user(user).change(notes).check(ChangePermission.READ);
+      permissionBackend.user(user).change(cd).check(ChangePermission.READ);
       return true;
     } catch (AuthException e) {
       return false;
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
index 3b77dd9..3430047 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
@@ -461,9 +461,12 @@
       // If we naively execute postUpdate even if the change is already merged when updateChange
       // being, then we are subject to a race where postUpdate steps are run twice if two submit
       // processes run at the same time.
-      logger.atFine().log("Skipping post-update steps for change %s", getId());
+      logger.atFine().log(
+          "Skipping post-update steps for change %s; submitter is %s", getId(), submitter);
       return;
     }
+    logger.atFine().log(
+        "Begin post-update steps for change %s; submitter is %s", getId(), submitter);
     postUpdateImpl(ctx);
 
     if (command != null) {
@@ -483,6 +486,9 @@
       }
     }
 
+    logger.atFine().log(
+        "Begin sending emails for submitting change %s; submitter is %s", getId(), submitter);
+
     // Assume the change must have been merged at this point, otherwise we would
     // have failed fast in one of the other steps.
     try {
diff --git a/java/com/google/gerrit/server/update/RetryHelper.java b/java/com/google/gerrit/server/update/RetryHelper.java
index 2db625b..409c808 100644
--- a/java/com/google/gerrit/server/update/RetryHelper.java
+++ b/java/com/google/gerrit/server/update/RetryHelper.java
@@ -481,7 +481,7 @@
                   if (!traceContext.isTracing()) {
                     String traceId = "retry-on-failure-" + new RequestId();
                     traceContext.addTag(RequestId.Type.TRACE_ID, traceId).forceLogging();
-                    logger.atFine().withCause(t).log(
+                    logger.atWarning().withCause(t).log(
                         "AutoRetry: %s failed, retry with tracing enabled (cause = %s)",
                         actionName, cause);
                     opts.onAutoTrace().ifPresent(c -> c.accept(traceId));
@@ -492,7 +492,7 @@
                   // A non-recoverable failure occurred. We retried the operation with tracing
                   // enabled and it failed again. Log the failure so that admin can see if it
                   // differs from the failure that triggered the retry.
-                  logger.atFine().withCause(t).log(
+                  logger.atWarning().withCause(t).log(
                       "AutoRetry: auto-retry of %s has failed (cause = %s)", actionName, cause);
                   metrics.failuresOnAutoRetryCount.increment(actionType, actionName, cause);
                   return false;
@@ -504,7 +504,7 @@
       return executeWithTimeoutCount(actionType, action, opts, retryerBuilder.build(), listener);
     } finally {
       if (listener.getAttemptCount() > 1) {
-        logger.atFine().log("%s was attempted %d times", actionType, listener.getAttemptCount());
+        logger.atWarning().log("%s was attempted %d times", actionType, listener.getAttemptCount());
         metrics.attemptCounts.incrementBy(
             actionType,
             opts.actionName().orElse("N/A"),
diff --git a/java/com/google/gerrit/server/update/SubmissionExecutor.java b/java/com/google/gerrit/server/update/SubmissionExecutor.java
index 5a3a789..39eda58 100644
--- a/java/com/google/gerrit/server/update/SubmissionExecutor.java
+++ b/java/com/google/gerrit/server/update/SubmissionExecutor.java
@@ -17,7 +17,6 @@
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.server.submit.MergeOpRepoManager;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Optional;
 import java.util.stream.Collectors;
@@ -28,14 +27,9 @@
   private final boolean dryrun;
   private ImmutableList<BatchUpdateListener> additionalListeners = ImmutableList.of();
 
-  public SubmissionExecutor(
-      boolean dryrun, SubmissionListener listener, SubmissionListener... otherListeners) {
+  public SubmissionExecutor(boolean dryrun, ImmutableList<SubmissionListener> submissionListeners) {
     this.dryrun = dryrun;
-    this.submissionListeners =
-        ImmutableList.<SubmissionListener>builder()
-            .add(listener)
-            .addAll(Arrays.asList(otherListeners))
-            .build();
+    this.submissionListeners = submissionListeners;
     if (dryrun) {
       submissionListeners.forEach(SubmissionListener::setDryrun);
     }
diff --git a/java/com/google/gerrit/server/update/SuperprojectUpdateSubmissionListener.java b/java/com/google/gerrit/server/update/SuperprojectUpdateSubmissionListener.java
index dffdff0..4c65c80 100644
--- a/java/com/google/gerrit/server/update/SuperprojectUpdateSubmissionListener.java
+++ b/java/com/google/gerrit/server/update/SuperprojectUpdateSubmissionListener.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.server.submit.MergeOpRepoManager;
 import com.google.gerrit.server.submit.SubmoduleOp;
 import com.google.inject.AbstractModule;
+import com.google.inject.Provides;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
@@ -39,11 +40,11 @@
   private boolean dryrun;
 
   public static class Module extends AbstractModule {
-    @Override
-    protected void configure() {
-      bind(SubmissionListener.class)
-          .annotatedWith(SuperprojectUpdateOnSubmission.class)
-          .to(SuperprojectUpdateSubmissionListener.class);
+    @Provides
+    @SuperprojectUpdateOnSubmission
+    ImmutableList<SubmissionListener> provideSubmissionListeners(
+        SuperprojectUpdateSubmissionListener listener) {
+      return ImmutableList.of(listener);
     }
   }
 
diff --git a/java/com/google/gerrit/server/util/AttentionSetUtil.java b/java/com/google/gerrit/server/util/AttentionSetUtil.java
index 62cad3f..26c862d 100644
--- a/java/com/google/gerrit/server/util/AttentionSetUtil.java
+++ b/java/com/google/gerrit/server/util/AttentionSetUtil.java
@@ -16,11 +16,16 @@
 
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AttentionSetUpdate;
 import com.google.gerrit.entities.AttentionSetUpdate.Operation;
 import com.google.gerrit.extensions.api.changes.AttentionSetInput;
 import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.server.account.AccountResolver;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import java.io.IOException;
 import java.util.Collection;
+import org.eclipse.jgit.errors.ConfigInvalidException;
 
 /** Common helpers for dealing with attention set data structures. */
 public class AttentionSetUtil {
@@ -49,5 +54,45 @@
     }
   }
 
+  /**
+   * Returns the {@code Account.Id} of {@code user} if the user is active on the change, and exists.
+   * If the user doesn't exist or is not active on the change, the same exception is thrown to
+   * disallow probing for account existence based on exception type.
+   */
+  public static Account.Id resolveAccount(
+      AccountResolver accountResolver, ChangeNotes changeNotes, String user)
+      throws ConfigInvalidException, IOException, BadRequestException {
+    // We will throw this exception if the account doesn't exist, or if the account is not active.
+    // This is purposely the same exception so that users can't probe for account existence based on
+    // the thrown exception.
+    BadRequestException possibleExceptionForNotFoundOrInactiveAccount =
+        new BadRequestException(
+            String.format(
+                "%s doesn't exist or is not active on the change as an owner, uploader, "
+                    + "reviewer, or cc so they can't be added to the attention set",
+                user));
+    Account.Id attentionUserId;
+    try {
+      attentionUserId = accountResolver.resolveIgnoreVisibility(user).asUnique().account().id();
+    } catch (AccountResolver.UnresolvableAccountException ex) {
+      possibleExceptionForNotFoundOrInactiveAccount.initCause(ex);
+      throw possibleExceptionForNotFoundOrInactiveAccount;
+    }
+    if (!isActiveOnTheChange(changeNotes, attentionUserId)) {
+      throw possibleExceptionForNotFoundOrInactiveAccount;
+    }
+    return attentionUserId;
+  }
+
+  /**
+   * Returns whether {@code attentionUserId} is active on a change. Activity is defined as being a
+   * part of the reviewers, an uploader, or an owner of a change.
+   */
+  private static boolean isActiveOnTheChange(ChangeNotes changeNotes, Account.Id attentionUserId) {
+    return changeNotes.getChange().getOwner().equals(attentionUserId)
+        || changeNotes.getCurrentPatchSet().uploader().equals(attentionUserId)
+        || changeNotes.getReviewers().all().stream().anyMatch(id -> id.equals(attentionUserId));
+  }
+
   private AttentionSetUtil() {}
 }
diff --git a/java/com/google/gerrit/server/util/CommitMessageUtil.java b/java/com/google/gerrit/server/util/CommitMessageUtil.java
index 1c8ce0c..55e3951 100644
--- a/java/com/google/gerrit/server/util/CommitMessageUtil.java
+++ b/java/com/google/gerrit/server/util/CommitMessageUtil.java
@@ -22,13 +22,19 @@
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.util.Optional;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.util.ChangeIdUtil;
 
 /** Utility functions to manipulate commit messages. */
 public class CommitMessageUtil {
   private static final SecureRandom rng;
+  private static final Pattern changeIdFooterPattern =
+      Pattern.compile("Change-Id: *(I[a-f0-9]{40})");
 
   static {
     try {
@@ -71,6 +77,31 @@
   }
 
   public static Change.Key generateKey() {
-    return Change.key("I" + generateChangeId().name());
+    return Change.key(getChangeIdFromObjectId(generateChangeId()));
+  }
+
+  public static String getChangeIdFromObjectId(ObjectId objectId) {
+    return "I" + objectId.name();
+  }
+
+  /**
+   * Return the value of Change-Id from the commit message footer.
+   *
+   * <p>The behaviour matches {@link org.eclipse.jgit.util.ChangeIdUtil}. If more than one matching
+   * Change-Id footer is found, return the value of the last one.
+   *
+   * @param commitMessage commit message to get Change-Id from.
+   * @return {@link Optional} value of Change-Id footer in the commit message.
+   */
+  public static Optional<String> getChangeIdFromCommitMessageFooter(String commitMessage) {
+    int indexOfChangeId = ChangeIdUtil.indexOfChangeId(commitMessage, "\n");
+    if (indexOfChangeId == -1) {
+      return Optional.empty();
+    }
+    Matcher matcher = changeIdFooterPattern.matcher(commitMessage);
+    if (matcher.find(indexOfChangeId)) {
+      return Optional.of(matcher.group(1));
+    }
+    return Optional.empty();
   }
 }
diff --git a/java/com/google/gerrit/server/util/PluginLogFile.java b/java/com/google/gerrit/server/util/PluginLogFile.java
index de8b3aa..345e1b3 100644
--- a/java/com/google/gerrit/server/util/PluginLogFile.java
+++ b/java/com/google/gerrit/server/util/PluginLogFile.java
@@ -16,7 +16,6 @@
 
 import com.google.gerrit.extensions.events.LifecycleListener;
 import com.google.gerrit.extensions.systemstatus.ServerInformation;
-import org.apache.log4j.AsyncAppender;
 import org.apache.log4j.Layout;
 import org.apache.log4j.LogManager;
 import org.apache.log4j.Logger;
@@ -38,10 +37,14 @@
 
   @Override
   public void start() {
-    AsyncAppender asyncAppender = systemLog.createAsyncAppender(logName, layout, true, true);
     Logger logger = LogManager.getLogger(logName);
-    logger.removeAppender(logName);
-    logger.addAppender(asyncAppender);
+    if (logger.getAppender(logName) == null) {
+      synchronized (systemLog) {
+        if (logger.getAppender(logName) == null) {
+          logger.addAppender(systemLog.createAsyncAppender(logName, layout, true, true));
+        }
+      }
+    }
     logger.setAdditivity(false);
   }
 
diff --git a/java/com/google/gerrit/sshd/AbstractGitCommand.java b/java/com/google/gerrit/sshd/AbstractGitCommand.java
index 9efcff2..b3753fd 100644
--- a/java/com/google/gerrit/sshd/AbstractGitCommand.java
+++ b/java/com/google/gerrit/sshd/AbstractGitCommand.java
@@ -16,6 +16,7 @@
 
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.AccessPath;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -64,8 +65,8 @@
       startThread(
           new ProjectCommandRunnable() {
             @Override
-            public void executeParseCommand() throws Exception {
-              parseCommandLine();
+            public void executeParseCommand(DynamicOptions pluginOptions) throws Exception {
+              parseCommandLine(pluginOptions);
             }
 
             @Override
diff --git a/java/com/google/gerrit/sshd/BaseCommand.java b/java/com/google/gerrit/sshd/BaseCommand.java
index 85d9eb2..0ce6766 100644
--- a/java/com/google/gerrit/sshd/BaseCommand.java
+++ b/java/com/google/gerrit/sshd/BaseCommand.java
@@ -102,9 +102,9 @@
   @PluginName
   private String pluginName;
 
-  @Inject private Injector injector;
+  @Inject protected Injector injector;
 
-  @Inject private DynamicMap<DynamicOptions.DynamicBean> dynamicBeans = null;
+  @Inject protected DynamicMap<DynamicOptions.DynamicBean> dynamicBeans = null;
 
   /** The task, as scheduled on a worker thread. */
   private final AtomicReference<Future<?>> task;
@@ -212,12 +212,13 @@
    *
    * <p>This method must be explicitly invoked to cause a parse.
    *
+   * @param pluginOptions which helps to define and parse options provided from plugins
    * @throws UnloggedFailure if the command line arguments were invalid.
    * @see Option
    * @see Argument
    */
-  protected void parseCommandLine() throws UnloggedFailure {
-    parseCommandLine(this);
+  protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
+    parseCommandLine(this, pluginOptions);
   }
 
   /**
@@ -227,13 +228,16 @@
    *
    * @param options object whose fields declare Option and Argument annotations to describe the
    *     parameters of the command. Usually {@code this}.
+   * @param pluginOptions which helps to define and parse options provided from plugins
    * @throws UnloggedFailure if the command line arguments were invalid.
    * @see Option
    * @see Argument
    */
-  protected void parseCommandLine(Object options) throws UnloggedFailure {
+  protected void parseCommandLine(Object options, DynamicOptions pluginOptions)
+      throws UnloggedFailure {
     final CmdLineParser clp = newCmdLineParser(options);
-    DynamicOptions pluginOptions = new DynamicOptions(options, injector, dynamicBeans);
+    pluginOptions.setBean(options);
+    pluginOptions.startLifecycleListeners();
     pluginOptions.parseDynamicBeans(clp);
     pluginOptions.setDynamicBeans();
     pluginOptions.onBeanParseStart();
@@ -479,13 +483,16 @@
           context.started = TimeUtil.nowMs();
           thisThread.setName("SSH " + taskName);
 
-          if (thunk instanceof ProjectCommandRunnable) {
-            ((ProjectCommandRunnable) thunk).executeParseCommand();
-            projectName = ((ProjectCommandRunnable) thunk).getProjectName();
-          }
-
           try {
-            thunk.run();
+            if (thunk instanceof ProjectCommandRunnable) {
+              try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
+                ((ProjectCommandRunnable) thunk).executeParseCommand(pluginOptions);
+                projectName = ((ProjectCommandRunnable) thunk).getProjectName();
+                thunk.run();
+              }
+            } else {
+              thunk.run();
+            }
           } catch (NoSuchProjectException e) {
             throw new UnloggedFailure(1, e.getMessage());
           } catch (NoSuchChangeException e) {
@@ -548,7 +555,7 @@
   public interface ProjectCommandRunnable extends CommandRunnable {
     // execute parser command before running, in order to be able to retrieve
     // project name
-    void executeParseCommand() throws Exception;
+    void executeParseCommand(DynamicOptions pluginOptions) throws Exception;
 
     Project.NameKey getProjectName();
   }
diff --git a/java/com/google/gerrit/sshd/DispatchCommand.java b/java/com/google/gerrit/sshd/DispatchCommand.java
index 7db65bd..54171a3 100644
--- a/java/com/google/gerrit/sshd/DispatchCommand.java
+++ b/java/com/google/gerrit/sshd/DispatchCommand.java
@@ -20,6 +20,7 @@
 import com.google.common.util.concurrent.Atomics;
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.args4j.SubcommandHandler;
 import com.google.gerrit.server.permissions.GlobalPermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
@@ -71,8 +72,8 @@
 
   @Override
   public void start(ChannelSession channel, Environment env) throws IOException {
-    try {
-      parseCommandLine();
+    try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
+      parseCommandLine(pluginOptions);
       if (Strings.isNullOrEmpty(commandName)) {
         StringWriter msg = new StringWriter();
         msg.write(usage());
diff --git a/java/com/google/gerrit/sshd/SshCommand.java b/java/com/google/gerrit/sshd/SshCommand.java
index e60ba6d..c94b25c 100644
--- a/java/com/google/gerrit/sshd/SshCommand.java
+++ b/java/com/google/gerrit/sshd/SshCommand.java
@@ -16,6 +16,7 @@
 
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.server.AccessPath;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.RequestInfo;
 import com.google.gerrit.server.RequestListener;
 import com.google.gerrit.server.config.GerritServerConfig;
@@ -49,19 +50,21 @@
   public void start(ChannelSession channel, Environment env) throws IOException {
     startThread(
         () -> {
-          parseCommandLine();
-          stdout = toPrintWriter(out);
-          stderr = toPrintWriter(err);
-          try (TraceContext traceContext = enableTracing();
-              PerformanceLogContext performanceLogContext =
-                  new PerformanceLogContext(config, performanceLoggers)) {
-            RequestInfo requestInfo =
-                RequestInfo.builder(RequestInfo.RequestType.SSH, user, traceContext).build();
-            requestListeners.runEach(l -> l.onRequest(requestInfo));
-            SshCommand.this.run();
-          } finally {
-            stdout.flush();
-            stderr.flush();
+          try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
+            parseCommandLine(pluginOptions);
+            stdout = toPrintWriter(out);
+            stderr = toPrintWriter(err);
+            try (TraceContext traceContext = enableTracing();
+                PerformanceLogContext performanceLogContext =
+                    new PerformanceLogContext(config, performanceLoggers)) {
+              RequestInfo requestInfo =
+                  RequestInfo.builder(RequestInfo.RequestType.SSH, user, traceContext).build();
+              requestListeners.runEach(l -> l.onRequest(requestInfo));
+              SshCommand.this.run();
+            } finally {
+              stdout.flush();
+              stderr.flush();
+            }
           }
         },
         AccessPath.SSH_COMMAND);
diff --git a/java/com/google/gerrit/sshd/SuExec.java b/java/com/google/gerrit/sshd/SuExec.java
index ea163d5..3c6e8c2 100644
--- a/java/com/google/gerrit/sshd/SuExec.java
+++ b/java/com/google/gerrit/sshd/SuExec.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PeerDaemonUser;
 import com.google.gerrit.server.config.AuthConfig;
@@ -92,9 +93,9 @@
 
   @Override
   public void start(ChannelSession channel, Environment env) throws IOException {
-    try {
+    try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
       checkCanRunAs();
-      parseCommandLine();
+      parseCommandLine(pluginOptions);
 
       final Context ctx = callingContext.subContext(newSession(), join(args));
       final Context old = sshScope.set(ctx);
diff --git a/java/com/google/gerrit/sshd/commands/ListMembersCommand.java b/java/com/google/gerrit/sshd/commands/ListMembersCommand.java
index 3269c2b..52d0468 100644
--- a/java/com/google/gerrit/sshd/commands/ListMembersCommand.java
+++ b/java/com/google/gerrit/sshd/commands/ListMembersCommand.java
@@ -20,6 +20,7 @@
 import com.google.common.base.Strings;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.account.AccountLoader;
 import com.google.gerrit.server.account.GroupCache;
 import com.google.gerrit.server.account.GroupControl;
@@ -50,8 +51,8 @@
   }
 
   @Override
-  protected void parseCommandLine() throws UnloggedFailure {
-    parseCommandLine(impl);
+  protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
+    parseCommandLine(impl, pluginOptions);
   }
 
   private static class ListMembersCommandImpl extends ListMembers {
diff --git a/java/com/google/gerrit/sshd/commands/Query.java b/java/com/google/gerrit/sshd/commands/Query.java
index 772eabe..da19153 100644
--- a/java/com/google/gerrit/sshd/commands/Query.java
+++ b/java/com/google/gerrit/sshd/commands/Query.java
@@ -116,9 +116,9 @@
   }
 
   @Override
-  protected void parseCommandLine() throws UnloggedFailure {
+  protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
     processor.setOutput(out, OutputFormat.TEXT);
-    super.parseCommandLine();
+    super.parseCommandLine(pluginOptions);
     if (processor.getIncludeFiles()
         && !(processor.getIncludePatchSets() || processor.getIncludeCurrentPatchSet())) {
       throw die("--files option needs --patch-sets or --current-patch-set");
diff --git a/java/com/google/gerrit/sshd/commands/ReviewCommand.java b/java/com/google/gerrit/sshd/commands/ReviewCommand.java
index b58cc45..4c84bd3 100644
--- a/java/com/google/gerrit/sshd/commands/ReviewCommand.java
+++ b/java/com/google/gerrit/sshd/commands/ReviewCommand.java
@@ -36,6 +36,7 @@
 import com.google.gerrit.extensions.api.changes.RevisionApi;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.json.OutputFormat;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.project.ProjectCache;
@@ -320,7 +321,7 @@
   }
 
   @Override
-  protected void parseCommandLine() throws UnloggedFailure {
+  protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
     optionMap = new LinkedHashMap<>();
     customLabels = new HashMap<>();
 
@@ -341,7 +342,7 @@
       optionMap.put(newApproveOption(type, usage.toString()), new LabelSetter(type));
     }
 
-    super.parseCommandLine();
+    super.parseCommandLine(pluginOptions);
   }
 
   private static String asOptionName(LabelType type) {
diff --git a/java/com/google/gerrit/sshd/commands/SetTopicCommand.java b/java/com/google/gerrit/sshd/commands/SetTopicCommand.java
index 70700f1..35cb3ba 100644
--- a/java/com/google/gerrit/sshd/commands/SetTopicCommand.java
+++ b/java/com/google/gerrit/sshd/commands/SetTopicCommand.java
@@ -16,12 +16,11 @@
 
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.exceptions.StorageException;
-import com.google.gerrit.extensions.api.changes.TopicInput;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.change.SetTopicOp;
 import com.google.gerrit.server.permissions.PermissionBackendException;
-import com.google.gerrit.server.restapi.change.SetTopicOp;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.util.time.TimeUtil;
 import com.google.gerrit.sshd.ChangeArgumentParser;
@@ -74,18 +73,17 @@
 
   @Override
   public void run() throws Exception {
-    TopicInput input = new TopicInput();
     if (topic != null) {
-      input.topic = topic.trim();
+      topic = topic.trim();
     }
 
-    if (input.topic != null && input.topic.length() > ChangeUtil.TOPIC_MAX_LENGTH) {
+    if (topic != null && topic.length() > ChangeUtil.TOPIC_MAX_LENGTH) {
       throw new BadRequestException(
           String.format("topic length exceeds the limit (%s)", ChangeUtil.TOPIC_MAX_LENGTH));
     }
 
     for (ChangeResource r : changes.values()) {
-      SetTopicOp op = topicOpFactory.create(input);
+      SetTopicOp op = topicOpFactory.create(topic);
       try (BatchUpdate u =
           updateFactory.create(r.getChange().getProject(), user, TimeUtil.nowTs())) {
         u.addOp(r.getId(), op);
diff --git a/java/com/google/gerrit/sshd/commands/StreamEvents.java b/java/com/google/gerrit/sshd/commands/StreamEvents.java
index 45540a0..c47d24c 100644
--- a/java/com/google/gerrit/sshd/commands/StreamEvents.java
+++ b/java/com/google/gerrit/sshd/commands/StreamEvents.java
@@ -22,6 +22,7 @@
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.extensions.registration.RegistrationHandle;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.DynamicOptions;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.events.Event;
 import com.google.gerrit.server.events.EventGson;
@@ -107,59 +108,62 @@
 
   @Override
   public void start(ChannelSession channel, Environment env) throws IOException {
-    try {
-      parseCommandLine();
-    } catch (UnloggedFailure e) {
-      String msg = e.getMessage();
-      if (!msg.endsWith("\n")) {
-        msg += "\n";
+    try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
+      try {
+        parseCommandLine(pluginOptions);
+      } catch (UnloggedFailure e) {
+        String msg = e.getMessage();
+        if (!msg.endsWith("\n")) {
+          msg += "\n";
+        }
+        err.write(msg.getBytes(UTF_8));
+        err.flush();
+        onExit(1);
+        return;
       }
-      err.write(msg.getBytes(UTF_8));
-      err.flush();
-      onExit(1);
-      return;
-    }
 
-    PrintWriter stdout = toPrintWriter(out);
-    CancelableRunnable writer =
-        new CancelableRunnable() {
-          @Override
-          public void run() {
-            writeEvents(this, stdout);
-          }
-
-          @Override
-          public void cancel() {
-            onExit(0);
-          }
-
-          @Override
-          public String toString() {
-            StringBuilder b = new StringBuilder();
-            b.append("Stream Events");
-            if (currentUser.getUserName().isPresent()) {
-              b.append(" (").append(currentUser.getUserName().get()).append(")");
+      PrintWriter stdout = toPrintWriter(out);
+      CancelableRunnable writer =
+          new CancelableRunnable() {
+            @Override
+            public void run() {
+              writeEvents(this, stdout);
             }
-            return b.toString();
-          }
-        };
 
-    eventListenerRegistration =
-        eventListeners.add(
-            "gerrit",
-            new UserScopedEventListener() {
-              @Override
-              public void onEvent(Event event) {
-                if (subscribedToEvents.isEmpty() || subscribedToEvents.contains(event.getType())) {
-                  offer(writer, event);
+            @Override
+            public void cancel() {
+              onExit(0);
+            }
+
+            @Override
+            public String toString() {
+              StringBuilder b = new StringBuilder();
+              b.append("Stream Events");
+              if (currentUser.getUserName().isPresent()) {
+                b.append(" (").append(currentUser.getUserName().get()).append(")");
+              }
+              return b.toString();
+            }
+          };
+
+      eventListenerRegistration =
+          eventListeners.add(
+              "gerrit",
+              new UserScopedEventListener() {
+                @Override
+                public void onEvent(Event event) {
+                  if (subscribedToEvents.isEmpty()
+                      || subscribedToEvents.contains(event.getType())) {
+                    offer(writer, event);
+                  }
                 }
-              }
 
-              @Override
-              public CurrentUser getUser() {
-                return currentUser;
-              }
-            });
+                @Override
+                public CurrentUser getUser() {
+                  return currentUser;
+                }
+              });
+    }
   }
 
   private void removeEventListenerRegistration() {
diff --git a/java/com/google/gerrit/acceptance/WaitUtilTest.java b/javatests/com/google/gerrit/acceptance/WaitUtilTest.java
similarity index 100%
rename from java/com/google/gerrit/acceptance/WaitUtilTest.java
rename to javatests/com/google/gerrit/acceptance/WaitUtilTest.java
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index 18f1223..4015ccb 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -91,6 +91,7 @@
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.Address;
+import com.google.gerrit.entities.BranchNameKey;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.LabelFunction;
 import com.google.gerrit.entities.LabelType;
@@ -154,6 +155,7 @@
 import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.change.testing.TestChangeETagComputation;
+import com.google.gerrit.server.git.ChangeMessageModifier;
 import com.google.gerrit.server.group.SystemGroupBackend;
 import com.google.gerrit.server.index.change.ChangeIndex;
 import com.google.gerrit.server.index.change.ChangeIndexCollection;
@@ -1504,19 +1506,19 @@
     assertThat(commit.author.email).isEqualTo(user.email());
     assertThat(commit.committer.email).isEqualTo(user.email());
 
-    // check that the author/committer was added as reviewer
-    Collection<AccountInfo> reviewers = change.reviewers.get(REVIEWER);
+    // check that the author/committer was added as cc
+    Collection<AccountInfo> reviewers = change.reviewers.get(CC);
     assertThat(reviewers).isNotNull();
     assertThat(reviewers).hasSize(1);
     assertThat(reviewers.iterator().next()._accountId).isEqualTo(user.id().get());
-    assertThat(change.reviewers.get(CC)).isNull();
+    assertThat(change.reviewers.get(REVIEWER)).isNull();
 
     List<Message> messages = sender.getMessages();
     assertThat(messages).hasSize(1);
     Message m = messages.get(0);
     assertThat(m.from().name()).isEqualTo("Administrator (Code Review)");
     assertThat(m.rcpt()).containsExactly(user.getNameEmail());
-    assertThat(m.body()).contains("I'd like you to do a code review");
+    assertThat(m.body()).contains("has uploaded this change for review");
     assertThat(m.body()).contains("Change subject: " + PushOneCommit.SUBJECT + "\n");
     assertMailReplyTo(m, admin.email());
   }
@@ -2258,6 +2260,10 @@
     assertThat(message.body()).contains("Removed reviewer " + user.fullName() + ".");
     assertThat(message.body()).doesNotContain("with the following votes");
 
+    // Make sure the change message for removing a reviewer is correct.
+    assertThat(Iterables.getLast(gApi.changes().id(changeId).messages()).message)
+        .contains("Removed reviewer " + user.fullName());
+
     // Make sure the reviewer can still be added again.
     gApi.changes().id(changeId).addReviewer(user.id().toString());
     c = gApi.changes().id(changeId).get();
@@ -2273,6 +2279,31 @@
   }
 
   @Test
+  public void removeCC() throws Exception {
+    PushOneCommit.Result result = createChange();
+    String changeId = result.getChangeId();
+    // Add a cc
+    AddReviewerInput addReviewerInput = new AddReviewerInput();
+    addReviewerInput.state = CC;
+    addReviewerInput.reviewer = user.id().toString();
+    gApi.changes().id(changeId).addReviewer(addReviewerInput);
+
+    // Remove a cc
+    sender.clear();
+    gApi.changes().id(changeId).reviewer(user.id().toString()).remove();
+    assertThat(gApi.changes().id(changeId).get().reviewers).isEmpty();
+
+    // Make sure the email for removing a cc is correct.
+    assertThat(sender.getMessages()).hasSize(1);
+    Message message = sender.getMessages().get(0);
+    assertThat(message.body()).contains("Removed cc " + user.fullName() + ".");
+
+    // Make sure the change message for removing a reviewer is correct.
+    assertThat(Iterables.getLast(gApi.changes().id(changeId).messages()).message)
+        .contains("Removed cc " + user.fullName());
+  }
+
+  @Test
   public void removeReviewer() throws Exception {
     testRemoveReviewer(true);
   }
@@ -2922,14 +2953,19 @@
   public void customCommitFooters() throws Exception {
     PushOneCommit.Result change = createChange();
     ChangeInfo actual;
-    try (Registration registration =
-        extensionRegistry
-            .newRegistration()
-            .add(
-                (newCommitMessage, original, mergeTip, destination) -> {
-                  assertThat(original.getName()).isNotEqualTo(mergeTip.getName());
-                  return newCommitMessage + "Custom: " + destination.branch();
-                })) {
+    ChangeMessageModifier link =
+        new ChangeMessageModifier() {
+          @Override
+          public String onSubmit(
+              String newCommitMessage,
+              RevCommit original,
+              RevCommit mergeTip,
+              BranchNameKey destination) {
+            assertThat(original.getName()).isNotEqualTo(mergeTip.getName());
+            return newCommitMessage + "Custom: " + destination.branch();
+          }
+        };
+    try (Registration registration = extensionRegistry.newRegistration().add(link)) {
       actual = gApi.changes().id(change.getChangeId()).get(ALL_REVISIONS, COMMIT_FOOTERS);
     }
     List<String> footers =
diff --git a/javatests/com/google/gerrit/acceptance/api/change/PluginFieldsIT.java b/javatests/com/google/gerrit/acceptance/api/change/PluginFieldsIT.java
index 31198d5..cebce0b 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/PluginFieldsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/PluginFieldsIT.java
@@ -16,9 +16,6 @@
 
 import com.google.gerrit.acceptance.AbstractPluginFieldsTest;
 import com.google.gerrit.acceptance.NoHttpd;
-import com.google.gerrit.extensions.annotations.Exports;
-import com.google.gerrit.server.change.ChangeAttributeFactory;
-import com.google.inject.AbstractModule;
 import java.util.Arrays;
 import org.junit.Test;
 
@@ -27,30 +24,6 @@
   // No tests for /detail via the extension API, since the extension API doesn't have that method.
 
   @Test
-  public void queryChangeWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(
-        id -> pluginInfoFromSingletonList(gApi.changes().query(id.toString()).get()));
-  }
-
-  @Test
-  public void getChangeWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(
-        id -> pluginInfoFromChangeInfo(gApi.changes().id(id.toString()).get()));
-  }
-
-  @Test
-  public void queryChangeWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromSingletonList(gApi.changes().query(id.toString()).get()));
-  }
-
-  @Test
-  public void getChangeWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromChangeInfo(gApi.changes().id(id.toString()).get()));
-  }
-
-  @Test
   public void querySingleChangeWithBulkAttribute() throws Exception {
     getSingleChangeWithPluginDefinedBulkAttribute(
         id -> pluginInfosFromChangeInfos(gApi.changes().query(id.toString()).get()));
@@ -63,22 +36,6 @@
   }
 
   @Test
-  public void queryChangeWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromSingletonList(gApi.changes().query(id.toString()).get()),
-        (id, opts) ->
-            pluginInfoFromSingletonList(
-                gApi.changes().query(id.toString()).withPluginOptions(opts).get()));
-  }
-
-  @Test
-  public void getChangeWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromChangeInfo(gApi.changes().id(id.get()).get()),
-        (id, opts) -> pluginInfoFromChangeInfo(gApi.changes().id(id.get()).get(opts)));
-  }
-
-  @Test
   public void queryChangeWithOptionBulkAttribute() throws Exception {
     getChangeWithPluginDefinedBulkAttributeOption(
         id -> pluginInfosFromChangeInfos(gApi.changes().query(id.toString()).get()),
@@ -108,12 +65,6 @@
   }
 
   @Test
-  public void getMultipleChangesWithPluginDefinedAndChangeAttributes() throws Exception {
-    getMultipleChangesWithPluginDefinedBulkAndChangeAttributes(
-        () -> pluginInfosFromChangeInfos(gApi.changes().query("status:open").get()));
-  }
-
-  @Test
   public void getMultipleChangesWithPluginDefinedAttributeInSingleCall() throws Exception {
     getMultipleChangesWithPluginDefinedBulkAttributeInSingleCall(
         () -> pluginInfosFromChangeInfos(gApi.changes().query("status:open").get()));
@@ -124,23 +75,4 @@
     getChangeWithPluginDefinedBulkAttributeWithException(
         id -> pluginInfosFromChangeInfos(Arrays.asList(gApi.changes().id(id.get()).get())));
   }
-
-  static class SimpleAttributeWithExplicitExportModule extends AbstractModule {
-    @Override
-    public void configure() {
-      bind(ChangeAttributeFactory.class)
-          .annotatedWith(Exports.named("simple"))
-          .toInstance((cd, bp, p) -> new MyInfo("change " + cd.getId()));
-    }
-  }
-
-  @Test
-  public void getChangeWithSimpleAttributeWithExplicitExport() throws Exception {
-    // For backwards compatibility with old plugins, allow modules to bind into the
-    // DynamicSet<ChangeAttributeFactory> as if it were a DynamicMap. We only need one variant of
-    // this test to prove that the mapping works.
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromChangeInfo(gApi.changes().id(id.toString()).get()),
-        SimpleAttributeWithExplicitExportModule.class);
-  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java b/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java
index 7d73374..029d5a2 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java
@@ -29,9 +29,16 @@
 import com.google.common.collect.Iterables;
 import com.google.common.truth.Correspondence;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.ExtensionRegistry;
+import com.google.gerrit.acceptance.ExtensionRegistry.Registration;
 import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.acceptance.config.GerritConfig;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.extensions.annotations.Exports;
 import com.google.gerrit.extensions.api.changes.DraftInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
@@ -49,6 +56,9 @@
 import com.google.gerrit.extensions.validators.CommentForValidation;
 import com.google.gerrit.extensions.validators.CommentValidationContext;
 import com.google.gerrit.extensions.validators.CommentValidator;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gerrit.server.restapi.change.OnPostReview;
 import com.google.gerrit.server.restapi.change.PostReview;
 import com.google.gerrit.server.update.CommentsRejectedException;
 import com.google.gerrit.testing.TestCommentHelper;
@@ -58,6 +68,7 @@
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
@@ -69,6 +80,7 @@
   @Inject private CommentValidator mockCommentValidator;
   @Inject private TestCommentHelper testCommentHelper;
   @Inject private RequestScopeOperations requestScopeOperations;
+  @Inject private ExtensionRegistry extensionRegistry;
 
   private static final String COMMENT_TEXT = "The comment text";
   private static final CommentForValidation FILE_COMMENT_FOR_VALIDATION =
@@ -474,6 +486,124 @@
     assertThat(reviewer._accountId).isEqualTo(user.id().get());
   }
 
+  @Test
+  public void extendChangeMessageFromPlugin() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    String testMessage = "hello from plugin";
+    TestOnPostReview testOnPostReview = new TestOnPostReview(testMessage);
+    try (Registration registration = extensionRegistry.newRegistration().add(testOnPostReview)) {
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      Collection<ChangeMessageInfo> messages = gApi.changes().id(r.getChangeId()).get().messages;
+      assertThat(Iterables.getLast(messages).message)
+          .isEqualTo(String.format("Patch Set 1: Code-Review+1\n\n%s\n", testMessage));
+    }
+  }
+
+  @Test
+  public void extendChangeMessageFromMultiplePlugins() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    String testMessage1 = "hello from plugin 1";
+    String testMessage2 = "message from plugin 2";
+    TestOnPostReview testOnPostReview1 = new TestOnPostReview(testMessage1);
+    TestOnPostReview testOnPostReview2 = new TestOnPostReview(testMessage2);
+    try (Registration registration =
+        extensionRegistry.newRegistration().add(testOnPostReview1).add(testOnPostReview2)) {
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      Collection<ChangeMessageInfo> messages = gApi.changes().id(r.getChangeId()).get().messages;
+      assertThat(Iterables.getLast(messages).message)
+          .isEqualTo(
+              String.format(
+                  "Patch Set 1: Code-Review+1\n\n%s\n\n%s\n", testMessage1, testMessage2));
+    }
+  }
+
+  @Test
+  public void onPostReviewExtensionThatDoesntExtendTheChangeMessage() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    TestOnPostReview testOnPostReview = new TestOnPostReview(/* message= */ null);
+    try (Registration registration = extensionRegistry.newRegistration().add(testOnPostReview)) {
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      Collection<ChangeMessageInfo> messages = gApi.changes().id(r.getChangeId()).get().messages;
+      assertThat(Iterables.getLast(messages).message).isEqualTo("Patch Set 1: Code-Review+1");
+    }
+  }
+
+  @Test
+  public void onPostReviewCallbackGetsCorrectChangeAndPatchSet() throws Exception {
+    PushOneCommit.Result r = createChange();
+    amendChange(r.getChangeId());
+
+    TestOnPostReview testOnPostReview = new TestOnPostReview(/* message= */ null);
+    try (Registration registration = extensionRegistry.newRegistration().add(testOnPostReview)) {
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+
+      // Vote on current patch set.
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertChangeAndPatchSet(r.getChange().getId(), 2);
+
+      // Vote on old patch set.
+      gApi.changes().id(r.getChangeId()).revision(1).review(input);
+      testOnPostReview.assertChangeAndPatchSet(r.getChange().getId(), 1);
+    }
+  }
+
+  @Test
+  public void onPostReviewCallbackGetsCorrectUser() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    TestOnPostReview testOnPostReview = new TestOnPostReview(/* message= */ null);
+    try (Registration registration = extensionRegistry.newRegistration().add(testOnPostReview)) {
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+
+      // Vote from admin.
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertUser(admin);
+
+      // Vote from user.
+      requestScopeOperations.setApiUser(user.id());
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertUser(user);
+    }
+  }
+
+  @Test
+  public void onPostReviewCallbackGetsCorrectApprovals() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    TestOnPostReview testOnPostReview = new TestOnPostReview(/* message= */ null);
+    try (Registration registration = extensionRegistry.newRegistration().add(testOnPostReview)) {
+      // Add a new vote.
+      ReviewInput input = new ReviewInput().label("Code-Review", 1);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertApproval(
+          "Code-Review", /* expectedOldValue= */ 0, /* expectedNewValue= */ 1);
+
+      // Update an existing vote.
+      input = new ReviewInput().label("Code-Review", 2);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertApproval(
+          "Code-Review", /* expectedOldValue= */ 1, /* expectedNewValue= */ 2);
+
+      // Post without changing the vote.
+      input = new ReviewInput().label("Code-Review", 2);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertApproval(
+          "Code-Review", /* expectedOldValue= */ null, /* expectedNewValue= */ 2);
+
+      // Delete the vote.
+      input = new ReviewInput().label("Code-Review", 0);
+      gApi.changes().id(r.getChangeId()).current().review(input);
+      testOnPostReview.assertApproval(
+          "Code-Review", /* expectedOldValue= */ 2, /* expectedNewValue= */ 0);
+    }
+  }
+
   private List<RobotCommentInfo> getRobotComments(String changeId) throws RestApiException {
     return gApi.changes().id(changeId).robotComments().values().stream()
         .flatMap(Collection::stream)
@@ -495,4 +625,50 @@
         .comparingElementsUsing(COMMENT_CORRESPONDENCE)
         .containsExactly(commentsForValidation);
   }
+
+  private static class TestOnPostReview implements OnPostReview {
+    private final Optional<String> message;
+
+    private Change.Id changeId;
+    private PatchSet.Id patchSetId;
+    private Account.Id accountId;
+    private Map<String, Short> oldApprovals;
+    private Map<String, Short> approvals;
+
+    TestOnPostReview(@Nullable String message) {
+      this.message = Optional.ofNullable(message);
+    }
+
+    @Override
+    public Optional<String> getChangeMessageAddOn(
+        IdentifiedUser user,
+        ChangeNotes changeNotes,
+        PatchSet patchSet,
+        Map<String, Short> oldApprovals,
+        Map<String, Short> approvals) {
+      this.changeId = changeNotes.getChangeId();
+      this.patchSetId = patchSet.id();
+      this.accountId = user.getAccountId();
+      this.oldApprovals = oldApprovals;
+      this.approvals = approvals;
+      return message;
+    }
+
+    public void assertChangeAndPatchSet(Change.Id expectedChangeId, int expectedPatchSetNum) {
+      assertThat(changeId).isEqualTo(expectedChangeId);
+      assertThat(patchSetId.get()).isEqualTo(expectedPatchSetNum);
+    }
+
+    public void assertUser(TestAccount expectedUser) {
+      assertThat(accountId).isEqualTo(expectedUser.id());
+    }
+
+    public void assertApproval(
+        String labelName, @Nullable Integer expectedOldValue, int expectedNewValue) {
+      assertThat(oldApprovals)
+          .containsExactly(
+              labelName, expectedOldValue != null ? expectedOldValue.shortValue() : null);
+      assertThat(approvals).containsExactly(labelName, (short) expectedNewValue);
+    }
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java b/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
index a3a089f..6cf3f3e 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/RevertIT.java
@@ -290,8 +290,28 @@
     gApi.changes().id(result.getChangeId()).revision(result.getCommit().name()).submit();
     RevertInput revertInput = new RevertInput();
     revertInput.message = "Message from input";
-    assertThat(gApi.changes().id(result.getChangeId()).revert(revertInput).get().subject)
-        .isEqualTo(revertInput.message);
+    ChangeInfo revertChange = gApi.changes().id(result.getChangeId()).revert(revertInput).get();
+    assertThat(revertChange.subject).isEqualTo(revertInput.message);
+    assertThat(gApi.changes().id(revertChange.id).current().commit(false).message)
+        .isEqualTo(String.format("Message from input\n\nChange-Id: %s\n", revertChange.changeId));
+  }
+
+  @Test
+  public void revertWithSetMessageChangeIdIgnored() throws Exception {
+    PushOneCommit.Result result = createChange();
+    gApi.changes().id(result.getChangeId()).current().review(ReviewInput.approve());
+    gApi.changes().id(result.getChangeId()).revision(result.getCommit().name()).submit();
+    RevertInput revertInput = new RevertInput();
+    String fakeChangeId = "Ideadbeefdeadbeefdeadbeefdeadbeefdeadbeef";
+    String commitSubject = "Message from input";
+    revertInput.message = String.format("%s\n\nChange-Id: %s\n", commitSubject, fakeChangeId);
+    ChangeInfo revertChange = gApi.changes().id(result.getChangeId()).revert(revertInput).get();
+    // ChangeId provided in revert input is ignored.
+    assertThat(revertChange.changeId).isNotEqualTo(fakeChangeId);
+    assertThat(revertChange.subject).isEqualTo(commitSubject);
+    // ChangeId footer was replaced in revert commit message.
+    assertThat(gApi.changes().id(revertChange.id).current().commit(false).message)
+        .isEqualTo(String.format("Message from input\n\nChange-Id: %s\n", revertChange.changeId));
   }
 
   @Test
@@ -825,6 +845,38 @@
   }
 
   @Test
+  public void revertSubmissionWithSetMessageChangeIdIgnored() throws Exception {
+    String firstResult = createChange("first change", "a.txt", "message").getChangeId();
+    String secondResult = createChange("second change", "b.txt", "message").getChangeId();
+    approve(firstResult);
+    approve(secondResult);
+    gApi.changes().id(secondResult).current().submit();
+    RevertInput revertInput = new RevertInput();
+    String fakeChangeId = "Ideadbeefdeadbeefdeadbeefdeadbeefdeadbeef";
+    String commitSubject = "Message from input";
+    String revertMessage = String.format("%s\n\nChange-Id: %s\n", commitSubject, fakeChangeId);
+    revertInput.message = revertMessage;
+    List<ChangeInfo> revertChanges =
+        gApi.changes().id(firstResult).revertSubmission(revertInput).revertChanges;
+    assertThat(revertChanges.get(0).subject).isEqualTo("Revert \"first change\"");
+    // ChangeId provided in revert input is ignored.
+    assertThat(revertChanges.get(0).changeId).isNotEqualTo(fakeChangeId);
+    assertThat(revertChanges.get(1).changeId).isNotEqualTo(fakeChangeId);
+    // ChangeId footer was replaced in revert commit message.
+    assertThat(gApi.changes().id(revertChanges.get(0).id).current().commit(false).message)
+        .isEqualTo(
+            String.format(
+                "Revert \"first change\"\n\n%s\n\nChange-Id: %s\n",
+                commitSubject, revertChanges.get(0).changeId));
+    assertThat(revertChanges.get(1).subject).isEqualTo("Revert \"second change\"");
+    assertThat(gApi.changes().id(revertChanges.get(1).id).current().commit(false).message)
+        .isEqualTo(
+            String.format(
+                "Revert \"second change\"\n\n%s\n\nChange-Id: %s\n",
+                commitSubject, revertChanges.get(1).changeId));
+  }
+
+  @Test
   public void revertSubmissionWithoutMessage() throws Exception {
     String firstResult = createChange("first change", "a.txt", "message").getChangeId();
     String secondResult = createChange("second change", "b.txt", "message").getChangeId();
diff --git a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
index 8dbec28..0af116a 100644
--- a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
@@ -85,6 +85,7 @@
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupIncludeCache;
 import com.google.gerrit.server.account.GroupsSnapshotReader;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.auth.ldap.FakeLdapGroupBackend;
 import com.google.gerrit.server.group.InternalGroup;
 import com.google.gerrit.server.group.PeriodicGroupIndexer;
@@ -916,7 +917,9 @@
   @Test
   public void defaultGroupsCreated() throws Exception {
     Iterable<String> names = gApi.groups().list().getAsMap().keySet();
-    assertThat(names).containsAtLeast("Administrators", "Service Users").inOrder();
+    assertThat(names)
+        .containsAtLeast("Administrators", ServiceUserClassifier.SERVICE_USERS)
+        .inOrder();
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/acceptance/api/project/CheckAccessIT.java b/javatests/com/google/gerrit/acceptance/api/project/CheckAccessIT.java
index f1d537f..45a895a 100644
--- a/javatests/com/google/gerrit/acceptance/api/project/CheckAccessIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/project/CheckAccessIT.java
@@ -19,14 +19,17 @@
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.block;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.deny;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.permissionKey;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.acceptance.Sandboxed;
 import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.acceptance.testsuite.group.GroupOperations;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
+import com.google.gerrit.entities.AccessSection;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.Permission;
 import com.google.gerrit.entities.Project;
@@ -36,9 +39,11 @@
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.group.SystemGroupBackend;
 import com.google.inject.Inject;
 import java.util.List;
+import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.RefUpdate.Result;
 import org.eclipse.jgit.lib.Repository;
@@ -48,6 +53,7 @@
 public class CheckAccessIT extends AbstractDaemonTest {
   @Inject private ProjectOperations projectOperations;
   @Inject private GroupOperations groupOperations;
+  @Inject private AllProjectsName allProjectsName;
 
   private Project.NameKey normalProject;
   private Project.NameKey secretProject;
@@ -162,28 +168,37 @@
     String project;
     String permission;
     int want;
+    List<String> expectedDebugLogs;
 
-    static TestCase project(String mail, String project, int want) {
+    static TestCase project(String mail, String project, int want, List<String> expectedDebugLogs) {
       TestCase t = new TestCase();
       t.input = new AccessCheckInput();
       t.input.account = mail;
       t.project = project;
       t.want = want;
+      t.expectedDebugLogs = expectedDebugLogs;
       return t;
     }
 
-    static TestCase projectRef(String mail, String project, String ref, int want) {
+    static TestCase projectRef(
+        String mail, String project, String ref, int want, List<String> expectedDebugLogs) {
       TestCase t = new TestCase();
       t.input = new AccessCheckInput();
       t.input.account = mail;
       t.input.ref = ref;
       t.project = project;
       t.want = want;
+      t.expectedDebugLogs = expectedDebugLogs;
       return t;
     }
 
     static TestCase projectRefPerm(
-        String mail, String project, String ref, String permission, int want) {
+        String mail,
+        String project,
+        String ref,
+        String permission,
+        int want,
+        List<String> expectedDebugLogs) {
       TestCase t = new TestCase();
       t.input = new AccessCheckInput();
       t.input.account = mail;
@@ -191,6 +206,7 @@
       t.input.permission = permission;
       t.project = project;
       t.want = want;
+      t.expectedDebugLogs = expectedDebugLogs;
       return t;
     }
   }
@@ -212,32 +228,115 @@
   public void accessible() throws Exception {
     List<TestCase> inputs =
         ImmutableList.of(
+            // Test 1
             TestCase.projectRefPerm(
                 user.email(),
                 normalProject.get(),
                 "refs/heads/master",
                 Permission.VIEW_PRIVATE_CHANGES,
-                403),
-            TestCase.project(user.email(), normalProject.get(), 200),
-            TestCase.project(user.email(), secretProject.get(), 403),
+                403,
+                ImmutableList.of(
+                    "'user' can perform 'read' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/*'",
+                    "'user' cannot perform 'viewPrivateChanges' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/master'")),
+            // Test 2
+            TestCase.project(
+                user.email(),
+                normalProject.get(),
+                200,
+                ImmutableList.of(
+                    "'user' can perform 'read' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/*'")),
+            // Test 3
+            TestCase.project(
+                user.email(),
+                secretProject.get(),
+                403,
+                ImmutableList.of(
+                    "'user' cannot perform 'read' with force=false on project '"
+                        + secretProject.get()
+                        + "' for ref 'refs/heads/*' because this permission is blocked",
+                    "'user' cannot perform 'read' with force=false on project '"
+                        + secretProject.get()
+                        + "' for ref 'refs/meta/version' because this permission is blocked")),
+            // Test 4
             TestCase.projectRef(
-                user.email(), secretRefProject.get(), "refs/heads/secret/master", 403),
+                user.email(),
+                secretRefProject.get(),
+                "refs/heads/secret/master",
+                403,
+                ImmutableList.of(
+                    "'user' can perform 'read' with force=false on project '"
+                        + secretRefProject.get()
+                        + "' for ref 'refs/heads/*'",
+                    "'user' cannot perform 'read' with force=false on project '"
+                        + secretRefProject.get()
+                        + "' for ref 'refs/heads/secret/master' because this permission is blocked")),
+            // Test 5
             TestCase.projectRef(
-                privilegedUser.email(), secretRefProject.get(), "refs/heads/secret/master", 200),
-            TestCase.projectRef(privilegedUser.email(), normalProject.get(), null, 200),
-            TestCase.projectRef(privilegedUser.email(), secretProject.get(), null, 200),
+                privilegedUser.email(),
+                secretRefProject.get(),
+                "refs/heads/secret/master",
+                200,
+                ImmutableList.of(
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + secretRefProject.get()
+                        + "' for ref 'refs/heads/*'",
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + secretRefProject.get()
+                        + "' for ref 'refs/heads/secret/master'")),
+            // Test 6
+            TestCase.projectRef(
+                privilegedUser.email(),
+                normalProject.get(),
+                null,
+                200,
+                ImmutableList.of(
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/*'")),
+            // Test 7
+            TestCase.projectRef(
+                privilegedUser.email(),
+                secretProject.get(),
+                null,
+                200,
+                ImmutableList.of(
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + secretProject.get()
+                        + "' for ref 'refs/*'")),
+            // Test 8
             TestCase.projectRefPerm(
                 privilegedUser.email(),
                 normalProject.get(),
                 "refs/heads/master",
                 Permission.VIEW_PRIVATE_CHANGES,
-                200),
+                200,
+                ImmutableList.of(
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/*'",
+                    "'privilegedUser' can perform 'viewPrivateChanges' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/master'")),
+            // Test 9
             TestCase.projectRefPerm(
                 privilegedUser.email(),
                 normalProject.get(),
                 "refs/heads/master",
                 Permission.FORGE_SERVER,
-                200));
+                200,
+                ImmutableList.of(
+                    "'privilegedUser' can perform 'read' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/*'",
+                    "'privilegedUser' can perform 'forgeServerAsCommitter' with force=false on project '"
+                        + normalProject.get()
+                        + "' for ref 'refs/heads/master'")));
 
     for (TestCase tc : inputs) {
       String in = newGson().toJson(tc.input);
@@ -273,6 +372,14 @@
         default:
           assertWithMessage(String.format("unknown code %d", want)).fail();
       }
+
+      if (!info.debugLogs.equals(tc.expectedDebugLogs)) {
+        assertWithMessage(
+                String.format(
+                    "check.access(%s, %s) = %s, want %s",
+                    tc.project, in, info.debugLogs, tc.expectedDebugLogs))
+            .fail();
+      }
     }
   }
 
@@ -290,4 +397,34 @@
     assertThat(info.status).isEqualTo(200);
     assertThat(info.message).contains("no branches");
   }
+
+  @Test
+  @Sandboxed
+  public void noRules() throws Exception {
+    normalProject = projectOperations.newProject().create();
+
+    for (AccessSection section :
+        projectOperations.project(allProjectsName).getProjectConfig().getAccessSections()) {
+      if (!section.getName().startsWith(Constants.R_REFS)) {
+        continue;
+      }
+      for (Permission permission : section.getPermissions()) {
+        projectOperations
+            .project(allProjectsName)
+            .forUpdate()
+            .remove(permissionKey(permission.getName()).ref(section.getName()).build())
+            .update();
+      }
+    }
+    AccessCheckInput input = new AccessCheckInput();
+    input.account = privilegedUser.email();
+    input.permission = Permission.READ;
+    input.ref = "refs/heads/main";
+
+    AccessCheckInfo info = gApi.projects().name(normalProject.get()).checkAccess(input);
+    assertThat(info.status).isEqualTo(403);
+
+    assertThat(info.debugLogs).isNotEmpty();
+    assertThat(info.debugLogs.get(0)).contains("Found no rules");
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/api/project/CommitIT.java b/javatests/com/google/gerrit/acceptance/api/project/CommitIT.java
index 80e04c0..bdb03d2 100644
--- a/javatests/com/google/gerrit/acceptance/api/project/CommitIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/project/CommitIT.java
@@ -16,11 +16,13 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 import static java.util.stream.Collectors.toList;
 import static org.eclipse.jgit.lib.Constants.R_TAGS;
 
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.PushOneCommit.Result;
 import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
@@ -36,6 +38,7 @@
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.extensions.common.GitPerson;
 import com.google.gerrit.extensions.common.RevisionInfo;
+import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.inject.Inject;
 import java.util.Iterator;
 import java.util.List;
@@ -96,77 +99,272 @@
   }
 
   @Test
-  public void cherryPickWithoutMessage() throws Exception {
-    String branch = "foo";
+  public void cherryPickWithoutMessageSameBranch() throws Exception {
+    String destBranch = "master";
 
     // Create change to cherry-pick
-    RevCommit revCommit = createChange().getCommit();
-
-    // Create target branch to cherry-pick to.
-    gApi.projects().name(project.get()).branch(branch).create(new BranchInput());
+    PushOneCommit.Result r = createChange();
+    ChangeInfo changeToCherryPick = info(r.getChangeId());
+    RevCommit commitToCherryPick = r.getCommit();
 
     // Cherry-pick without message.
     CherryPickInput input = new CherryPickInput();
-    input.destination = branch;
-    String changeId =
-        gApi.projects().name(project.get()).commit(revCommit.name()).cherryPick(input).get().id;
+    input.destination = destBranch;
+    ChangeInfo cherryPickResult =
+        gApi.projects()
+            .name(project.get())
+            .commit(commitToCherryPick.name())
+            .cherryPick(input)
+            .get();
 
+    // Expect that the Change-Id of the cherry-picked commit was used for the cherry-pick change.
+    // New patch-set to existing change was uploaded.
+    assertThat(cherryPickResult._number).isEqualTo(changeToCherryPick._number);
+    assertThat(cherryPickResult.revisions).hasSize(2);
+    assertThat(cherryPickResult.changeId).isEqualTo(changeToCherryPick.changeId);
+    assertThat(cherryPickResult.messages).hasSize(2);
+
+    // Cherry-pick of is not set, because the source change was not provided.
+    assertThat(cherryPickResult.cherryPickOfChange).isNull();
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isNull();
     // Expect that the message of the cherry-picked commit was used for the cherry-pick change.
-    ChangeInfo changeInfo = gApi.changes().id(changeId).get();
-    RevisionInfo revInfo = changeInfo.revisions.get(changeInfo.currentRevision);
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
     assertThat(revInfo).isNotNull();
-    assertThat(revInfo.commit.message).isEqualTo(revCommit.getFullMessage());
+    assertThat(revInfo.commit.message).isEqualTo(commitToCherryPick.getFullMessage());
   }
 
   @Test
-  public void cherryPickCommitWithoutChangeId() throws Exception {
+  public void cherryPickWithoutMessageOtherBranch() throws Exception {
+    String destBranch = "foo";
+    createBranch(BranchNameKey.create(project, destBranch));
+
+    // Create change to cherry-pick
+    PushOneCommit.Result r = createChange();
+    ChangeInfo changeToCherryPick = info(r.getChangeId());
+    RevCommit commitToCherryPick = r.getCommit();
+
+    // Cherry-pick without message.
     CherryPickInput input = new CherryPickInput();
-    input.destination = "foo";
+    input.destination = destBranch;
+    ChangeInfo cherryPickResult =
+        gApi.projects()
+            .name(project.get())
+            .commit(commitToCherryPick.name())
+            .cherryPick(input)
+            .get();
+
+    // Expect that the Change-Id of the cherry-picked commit was used for the cherry-pick change.
+    // New change in destination branch was created.
+    assertThat(cherryPickResult._number).isGreaterThan(changeToCherryPick._number);
+    assertThat(cherryPickResult.revisions).hasSize(1);
+    assertThat(cherryPickResult.changeId).isEqualTo(changeToCherryPick.changeId);
+    assertThat(cherryPickResult.messages).hasSize(1);
+
+    // Cherry-pick of is not set, because the source change was not provided.
+    assertThat(cherryPickResult.cherryPickOfChange).isNull();
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isNull();
+    // Expect that the message of the cherry-picked commit was used for the cherry-pick change.
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
+    assertThat(revInfo).isNotNull();
+    assertThat(revInfo.commit.message).isEqualTo(commitToCherryPick.getFullMessage());
+  }
+
+  @Test
+  public void cherryPickCommitWithoutChangeIdCreateNewChange() throws Exception {
+    String destBranch = "foo";
+    createBranch(BranchNameKey.create(project, destBranch));
+
+    CherryPickInput input = new CherryPickInput();
+    input.destination = destBranch;
     input.message = "it goes to foo branch";
-    gApi.projects().name(project.get()).branch(input.destination).create(new BranchInput());
 
-    RevCommit revCommit = createNewCommitWithoutChangeId("refs/heads/master", "a.txt", "content");
-    ChangeInfo changeInfo =
-        gApi.projects().name(project.get()).commit(revCommit.getName()).cherryPick(input).get();
+    RevCommit commitToCherryPick =
+        createNewCommitWithoutChangeId("refs/heads/master", "a.txt", "content");
+    ChangeInfo cherryPickResult =
+        gApi.projects()
+            .name(project.get())
+            .commit(commitToCherryPick.getName())
+            .cherryPick(input)
+            .get();
 
-    assertThat(changeInfo.messages).hasSize(1);
-    Iterator<ChangeMessageInfo> messageIterator = changeInfo.messages.iterator();
+    assertThat(cherryPickResult.messages).hasSize(1);
+    Iterator<ChangeMessageInfo> messageIterator = cherryPickResult.messages.iterator();
     String expectedMessage =
-        String.format("Patch Set 1: Cherry Picked from commit %s.", revCommit.getName());
+        String.format("Patch Set 1: Cherry Picked from commit %s.", commitToCherryPick.getName());
     assertThat(messageIterator.next().message).isEqualTo(expectedMessage);
 
-    RevisionInfo revInfo = changeInfo.revisions.get(changeInfo.currentRevision);
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
     assertThat(revInfo).isNotNull();
     CommitInfo commitInfo = revInfo.commit;
     assertThat(commitInfo.message)
-        .isEqualTo(input.message + "\n\nChange-Id: " + changeInfo.changeId + "\n");
+        .isEqualTo(input.message + "\n\nChange-Id: " + cherryPickResult.changeId + "\n");
   }
 
   @Test
-  public void cherryPickCommitWithChangeId() throws Exception {
-    CherryPickInput input = new CherryPickInput();
-    input.destination = "foo";
+  public void cherryPickCommitWithChangeIdCreateNewChange() throws Exception {
+    String destBranch = "foo";
+    createBranch(BranchNameKey.create(project, destBranch));
 
-    RevCommit revCommit = createChange().getCommit();
-    List<String> footers = revCommit.getFooterLines("Change-Id");
+    PushOneCommit.Result r = createChange();
+    ChangeInfo changeToCherryPick = info(r.getChangeId());
+    RevCommit commitToCherryPick = r.getCommit();
+    List<String> footers = commitToCherryPick.getFooterLines("Change-Id");
     assertThat(footers).hasSize(1);
     String changeId = footers.get(0);
 
-    input.message = "it goes to foo branch\n\nChange-Id: " + changeId;
-    gApi.projects().name(project.get()).branch(input.destination).create(new BranchInput());
+    CherryPickInput input = new CherryPickInput();
+    input.destination = destBranch;
+    input.message =
+        String.format(
+            "it goes to foo branch\n\nChange-Id: Ideadbeefdeadbeefdeadbeefdeadbeefdeadbeef\n\nChange-Id: %s\n",
+            changeId);
 
-    ChangeInfo changeInfo =
-        gApi.projects().name(project.get()).commit(revCommit.getName()).cherryPick(input).get();
+    ChangeInfo cherryPickResult =
+        gApi.projects()
+            .name(project.get())
+            .commit(commitToCherryPick.getName())
+            .cherryPick(input)
+            .get();
 
-    assertThat(changeInfo.messages).hasSize(1);
-    Iterator<ChangeMessageInfo> messageIterator = changeInfo.messages.iterator();
+    // No change was found in destination branch with the provided Change-Id.
+    assertThat(cherryPickResult._number).isGreaterThan(changeToCherryPick._number);
+    assertThat(cherryPickResult.changeId).isEqualTo(changeId);
+    assertThat(cherryPickResult.revisions).hasSize(1);
+    assertThat(cherryPickResult.messages).hasSize(1);
+    Iterator<ChangeMessageInfo> messageIterator = cherryPickResult.messages.iterator();
     String expectedMessage =
-        String.format("Patch Set 1: Cherry Picked from commit %s.", revCommit.getName());
+        String.format("Patch Set 1: Cherry Picked from commit %s.", commitToCherryPick.getName());
     assertThat(messageIterator.next().message).isEqualTo(expectedMessage);
 
-    RevisionInfo revInfo = changeInfo.revisions.get(changeInfo.currentRevision);
+    // Cherry-pick of is not set, because the source change was not provided.
+    assertThat(cherryPickResult.cherryPickOfChange).isNull();
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isNull();
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
     assertThat(revInfo).isNotNull();
-    assertThat(revInfo.commit.message).isEqualTo(input.message + "\n");
+    assertThat(revInfo.commit.message).isEqualTo(input.message);
+  }
+
+  @Test
+  public void cherryPickCommitToExistingChange() throws Exception {
+    String destBranch = "foo";
+    createBranch(BranchNameKey.create(project, destBranch));
+
+    PushOneCommit.Result r = createChange("refs/for/" + destBranch);
+    ChangeInfo existingDestChange = info(r.getChangeId());
+
+    String commitToCherryPick = createChange().getCommit().getName();
+
+    CherryPickInput input = new CherryPickInput();
+    input.destination = destBranch;
+    input.message =
+        String.format(
+            "it goes to foo branch\n\nChange-Id: Ideadbeefdeadbeefdeadbeefdeadbeefdeadbeef\n\nChange-Id: %s\n",
+            existingDestChange.changeId);
+    input.allowConflicts = true;
+    input.allowEmpty = true;
+
+    ChangeInfo cherryPickResult =
+        gApi.projects().name(project.get()).commit(commitToCherryPick).cherryPick(input).get();
+
+    // New patch-set to existing change was uploaded.
+    assertThat(cherryPickResult._number).isEqualTo(existingDestChange._number);
+    assertThat(cherryPickResult.changeId).isEqualTo(existingDestChange.changeId);
+    assertThat(cherryPickResult.messages).hasSize(2);
+    assertThat(cherryPickResult.revisions).hasSize(2);
+    Iterator<ChangeMessageInfo> messageIterator = cherryPickResult.messages.iterator();
+
+    assertThat(messageIterator.next().message).isEqualTo("Uploaded patch set 1.");
+    assertThat(messageIterator.next().message).isEqualTo("Uploaded patch set 2.");
+    // Cherry-pick of is not set, because the source change was not provided.
+    assertThat(cherryPickResult.cherryPickOfChange).isNull();
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isNull();
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
+    assertThat(revInfo).isNotNull();
+    assertThat(revInfo.commit.message).isEqualTo(input.message);
+  }
+
+  @Test
+  public void cherryPickCommitToExistingCherryPickedChange() throws Exception {
+    String destBranch = "foo";
+    createBranch(BranchNameKey.create(project, destBranch));
+
+    PushOneCommit.Result r = createChange("refs/for/" + destBranch);
+    ChangeInfo existingDestChange = info(r.getChangeId());
+
+    r = createChange();
+    ChangeInfo changeToCherryPick = info(r.getChangeId());
+    RevCommit commitToCherryPick = r.getCommit();
+
+    CherryPickInput input = new CherryPickInput();
+    input.destination = destBranch;
+    input.message =
+        String.format("it goes to foo branch\n\nChange-Id: %s\n", existingDestChange.changeId);
+    input.allowConflicts = true;
+    input.allowEmpty = true;
+    // Use RevisionAPI to submit initial cherryPick.
+    ChangeInfo cherryPickResult =
+        gApi.changes().id(changeToCherryPick.changeId).current().cherryPick(input).get();
+    assertThat(cherryPickResult.changeId).isEqualTo(existingDestChange.changeId);
+    // Cherry-pick was set.
+    assertThat(cherryPickResult.cherryPickOfChange).isEqualTo(changeToCherryPick._number);
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isEqualTo(1);
+    RevisionInfo revInfo = cherryPickResult.revisions.get(cherryPickResult.currentRevision);
+    assertThat(revInfo).isNotNull();
+    assertThat(revInfo.commit.message).isEqualTo(input.message);
+    // Use CommitApi to update the cherryPick change.
+    cherryPickResult =
+        gApi.projects()
+            .name(project.get())
+            .commit(commitToCherryPick.getName())
+            .cherryPick(input)
+            .get();
+
+    assertThat(cherryPickResult.changeId).isEqualTo(existingDestChange.changeId);
+    assertThat(cherryPickResult.messages).hasSize(3);
+    Iterator<ChangeMessageInfo> messageIterator = cherryPickResult.messages.iterator();
+
+    assertThat(messageIterator.next().message).isEqualTo("Uploaded patch set 1.");
+    assertThat(messageIterator.next().message).isEqualTo("Uploaded patch set 2.");
+    assertThat(messageIterator.next().message).isEqualTo("Uploaded patch set 3.");
+    // Cherry-pick was reset to empty value.
+    assertThat(cherryPickResult._number).isEqualTo(existingDestChange._number);
+    assertThat(cherryPickResult.cherryPickOfChange).isNull();
+    assertThat(cherryPickResult.cherryPickOfPatchSet).isNull();
+  }
+
+  @Test
+  public void cherryPickCommitWithChangeIdToClosedChange() throws Exception {
+    String destBranch = "refs/heads/foo";
+    createBranch(BranchNameKey.create(project, destBranch));
+
+    PushOneCommit.Result r = createChange("refs/for/" + destBranch);
+    ChangeInfo existingDestChange = info(r.getChangeId());
+    String commitToCherryPick = createChange().getCommit().getName();
+
+    gApi.changes().id(existingDestChange.changeId).current().review(ReviewInput.approve());
+    gApi.changes().id(existingDestChange.changeId).current().submit();
+
+    CherryPickInput input = new CherryPickInput();
+    input.destination = destBranch;
+    input.message =
+        String.format("it goes to foo branch\n\nChange-Id: %s\n", existingDestChange.changeId);
+    input.allowConflicts = true;
+    input.allowEmpty = true;
+
+    BadRequestException thrown =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.projects().name(project.get()).commit(commitToCherryPick).cherryPick(input));
+    assertThat(thrown)
+        .hasMessageThat()
+        .isEqualTo(
+            String.format(
+                "Cherry-pick with Change-Id %s could not update the existing change %d in "
+                    + "destination branch %s of project %s, because the change was closed (MERGED)",
+                existingDestChange.changeId,
+                existingDestChange._number,
+                destBranch,
+                project.get()));
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/PortedCommentsIT.java b/javatests/com/google/gerrit/acceptance/api/revision/PortedCommentsIT.java
index d3d8457..7197425 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/PortedCommentsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/PortedCommentsIT.java
@@ -20,6 +20,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.extensions.common.testing.CommentInfoSubject.assertThat;
 import static com.google.gerrit.extensions.common.testing.CommentInfoSubject.assertThatList;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 import static com.google.gerrit.truth.MapSubject.assertThatMap;
 
 import com.google.common.collect.ImmutableList;
@@ -37,6 +38,7 @@
 import com.google.gerrit.extensions.api.changes.DeleteCommentInput;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.truth.NullAwareCorrespondence;
 import com.google.inject.Inject;
@@ -496,6 +498,25 @@
   }
 
   @Test
+  public void anonymousUsersGetAuthExceptionForPortedDrafts() throws Exception {
+    Change.Id changeId = changeOps.newChange().create();
+    PatchSet.Id patchsetId = changeOps.change(changeId).currentPatchset().get().patchsetId();
+
+    requestScopeOps.setApiUserAnonymous();
+    AuthException thrown =
+        assertThrows(
+            AuthException.class,
+            () ->
+                gApi.changes()
+                    .id(patchsetId.changeId().get())
+                    .revision(patchsetId.get())
+                    .portedDrafts());
+    assertThat(thrown)
+        .hasMessageThat()
+        .contains("requires authentication; only authenticated users can have drafts");
+  }
+
+  @Test
   public void portedDraftCommentHasNoAuthor() throws Exception {
     // Set up change and patchsets.
     Account.Id authorId = accountOps.newAccount().create();
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
index 82215b6..ff785a2 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RevisionDiffIT.java
@@ -118,6 +118,12 @@
     assertDiffForNewFile(result, COMMIT_MSG, result.getCommit().getFullMessage());
   }
 
+  @Ignore
+  @Test
+  public void diffWithRootCommit() throws Exception {
+    // TODO(ghareeb): Implement this test
+  }
+
   @Test
   public void patchsetLevelFileDiffIsEmpty() throws Exception {
     PushOneCommit.Result result = createChange();
@@ -446,6 +452,57 @@
   }
 
   @Test
+  public void diffWithThreeParentsMergeCommitChange() throws Exception {
+    // Create a merge commit of 3 files: foo, bar, baz. The merge commit is pointing to 3 different
+    // parents: the merge commit contains foo of parent1, bar of parent2 and baz of parent3.
+    PushOneCommit.Result r =
+        createNParentsMergeCommitChange("refs/for/master", ImmutableList.of("foo", "bar", "baz"));
+
+    DiffInfo diff;
+
+    // parent 1
+    Map<String, FileInfo> changedFiles = gApi.changes().id(r.getChangeId()).current().files(1);
+    assertThat(changedFiles.keySet()).containsExactly(COMMIT_MSG, MERGE_LIST, "bar", "baz");
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "foo").withParent(1).get();
+    assertThat(diff.diffHeader).isNull();
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "bar").withParent(1).get();
+    assertThat(diff.diffHeader).hasSize(4);
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "baz").withParent(1).get();
+    assertThat(diff.diffHeader).hasSize(4);
+
+    // parent 2
+    changedFiles = gApi.changes().id(r.getChangeId()).current().files(2);
+    assertThat(changedFiles.keySet()).containsExactly(COMMIT_MSG, MERGE_LIST, "foo", "baz");
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "foo").withParent(2).get();
+    assertThat(diff.diffHeader).hasSize(4);
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "bar").withParent(2).get();
+    assertThat(diff.diffHeader).isNull();
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "baz").withParent(2).get();
+    assertThat(diff.diffHeader).hasSize(4);
+
+    // parent 3
+    changedFiles = gApi.changes().id(r.getChangeId()).current().files(3);
+    assertThat(changedFiles.keySet()).containsExactly(COMMIT_MSG, MERGE_LIST, "foo", "bar");
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "foo").withParent(3).get();
+    assertThat(diff.diffHeader).hasSize(4);
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "bar").withParent(3).get();
+    assertThat(diff.diffHeader).hasSize(4);
+    diff = getDiffRequest(r.getChangeId(), r.getCommit().name(), "baz").withParent(3).get();
+    assertThat(diff.diffHeader).isNull();
+  }
+
+  @Test
+  public void diffWithThreeParentsMergeCommitAgainstAutoMergeIsNotSupported() throws Exception {
+    PushOneCommit.Result r =
+        createNParentsMergeCommitChange("refs/for/master", ImmutableList.of("foo", "bar", "baz"));
+
+    // Diff against auto-merge returns COMMIT_MSG and MERGE_LIST only
+    // todo(ghareeb): We could throw an exception in this case for better handling at the client.
+    Map<String, FileInfo> changedFiles = gApi.changes().id(r.getChangeId()).current().files();
+    assertThat(changedFiles.keySet()).containsExactly(COMMIT_MSG, MERGE_LIST);
+  }
+
+  @Test
   public void diffBetweenPatchSetsOfMergeCommitCanBeRetrievedForCommitMessageAndMergeList()
       throws Exception {
     PushOneCommit.Result result = createMergeCommitChange("refs/for/master", "my_file.txt");
@@ -874,6 +931,37 @@
   }
 
   @Test
+  public void intralineEditsAreIdentified() throws Exception {
+    // TODO(ghareeb): This test asserts the wrong behavior due to the following issue
+    // bugs.chromium.org/p/gerrit/issues/detail?id=13563
+    // Please remove this comment and assert the correct behavior when the bug is fixed.
+
+    assume().that(intraline).isTrue();
+
+    String orig = "[-9999,9999]";
+    String replace = "[-999,999]";
+
+    addModifiedPatchSet(changeId, FILE_NAME, fileContent -> fileContent.concat(orig));
+    String previousPatchSetId = gApi.changes().id(changeId).get().currentRevision;
+    addModifiedPatchSet(changeId, FILE_NAME, fileContent -> fileContent.replace(orig, replace));
+
+    // TODO(ghareeb): remove this comment when the issue is fixed.
+    // The returned diff incorrectly contains:
+    // replace [-9999{,99}99] with [-999{,}999].
+    // If this replace edit is done, the resulting string incorrectly becomes [-9999,99].
+
+    DiffInfo diffInfo =
+        getDiffRequest(changeId, CURRENT, FILE_NAME).withBase(previousPatchSetId).get();
+
+    List<List<Integer>> editsA = diffInfo.content.get(1).editA;
+    List<List<Integer>> editsB = diffInfo.content.get(1).editB;
+    String reconstructed = transformStringUsingEditList(orig, replace, editsA, editsB);
+
+    // TODO(ghareeb): assert equals when the issue is fixed.
+    assertThat(reconstructed).isNotEqualTo(replace);
+  }
+
+  @Test
   public void intralineEditsForModifiedLastLineArePreservedWhenNewlineIsAlsoAddedAtEnd()
       throws Exception {
     assume().that(intraline).isTrue();
@@ -2657,6 +2745,55 @@
   }
 
   @Test
+  public void symlinkConveredToRegularFileIsIdentifiedAsDeleted() throws Exception {
+    // TODO(ghareeb): See https://bugs.chromium.org/p/gerrit/issues/detail?id=13914.
+    // This test creates a corner scenario of replacing a symlink with a regular file
+    // of the same name. When both patchsets are diffed, the List Files endpoint identifies the
+    // file as a 'REWRITE', however the diff endpoint for the symlink file identifies the file as
+    // deleted. This case is a bit risky since it hides from the user the new content that was added
+    // in the new regular file. Ideally, the diff endpoint should show two entries for the deleted
+    // symlink and the added file, or only one entry "REWRITE" with the content that was added to
+    // the new file.
+    String target = "file.txt";
+    String symlink = "link.lnk";
+
+    // Create a change adding file "FileName" and a symlink "symLink" pointing to the file
+    PushOneCommit push =
+        pushFactory
+            .create(admin.newIdent(), testRepo, "Commit Subject", target, "content")
+            .addSymlink(symlink, target);
+
+    PushOneCommit.Result result = push.to("refs/for/master");
+    String initialRev = gApi.changes().id(result.getChangeId()).get().currentRevision;
+
+    // Delete the symlink with patchset 2
+    gApi.changes().id(result.getChangeId()).edit().deleteFile(symlink);
+    gApi.changes().id(result.getChangeId()).edit().publish();
+
+    // Re-add the symlink as a regular file with patchset 3
+    gApi.changes()
+        .id(result.getChangeId())
+        .edit()
+        .modifyFile(symlink, RawInputUtil.create("Content of the new file named 'symlink'"));
+    gApi.changes().id(result.getChangeId()).edit().publish();
+
+    Map<String, FileInfo> changedFiles =
+        gApi.changes().id(result.getChangeId()).current().files(initialRev);
+
+    assertThat(changedFiles.keySet()).containsExactly("/COMMIT_MSG", symlink);
+    assertThat(changedFiles.get(symlink).status).isEqualTo('W'); // Rewrite
+
+    DiffInfo diffInfo =
+        gApi.changes().id(result.getChangeId()).current().file(symlink).diff(initialRev);
+
+    // TODO(ghareeb): This is not a desired behaviour. The diff endpoint treats the file as
+    // 'DELETED', hence hiding any new content that was added to the new regular file. It is better
+    // to show the file as 'ADDED'. See https://bugs.chromium.org/p/gerrit/issues/detail?id=13914
+    // for more details.
+    assertThat(diffInfo.changeType).isEqualTo(ChangeType.DELETED);
+  }
+
+  @Test
   public void diffOfNonExistentFileIsAnEmptyDiffResult() throws Exception {
     addModifiedPatchSet(changeId, FILE_NAME, content -> content.replace("Line 2\n", "Line two\n"));
 
@@ -2839,4 +2976,29 @@
         .diffRequest()
         .withIntraline(intraline);
   }
+
+  /**
+   * This method transforms the {@code orig} input String using the list of replace edits {@code
+   * editsA}, {@code editsB} and the resulting {@code replace} String. This method currently assumes
+   * that all input edits are replace edits, and that the edits are sorted according to their
+   * indices.
+   *
+   * @return The transformed String after applying the list of replace edits to the original String.
+   */
+  private String transformStringUsingEditList(
+      String orig, String replace, List<List<Integer>> editsA, List<List<Integer>> editsB) {
+    assertThat(editsA).hasSize(editsB.size());
+    StringBuilder process = new StringBuilder(orig);
+    // The edits are processed right to left to avoid recomputation of indices when characters
+    // are removed.
+    for (int i = editsA.size() - 1; i >= 0; i--) {
+      List<Integer> leftEdit = editsA.get(i);
+      List<Integer> rightEdit = editsB.get(i);
+      process.replace(
+          leftEdit.get(0),
+          leftEdit.get(0) + leftEdit.get(1),
+          replace.substring(rightEdit.get(0), rightEdit.get(0) + rightEdit.get(1)));
+    }
+    return process.toString();
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RevisionIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RevisionIT.java
index 2f9530c..8e31e904 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RevisionIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RevisionIT.java
@@ -386,8 +386,11 @@
 
     // The cherry-pick honors the ChangeId specified in the input message:
     RevisionInfo revInfo = changeInfo.revisions.get(changeInfo.currentRevision);
+    // New change was created.
+    assertThat(changeInfo._number).isGreaterThan(orig.get()._number);
+    assertThat(changeInfo.changeId).isEqualTo(id);
     assertThat(revInfo).isNotNull();
-    assertThat(revInfo.commit.message).endsWith(id + "\n");
+    assertThat(revInfo.commit.message.trim()).endsWith(id);
   }
 
   @Test
@@ -477,6 +480,9 @@
     assertThat(cherryInfo.messages).hasSize(2);
     Iterator<ChangeMessageInfo> cherryIt = cherryInfo.messages.iterator();
     assertThat(cherryInfo.cherryPickOfChange).isEqualTo(change.get()._number);
+
+    // Existing change was updated.
+    assertThat(cherryInfo._number).isEqualTo(change.get()._number);
     assertThat(cherryInfo.cherryPickOfPatchSet).isEqualTo(1);
     assertThat(cherryIt.next().message).isEqualTo("Uploaded patch set 1.");
     assertThat(cherryIt.next().message).isEqualTo("Uploaded patch set 2.");
@@ -708,12 +714,13 @@
     in.destination = "foo";
     in.message = r3.getCommit().getFullMessage();
     cherry = gApi.changes().id(t1).current().cherryPick(in);
+    assertThat(cherry.get()._number).isEqualTo(info(t2)._number);
     assertThat(cherry.get().cherryPickOfChange).isEqualTo(orig.get()._number);
     assertThat(cherry.get().cherryPickOfPatchSet).isEqualTo(2);
   }
 
   @Test
-  public void cherryPickToExistingChange() throws Exception {
+  public void cherryPickToAbandonedChange() throws Exception {
     PushOneCommit.Result r1 =
         pushFactory
             .create(admin.newIdent(), testRepo, SUBJECT, FILE_NAME, "a")
@@ -734,15 +741,17 @@
     CherryPickInput in = new CherryPickInput();
     in.destination = "foo";
     in.message = r1.getCommit().getFullMessage();
-    ResourceConflictException thrown =
+    BadRequestException thrown =
         assertThrows(
-            ResourceConflictException.class, () -> gApi.changes().id(t1).current().cherryPick(in));
+            BadRequestException.class, () -> gApi.changes().id(t1).current().cherryPick(in));
     assertThat(thrown)
         .hasMessageThat()
         .isEqualTo(
-            "Cannot create new patch set of change "
-                + info(t2)._number
-                + " because it is abandoned");
+            String.format(
+                "Cherry-pick with Change-Id %s could not update the existing change %d in "
+                    + "destination branch refs/heads/foo of project %s, because "
+                    + "the change was closed (ABANDONED)",
+                r1.getChangeId(), info(t2)._number, project.get()));
 
     gApi.changes().id(t2).restore();
     gApi.changes().id(t1).current().cherryPick(in);
@@ -751,6 +760,45 @@
   }
 
   @Test
+  public void cherryPickToExistingMergedChange() throws Exception {
+    PushOneCommit.Result r1 =
+        pushFactory
+            .create(admin.newIdent(), testRepo, SUBJECT, FILE_NAME, "a")
+            .to("refs/for/master");
+    String t1 = project.get() + "~master~" + r1.getChangeId();
+
+    BranchInput bin = new BranchInput();
+    bin.revision = r1.getCommit().getParent(0).name();
+    gApi.projects().name(project.get()).branch("foo").create(bin);
+
+    PushOneCommit.Result r2 =
+        pushFactory
+            .create(admin.newIdent(), testRepo, SUBJECT, FILE_NAME, "b", r1.getChangeId())
+            .to("refs/for/foo");
+    String t2 = project.get() + "~foo~" + r2.getChangeId();
+
+    gApi.changes().id(t2).current().review(ReviewInput.approve());
+    gApi.changes().id(t2).current().submit();
+
+    CherryPickInput in = new CherryPickInput();
+    in.destination = "foo";
+    in.message = r1.getCommit().getFullMessage();
+    in.allowConflicts = true;
+    in.allowEmpty = true;
+    BadRequestException thrown =
+        assertThrows(
+            BadRequestException.class, () -> gApi.changes().id(t2).current().cherryPick(in));
+    assertThat(thrown)
+        .hasMessageThat()
+        .isEqualTo(
+            String.format(
+                "Cherry-pick with Change-Id %s could not update the existing change %d in "
+                    + "destination branch refs/heads/foo of project %s, because "
+                    + "the change was closed (MERGED)",
+                r1.getChangeId(), info(t2)._number, project.get()));
+  }
+
+  @Test
   public void cherryPickMergeRelativeToDefaultParent() throws Exception {
     String parent1FileName = "a.txt";
     String parent2FileName = "b.txt";
@@ -872,7 +920,7 @@
     String changeId = project.get() + "~master~" + result.getChangeId();
 
     // 'user' cherry-picks the change to a new branch, the source change's author/committer('admin')
-    // will be added as a reviewer of the newly created change.
+    // will be added as cc of the newly created change.
     requestScopeOperations.setApiUser(user.id());
     CherryPickInput input = new CherryPickInput();
     input.message = "it goes to a new branch";
@@ -882,7 +930,7 @@
     input.notify = NotifyHandling.ALL;
     sender.clear();
     gApi.changes().id(changeId).current().cherryPick(input);
-    assertNotifyTo(admin);
+    assertNotifyCc(admin);
 
     // Disable the notification. 'admin' as a reviewer should not be notified any more.
     input.destination = "branch-2";
@@ -1573,7 +1621,8 @@
     PatchSetWebLink link =
         new PatchSetWebLink() {
           @Override
-          public WebLinkInfo getPatchSetWebLink(String projectName, String commit) {
+          public WebLinkInfo getPatchSetWebLink(
+              String projectName, String commit, String commitMessage, String branchName) {
             return expectedWebLinkInfo;
           }
         };
diff --git a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
index bb1a2eb..a50bbcf 100644
--- a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
+++ b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
@@ -87,12 +87,14 @@
 import com.google.gerrit.extensions.client.ReviewerState;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.extensions.common.ApprovalInfo;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.common.LabelInfo;
 import com.google.gerrit.extensions.common.RevisionInfo;
+import com.google.gerrit.extensions.events.TopicEditedListener;
 import com.google.gerrit.git.ObjectIds;
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.events.CommitReceivedEvent;
@@ -487,26 +489,34 @@
 
   @Test
   public void pushForMasterWithTopic() throws Exception {
-    String topic = "my/topic";
-    // specify topic as option
-    PushOneCommit.Result r = pushTo("refs/for/master%topic=" + topic);
-    r.assertOkStatus();
-    r.assertChange(Change.Status.NEW, topic);
+    TopicValidator topicValidator = new TopicValidator();
+    try (Registration registration = extensionRegistry.newRegistration().add(topicValidator)) {
+      String topic = "my/topic";
+      // specify topic as option
+      PushOneCommit.Result r = pushTo("refs/for/master%topic=" + topic);
+      r.assertOkStatus();
+      r.assertChange(Change.Status.NEW, topic);
+      assertThat(topicValidator.count()).isEqualTo(1);
+    }
   }
 
   @Test
   public void pushForMasterWithTopicOption() throws Exception {
-    String topicOption = "topic=myTopic";
-    List<String> pushOptions = new ArrayList<>();
-    pushOptions.add(topicOption);
+    TopicValidator topicValidator = new TopicValidator();
+    try (Registration registration = extensionRegistry.newRegistration().add(topicValidator)) {
+      String topicOption = "topic=myTopic";
+      List<String> pushOptions = new ArrayList<>();
+      pushOptions.add(topicOption);
 
-    PushOneCommit push = pushFactory.create(admin.newIdent(), testRepo);
-    push.setPushOptions(pushOptions);
-    PushOneCommit.Result r = push.to("refs/for/master");
+      PushOneCommit push = pushFactory.create(admin.newIdent(), testRepo);
+      push.setPushOptions(pushOptions);
+      PushOneCommit.Result r = push.to("refs/for/master");
 
-    r.assertOkStatus();
-    r.assertChange(Change.Status.NEW, "myTopic");
-    r.assertPushOptions(pushOptions);
+      r.assertOkStatus();
+      r.assertChange(Change.Status.NEW, "myTopic");
+      r.assertPushOptions(pushOptions);
+      assertThat(topicValidator.count()).isEqualTo(1);
+    }
   }
 
   @Test
@@ -1126,7 +1136,7 @@
 
     String changeId = GitUtil.getChangeId(testRepo, c).get();
     assertThat(getOwnerEmail(changeId)).isEqualTo(admin.email());
-    assertThat(getReviewerEmails(changeId, ReviewerState.REVIEWER))
+    assertThat(getReviewerEmails(changeId, ReviewerState.CC))
         .containsExactly(user.email(), user2.email());
 
     assertThat(sender.getMessages()).hasSize(1);
@@ -1151,7 +1161,7 @@
     pushHead(testRepo, "refs/for/master");
 
     assertThat(getOwnerEmail(r.getChangeId())).isEqualTo(admin.email());
-    assertThat(getReviewerEmails(r.getChangeId(), ReviewerState.REVIEWER))
+    assertThat(getReviewerEmails(r.getChangeId(), ReviewerState.CC))
         .containsExactly(user.email(), user2.email());
 
     assertThat(sender.getMessages()).hasSize(1);
@@ -1183,27 +1193,20 @@
     // Push this commit as "Administrator" (requires Forge Committer Identity)
     pushHead(testRepo, "refs/for/master%l=Code-Review+1", false);
 
-    // Expected Code-Review votes:
-    // 1. 0 from User (committer):
-    //    When the committer is forged, the committer is automatically added as
-    //    reviewer, hence we expect a dummy 0 vote for the committer.
-    // 2. +1 from Administrator (uploader):
-    //    On push Code-Review+1 was specified, hence we expect a +1 vote from
-    //    the uploader.
+    // Expected Code-Review vote:
+    // +1 from Administrator (uploader):
+    // On push Code-Review+1 was specified, hence we expect a +1 vote from the uploader. When the
+    // committer is forged, the committer is automatically added as cc, but that doesn't add votes
+    // (as opposted to being added as reviewer that adds a dummy +0 vote). We ensure there are no
+    // votes from the committer.
     ChangeInfo ci =
         get(GitUtil.getChangeId(testRepo, c).get(), DETAILED_LABELS, MESSAGES, DETAILED_ACCOUNTS);
     LabelInfo cr = ci.labels.get("Code-Review");
-    assertThat(cr.all).hasSize(2);
-    int indexAdmin = admin.fullName().equals(cr.all.get(0).name) ? 0 : 1;
-    int indexUser = indexAdmin == 0 ? 1 : 0;
-    assertThat(cr.all.get(indexAdmin).name).isEqualTo(admin.fullName());
-    assertThat(cr.all.get(indexAdmin).value.intValue()).isEqualTo(1);
-    assertThat(cr.all.get(indexUser).name).isEqualTo(user.fullName());
-    assertThat(cr.all.get(indexUser).value.intValue()).isEqualTo(0);
+    ApprovalInfo approvalInfo = Iterables.getOnlyElement(cr.all);
+    assertThat(approvalInfo.name).isEqualTo(admin.fullName());
+    assertThat(approvalInfo.value.intValue()).isEqualTo(1);
     assertThat(Iterables.getLast(ci.messages).message)
         .isEqualTo("Uploaded patch set 1: Code-Review+1.");
-    // Check that the user who pushed the change was added as a reviewer since they added a vote
-    assertThatUserIsOnlyReviewer(ci, admin);
   }
 
   @Test
@@ -2384,6 +2387,19 @@
     }
   }
 
+  private static class TopicValidator implements TopicEditedListener {
+    private final AtomicInteger count = new AtomicInteger();
+
+    @Override
+    public void onTopicEdited(Event event) {
+      count.incrementAndGet();
+    }
+
+    public int count() {
+      return count.get();
+    }
+  }
+
   @Test
   public void skipValidation() throws Exception {
     String master = "refs/heads/master";
@@ -2728,6 +2744,14 @@
     assertPushOk(r, "refs/for/otherBranch");
   }
 
+  @Test
+  public void pushWithVoteDoesNotAddToAttentionSet() throws Exception {
+    String pushSpec = "refs/for/master%l=Code-Review+1";
+    PushOneCommit.Result r = pushTo(pushSpec);
+    r.assertOkStatus();
+    assertThat(r.getChange().attentionSet()).isEmpty();
+  }
+
   private DraftInput newDraft(String path, int line, String message) {
     DraftInput d = new DraftInput();
     d.path = path;
diff --git a/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java b/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
index 1a2ae7c..78be4ab 100644
--- a/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/PushPermissionsIT.java
@@ -364,7 +364,7 @@
         .update();
 
     String project2 = name("project2");
-    gApi.projects().create(project2);
+    projectOperations.newProject().name(project2).create();
 
     ObjectId oldId = forceFetch("refs/meta/config");
 
diff --git a/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java b/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
index 0930815..c6e610f 100644
--- a/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/RefAdvertisementIT.java
@@ -48,6 +48,7 @@
 import com.google.gerrit.extensions.api.groups.GroupInput;
 import com.google.gerrit.extensions.api.projects.BranchInput;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.receive.ReceiveCommitsAdvertiseRefsHookChain;
 import com.google.gerrit.server.git.receive.testing.TestRefAdvertiser;
@@ -118,7 +119,7 @@
   @Before
   public void setUp() throws Exception {
     admins = adminGroupUuid();
-    nonInteractiveUsers = groupUuid("Service Users");
+    nonInteractiveUsers = groupUuid(ServiceUserClassifier.SERVICE_USERS);
     setUpPermissions();
     setUpChanges();
   }
diff --git a/javatests/com/google/gerrit/acceptance/pgm/Schema_184IT.java b/javatests/com/google/gerrit/acceptance/pgm/Schema_184IT.java
index 23d7658..093711f 100644
--- a/javatests/com/google/gerrit/acceptance/pgm/Schema_184IT.java
+++ b/javatests/com/google/gerrit/acceptance/pgm/Schema_184IT.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.testsuite.group.GroupOperations;
 import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.schema.NoteDbSchemaVersion;
 import com.google.gerrit.server.schema.Schema_184;
 import com.google.gerrit.testing.TestUpdateUI;
@@ -26,7 +27,8 @@
 import org.junit.Test;
 
 public class Schema_184IT extends AbstractDaemonTest {
-  private static final AccountGroup.NameKey SERVICE_USERS = AccountGroup.nameKey("Service Users");
+  private static final AccountGroup.NameKey SERVICE_USERS =
+      AccountGroup.nameKey(ServiceUserClassifier.SERVICE_USERS);
   private static final AccountGroup.NameKey NON_INTERACTIVE_USERS =
       AccountGroup.nameKey("Non-Interactive Users");
 
diff --git a/javatests/com/google/gerrit/acceptance/rest/TraceIT.java b/javatests/com/google/gerrit/acceptance/rest/TraceIT.java
index f5d9e3a..7f8add8 100644
--- a/javatests/com/google/gerrit/acceptance/rest/TraceIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/TraceIT.java
@@ -18,6 +18,13 @@
 import static org.apache.http.HttpStatus.SC_CREATED;
 import static org.apache.http.HttpStatus.SC_INTERNAL_SERVER_ERROR;
 import static org.apache.http.HttpStatus.SC_OK;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyZeroInteractions;
 
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
@@ -52,11 +59,10 @@
 import com.google.gerrit.server.validators.ProjectCreationValidationListener;
 import com.google.gerrit.server.validators.ValidationException;
 import com.google.inject.Inject;
-import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
-import java.util.SortedMap;
-import java.util.SortedSet;
+import java.util.Set;
 import org.apache.http.message.BasicHeader;
 import org.junit.Rule;
 import org.junit.Test;
@@ -337,7 +343,7 @@
     assertThat(LoggingContext.getInstance().getTags().isEmpty()).isTrue();
     assertForceLogging(false);
     try (TraceContext traceContext = TraceContext.open().forceLogging().addTag("foo", "bar")) {
-      SortedMap<String, SortedSet<Object>> tagMap = LoggingContext.getInstance().getTags().asMap();
+      Map<String, ? extends Set<Object>> tagMap = LoggingContext.getInstance().getTags().asMap();
       assertThat(tagMap.keySet()).containsExactly("foo");
       assertThat(tagMap.get("foo")).containsExactly("bar");
       assertForceLogging(true);
@@ -348,7 +354,7 @@
               () -> {
                 // Verify that the tags and force logging flag have been propagated to the new
                 // thread.
-                SortedMap<String, SortedSet<Object>> threadTagMap =
+                Map<String, ? extends Set<Object>> threadTagMap =
                     LoggingContext.getInstance().getTags().asMap();
                 expect.that(threadTagMap.keySet()).containsExactly("foo");
                 expect.that(threadTagMap.get("foo")).containsExactly("bar");
@@ -370,37 +376,31 @@
 
   @Test
   public void performanceLoggingForRestCall() throws Exception {
-    TestPerformanceLogger testPerformanceLogger = new TestPerformanceLogger();
+    PerformanceLogger testPerformanceLogger = mock(PerformanceLogger.class);
     try (Registration registration =
         extensionRegistry.newRegistration().add(testPerformanceLogger)) {
       RestResponse response = adminRestSession.put("/projects/new10");
       assertThat(response.getStatusCode()).isEqualTo(SC_CREATED);
-
-      // This assertion assumes that the server invokes the PerformanceLogger plugins before it
-      // sends
-      // the response to the client. If this assertion gets flaky it's likely that this got changed
-      // on
-      // server-side.
-      assertThat(testPerformanceLogger.logEntries()).isNotEmpty();
+      verify(testPerformanceLogger, timeout(5000).atLeastOnce()).log(anyString(), anyLong(), any());
     }
   }
 
   @Test
   public void performanceLoggingForPush() throws Exception {
-    TestPerformanceLogger testPerformanceLogger = new TestPerformanceLogger();
+    PerformanceLogger testPerformanceLogger = mock(PerformanceLogger.class);
     try (Registration registration =
         extensionRegistry.newRegistration().add(testPerformanceLogger)) {
       PushOneCommit push = pushFactory.create(admin.newIdent(), testRepo);
       PushOneCommit.Result r = push.to("refs/heads/master");
       r.assertOkStatus();
-      assertThat(testPerformanceLogger.logEntries()).isNotEmpty();
+      verify(testPerformanceLogger, timeout(5000).atLeastOnce()).log(anyString(), anyLong(), any());
     }
   }
 
   @Test
   @GerritConfig(name = "tracing.performanceLogging", value = "false")
   public void noPerformanceLoggingIfDisabled() throws Exception {
-    TestPerformanceLogger testPerformanceLogger = new TestPerformanceLogger();
+    PerformanceLogger testPerformanceLogger = mock(PerformanceLogger.class);
     try (Registration registration =
         extensionRegistry.newRegistration().add(testPerformanceLogger)) {
       RestResponse response = adminRestSession.put("/projects/new11");
@@ -410,7 +410,7 @@
       PushOneCommit.Result r = push.to("refs/heads/master");
       r.assertOkStatus();
 
-      assertThat(testPerformanceLogger.logEntries()).isEmpty();
+      verifyZeroInteractions(testPerformanceLogger);
     }
   }
 
@@ -844,19 +844,6 @@
     }
   }
 
-  private static class TestPerformanceLogger implements PerformanceLogger {
-    private List<PerformanceLogEntry> logEntries = new ArrayList<>();
-
-    @Override
-    public void log(String operation, long durationMs, Metadata metadata) {
-      logEntries.add(PerformanceLogEntry.create(operation, metadata));
-    }
-
-    ImmutableList<PerformanceLogEntry> logEntries() {
-      return ImmutableList.copyOf(logEntries);
-    }
-  }
-
   @AutoValue
   abstract static class PerformanceLogEntry {
     static PerformanceLogEntry create(String operation, Metadata metadata) {
diff --git a/javatests/com/google/gerrit/acceptance/rest/account/GetAccountDetailIT.java b/javatests/com/google/gerrit/acceptance/rest/account/GetAccountDetailIT.java
index a5cf3e1..b999abd 100644
--- a/javatests/com/google/gerrit/acceptance/rest/account/GetAccountDetailIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/account/GetAccountDetailIT.java
@@ -25,6 +25,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.extensions.common.AccountDetailInfo;
 import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.inject.Inject;
 import org.junit.Test;
 
@@ -45,7 +46,11 @@
   public void getDetailForServiceUser() throws Exception {
     Account.Id serviceUser = accountOperations.newAccount().create();
     groupOperations
-        .group(groupCache.get(AccountGroup.nameKey("Service Users")).get().getGroupUUID())
+        .group(
+            groupCache
+                .get(AccountGroup.nameKey(ServiceUserClassifier.SERVICE_USERS))
+                .get()
+                .getGroupUUID())
         .forUpdate()
         .addMember(serviceUser)
         .update();
diff --git a/javatests/com/google/gerrit/acceptance/rest/account/GetAccountIT.java b/javatests/com/google/gerrit/acceptance/rest/account/GetAccountIT.java
index 2e2f5d9..1e61d0a 100644
--- a/javatests/com/google/gerrit/acceptance/rest/account/GetAccountIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/account/GetAccountIT.java
@@ -24,6 +24,7 @@
 import com.google.gerrit.acceptance.testsuite.account.AccountOperations;
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.inject.Inject;
 import org.junit.Test;
 
@@ -70,7 +71,8 @@
   @Test
   public void getServiceUserAccount() throws Exception {
     TestAccount serviceUser =
-        accountCreator.create("robot1", "robot1@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot1", "robot1@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     assertThat(serviceUser.tags()).containsExactly("SERVICE_USER");
     testGetAccount(serviceUser.id().toString(), serviceUser);
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/account/WatchedProjectsIT.java b/javatests/com/google/gerrit/acceptance/rest/account/WatchedProjectsIT.java
index 2c9107c..b70cab8 100644
--- a/javatests/com/google/gerrit/acceptance/rest/account/WatchedProjectsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/account/WatchedProjectsIT.java
@@ -249,4 +249,30 @@
   public void postWithoutBody() throws Exception {
     adminRestSession.post("/accounts/" + admin.username() + "/watched.projects").assertOK();
   }
+
+  @Test
+  public void nullProjectThrowsBadRequestException() {
+    List<ProjectWatchInfo> projectsToWatch = new ArrayList<>();
+    ProjectWatchInfo pwi = new ProjectWatchInfo();
+    pwi.project = null;
+    projectsToWatch.add(pwi);
+    Throwable t =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.accounts().self().setWatchedProjects(projectsToWatch));
+    assertThat(t.getMessage()).isEqualTo("project name must be specified");
+  }
+
+  @Test
+  public void emptyProjectThrowsBadRequestException() {
+    List<ProjectWatchInfo> projectsToWatch = new ArrayList<>();
+    ProjectWatchInfo pwi = new ProjectWatchInfo();
+    pwi.project = "  ";
+    projectsToWatch.add(pwi);
+    Throwable t =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.accounts().self().setWatchedProjects(projectsToWatch));
+    assertThat(t.getMessage()).isEqualTo("project name must be specified");
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/auth/AuthenticationCheckIT.java b/javatests/com/google/gerrit/acceptance/rest/auth/AuthenticationCheckIT.java
index 9298b43..00b1c55 100644
--- a/javatests/com/google/gerrit/acceptance/rest/auth/AuthenticationCheckIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/auth/AuthenticationCheckIT.java
@@ -14,8 +14,6 @@
 
 package com.google.gerrit.acceptance.rest.auth;
 
-import static com.google.common.truth.Truth.assertThat;
-
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.acceptance.RestSession;
@@ -34,6 +32,5 @@
     RestSession anonymous = new RestSession(server, null);
     RestResponse r = anonymous.get("/auth-check");
     r.assertForbidden();
-    assertThat(r.getHeader("Content-Length")).isEqualTo("0");
   }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/binding/PluginProvidedRootRestApiBindingsIT.java b/javatests/com/google/gerrit/acceptance/rest/binding/PluginProvidedRootRestApiBindingsIT.java
index b447534..16dc294 100644
--- a/javatests/com/google/gerrit/acceptance/rest/binding/PluginProvidedRootRestApiBindingsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/binding/PluginProvidedRootRestApiBindingsIT.java
@@ -16,6 +16,7 @@
 
 import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
 
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
@@ -48,6 +49,7 @@
 import javax.servlet.http.HttpServletRequestWrapper;
 import javax.servlet.http.HttpServletResponse;
 import org.junit.Test;
+import org.kohsuke.args4j.Option;
 
 /**
  * Tests for checking plugin-provided REST API bindings directly under {@code /}.
@@ -192,8 +194,15 @@
 
   @Singleton
   static class TestGet implements RestReadView<TestPluginResource> {
+
+    @Option(name = "--crash")
+    String crash;
+
     @Override
     public Response<String> apply(TestPluginResource resource) throws Exception {
+      if (!Strings.nullToEmpty(crash).isEmpty()) {
+        throw new IllegalStateException();
+      }
       return Response.ok("test");
     }
   }
@@ -204,4 +213,13 @@
       RestApiCallHelper.execute(adminRestSession, TEST_CALLS.asList());
     }
   }
+
+  @Test
+  public void testOptionOnSingletonIsIgnored() throws Exception {
+    try (AutoCloseable ignored = installPlugin(PLUGIN_NAME, null, MyPluginHttpModule.class, null)) {
+      RestApiCallHelper.execute(
+          adminRestSession,
+          RestCall.get("/plugins/" + PLUGIN_NAME + "/test-collection/1/detail?crash=xyz"));
+    }
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
index faef5aa..2891d4b 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
@@ -1386,6 +1386,17 @@
     }
   }
 
+  @Test
+  public void submitSetsMergedOn() throws Throwable {
+    PushOneCommit.Result r = createChange();
+    assertThat(r.getChange().getMergedOn()).isEmpty();
+    submit(r.getChangeId());
+    assertThat(r.getChange().getMergedOn()).isPresent();
+    ChangeInfo change = gApi.changes().id(r.getChangeId()).get();
+    assertThat(r.getChange().getMergedOn().get()).isEqualTo(change.updated);
+    assertThat(r.getChange().getMergedOn().get()).isEqualTo(change.submitted);
+  }
+
   @Override
   protected void updateProjectInput(ProjectInput in) {
     in.submitType = getSubmitType();
@@ -1439,6 +1450,12 @@
     assertWithMessage("enabled bit on submit action").that(desc.isEnabled()).isTrue();
   }
 
+  protected void assertSubmitDisabled(String changeId) throws Throwable {
+    RevisionResource rsrc = parseCurrentRevisionResource(changeId);
+    UiAction.Description desc = submitHandler.getDescription(rsrc);
+    assertWithMessage("enabled bit on submit action").that(desc.isEnabled()).isFalse();
+  }
+
   protected void assertChangeMergedEvents(String... expected) throws Throwable {
     eventRecorder.assertChangeMergedEvents(project.get(), "refs/heads/master", expected);
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByMerge.java b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByMerge.java
index f77552d..9c496fa 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByMerge.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByMerge.java
@@ -20,6 +20,7 @@
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.TestProjectInput;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.inject.Inject;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -117,4 +118,49 @@
     assertThat(head.getParent(0)).isEqualTo(change1.getCommit());
     assertThat(head.getParent(1)).isEqualTo(change2.getCommit());
   }
+
+  @Test
+  public void dependencyOnOutdatedPatchSetPreventsMerge() throws Throwable {
+    // Create a change
+    PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
+    PushOneCommit.Result changeResult = change.to("refs/for/master");
+    PatchSet.Id patchSetId = changeResult.getPatchSetId();
+
+    // Create a successor change.
+    PushOneCommit change2 =
+        pushFactory.create(user.newIdent(), testRepo, "feature", "b.txt", "bar");
+    PushOneCommit.Result change2Result = change2.to("refs/for/master");
+
+    // Create new patch set for first change.
+    testRepo.reset(changeResult.getCommit().name());
+    amendChange(changeResult.getChangeId());
+
+    // Approve both changes
+    approve(changeResult.getChangeId());
+    approve(change2Result.getChangeId());
+
+    // submit button is disabled.
+    assertSubmitDisabled(change2Result.getChangeId());
+
+    submitWithConflict(
+        change2Result.getChangeId(),
+        "Failed to submit 2 changes due to the following problems:\n"
+            + "Change "
+            + change2Result.getChange().getId()
+            + ": Depends on change that was not submitted."
+            + " Commit "
+            + change2Result.getCommit().name()
+            + " depends on commit "
+            + changeResult.getCommit().name()
+            + ", which is outdated patch set "
+            + patchSetId.get()
+            + " of change "
+            + changeResult.getChange().getId()
+            + ". The latest patch set is "
+            + changeResult.getPatchSetId().get()
+            + ".");
+
+    assertRefUpdatedEvents();
+    assertChangeMergedEvents();
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByRebase.java b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByRebase.java
index 955dd7a..5eb19df 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByRebase.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmitByRebase.java
@@ -29,6 +29,7 @@
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.entities.BranchNameKey;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Permission;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.extensions.client.ChangeStatus;
@@ -384,4 +385,49 @@
     gApi.changes().id(change2.getChangeId()).current().rebase();
     submit(change2.getChangeId());
   }
+
+  @Test
+  public void dependencyOnOutdatedPatchSetPreventsRebase() throws Throwable {
+    // Create a change
+    PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
+    PushOneCommit.Result changeResult = change.to("refs/for/master");
+    PatchSet.Id patchSetId = changeResult.getPatchSetId();
+
+    // Create a successor change.
+    PushOneCommit change2 =
+        pushFactory.create(user.newIdent(), testRepo, "feature", "b.txt", "bar");
+    PushOneCommit.Result change2Result = change2.to("refs/for/master");
+
+    // Create new patch set for first change.
+    testRepo.reset(changeResult.getCommit().name());
+    amendChange(changeResult.getChangeId());
+
+    // Approve both changes
+    approve(changeResult.getChangeId());
+    approve(change2Result.getChangeId());
+
+    // submit button is disabled.
+    assertSubmitDisabled(change2Result.getChangeId());
+
+    submitWithConflict(
+        change2Result.getChangeId(),
+        "Failed to submit 2 changes due to the following problems:\n"
+            + "Change "
+            + change2Result.getChange().getId()
+            + ": Depends on change that was not submitted."
+            + " Commit "
+            + change2Result.getCommit().name()
+            + " depends on commit "
+            + changeResult.getCommit().name()
+            + ", which is outdated patch set "
+            + patchSetId.get()
+            + " of change "
+            + changeResult.getChange().getId()
+            + ". The latest patch set is "
+            + changeResult.getPatchSetId().get()
+            + ".");
+
+    assertRefUpdatedEvents();
+    assertChangeMergedEvents();
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AttentionSetIT.java b/javatests/com/google/gerrit/acceptance/rest/change/AttentionSetIT.java
index 61eef63..9e944a2 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AttentionSetIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AttentionSetIT.java
@@ -35,6 +35,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AttentionSetUpdate;
+import com.google.gerrit.entities.AttentionSetUpdate.Operation;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.Patch;
 import com.google.gerrit.extensions.api.changes.AddReviewerInput;
@@ -47,6 +48,7 @@
 import com.google.gerrit.extensions.client.ReviewerState;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gerrit.server.util.time.TimeUtil;
@@ -61,6 +63,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.function.LongSupplier;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import org.junit.Before;
 import org.junit.Test;
@@ -113,48 +116,48 @@
     PushOneCommit.Result r = createChange();
     requestScopeOperations.setApiUser(user.id());
     int accountId =
-        change(r).addToAttentionSet(new AttentionSetInput(user.email(), "first"))._accountId;
-    assertThat(accountId).isEqualTo(user.id().get());
+        change(r).addToAttentionSet(new AttentionSetInput(admin.email(), "first"))._accountId;
+    assertThat(accountId).isEqualTo(admin.id().get());
     AttentionSetUpdate expectedAttentionSetUpdate =
         AttentionSetUpdate.createFromRead(
-            fakeClock.now(), user.id(), AttentionSetUpdate.Operation.ADD, "first");
+            fakeClock.now(), admin.id(), AttentionSetUpdate.Operation.ADD, "first");
     assertThat(r.getChange().attentionSet()).containsExactly(expectedAttentionSetUpdate);
 
     // Second add is ignored.
     accountId =
-        change(r).addToAttentionSet(new AttentionSetInput(user.email(), "second"))._accountId;
-    assertThat(accountId).isEqualTo(user.id().get());
+        change(r).addToAttentionSet(new AttentionSetInput(admin.email(), "second"))._accountId;
+    assertThat(accountId).isEqualTo(admin.id().get());
     assertThat(r.getChange().attentionSet()).containsExactly(expectedAttentionSetUpdate);
 
     // Only one email since the second add was ignored.
     String emailBody = Iterables.getOnlyElement(email.getMessages()).body();
     assertThat(emailBody)
         .contains(
-            user.fullName()
-                + " added themselves to the attention set of this change.\n The reason is: first.");
+            String.format(
+                "%s requires the attention of %s to this change.\n The reason is: first.",
+                user.fullName(), admin.fullName()));
   }
 
   @Test
   public void addMultipleUsers() throws Exception {
     PushOneCommit.Result r = createChange();
     Instant timestamp1 = fakeClock.now();
-    int accountId1 =
-        change(r).addToAttentionSet(new AttentionSetInput(user.email(), "user"))._accountId;
-    assertThat(accountId1).isEqualTo(user.id().get());
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
     fakeClock.advance(Duration.ofSeconds(42));
     Instant timestamp2 = fakeClock.now();
     int accountId2 =
         change(r)
-            .addToAttentionSet(new AttentionSetInput(admin.id().toString(), "admin"))
+            .addToAttentionSet(new AttentionSetInput(admin.id().toString(), "manual update"))
             ._accountId;
     assertThat(accountId2).isEqualTo(admin.id().get());
 
     AttentionSetUpdate expectedAttentionSetUpdate1 =
         AttentionSetUpdate.createFromRead(
-            timestamp1, user.id(), AttentionSetUpdate.Operation.ADD, "user");
+            timestamp1, user.id(), AttentionSetUpdate.Operation.ADD, "Reviewer was added");
     AttentionSetUpdate expectedAttentionSetUpdate2 =
         AttentionSetUpdate.createFromRead(
-            timestamp2, admin.id(), AttentionSetUpdate.Operation.ADD, "admin");
+            timestamp2, admin.id(), AttentionSetUpdate.Operation.ADD, "manual update");
     assertThat(r.getChange().attentionSet())
         .containsExactly(expectedAttentionSetUpdate1, expectedAttentionSetUpdate2);
   }
@@ -162,7 +165,9 @@
   @Test
   public void removeUser() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "added"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
+    sender.clear();
     requestScopeOperations.setApiUser(user.id());
 
     fakeClock.advance(Duration.ofSeconds(42));
@@ -189,6 +194,9 @@
   @Test
   public void removeUserWithInvalidUserInput() throws Exception {
     PushOneCommit.Result r = createChange();
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
+
     BadRequestException exception =
         assertThrows(
             BadRequestException.class,
@@ -197,7 +205,9 @@
                     .attention(user.id().toString())
                     .remove(new AttentionSetInput("invalid user", "reason")));
     assertThat(exception.getMessage())
-        .isEqualTo("The user specified in the input body couldn't be found.");
+        .isEqualTo(
+            "invalid user doesn't exist or is not active on the change as an owner, "
+                + "uploader, reviewer, or cc so they can't be added to the attention set");
 
     exception =
         assertThrows(
@@ -212,16 +222,10 @@
   }
 
   @Test
-  public void removeUnrelatedUser() throws Exception {
-    PushOneCommit.Result r = createChange();
-    change(r).attention(user.id().toString()).remove(new AttentionSetInput("foo"));
-    assertThat(r.getChange().attentionSet()).isEmpty();
-  }
-
-  @Test
   public void abandonRemovesUsers() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "user"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
     change(r).addToAttentionSet(new AttentionSetInput(admin.email(), "admin"));
 
     change(r).abandon();
@@ -242,7 +246,8 @@
   @Test
   public void workInProgressRemovesUsers() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "reason"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
 
     change(r).setWorkInProgress();
 
@@ -256,13 +261,10 @@
   public void submitRemovesUsersForAllSubmittedChanges() throws Exception {
     PushOneCommit.Result r1 = createChange("refs/heads/master", "file1", "content");
 
-    change(r1)
-        .current()
-        .review(ReviewInput.approve().addUserToAttentionSet(user.email(), "reason"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r1).current().review(ReviewInput.approve().reviewer(user.email()));
     PushOneCommit.Result r2 = createChange("refs/heads/master", "file2", "content");
-    change(r2)
-        .current()
-        .review(ReviewInput.approve().addUserToAttentionSet(user.email(), "reason"));
+    change(r2).current().review(ReviewInput.approve().reviewer(user.email()));
 
     change(r2).current().submit();
 
@@ -284,21 +286,26 @@
 
   @Test
   public void robotSubmitsRemovesUsers() throws Exception {
-    PushOneCommit.Result r1 = createChange("refs/heads/master", "file1", "content");
+    PushOneCommit.Result r = createChange("refs/heads/master", "file1", "content");
 
-    change(r1)
-        .current()
-        .review(ReviewInput.approve().addUserToAttentionSet(user.email(), "reason"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
 
     TestAccount robot =
         accountCreator.create(
-            "robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users", "Administrators");
+            "robot2",
+            "robot2@example.com",
+            "Ro Bot",
+            "Ro",
+            ServiceUserClassifier.SERVICE_USERS,
+            "Administrators");
     requestScopeOperations.setApiUser(robot.id());
-    change(r1).current().submit();
+    change(r).current().review(ReviewInput.approve());
+    change(r).current().submit();
 
     // Attention set updates that relate to the admin (the person who replied) are filtered out.
     AttentionSetUpdate attentionSet =
-        Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r1, user));
+        Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, user));
 
     assertThat(attentionSet).hasAccountIdThat().isEqualTo(user.id());
     assertThat(attentionSet).hasOperationThat().isEqualTo(AttentionSetUpdate.Operation.REMOVE);
@@ -460,7 +467,12 @@
 
     TestAccount robot =
         accountCreator.create(
-            "robot1", "robot1@example.com", "Ro Bot", "Ro", "Service Users", "Administrators");
+            "robot1",
+            "robot1@example.com",
+            "Ro Bot",
+            "Ro",
+            ServiceUserClassifier.SERVICE_USERS,
+            "Administrators");
     requestScopeOperations.setApiUser(robot.id());
     change(r).setReadyForReview();
     AttentionSetUpdate attentionSet = Iterables.getOnlyElement(r.getChange().attentionSet());
@@ -521,7 +533,9 @@
   @Test
   public void reviewersAreNotAddedForNoReasonBecauseOfAnUpdate() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "user"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
+
     change(r).attention(user.id().toString()).remove(new AttentionSetInput("removed"));
 
     HashtagsInput hashtagsInput = new HashtagsInput();
@@ -555,7 +569,8 @@
   @Test
   public void reviewRemovesManuallyRemovedUserFromAttentionSet() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "reason"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
     requestScopeOperations.setApiUser(user.id());
 
     ReviewInput reviewInput =
@@ -575,7 +590,8 @@
   @Test
   public void reviewWithManualAdditionToAttentionSetFailsWithoutReason() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "reason"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
 
     ReviewInput reviewInput = ReviewInput.create().addUserToAttentionSet(user.email(), "");
 
@@ -599,7 +615,8 @@
   @Test
   public void reviewAddReviewerWhileRemovingFromAttentionSetJustRemovesUser() throws Exception {
     PushOneCommit.Result r = createChange();
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "addition"));
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
 
     ReviewInput reviewInput =
         ReviewInput.create()
@@ -760,7 +777,15 @@
 
     requestScopeOperations.setApiUser(user.id());
 
-    change(r).addToAttentionSet(new AttentionSetInput(user.email(), "reason"));
+    // add the user to the attention set.
+    change(r)
+        .current()
+        .review(
+            ReviewInput.create()
+                .reviewer(user.email(), ReviewerState.CC, true)
+                .addUserToAttentionSet(user.email(), "reason"));
+
+    // add the user as reviewer but still be removed on reply.
     ReviewInput reviewInput = ReviewInput.create().reviewer(user.email());
     change(r).current().review(reviewInput);
 
@@ -1132,6 +1157,9 @@
   @Test
   public void repliesWhileAddingAsReviewerStillRemovesUser() throws Exception {
     PushOneCommit.Result r = createChange();
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
+
     change(r).addToAttentionSet(new AttentionSetInput(user.email(), "remove"));
 
     requestScopeOperations.setApiUser(user.id());
@@ -1222,8 +1250,11 @@
   @Test
   public void robotsNotAddedToAttentionSet() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot1", "robot1@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot1", "robot1@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
+    // Make the robot active on the change.
+    change(r).addReviewer(robot.email());
 
     // Throw an error when adding a robot explicitly.
     BadRequestException exception =
@@ -1242,7 +1273,8 @@
   @Test
   public void robotAddingAReviewerChangeAttentionSet() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot2", "robot2@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
     requestScopeOperations.setApiUser(robot.id());
     change(r).addReviewer(user.id().toString());
@@ -1258,7 +1290,8 @@
   @Test
   public void robotReviewDoesNotChangeAttentionSet() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot2", "robot2@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
     requestScopeOperations.setApiUser(robot.id());
     change(r).current().review(ReviewInput.recommend());
@@ -1269,7 +1302,8 @@
   @Test
   public void robotReviewWithNegativeLabelAddsOwner() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot2", "robot2@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
     requestScopeOperations.setApiUser(robot.id());
     change(r).current().review(ReviewInput.dislike());
@@ -1284,7 +1318,8 @@
   @Test
   public void robotCommentDoesNotAddOwnerOnClosedChanges() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot2", "robot2@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
     gApi.changes().id(r.getChangeId()).abandon();
 
@@ -1301,7 +1336,8 @@
   @Test
   public void robotCanChangeAttentionSetExplicitly() throws Exception {
     TestAccount robot =
-        accountCreator.create("robot2", "robot2@example.com", "Ro Bot", "Ro", "Service Users");
+        accountCreator.create(
+            "robot2", "robot2@example.com", "Ro Bot", "Ro", ServiceUserClassifier.SERVICE_USERS);
     PushOneCommit.Result r = createChange();
     requestScopeOperations.setApiUser(robot.id());
     change(r).current().review(new ReviewInput().addUserToAttentionSet(admin.email(), "reason"));
@@ -1317,13 +1353,15 @@
   public void addUsersToAttentionSetInPrivateChanges() throws Exception {
     PushOneCommit.Result r = createChange();
     change(r).setPrivate(true);
-    change(r).current().review(new ReviewInput().addUserToAttentionSet(user.email(), "reason"));
+
+    // implictly adds the user to the attention set when adding as reviewer
+    change(r).addReviewer(user.email());
 
     AttentionSetUpdate attentionSet =
         Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, user));
     assertThat(attentionSet).hasAccountIdThat().isEqualTo(user.id());
     assertThat(attentionSet).hasOperationThat().isEqualTo(AttentionSetUpdate.Operation.ADD);
-    assertThat(attentionSet).hasReasonThat().isEqualTo("reason");
+    assertThat(attentionSet).hasReasonThat().isEqualTo("Reviewer was added");
   }
 
   @Test
@@ -1368,43 +1406,30 @@
   public void attentionSetEmailHeader() throws Exception {
     PushOneCommit.Result r = createChange();
     TestAccount user2 = accountCreator.user2();
+
+    // The pattern ensures the header mentions the attention set requirements in any order.
+    Pattern attentionSetHeaderPattern =
+        Pattern.compile(
+            String.format(
+                "Attention is currently required from: (%s|%s), (%s|%s).",
+                user2.fullName(), user.fullName(), user.fullName(), user2.fullName()));
     // Add user and user2 to the attention set.
     change(r)
         .current()
         .review(
             ReviewInput.create().reviewer(user.email()).reviewer(accountCreator.user2().email()));
     assertThat(Iterables.getOnlyElement(sender.getMessages()).body())
-        .contains(
-            "Attention is currently required from: "
-                + user2.fullName()
-                + ", "
-                + user.fullName()
-                + ".");
+        .containsMatch(attentionSetHeaderPattern);
     assertThat(Iterables.getOnlyElement(sender.getMessages()).htmlBody())
-        .contains(
-            "Attention is currently required from: "
-                + user2.fullName()
-                + ", "
-                + user.fullName()
-                + ".");
+        .containsMatch(attentionSetHeaderPattern);
     sender.clear();
 
     // Irrelevant reply, User and User2 are still in the attention set.
     change(r).current().review(ReviewInput.approve());
     assertThat(Iterables.getOnlyElement(sender.getMessages()).body())
-        .contains(
-            "Attention is currently required from: "
-                + user2.fullName()
-                + ", "
-                + user.fullName()
-                + ".");
+        .containsMatch(attentionSetHeaderPattern);
     assertThat(Iterables.getOnlyElement(sender.getMessages()).htmlBody())
-        .contains(
-            "Attention is currently required from: "
-                + user2.fullName()
-                + ", "
-                + user.fullName()
-                + ".");
+        .containsMatch(attentionSetHeaderPattern);
     sender.clear();
 
     // Abandon the change which removes user from attention set; there is an email but without the
@@ -1461,6 +1486,58 @@
   }
 
   @Test
+  public void attentionSetWithEmailFilterFiltersNewPatchsets() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    // Add preference for the user such that they only receive an email on changes that require
+    // their attention.
+    requestScopeOperations.setApiUser(user.id());
+    GeneralPreferencesInfo prefs = gApi.accounts().self().getPreferences();
+    prefs.emailStrategy = EmailStrategy.ATTENTION_SET_ONLY;
+    gApi.accounts().self().setPreferences(prefs);
+    requestScopeOperations.setApiUser(admin.id());
+
+    // Add user to reviewers but not to the attention set
+    change(r)
+        .current()
+        .review(
+            ReviewInput.create()
+                .reviewer(user.email())
+                .removeUserFromAttentionSet(user.email(), "reason"));
+    sender.clear();
+
+    // amending a change doesn't send an email when user is not in the attention set.
+    amendChange(r.getChangeId());
+    assertThat(sender.getMessages()).isEmpty();
+  }
+
+  @Test
+  public void attentionSetWithEmailFilterStillReceivesSubmitEmail() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    // Add preference for the user such that they only receive an email on changes that require
+    // their attention.
+    requestScopeOperations.setApiUser(user.id());
+    GeneralPreferencesInfo prefs = gApi.accounts().self().getPreferences();
+    prefs.emailStrategy = EmailStrategy.ATTENTION_SET_ONLY;
+    gApi.accounts().self().setPreferences(prefs);
+    requestScopeOperations.setApiUser(admin.id());
+
+    // Add user to reviewers but not to the attention set
+    change(r)
+        .current()
+        .review(
+            ReviewInput.approve()
+                .reviewer(user.email())
+                .removeUserFromAttentionSet(user.email(), "reason"));
+    sender.clear();
+
+    // submitting the change sends an email even when user is not in the attention set.
+    change(r).current().submit();
+    assertThat(sender.getMessages()).isNotEmpty();
+  }
+
+  @Test
   public void attentionSetWithEmailFilterImpactingOnlyChangeEmails() throws Exception {
     // Add preference for the user such that they only receive an email on changes that require
     // their attention.
@@ -1475,6 +1552,156 @@
     assertThat(sender.getMessages()).isNotEmpty();
   }
 
+  @Test
+  public void cannotAddIrrelevantUserToAttentionSet() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    BadRequestException exception =
+        assertThrows(
+            BadRequestException.class,
+            () -> change(r).addToAttentionSet(new AttentionSetInput(user.email(), "reason")));
+    assertThat(exception.getMessage())
+        .isEqualTo(
+            String.format(
+                "%s doesn't exist or is not active on the change as an owner, uploader, reviewer, "
+                    + "or cc so they can't be added to the attention set",
+                user.email()));
+  }
+
+  @Test
+  public void cannotAddNonExistingUserToAttentionSet() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    BadRequestException exception =
+        assertThrows(
+            BadRequestException.class,
+            () -> change(r).addToAttentionSet(new AttentionSetInput("INVALID USER", "reason")));
+    assertThat(exception.getMessage())
+        .isEqualTo(
+            "INVALID USER doesn't exist or is not active on the change as an owner,"
+                + " uploader, reviewer, or cc so they can't be added to the attention set");
+  }
+
+  @Test
+  public void cannotRemoveIrrelevantUserToAttentionSet() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    BadRequestException exception =
+        assertThrows(
+            BadRequestException.class,
+            () -> change(r).attention(user.email()).remove(new AttentionSetInput("reason")));
+    assertThat(exception.getMessage())
+        .isEqualTo(
+            String.format(
+                "%s doesn't exist or is not active on the change as an owner, uploader, reviewer, "
+                    + "or cc so they can't be added to the attention set",
+                user.email()));
+  }
+
+  @Test
+  public void cannotRemoveIrrelevantUserToAttentionSetWithUserInInput() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    BadRequestException exception =
+        assertThrows(
+            BadRequestException.class,
+            () ->
+                change(r)
+                    .attention(user.email())
+                    .remove(new AttentionSetInput(user.email(), "reason")));
+    assertThat(exception.getMessage())
+        .isEqualTo(
+            String.format(
+                "%s doesn't exist or is not active on the change as an owner, uploader, reviewer, "
+                    + "or cc so they can't be added to the attention set",
+                user.email()));
+  }
+
+  @Test
+  public void cannotRemoveNonExistingUser() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    BadRequestException exception =
+        assertThrows(
+            BadRequestException.class,
+            () -> change(r).attention("INVALID USER").remove(new AttentionSetInput("reason")));
+    assertThat(exception.getMessage())
+        .isEqualTo(
+            "INVALID USER doesn't exist or is not active on the change as an owner,"
+                + " uploader, reviewer, or cc so they can't be added to the attention set");
+  }
+
+  @Test
+  public void irrelevantUsersAddedToAttentionSetAreIgnoredOnReply() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    change(r).current().review(ReviewInput.create().addUserToAttentionSet(user.email(), "reason"));
+    assertThat(getAttentionSetUpdatesForUser(r, user)).isEmpty();
+  }
+
+  @Test
+  public void newReviewerCanBeAddedToTheAttentionSetManually() throws Exception {
+    PushOneCommit.Result r = createChange();
+    change(r)
+        .current()
+        .review(
+            ReviewInput.create()
+                .reviewer(user.email())
+                .addUserToAttentionSet(user.email(), "reason")
+                .blockAutomaticAttentionSetRules());
+    assertThat(Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, user)).operation())
+        .isEqualTo(Operation.ADD);
+  }
+
+  @Test
+  public void newReviewerCanBeAddedToTheAttentionSetAutomatically() throws Exception {
+    PushOneCommit.Result r = createChange();
+    change(r).current().review(ReviewInput.create().reviewer(user.email()));
+    assertThat(Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, user)).operation())
+        .isEqualTo(Operation.ADD);
+  }
+
+  @GerritConfig(name = "accounts.visibility", value = "NONE")
+  public void onReplyCanAddInvisibleUsersToAttentionSetOnVisibleChanges() throws Exception {
+    PushOneCommit.Result r = createChange();
+    requestScopeOperations.setApiUser(user.id());
+
+    // admin is invisible to the user, but they can still add them to the attention set since they
+    // see the change.
+    change(r).current().review(ReviewInput.create().addUserToAttentionSet(admin.email(), "reason"));
+    assertThat(Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, admin)).operation())
+        .isEqualTo(Operation.ADD);
+  }
+
+  @Test
+  public void onReplyNonExistingUsersAreSilentlyIgnored() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    change(r)
+        .current()
+        .review(ReviewInput.create().addUserToAttentionSet("INVALID USER", "reason"));
+    assertThat(getAttentionSetUpdates(r.getChange().getId())).isEmpty();
+  }
+
+  @Test
+  @GerritConfig(name = "accounts.visibility", value = "NONE")
+  public void canModifyAttentionSetForInvisibleUsersOnVisibleChanges() throws Exception {
+    PushOneCommit.Result r = createChange();
+    requestScopeOperations.setApiUser(user.id());
+
+    // admin is invisible to the user, but they can still add them to the attention set since they
+    // see the change.
+    change(r).addToAttentionSet(new AttentionSetInput(admin.email(), "reason"));
+    assertThat(Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, admin)).operation())
+        .isEqualTo(Operation.ADD);
+
+    // admin is invisible to the user, but they can still remove them to the attention set since
+    // they see the change.
+    change(r).attention(admin.id().toString()).remove(new AttentionSetInput("removed"));
+    assertThat(Iterables.getOnlyElement(getAttentionSetUpdatesForUser(r, admin)).operation())
+        .isEqualTo(Operation.REMOVE);
+  }
+
   private List<AttentionSetUpdate> getAttentionSetUpdatesForUser(
       PushOneCommit.Result r, TestAccount account) {
     return getAttentionSetUpdates(r.getChange().getId()).stream()
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/CreateChangeIT.java b/javatests/com/google/gerrit/acceptance/rest/change/CreateChangeIT.java
index 7fe2a50..a539bd5 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/CreateChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/CreateChangeIT.java
@@ -15,7 +15,9 @@
 package com.google.gerrit.acceptance.rest.change;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.block;
+import static com.google.gerrit.entities.Permission.CREATE;
 import static com.google.gerrit.entities.Permission.READ;
 import static com.google.gerrit.entities.RefNames.changeMetaRef;
 import static com.google.gerrit.extensions.common.testing.GitPersonSubject.assertThat;
@@ -180,6 +182,87 @@
   }
 
   @Test
+  public void cannotCreateChangeOnGerritInternalRefs() throws Exception {
+    requestScopeOperations.setApiUser(admin.id());
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(CREATE).ref("refs/*").group(REGISTERED_USERS))
+        .update();
+
+    String disallowedRef = "refs/changes/00/1000"; // All Gerrit internal refs behave the same way
+    requestScopeOperations.setApiUser(admin.id());
+    BranchNameKey branchNameKey = BranchNameKey.create(project, disallowedRef);
+    createBranch(branchNameKey);
+
+    requestScopeOperations.setApiUser(user.id());
+    ChangeInput ci = newChangeInput(ChangeStatus.NEW);
+    ci.subject = "Subject";
+    ci.branch = disallowedRef;
+
+    Throwable thrown = assertThrows(RestApiException.class, () -> gApi.changes().create(ci));
+    assertThat(thrown).hasMessageThat().contains("Cannot create a change on ref " + ci.branch);
+  }
+
+  @Test
+  public void cannotCreateChangeOnTagRefs() throws Exception {
+    requestScopeOperations.setApiUser(admin.id());
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(CREATE).ref("refs/*").group(REGISTERED_USERS))
+        .update();
+
+    String branchName = "refs/tags/v1.0";
+    requestScopeOperations.setApiUser(admin.id());
+    BranchNameKey branchNameKey = BranchNameKey.create(project, branchName);
+    createBranch(branchNameKey);
+
+    requestScopeOperations.setApiUser(user.id());
+    ChangeInput ci = newChangeInput(ChangeStatus.NEW);
+    ci.subject = "Subject";
+    ci.branch = branchName;
+
+    Throwable thrown = assertThrows(RestApiException.class, () -> gApi.changes().create(ci));
+    assertThat(thrown).hasMessageThat().contains("Cannot create a change on ref " + ci.branch);
+  }
+
+  @Test
+  public void canCreateChangeOnRefsMetaConfig() throws Exception {
+    requestScopeOperations.setApiUser(admin.id());
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(CREATE).ref("refs/*").group(REGISTERED_USERS))
+        .add(allow(READ).ref("refs/meta/config").group(REGISTERED_USERS))
+        .update();
+    requestScopeOperations.setApiUser(user.id());
+    ChangeInput ci = newChangeInput(ChangeStatus.NEW);
+    ci.subject = "Subject";
+    ci.branch = RefNames.REFS_CONFIG;
+    assertThat(gApi.changes().create(ci).info().branch).isEqualTo(RefNames.REFS_CONFIG);
+  }
+
+  @Test
+  public void canCreateChangeOnRefsMetaDashboards() throws Exception {
+    String branchName = "refs/meta/dashboards/project_1";
+    requestScopeOperations.setApiUser(admin.id());
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(CREATE).ref(branchName).group(REGISTERED_USERS))
+        .add(allow(READ).ref(branchName).group(REGISTERED_USERS))
+        .update();
+    BranchNameKey branchNameKey = BranchNameKey.create(project, branchName);
+    createBranch(branchNameKey);
+    requestScopeOperations.setApiUser(user.id());
+    ChangeInput ci = newChangeInput(ChangeStatus.NEW);
+    ci.subject = "Subject";
+    ci.branch = branchName;
+    assertThat(gApi.changes().create(ci).info().branch).isEqualTo(branchName);
+  }
+
+  @Test
   public void cannotCreateChangeWithChangeIfOfExistingChangeOnSameBranch() throws Exception {
     String changeId = createChange().getChangeId();
 
@@ -708,6 +791,9 @@
     projectOperations
         .project(project)
         .forUpdate()
+        // Allow reading for refs/meta/config so that the project is visible to the user. Otherwise
+        // the request will fail with an UnprocessableEntityException "Project not found:".
+        .add(allow(READ).ref("refs/meta/config").group(REGISTERED_USERS))
         .add(block(READ).ref("refs/heads/*").group(REGISTERED_USERS))
         .update();
     requestScopeOperations.setApiUser(user.id());
@@ -731,6 +817,9 @@
     projectOperations
         .project(project)
         .forUpdate()
+        // Allow reading for refs/meta/config so that the project is visible to the user. Otherwise
+        // the request will fail with an UnprocessableEntityException "Project not found:".
+        .add(allow(READ).ref("refs/meta/config").group(REGISTERED_USERS))
         .add(block(READ).ref("refs/heads/*").group(REGISTERED_USERS))
         .update();
     requestScopeOperations.setApiUser(user.id());
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/LifecycleListenersIT.java b/javatests/com/google/gerrit/acceptance/rest/change/LifecycleListenersIT.java
new file mode 100644
index 0000000..59914bc
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/rest/change/LifecycleListenersIT.java
@@ -0,0 +1,54 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.rest.change;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gerrit.acceptance.AbstractLifecycleListenersTest;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.inject.Inject;
+import org.junit.Before;
+import org.junit.Test;
+
+public class LifecycleListenersIT extends AbstractLifecycleListenersTest {
+  @Inject private InvocationCheck invocationCheck;
+
+  @Before
+  public void before() {
+    invocationCheck.setStartInvoked(false);
+    invocationCheck.setStopInvoked(false);
+  }
+
+  @Test
+  public void lifecycleListenerSuccessfulInvocation() throws Exception {
+    try (AutoCloseable ignored = installPlugin("my-plugin", SimpleModule.class)) {
+      RestResponse response = adminRestSession.get("/changes/?--my-plugin--opt&q=status:open");
+      response.assertOK();
+      assertTrue(invocationCheck.isStartInvoked());
+      assertTrue(invocationCheck.isStopInvoked());
+    }
+  }
+
+  @Test
+  public void lifecycleListenerUnsuccessfulInvocation() throws Exception {
+    try (AutoCloseable ignored = installPlugin("my-plugin", SimpleModule.class)) {
+      RestResponse response = adminRestSession.get("/projects/");
+      response.assertOK();
+      assertFalse(invocationCheck.isStartInvoked());
+      assertFalse(invocationCheck.isStopInvoked());
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
index d5881ea..19e36f2 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
@@ -16,15 +16,19 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.acceptance.GitUtil.pushHead;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allowLabel;
 import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.block;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static com.google.gerrit.server.project.testing.TestLabels.value;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.GitUtil;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.acceptance.config.GerritConfig;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
@@ -190,7 +194,7 @@
         .update();
     AuthException thrown =
         assertThrows(AuthException.class, () -> move(r.getChangeId(), newBranch.branch()));
-    assertThat(thrown).hasMessageThat().contains("move not permitted");
+    assertThat(thrown).hasMessageThat().isEqualTo("move not permitted");
   }
 
   @Test
@@ -210,7 +214,7 @@
     requestScopeOperations.setApiUser(user.id());
     AuthException thrown =
         assertThrows(AuthException.class, () -> move(r.getChangeId(), newBranch.branch()));
-    assertThat(thrown).hasMessageThat().contains("move not permitted");
+    assertThat(thrown).hasMessageThat().isEqualTo("move not permitted");
   }
 
   @Test
@@ -269,6 +273,224 @@
   }
 
   @Test
+  public void moveChangeKeepAllVotesOnlyAllowedForAdmins() throws Exception {
+    // Keep all votes options is only permitted for admins.
+    BranchNameKey destinationBranch = BranchNameKey.create(project, "dest");
+    createBranch(destinationBranch);
+    BranchNameKey sourceBranch = BranchNameKey.create(project, "source");
+    createBranch(sourceBranch);
+    String changeId = createChangeInBranch(sourceBranch.branch()).getChangeId();
+
+    // Grant change permissions to the registered users.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.PUSH).ref(destinationBranch.branch()).group(REGISTERED_USERS))
+        .update();
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.ABANDON).ref(sourceBranch.branch()).group(REGISTERED_USERS))
+        .update();
+
+    requestScopeOperations.setApiUser(user.id());
+
+    AuthException thrown =
+        assertThrows(
+            AuthException.class, () -> move(changeId, destinationBranch.shortName(), true));
+    assertThat(thrown).hasMessageThat().isEqualTo("move is not permitted with keepAllVotes option");
+
+    requestScopeOperations.setApiUser(admin.id());
+
+    move(changeId, destinationBranch.branch(), true);
+    assertThat(info(changeId).branch).isEqualTo(destinationBranch.shortName());
+  }
+
+  @Test
+  public void moveChangeKeepAllVotesNoLabelInDestination() throws Exception {
+    BranchNameKey destinationBranch = BranchNameKey.create(project, "dest");
+    createBranch(destinationBranch);
+    BranchNameKey sourceBranch = BranchNameKey.create(project, "source");
+    createBranch(sourceBranch);
+
+    String testLabelA = "Label-A";
+    // The label has the range [-1; 1]
+    configLabel(testLabelA, LabelFunction.NO_BLOCK, ImmutableList.of(sourceBranch.branch()));
+    // Registered users have permissions for the entire range [-1; 1] on all branches.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allowLabel(testLabelA).ref("refs/heads/*").group(REGISTERED_USERS).range(-1, +1))
+        .update();
+
+    String changeId = createChangeInBranch(sourceBranch.branch()).getChangeId();
+    requestScopeOperations.setApiUser(user.id());
+    ReviewInput userReviewInput = new ReviewInput();
+    userReviewInput.label(testLabelA, 1);
+    gApi.changes().id(changeId).current().review(userReviewInput);
+
+    assertLabelVote(user, changeId, testLabelA, (short) 1);
+
+    requestScopeOperations.setApiUser(admin.id());
+    assertThat(atrScope.get().getUser().getAccountId()).isEqualTo(admin.id());
+
+    // Move the change to the destination branch.
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    move(changeId, destinationBranch.shortName(), true);
+    assertThat(info(changeId).branch).isEqualTo(destinationBranch.shortName());
+
+    // Label is missing in the destination branch.
+    assertThat(gApi.changes().id(changeId).current().reviewer(user.email()).votes()).isEmpty();
+
+    // Move the change back to the source, the label is kept.
+    move(changeId, sourceBranch.shortName(), true);
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    assertLabelVote(user, changeId, testLabelA, (short) 1);
+  }
+
+  @Test
+  public void moveChangeKeepAllVotesOutOfUserPermissionRange() throws Exception {
+    BranchNameKey destinationBranch = BranchNameKey.create(project, "dest");
+    createBranch(destinationBranch);
+    BranchNameKey sourceBranch = BranchNameKey.create(project, "source");
+    createBranch(sourceBranch);
+
+    String testLabelA = "Label-A";
+    // The label has the range [-2; 2]
+    configLabel(
+        project,
+        testLabelA,
+        LabelFunction.NO_BLOCK,
+        value(2, "Passes"),
+        value(1, "Mostly ok"),
+        value(0, "No score"),
+        value(-1, "Needs work"),
+        value(-2, "Failed"));
+    // Registered users have [-2; 2] permissions on the source.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel(testLabelA).ref(sourceBranch.branch()).group(REGISTERED_USERS).range(-2, +2))
+        .update();
+
+    // Registered users have [-1; 1] permissions on the destination.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel(testLabelA)
+                .ref(destinationBranch.branch())
+                .group(REGISTERED_USERS)
+                .range(-1, +1))
+        .update();
+
+    String changeId = createChangeInBranch(sourceBranch.branch()).getChangeId();
+    requestScopeOperations.setApiUser(user.id());
+    // Vote within the range of the source branch.
+    ReviewInput userReviewInput = new ReviewInput();
+    userReviewInput.label(testLabelA, 2);
+    gApi.changes().id(changeId).current().review(userReviewInput);
+
+    assertLabelVote(user, changeId, testLabelA, (short) 2);
+
+    requestScopeOperations.setApiUser(admin.id());
+    assertThat(atrScope.get().getUser().getAccountId()).isEqualTo(admin.id());
+
+    // Move the change to the destination branch.
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    move(changeId, destinationBranch.branch(), true);
+    // User does not have label permissions for the same vote on the destination branch.
+    requestScopeOperations.setApiUser(user.id());
+    AuthException thrown =
+        assertThrows(
+            AuthException.class,
+            () -> gApi.changes().id(changeId).current().review(userReviewInput));
+    assertThat(thrown)
+        .hasMessageThat()
+        .isEqualTo(String.format("Applying label \"%s\": 2 is restricted", testLabelA));
+
+    // Label is kept even though the user's permission range is different from the source.
+    // Since we do not squash users votes based on the destination branch access label
+    // configuration, this is working as intended.
+    // It's the same behavior as when a project owner reduces user's permission range on label.
+    // Administrators should take this into account.
+    assertThat(info(changeId).branch).isEqualTo(destinationBranch.shortName());
+    assertLabelVote(user, changeId, testLabelA, (short) 2);
+
+    requestScopeOperations.setApiUser(admin.id());
+    // Move the change back to the source, the label is kept.
+    move(changeId, sourceBranch.shortName(), true);
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    assertLabelVote(user, changeId, testLabelA, (short) 2);
+  }
+
+  @Test
+  public void moveKeepAllVotesCanMoveAllInRange() throws Exception {
+    BranchNameKey destinationBranch = BranchNameKey.create(project, "dest");
+    createBranch(destinationBranch);
+    BranchNameKey sourceBranch = BranchNameKey.create(project, "source");
+    createBranch(sourceBranch);
+
+    // The non-block label has the range [-2; 2]
+    String testLabelA = "Label-A";
+    configLabel(
+        project,
+        testLabelA,
+        LabelFunction.NO_BLOCK,
+        value(2, "Passes"),
+        value(1, "Mostly ok"),
+        value(0, "No score"),
+        value(-1, "Needs work"),
+        value(-2, "Failed"));
+
+    // Registered users have [-2; 2] permissions on all branches.
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allowLabel(testLabelA).ref("refs/heads/*").group(REGISTERED_USERS).range(-2, +2))
+        .update();
+
+    String changeId = createChangeInBranch(sourceBranch.branch()).getChangeId();
+
+    for (int vote = -2; vote <= 2; vote++) {
+      TestAccount testUser = accountCreator.create("TestUser" + vote);
+      requestScopeOperations.setApiUser(testUser.id());
+      ReviewInput userReviewInput = new ReviewInput();
+      userReviewInput.label(testLabelA, vote);
+      gApi.changes().id(changeId).current().review(userReviewInput);
+    }
+
+    assertThat(
+            gApi.changes().id(changeId).current().votes().get(testLabelA).stream()
+                .map(approvalInfo -> approvalInfo.value)
+                .collect(ImmutableList.toImmutableList()))
+        .containsExactly(-2, -1, 1, 2);
+
+    requestScopeOperations.setApiUser(admin.id());
+    // Move the change to the destination branch.
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    move(changeId, destinationBranch.shortName(), true);
+    assertThat(info(changeId).branch).isEqualTo(destinationBranch.shortName());
+
+    // All votes are kept
+    assertThat(
+            gApi.changes().id(changeId).current().votes().get(testLabelA).stream()
+                .map(approvalInfo -> approvalInfo.value)
+                .collect(ImmutableList.toImmutableList()))
+        .containsExactly(-2, -1, 1, 2);
+
+    // Move the change back to the source, the label is kept.
+    move(changeId, sourceBranch.shortName(), true);
+    assertThat(info(changeId).branch).isEqualTo(sourceBranch.shortName());
+    assertThat(
+            gApi.changes().id(changeId).current().votes().get(testLabelA).stream()
+                .map(approvalInfo -> approvalInfo.value)
+                .collect(ImmutableList.toImmutableList()))
+        .containsExactly(-2, -1, 1, 2);
+  }
+
+  @Test
   public void moveChangeOnlyKeepVetoVotes() throws Exception {
     // A vote for a label will be kept after moving if the label's function is *WithBlock and the
     // vote holds the minimum value.
@@ -394,10 +616,28 @@
     gApi.changes().id(changeId).move(in);
   }
 
+  private void move(String changeId, String destination, boolean keepAllVotes)
+      throws RestApiException {
+    MoveInput in = new MoveInput();
+    in.destinationBranch = destination;
+    in.keepAllVotes = keepAllVotes;
+    gApi.changes().id(changeId).move(in);
+  }
+
   private PushOneCommit.Result createChange(String branch, String changeId) throws Exception {
     PushOneCommit push = pushFactory.create(admin.newIdent(), testRepo, changeId);
     PushOneCommit.Result result = push.to("refs/for/" + branch);
     result.assertOkStatus();
     return result;
   }
+
+  private PushOneCommit.Result createChangeInBranch(String branch) throws Exception {
+    return createChange("refs/for/" + branch);
+  }
+
+  private void assertLabelVote(TestAccount user, String changeId, String label, short vote)
+      throws Exception {
+    assertThat(gApi.changes().id(changeId).current().reviewer(user.email()).votes())
+        .containsEntry(label, vote);
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/PluginFieldsIT.java b/javatests/com/google/gerrit/acceptance/rest/change/PluginFieldsIT.java
index 17bf37e..a4ec40e 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/PluginFieldsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/PluginFieldsIT.java
@@ -14,8 +14,6 @@
 
 package com.google.gerrit.acceptance.rest.change;
 
-import static com.google.common.truth.Truth.assertThat;
-
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.gerrit.acceptance.AbstractPluginFieldsTest;
@@ -35,41 +33,6 @@
   private static final Gson GSON = OutputFormat.JSON.newGson();
 
   @Test
-  public void queryChangeWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(
-        id -> pluginInfoFromSingletonList(adminRestSession.get(changeQueryUrl(id))));
-  }
-
-  @Test
-  public void getChangeWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(id -> pluginInfoFromChangeInfo(adminRestSession.get(changeUrl(id))));
-  }
-
-  @Test
-  public void getChangeDetailWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(
-        id -> pluginInfoFromChangeInfo(adminRestSession.get(changeDetailUrl(id))));
-  }
-
-  @Test
-  public void queryChangeWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromSingletonList(adminRestSession.get(changeQueryUrl(id))));
-  }
-
-  @Test
-  public void getChangeWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromChangeInfo(adminRestSession.get(changeUrl(id))));
-  }
-
-  @Test
-  public void getChangeDetailWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromChangeInfo(adminRestSession.get(changeDetailUrl(id))));
-  }
-
-  @Test
   public void querySingleChangeWithBulkAttribute() throws Exception {
     getSingleChangeWithPluginDefinedBulkAttribute(
         id -> pluginInfosFromChangeInfos(adminRestSession.get(changeQueryUrl(id))));
@@ -88,27 +51,6 @@
   }
 
   @Test
-  public void queryChangeWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromSingletonList(adminRestSession.get(changeQueryUrl(id))),
-        (id, opts) -> pluginInfoFromSingletonList(adminRestSession.get(changeQueryUrl(id, opts))));
-  }
-
-  @Test
-  public void getChangeWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromChangeInfo(adminRestSession.get(changeUrl(id))),
-        (id, opts) -> pluginInfoFromChangeInfo(adminRestSession.get(changeUrl(id, opts))));
-  }
-
-  @Test
-  public void getChangeDetailWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromChangeInfo(adminRestSession.get(changeDetailUrl(id))),
-        (id, opts) -> pluginInfoFromChangeInfo(adminRestSession.get(changeDetailUrl(id, opts))));
-  }
-
-  @Test
   public void pluginDefinedQueryChangeWithOption() throws Exception {
     getChangeWithPluginDefinedBulkAttributeOption(
         id -> pluginInfosFromChangeInfos(adminRestSession.get(changeQueryUrl(id))),
@@ -142,12 +84,6 @@
   }
 
   @Test
-  public void getMultipleChangesWithPluginDefinedAndChangeAttributes() throws Exception {
-    getMultipleChangesWithPluginDefinedBulkAndChangeAttributes(
-        () -> pluginInfosFromChangeInfos(adminRestSession.get("/changes/?q=status:open")));
-  }
-
-  @Test
   public void getMultipleChangesWithPluginDefinedAttributeInSingleCall() throws Exception {
     getMultipleChangesWithPluginDefinedBulkAttributeInSingleCall(
         () -> pluginInfosFromChangeInfos(adminRestSession.get("/changes/?q=status:open")));
@@ -204,24 +140,6 @@
   }
 
   @Nullable
-  private static List<PluginDefinedInfo> pluginInfoFromSingletonList(RestResponse res)
-      throws Exception {
-    res.assertOK();
-    List<Map<String, Object>> changeInfos =
-        GSON.fromJson(res.getReader(), new TypeToken<List<Map<String, Object>>>() {}.getType());
-    assertThat(changeInfos).hasSize(1);
-    return decodeRawPluginsList(GSON, changeInfos.get(0).get("plugins"));
-  }
-
-  @Nullable
-  private List<PluginDefinedInfo> pluginInfoFromChangeInfo(RestResponse res) throws Exception {
-    res.assertOK();
-    Map<String, Object> changeInfo =
-        GSON.fromJson(res.getReader(), new TypeToken<Map<String, Object>>() {}.getType());
-    return decodeRawPluginsList(GSON, changeInfo.get("plugins"));
-  }
-
-  @Nullable
   private Map<Change.Id, List<PluginDefinedInfo>> pluginInfoMapFromChangeInfo(RestResponse res)
       throws Exception {
     res.assertOK();
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByCherryPickIT.java b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByCherryPickIT.java
index 6f519f1..a322faf 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByCherryPickIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByCherryPickIT.java
@@ -25,12 +25,15 @@
 import com.google.gerrit.acceptance.TestProjectInput;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.common.FooterConstants;
+import com.google.gerrit.entities.BranchNameKey;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.extensions.api.changes.SubmitInput;
 import com.google.gerrit.extensions.client.ChangeStatus;
 import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.gerrit.extensions.client.ListChangesOption;
 import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ChangeInfo;
+import com.google.gerrit.server.git.ChangeMessageModifier;
 import com.google.gerrit.server.submit.CommitMergeStatus;
 import com.google.inject.Inject;
 import java.util.List;
@@ -88,12 +91,18 @@
   @Test
   public void changeMessageOnSubmit() throws Throwable {
     PushOneCommit.Result change = createChange();
-    try (Registration registration =
-        extensionRegistry
-            .newRegistration()
-            .add(
-                (newCommitMessage, original, mergeTip, destination) ->
-                    newCommitMessage + "Custom: " + destination.branch())) {
+    ChangeMessageModifier link =
+        new ChangeMessageModifier() {
+          @Override
+          public String onSubmit(
+              String newCommitMessage,
+              RevCommit original,
+              RevCommit mergeTip,
+              BranchNameKey destination) {
+            return newCommitMessage + "Custom: " + destination.branch();
+          }
+        };
+    try (Registration registration = extensionRegistry.newRegistration().add(link)) {
       submit(change.getChangeId());
     }
     testRepo.git().fetch().setRemote("origin").call();
@@ -373,4 +382,27 @@
         change2.getChangeId(),
         headAfterFirstSubmit.name());
   }
+
+  @Test
+  public void dependencyOnOutdatedPatchSetNotPreventingCherryPick() throws Throwable {
+    // Create a change
+    PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
+    PushOneCommit.Result changeResult = change.to("refs/for/master");
+    PatchSet.Id patchSetId = changeResult.getPatchSetId();
+
+    // Create a successor change.
+    PushOneCommit change2 =
+        pushFactory.create(user.newIdent(), testRepo, "feature", "b.txt", "bar");
+    PushOneCommit.Result change2Result = change2.to("refs/for/master");
+
+    // Create new patch set for first change.
+    testRepo.reset(changeResult.getCommit().name());
+    amendChange(changeResult.getChangeId());
+
+    // Approve both changes
+    approve(changeResult.getChangeId());
+    approve(change2Result.getChangeId());
+
+    assertSubmittable(change2Result.getChangeId());
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByFastForwardIT.java b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByFastForwardIT.java
index 1912697..66eb48c 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByFastForwardIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByFastForwardIT.java
@@ -22,6 +22,7 @@
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Permission;
 import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ActionInfo;
@@ -170,4 +171,49 @@
     assertRefUpdatedEvents(initialHead, headAfterSubmit);
     assertChangeMergedEvents(id1, headAfterSubmit.name());
   }
+
+  @Test
+  public void dependencyOnOutdatedPatchSetPreventsFastForward() throws Throwable {
+    // Create a change
+    PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
+    PushOneCommit.Result changeResult = change.to("refs/for/master");
+    PatchSet.Id patchSetId = changeResult.getPatchSetId();
+
+    // Create a successor change.
+    PushOneCommit change2 =
+        pushFactory.create(user.newIdent(), testRepo, "feature", "b.txt", "bar");
+    PushOneCommit.Result change2Result = change2.to("refs/for/master");
+
+    // Create new patch set for first change.
+    testRepo.reset(changeResult.getCommit().name());
+    amendChange(changeResult.getChangeId());
+
+    // Approve both changes
+    approve(changeResult.getChangeId());
+    approve(change2Result.getChangeId());
+
+    // submit button is disabled.
+    assertSubmitDisabled(change2Result.getChangeId());
+
+    submitWithConflict(
+        change2Result.getChangeId(),
+        "Failed to submit 2 changes due to the following problems:\n"
+            + "Change "
+            + change2Result.getChange().getId()
+            + ": Depends on change that was not submitted."
+            + " Commit "
+            + change2Result.getCommit().name()
+            + " depends on commit "
+            + changeResult.getCommit().name()
+            + ", which is outdated patch set "
+            + patchSetId.get()
+            + " of change "
+            + changeResult.getChange().getId()
+            + ". The latest patch set is "
+            + changeResult.getPatchSetId().get()
+            + ".");
+
+    assertRefUpdatedEvents();
+    assertChangeMergedEvents();
+  }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
index 5fe741d..995de0d 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
@@ -29,7 +29,6 @@
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.entities.BranchNameKey;
-import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Permission;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.extensions.api.changes.ChangeApi;
@@ -534,48 +533,6 @@
   }
 
   @Test
-  public void dependencyOnOutdatedPatchSetPreventsMerge() throws Throwable {
-    // Create a change
-    PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
-    PushOneCommit.Result changeResult = change.to("refs/for/master");
-    PatchSet.Id patchSetId = changeResult.getPatchSetId();
-
-    // Create a successor change.
-    PushOneCommit change2 =
-        pushFactory.create(user.newIdent(), testRepo, "feature", "b.txt", "bar");
-    PushOneCommit.Result change2Result = change2.to("refs/for/master");
-
-    // Create new patch set for first change.
-    testRepo.reset(changeResult.getCommit().name());
-    amendChange(changeResult.getChangeId());
-
-    // Approve both changes
-    approve(changeResult.getChangeId());
-    approve(change2Result.getChangeId());
-
-    submitWithConflict(
-        change2Result.getChangeId(),
-        "Failed to submit 2 changes due to the following problems:\n"
-            + "Change "
-            + change2Result.getChange().getId()
-            + ": Depends on change that was not submitted."
-            + " Commit "
-            + change2Result.getCommit().name()
-            + " depends on commit "
-            + changeResult.getCommit().name()
-            + ", which is outdated patch set "
-            + patchSetId.get()
-            + " of change "
-            + changeResult.getChange().getId()
-            + ". The latest patch set is "
-            + changeResult.getPatchSetId().get()
-            + ".");
-
-    assertRefUpdatedEvents();
-    assertChangeMergedEvents();
-  }
-
-  @Test
   public void dependencyOnDeletedChangePreventsMerge() throws Throwable {
     // Create a change
     PushOneCommit change = pushFactory.create(user.newIdent(), testRepo, "fix", "a.txt", "foo");
diff --git a/javatests/com/google/gerrit/acceptance/rest/group/ListGroupsIT.java b/javatests/com/google/gerrit/acceptance/rest/group/ListGroupsIT.java
index 9c17a5a..4453345 100644
--- a/javatests/com/google/gerrit/acceptance/rest/group/ListGroupsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/group/ListGroupsIT.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.extensions.common.GroupInfo;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gson.reflect.TypeToken;
 import java.util.Map;
 import org.junit.Test;
@@ -32,6 +33,7 @@
     Map<String, GroupInfo> groupMap =
         newGson()
             .fromJson(response.getReader(), new TypeToken<Map<String, GroupInfo>>() {}.getType());
-    assertThat(groupMap.keySet()).containsExactly("Administrators", "Service Users");
+    assertThat(groupMap.keySet())
+        .containsExactly("Administrators", ServiceUserClassifier.SERVICE_USERS);
   }
 }
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/AccessIT.java b/javatests/com/google/gerrit/acceptance/rest/project/AccessIT.java
index 33d0d29..cf8efa7 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/AccessIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/AccessIT.java
@@ -78,6 +78,9 @@
 
   private static final String REFS_ALL = Constants.R_REFS + "*";
   private static final String REFS_HEADS = Constants.R_HEADS + "*";
+  private static final String REFS_META_VERSION = "refs/meta/version";
+  private static final String REFS_DRAFTS = "refs/draft-comments/*";
+  private static final String REFS_STARRED_CHANGES = "refs/starred-changes/*";
 
   private static final String LABEL_CODE_REVIEW = "Code-Review";
 
@@ -496,7 +499,10 @@
     AccessSectionInfo accessSectionInfo = createAccessSectionInfoDenyAll();
 
     // Disallow READ
-    accessInput.add.put(REFS_ALL, accessSectionInfo);
+    accessInput.add.put(REFS_META_VERSION, accessSectionInfo);
+    accessInput.add.put(REFS_DRAFTS, accessSectionInfo);
+    accessInput.add.put(REFS_STARRED_CHANGES, accessSectionInfo);
+    accessInput.add.put(REFS_HEADS, accessSectionInfo);
     pApi().access(accessInput);
 
     requestScopeOperations.setApiUser(user.id());
@@ -510,7 +516,10 @@
     AccessSectionInfo accessSectionInfo = createAccessSectionInfoDenyAll();
 
     // Disallow READ
-    accessInput.add.put(REFS_ALL, accessSectionInfo);
+    accessInput.add.put(REFS_META_VERSION, accessSectionInfo);
+    accessInput.add.put(REFS_DRAFTS, accessSectionInfo);
+    accessInput.add.put(REFS_STARRED_CHANGES, accessSectionInfo);
+    accessInput.add.put(REFS_HEADS, accessSectionInfo);
     pApi().access(accessInput);
 
     // Create a change to apply
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/DeleteBranchIT.java b/javatests/com/google/gerrit/acceptance/rest/project/DeleteBranchIT.java
index c98a58e..ce92536 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/DeleteBranchIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/DeleteBranchIT.java
@@ -128,6 +128,7 @@
     projectOperations
         .project(project)
         .forUpdate()
+        .add(allow(Permission.READ).ref(metaRef).group(REGISTERED_USERS))
         .add(allow(Permission.CREATE).ref(metaRef).group(REGISTERED_USERS))
         .add(allow(Permission.PUSH).ref(metaRef).group(REGISTERED_USERS))
         .update();
diff --git a/javatests/com/google/gerrit/acceptance/rest/project/GetBranchIT.java b/javatests/com/google/gerrit/acceptance/rest/project/GetBranchIT.java
index b4b1be0..13c20dd 100644
--- a/javatests/com/google/gerrit/acceptance/rest/project/GetBranchIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/project/GetBranchIT.java
@@ -262,9 +262,12 @@
     requestScopeOperations.setApiUser(user.id());
     assertBranchFound(allUsers, RefNames.refsUsers(user.id()));
 
-    // TODO: every user can see the own user ref via the magic ref/users/self ref
-    // requestScopeOperations.setApiUser(user.id());
-    // assertBranchFound(allUsers, RefNames.REFS_USERS_SELF);
+    // every user can see the own user ref via the magic ref/users/self ref. For this special case,
+    // the branch in the request is refs/users/self, but the response contains the actual
+    // refs/users/$sharded_id/$id
+    BranchInfo branchInfo =
+        gApi.projects().name(allUsers.get()).branch(RefNames.REFS_USERS_SELF).get();
+    assertThat(branchInfo.ref).isEqualTo(RefNames.refsUsers(user.id()));
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/acceptance/server/account/ServiceUserClassifierIT.java b/javatests/com/google/gerrit/acceptance/server/account/ServiceUserClassifierIT.java
index 1e33c69..df84fd7 100644
--- a/javatests/com/google/gerrit/acceptance/server/account/ServiceUserClassifierIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/account/ServiceUserClassifierIT.java
@@ -44,7 +44,7 @@
 
   @Test
   public void userWithDirectMembershipInServiceUserIsAServiceUser() throws Exception {
-    TestAccount user = accountCreator.create(null, "Service Users");
+    TestAccount user = accountCreator.create(null, ServiceUserClassifier.SERVICE_USERS);
     assertThat(serviceUserClassifier.isServiceUser(user.id())).isTrue();
   }
 
@@ -91,7 +91,7 @@
 
   private AccountGroup.UUID serviceUsersUUID() {
     return groupCache
-        .get(AccountGroup.nameKey("Service Users"))
+        .get(AccountGroup.nameKey(ServiceUserClassifier.SERVICE_USERS))
         .orElseThrow(() -> new IllegalStateException("unable to find 'Service Users'"))
         .getGroupUUID();
   }
diff --git a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
index b4dd4b3..2c42d0a 100644
--- a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
@@ -1090,6 +1090,76 @@
             contextLines("2", "line_2", "3", "line_3", "4", "line_4", "5", "line_5"));
   }
 
+  @Test
+  public void commentContextForCommentsOnDifferentPatchsets() throws Exception {
+    PushOneCommit.Result r1 = createChange();
+
+    ImmutableList.Builder<String> content = ImmutableList.builder();
+    for (int i = 1; i <= 10; i++) {
+      content.add("line_" + i);
+    }
+
+    PushOneCommit.Result r2 =
+        pushFactory
+            .create(
+                admin.newIdent(),
+                testRepo,
+                SUBJECT,
+                FILE_NAME,
+                String.join("\n", content.build()),
+                r1.getChangeId())
+            .to("refs/for/master");
+
+    PushOneCommit.Result r3 =
+        pushFactory
+            .create(
+                admin.newIdent(),
+                testRepo,
+                SUBJECT,
+                FILE_NAME,
+                content.build().stream().collect(Collectors.joining("\n")),
+                r1.getChangeId())
+            .to("refs/for/master");
+
+    addCommentOnLine(r2, "r2: please fix", 1);
+    addCommentOnRange(r2, "r2: looks good", commentRangeInLines(2, 3));
+    addCommentOnLine(r3, "r3: please fix", 6);
+    addCommentOnRange(r3, "r3: looks good", commentRangeInLines(7, 8));
+
+    List<CommentInfo> comments =
+        gApi.changes().id(r2.getChangeId()).commentsRequest().withContext(true).getAsList();
+
+    assertThat(comments).hasSize(4);
+
+    assertThat(
+            comments.stream()
+                .filter(c -> c.message.equals("r2: please fix"))
+                .collect(MoreCollectors.onlyElement())
+                .contextLines)
+        .containsExactlyElementsIn(contextLines("1", "line_1"));
+
+    assertThat(
+            comments.stream()
+                .filter(c -> c.message.equals("r2: looks good"))
+                .collect(MoreCollectors.onlyElement())
+                .contextLines)
+        .containsExactlyElementsIn(contextLines("2", "line_2", "3", "line_3"));
+
+    assertThat(
+            comments.stream()
+                .filter(c -> c.message.equals("r3: please fix"))
+                .collect(MoreCollectors.onlyElement())
+                .contextLines)
+        .containsExactlyElementsIn(contextLines("6", "line_6"));
+
+    assertThat(
+            comments.stream()
+                .filter(c -> c.message.equals("r3: looks good"))
+                .collect(MoreCollectors.onlyElement())
+                .contextLines)
+        .containsExactlyElementsIn(contextLines("7", "line_7", "8", "line_8"));
+  }
+
   private List<ContextLineInfo> contextLines(String... args) {
     List<ContextLineInfo> result = new ArrayList<>();
     for (int i = 0; i < args.length; i += 2) {
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java b/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
index 9b12f29..b2a349e 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/ChangeNotificationsIT.java
@@ -1714,7 +1714,7 @@
         .sent("newpatchset", sc)
         .notTo(sc.owner) // TODO(logan): This shouldn't be sent *from* the owner.
         .to(sc.reviewer)
-        .to(other)
+        .cc(other)
         .cc(sc.ccer)
         .cc(StagedUsers.REVIEWER_BY_EMAIL, StagedUsers.CC_BY_EMAIL)
         .noOneElse();
@@ -1730,7 +1730,7 @@
         .sent("newpatchset", sc)
         .notTo(sc.owner) // TODO(logan): This shouldn't be sent *from* the owner.
         .to(sc.reviewer)
-        .to(other)
+        .cc(other)
         .cc(sc.ccer)
         .cc(StagedUsers.REVIEWER_BY_EMAIL, StagedUsers.CC_BY_EMAIL)
         .noOneElse();
diff --git a/javatests/com/google/gerrit/acceptance/server/permissions/BUILD b/javatests/com/google/gerrit/acceptance/server/permissions/BUILD
new file mode 100644
index 0000000..e89e8d1
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/permissions/BUILD
@@ -0,0 +1,7 @@
+load("//javatests/com/google/gerrit/acceptance:tests.bzl", "acceptance_tests")
+
+acceptance_tests(
+    srcs = glob(["*IT.java"]),
+    group = "server_permissions",
+    labels = ["server"],
+)
diff --git a/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java b/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java
new file mode 100644
index 0000000..9e4907c
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java
@@ -0,0 +1,301 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.server.permissions;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.permissionKey;
+import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
+import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.config.GerritConfig;
+import com.google.gerrit.acceptance.testsuite.change.ChangeOperations;
+import com.google.gerrit.acceptance.testsuite.group.GroupOperations;
+import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
+import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.GroupDescription;
+import com.google.gerrit.entities.GroupReference;
+import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.entities.Permission;
+import com.google.gerrit.entities.RefNames;
+import com.google.gerrit.extensions.registration.DynamicSet;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.ExternalUser;
+import com.google.gerrit.server.PropertyMap;
+import com.google.gerrit.server.account.GroupBackend;
+import com.google.gerrit.server.account.GroupMembership;
+import com.google.gerrit.server.account.externalids.ExternalId;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gerrit.server.permissions.ChangePermission;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.project.ProjectState;
+import com.google.inject.AbstractModule;
+import com.google.inject.Module;
+import java.util.Collection;
+import java.util.Set;
+import javax.inject.Inject;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+
+/** Tests that permission logic used by {@link ExternalUser} works as expected. */
+public class ExternalUserPermissionIT extends AbstractDaemonTest {
+  private static final AccountGroup.UUID EXTERNAL_GROUP =
+      AccountGroup.uuid("company-auth:it-department");
+
+  @Inject private ChangeOperations changeOperations;
+  @Inject private ProjectOperations projectOperations;
+  @Inject private PermissionBackend permissionBackend;
+  @Inject private ChangeNotes.Factory changeNotesFactory;
+  @Inject private ExternalUser.Factory externalUserFactory;
+  @Inject private GroupOperations groupOperations;
+
+  @Before
+  public void setUp() {
+    // Allow only read on refs/heads/master by default
+    projectOperations
+        .project(allProjects)
+        .forUpdate()
+        .remove(permissionKey(Permission.READ).ref("refs/heads/*").group(ANONYMOUS_USERS))
+        .add(allow(Permission.READ).ref("refs/heads/master").group(ANONYMOUS_USERS))
+        .update();
+  }
+
+  @Override
+  public Module createModule() {
+    /**
+     * Binding a {@link GroupBackend} that pretends a user is part of a group if the external ID
+     * starts with the group UUID.
+     *
+     * <p>Example: Users "company-auth:it-department-1" and "company-auth:it-department-2" are a
+     * member of the group "company-auth:it-department"
+     */
+    return new AbstractModule() {
+      @Override
+      protected void configure() {
+        DynamicSet.bind(binder(), GroupBackend.class)
+            .toInstance(
+                new GroupBackend() {
+                  @Override
+                  public boolean handles(AccountGroup.UUID uuid) {
+                    return uuid.get().startsWith("company-auth:");
+                  }
+
+                  @Override
+                  public GroupDescription.Basic get(AccountGroup.UUID uuid) {
+                    return new GroupDescription.Basic() {
+                      @Override
+                      public AccountGroup.UUID getGroupUUID() {
+                        return uuid;
+                      }
+
+                      @Override
+                      public String getName() {
+                        return uuid.get();
+                      }
+
+                      @Override
+                      public String getEmailAddress() {
+                        return uuid.get() + "@example.com";
+                      }
+
+                      @Override
+                      public String getUrl() {
+                        return null;
+                      }
+                    };
+                  }
+
+                  @Override
+                  public Collection<GroupReference> suggest(String name, ProjectState project) {
+                    throw new UnsupportedOperationException("not implemented");
+                  }
+
+                  @Override
+                  public GroupMembership membershipsOf(CurrentUser user) {
+                    return new GroupMembership() {
+                      @Override
+                      public boolean contains(AccountGroup.UUID groupId) {
+                        return user.getExternalIdKeys().stream()
+                            .anyMatch(e -> e.get().startsWith(groupId.get()));
+                      }
+
+                      @Override
+                      public boolean containsAnyOf(Iterable<AccountGroup.UUID> groupIds) {
+                        return ImmutableList.copyOf(groupIds).stream().anyMatch(g -> contains(g));
+                      }
+
+                      @Override
+                      public Set<AccountGroup.UUID> intersection(
+                          Iterable<AccountGroup.UUID> groupIds) {
+                        return ImmutableList.copyOf(groupIds).stream()
+                            .filter(g -> contains(g))
+                            .collect(toImmutableSet());
+                      }
+
+                      @Override
+                      public Set<AccountGroup.UUID> getKnownGroups() {
+                        return ImmutableSet.of();
+                      }
+                    };
+                  }
+
+                  @Override
+                  public boolean isVisibleToAll(AccountGroup.UUID uuid) {
+                    return false;
+                  }
+                });
+      }
+    };
+  }
+
+  @Test
+  public void defaultRefFilter_changeVisibilityIsAgnosticOfProvidedGroups() throws Exception {
+    ExternalUser user = createUserInGroup("1", "it-department");
+
+    Change.Id changeOnMaster = changeOperations.newChange().project(project).create();
+    Change.Id changeOnRefsMetaConfig =
+        changeOperations.newChange().project(project).branch("refs/meta/config").create();
+    // Check that only the change on the default branch is visible
+    assertThat(getVisibleRefNames(user))
+        .containsExactly(
+            "HEAD",
+            "refs/heads/master",
+            RefNames.changeMetaRef(changeOnMaster),
+            RefNames.patchSetRef(PatchSet.id(changeOnMaster, 1)));
+    // Grant access
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.READ).ref("refs/meta/config").group(EXTERNAL_GROUP))
+        .update();
+    // Check that both changes are visible now
+    assertThat(getVisibleRefNames(user))
+        .containsExactly(
+            "HEAD",
+            "refs/heads/master",
+            "refs/meta/config",
+            RefNames.changeMetaRef(changeOnMaster),
+            RefNames.patchSetRef(PatchSet.id(changeOnMaster, 1)),
+            RefNames.changeMetaRef(changeOnRefsMetaConfig),
+            RefNames.patchSetRef(PatchSet.id(changeOnRefsMetaConfig, 1)));
+  }
+
+  @Test
+  public void defaultRefFilter_refVisibilityIsAgnosticOfProvidedGroups() throws Exception {
+    ExternalUser user = createUserInGroup("1", "it-department");
+    // Check that refs/meta/config isn't visible by default
+    assertThat(getVisibleRefNames(user)).containsExactly("HEAD", "refs/heads/master");
+    // Grant access
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.READ).ref("refs/meta/config").group(EXTERNAL_GROUP))
+        .update();
+    // Check that refs/meta/config became visible
+    assertThat(getVisibleRefNames(user))
+        .containsExactly("HEAD", "refs/heads/master", "refs/meta/config");
+  }
+
+  @Test
+  public void changeVisibility_changeOnInvisibleBranchNotVisible() throws Exception {
+    // Create a change that is not visible to members of 'externalGroup'
+    Change.Id invisibleChange =
+        changeOperations.newChange().project(project).branch("refs/meta/config").create();
+    ExternalUser user = createUserInGroup("1", "it-department");
+    AuthException thrown =
+        assertThrows(
+            AuthException.class,
+            () ->
+                permissionBackend
+                    .user(user)
+                    .change(changeNotesFactory.create(project, invisibleChange))
+                    .check(ChangePermission.READ));
+    assertThat(thrown).hasMessageThat().isEqualTo("read not permitted");
+  }
+
+  @Test
+  public void changeVisibility_changeOnBranchVisibleToAnonymousIsVisible() throws Exception {
+    Change.Id changeId = changeOperations.newChange().project(project).create();
+    ExternalUser user = createUserInGroup("1", "it-department");
+    permissionBackend
+        .user(user)
+        .change(changeNotesFactory.create(project, changeId))
+        .check(ChangePermission.READ);
+  }
+
+  @Test
+  public void changeVisibility_changeOnBranchVisibleToRegisteredUsersIsVisible() throws Exception {
+    Change.Id changeId = changeOperations.newChange().project(project).create();
+    ExternalUser user = createUserInGroup("1", "it-department");
+    blockAnonymousRead();
+    permissionBackend
+        .user(user)
+        .change(changeNotesFactory.create(project, changeId))
+        .check(ChangePermission.READ);
+  }
+
+  @Test
+  public void externalUser_isContainedInternalGroupThatContainsExternalGroup() {
+    AccountGroup.UUID internalGroup =
+        groupOperations.newGroup().addSubgroup(EXTERNAL_GROUP).create();
+    ExternalUser user = createUserInGroup("1", "it-department");
+    assertThat(user.getEffectiveGroups().contains(internalGroup)).isTrue();
+    assertThat(user.getEffectiveGroups().contains(EXTERNAL_GROUP)).isTrue();
+    assertThat(user.getEffectiveGroups().contains(REGISTERED_USERS)).isTrue();
+    assertThat(user.getEffectiveGroups().contains(ANONYMOUS_USERS)).isTrue();
+  }
+
+  @GerritConfig(name = "groups.includeExternalUsersInRegisteredUsersGroup", value = "true")
+  @Test
+  public void externalUser_isContainedInRegisteredUsersIfConfigured() {
+    ExternalUser user = createUserInGroup("1", "it-department");
+    assertThat(user.getEffectiveGroups().contains(REGISTERED_USERS)).isTrue();
+  }
+
+  @GerritConfig(name = "groups.includeExternalUsersInRegisteredUsersGroup", value = "false")
+  @Test
+  public void externalUser_isNotContainedInRegisteredUsersIfNotConfigured() {
+    ExternalUser user = createUserInGroup("1", "it-department");
+    assertThat(user.getEffectiveGroups().contains(REGISTERED_USERS)).isFalse();
+  }
+
+  private ImmutableList<String> getVisibleRefNames(CurrentUser user) throws Exception {
+    try (Repository repo = repoManager.openRepository(project)) {
+      return permissionBackend.user(user).project(project)
+          .filter(
+              repo.getRefDatabase().getRefs(), repo, PermissionBackend.RefFilterOptions.defaults())
+          .stream()
+          .map(Ref::getName)
+          .collect(toImmutableList());
+    }
+  }
+
+  ExternalUser createUserInGroup(String userId, String groupId) {
+    return externalUserFactory.create(
+        ImmutableSet.of(),
+        ImmutableSet.of(ExternalId.Key.parse("company-auth:" + groupId + "-" + userId)),
+        PropertyMap.EMPTY);
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/server/permissions/GroupBackedUserPermissionIT.java b/javatests/com/google/gerrit/acceptance/server/permissions/GroupBackedUserPermissionIT.java
new file mode 100644
index 0000000..d68d681
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/permissions/GroupBackedUserPermissionIT.java
@@ -0,0 +1,184 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.server.permissions;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
+import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.permissionKey;
+import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
+import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.testsuite.change.ChangeOperations;
+import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
+import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.entities.Permission;
+import com.google.gerrit.entities.RefNames;
+import com.google.gerrit.extensions.registration.DynamicSet;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.account.GroupBackend;
+import com.google.gerrit.server.group.testing.TestGroupBackend;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gerrit.server.permissions.ChangePermission;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.query.change.GroupBackedUser;
+import com.google.inject.AbstractModule;
+import com.google.inject.Module;
+import javax.inject.Inject;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+
+/** Tests that permission logic used by {@link GroupBackedUser} works as expected. */
+public class GroupBackedUserPermissionIT extends AbstractDaemonTest {
+  @Inject private ChangeOperations changeOperations;
+  @Inject private ProjectOperations projectOperations;
+  @Inject private PermissionBackend permissionBackend;
+  @Inject private ChangeNotes.Factory changeNotesFactory;
+
+  private final TestGroupBackend testGroupBackend = new TestGroupBackend();
+  private final AccountGroup.UUID externalGroup = AccountGroup.uuid("testbackend:test");
+
+  @Before
+  public void setUp() {
+    // Allow only read on refs/heads/master by default
+    projectOperations
+        .project(allProjects)
+        .forUpdate()
+        .remove(permissionKey(Permission.READ).ref("refs/*").group(ANONYMOUS_USERS))
+        .add(allow(Permission.READ).ref("refs/heads/master").group(ANONYMOUS_USERS))
+        .update();
+  }
+
+  @Override
+  public Module createModule() {
+    /** Binding a {@link TestGroupBackend} to test adding external groups * */
+    return new AbstractModule() {
+      @Override
+      protected void configure() {
+        DynamicSet.bind(binder(), GroupBackend.class).toInstance(testGroupBackend);
+      }
+    };
+  }
+
+  @Test
+  public void defaultRefFilter_changeVisibilityIsAgnosticOfProvidedGroups() throws Exception {
+    GroupBackedUser user =
+        new GroupBackedUser(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS, externalGroup));
+    Change.Id changeOnMaster = changeOperations.newChange().project(project).create();
+    Change.Id changeOnRefsMetaConfig =
+        changeOperations.newChange().project(project).branch("refs/meta/config").create();
+    // Check that only the change on the default branch is visible
+    assertThat(getVisibleRefNames(user))
+        .containsExactly(
+            "HEAD",
+            "refs/heads/master",
+            RefNames.changeMetaRef(changeOnMaster),
+            RefNames.patchSetRef(PatchSet.id(changeOnMaster, 1)));
+    // Grant access
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.READ).ref("refs/meta/config").group(externalGroup))
+        .update();
+    // Check that both changes are visible now
+    assertThat(getVisibleRefNames(user))
+        .containsExactly(
+            "HEAD",
+            "refs/heads/master",
+            "refs/meta/config",
+            RefNames.changeMetaRef(changeOnMaster),
+            RefNames.patchSetRef(PatchSet.id(changeOnMaster, 1)),
+            RefNames.changeMetaRef(changeOnRefsMetaConfig),
+            RefNames.patchSetRef(PatchSet.id(changeOnRefsMetaConfig, 1)));
+  }
+
+  @Test
+  public void defaultRefFilter_refVisibilityIsAgnosticOfProvidedGroups() throws Exception {
+    GroupBackedUser user =
+        new GroupBackedUser(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS, externalGroup));
+    // Check that refs/meta/config isn't visible by default
+    assertThat(getVisibleRefNames(user)).containsExactly("HEAD", "refs/heads/master");
+    // Grant access
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(allow(Permission.READ).ref("refs/meta/config").group(externalGroup))
+        .update();
+    // Check that refs/meta/config became visible
+    assertThat(getVisibleRefNames(user))
+        .containsExactly("HEAD", "refs/heads/master", "refs/meta/config");
+  }
+
+  @Test
+  public void changeVisibility_changeOnInvisibleBranchNotVisible() throws Exception {
+    // Create a change that is not visible to members of 'externalGroup'
+    Change.Id invisibleChange =
+        changeOperations.newChange().project(project).branch("refs/meta/config").create();
+    GroupBackedUser user =
+        new GroupBackedUser(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS, externalGroup));
+    AuthException thrown =
+        assertThrows(
+            AuthException.class,
+            () ->
+                permissionBackend
+                    .user(user)
+                    .change(changeNotesFactory.create(project, invisibleChange))
+                    .check(ChangePermission.READ));
+    assertThat(thrown).hasMessageThat().isEqualTo("read not permitted");
+  }
+
+  @Test
+  public void changeVisibility_changeOnBranchVisibleToAnonymousIsVisible() throws Exception {
+    Change.Id changeId = changeOperations.newChange().project(project).create();
+    GroupBackedUser user =
+        new GroupBackedUser(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS, externalGroup));
+    permissionBackend
+        .user(user)
+        .change(changeNotesFactory.create(project, changeId))
+        .check(ChangePermission.READ);
+  }
+
+  @Test
+  public void changeVisibility_changeOnBranchVisibleToRegisteredUsersIsVisible() throws Exception {
+    Change.Id changeId = changeOperations.newChange().project(project).create();
+    GroupBackedUser user =
+        new GroupBackedUser(ImmutableSet.of(ANONYMOUS_USERS, REGISTERED_USERS, externalGroup));
+    blockAnonymousRead();
+    permissionBackend
+        .user(user)
+        .change(changeNotesFactory.create(project, changeId))
+        .check(ChangePermission.READ);
+  }
+
+  private ImmutableList<String> getVisibleRefNames(CurrentUser user) throws Exception {
+    try (Repository repo = repoManager.openRepository(project)) {
+      return permissionBackend.user(user).project(project)
+          .filter(
+              repo.getRefDatabase().getRefs(), repo, PermissionBackend.RefFilterOptions.defaults())
+          .stream()
+          .map(Ref::getName)
+          .collect(toImmutableList());
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/server/util/BUILD b/javatests/com/google/gerrit/acceptance/server/util/BUILD
new file mode 100644
index 0000000..ea25784
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/util/BUILD
@@ -0,0 +1,7 @@
+load("//javatests/com/google/gerrit/acceptance:tests.bzl", "acceptance_tests")
+
+acceptance_tests(
+    srcs = glob(["*IT.java"]),
+    group = "server_util",
+    labels = ["server"],
+)
diff --git a/javatests/com/google/gerrit/acceptance/server/util/PluginLogFileIT.java b/javatests/com/google/gerrit/acceptance/server/util/PluginLogFileIT.java
new file mode 100644
index 0000000..06bf1ae
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/util/PluginLogFileIT.java
@@ -0,0 +1,58 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.server.util;
+
+import static junit.framework.TestCase.assertEquals;
+import static org.junit.Assert.fail;
+
+import com.google.gerrit.acceptance.AbstractPluginLogFileTest;
+import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.UseSsh;
+import com.google.inject.Inject;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import org.junit.Test;
+
+@NoHttpd
+@UseSsh
+public class PluginLogFileIT extends AbstractPluginLogFileTest {
+  @Inject private InvocationCounter invocationCounter;
+  private static final int NUMBER_OF_THREADS = 5;
+
+  @Test
+  public void testMultiThreadedPluginLogFile() throws Exception {
+    try (AutoCloseable ignored = installPlugin("my-plugin", Module.class)) {
+      ExecutorService service = Executors.newFixedThreadPool(NUMBER_OF_THREADS);
+      CountDownLatch latch = new CountDownLatch(NUMBER_OF_THREADS);
+      createChange();
+      for (int i = 0; i < NUMBER_OF_THREADS; i++) {
+        service.execute(
+            () -> {
+              try {
+                adminSshSession.exec("gerrit query --format json status:open --my-plugin--opt");
+                adminSshSession.assertSuccess();
+              } catch (Exception e) {
+                fail(e.getMessage());
+              } finally {
+                latch.countDown();
+              }
+            });
+      }
+      latch.await();
+      assertEquals(1, invocationCounter.getCounter());
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/ssh/DynamicOptionsIT.java b/javatests/com/google/gerrit/acceptance/ssh/DynamicOptionsIT.java
new file mode 100644
index 0000000..c0f2b36
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/ssh/DynamicOptionsIT.java
@@ -0,0 +1,52 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.ssh;
+
+import static com.google.gerrit.server.query.change.OutputStreamQuery.GSON;
+import static junit.framework.TestCase.assertEquals;
+
+import com.google.common.collect.Lists;
+import com.google.gerrit.acceptance.AbstractDynamicOptionsTest;
+import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.UseSsh;
+import com.google.gson.reflect.TypeToken;
+import com.google.inject.Module;
+import java.io.IOException;
+import java.util.List;
+import org.junit.Test;
+
+@NoHttpd
+@UseSsh
+public class DynamicOptionsIT extends AbstractDynamicOptionsTest {
+
+  @Override
+  public Module createSshModule() {
+    return new AbstractDynamicOptionsTest.PluginOneSshModule();
+  }
+
+  @Test
+  public void testDynamicPluginOptions() throws Exception {
+    try (AutoCloseable ignored =
+        installPlugin("my-plugin", AbstractDynamicOptionsTest.PluginTwoModule.class)) {
+      List<String> samples = getSamplesList(adminSshSession.exec("ls-samples"));
+      adminSshSession.assertSuccess();
+      assertEquals(Lists.newArrayList("sample1", "sample2"), samples);
+    }
+  }
+
+  protected List<String> getSamplesList(String sshOutput) throws IOException {
+    return GSON.fromJson(sshOutput, new TypeToken<List<String>>() {}.getType());
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/ssh/LifecycleListenersIT.java b/javatests/com/google/gerrit/acceptance/ssh/LifecycleListenersIT.java
new file mode 100644
index 0000000..0596cad
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/ssh/LifecycleListenersIT.java
@@ -0,0 +1,57 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.ssh;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gerrit.acceptance.AbstractLifecycleListenersTest;
+import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.UseSsh;
+import com.google.inject.Inject;
+import org.junit.Before;
+import org.junit.Test;
+
+@NoHttpd
+@UseSsh
+public class LifecycleListenersIT extends AbstractLifecycleListenersTest {
+  @Inject private InvocationCheck invocationCheck;
+
+  @Before
+  public void before() {
+    invocationCheck.setStartInvoked(false);
+    invocationCheck.setStopInvoked(false);
+  }
+
+  @Test
+  public void lifecycleListenerSuccessfulInvocation() throws Exception {
+    try (AutoCloseable ignored = installPlugin("my-plugin", SimpleModule.class)) {
+      adminSshSession.exec("gerrit query --format json status:open --my-plugin--opt");
+      adminSshSession.assertSuccess();
+      assertTrue(invocationCheck.isStartInvoked());
+      assertTrue(invocationCheck.isStopInvoked());
+    }
+  }
+
+  @Test
+  public void lifecycleListenerUnsuccessfulInvocation() throws Exception {
+    try (AutoCloseable ignored = installPlugin("my-plugin", SimpleModule.class)) {
+      adminSshSession.exec("gerrit ls-projects");
+      adminSshSession.assertSuccess();
+      assertFalse(invocationCheck.isStartInvoked());
+      assertFalse(invocationCheck.isStopInvoked());
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/ssh/PluginChangeFieldsIT.java b/javatests/com/google/gerrit/acceptance/ssh/PluginChangeFieldsIT.java
index 38293f9..009e05d 100644
--- a/javatests/com/google/gerrit/acceptance/ssh/PluginChangeFieldsIT.java
+++ b/javatests/com/google/gerrit/acceptance/ssh/PluginChangeFieldsIT.java
@@ -14,7 +14,6 @@
 
 package com.google.gerrit.acceptance.ssh;
 
-import static com.google.common.truth.Truth.assertThat;
 import static java.util.stream.Collectors.joining;
 
 import com.google.common.collect.ImmutableListMultimap;
@@ -41,31 +40,12 @@
   private static final Gson GSON = OutputStreamQuery.GSON;
 
   @Test
-  public void queryChangeWithNullAttribute() throws Exception {
-    getChangeWithNullAttribute(
-        id -> pluginInfoFromSingletonList(adminSshSession.exec(changeQueryCmd(id))));
-  }
-
-  @Test
-  public void queryChangeWithSimpleAttribute() throws Exception {
-    getChangeWithSimpleAttribute(
-        id -> pluginInfoFromSingletonList(adminSshSession.exec(changeQueryCmd(id))));
-  }
-
-  @Test
   public void querySingleChangeWithBulkAttribute() throws Exception {
     getSingleChangeWithPluginDefinedBulkAttribute(
         id -> pluginInfosFromList(adminSshSession.exec(changeQueryCmd(id))));
   }
 
   @Test
-  public void queryChangeWithOption() throws Exception {
-    getChangeWithOption(
-        id -> pluginInfoFromSingletonList(adminSshSession.exec(changeQueryCmd(id))),
-        (id, opts) -> pluginInfoFromSingletonList(adminSshSession.exec(changeQueryCmd(id, opts))));
-  }
-
-  @Test
   public void queryPluginDefinedAttributeChangeWithOption() throws Exception {
     getChangeWithPluginDefinedBulkAttributeOption(
         id -> pluginInfosFromList(adminSshSession.exec(changeQueryCmd(id))),
@@ -85,12 +65,6 @@
   }
 
   @Test
-  public void getMultipleChangesWithPluginDefinedAndChangeAttributes() throws Exception {
-    getMultipleChangesWithPluginDefinedBulkAndChangeAttributes(
-        () -> pluginInfosFromList(adminSshSession.exec("gerrit query --format json status:open")));
-  }
-
-  @Test
   public void getMultipleChangesWithPluginDefinedAttributeInSingleCall() throws Exception {
     getMultipleChangesWithPluginDefinedBulkAttributeInSingleCall(
         () -> pluginInfosFromList(adminSshSession.exec("gerrit query --format json status:open")));
@@ -116,15 +90,6 @@
   }
 
   @Nullable
-  private static List<PluginDefinedInfo> pluginInfoFromSingletonList(String sshOutput)
-      throws Exception {
-    List<Map<String, Object>> changeAttrs = getChangeAttrs(sshOutput);
-
-    assertThat(changeAttrs).hasSize(1);
-    return decodeRawPluginsList(GSON, changeAttrs.get(0).get("plugins"));
-  }
-
-  @Nullable
   private static Map<Change.Id, List<PluginDefinedInfo>> pluginInfosFromList(String sshOutput)
       throws Exception {
     List<Map<String, Object>> changeAttrs = getChangeAttrs(sshOutput);
diff --git a/javatests/com/google/gerrit/acceptance/testsuite/request/RequestScopeOperationsImplTest.java b/javatests/com/google/gerrit/acceptance/testsuite/request/RequestScopeOperationsImplTest.java
index f6421a5..48fd38c 100644
--- a/javatests/com/google/gerrit/acceptance/testsuite/request/RequestScopeOperationsImplTest.java
+++ b/javatests/com/google/gerrit/acceptance/testsuite/request/RequestScopeOperationsImplTest.java
@@ -16,7 +16,6 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
-import static com.google.common.truth.Truth8.assertThat;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
 import com.google.common.collect.ImmutableSet;
@@ -29,7 +28,6 @@
 import com.google.gerrit.extensions.common.ChangeInput;
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.CurrentUser.PropertyKey;
 import com.google.gerrit.server.notedb.Sequences;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -75,19 +73,6 @@
   }
 
   @Test
-  public void resetCurrentApiUserClearsCachedState() throws Exception {
-    requestScopeOperations.setApiUser(user.id());
-    PropertyKey<String> key = PropertyKey.create();
-    atrScope.get().getUser().put(key, "foo");
-    assertThat(atrScope.get().getUser().get(key)).hasValue("foo");
-
-    AcceptanceTestRequestScope.Context oldCtx = requestScopeOperations.resetCurrentApiUser();
-    checkCurrentUser(user.id());
-    assertThat(atrScope.get().getUser().get(key)).isEmpty();
-    assertThat(oldCtx.getUser().get(key)).hasValue("foo");
-  }
-
-  @Test
   public void setApiUserAnonymousSetsAnonymousUser() throws Exception {
     fastCheckCurrentUser(admin.id());
     requestScopeOperations.setApiUserAnonymous();
diff --git a/javatests/com/google/gerrit/integration/git/GitProtocolV2IT.java b/javatests/com/google/gerrit/integration/git/GitProtocolV2IT.java
index 76ce956..b52fcf46 100644
--- a/javatests/com/google/gerrit/integration/git/GitProtocolV2IT.java
+++ b/javatests/com/google/gerrit/integration/git/GitProtocolV2IT.java
@@ -91,7 +91,7 @@
       projectOperations
           .project(project)
           .forUpdate()
-          .add(deny(Permission.READ).ref("refs/*").group(SystemGroupBackend.ANONYMOUS_USERS))
+          .add(deny(Permission.READ).ref("refs/heads/*").group(SystemGroupBackend.ANONYMOUS_USERS))
           .add(
               allow(Permission.READ)
                   .ref("refs/heads/master")
diff --git a/javatests/com/google/gerrit/server/cache/serialize/BUILD b/javatests/com/google/gerrit/server/cache/serialize/BUILD
index fa6a717..6976d19 100644
--- a/javatests/com/google/gerrit/server/cache/serialize/BUILD
+++ b/javatests/com/google/gerrit/server/cache/serialize/BUILD
@@ -5,6 +5,7 @@
     srcs = glob(["*.java"]),
     deps = [
         "//java/com/google/gerrit/entities",
+        "//java/com/google/gerrit/extensions:api",
         "//java/com/google/gerrit/server",
         "//java/com/google/gerrit/server/cache/serialize",
         "//java/com/google/gerrit/server/cache/testing",
diff --git a/javatests/com/google/gerrit/server/cache/serialize/CommentContextSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/CommentContextSerializerTest.java
new file mode 100644
index 0000000..84f290c
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/CommentContextSerializerTest.java
@@ -0,0 +1,41 @@
+package com.google.gerrit.server.cache.serialize;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.server.comment.CommentContextCacheImpl.CommentContextSerializer.INSTANCE;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.CommentContext;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.server.comment.CommentContextKey;
+import org.junit.Test;
+
+public class CommentContextSerializerTest {
+  @Test
+  public void roundTripValue() {
+    CommentContext commentContext =
+        CommentContext.create(ImmutableMap.of(1, "line_1", 2, "line_2"));
+
+    byte[] serialized = INSTANCE.serialize(commentContext);
+    CommentContext deserialized = INSTANCE.deserialize(serialized);
+
+    assertThat(commentContext).isEqualTo(deserialized);
+  }
+
+  @Test
+  public void roundTripKey() {
+    Project.NameKey proj = Project.NameKey.parse("project");
+    Change.Id changeId = Change.Id.tryParse("1234").get();
+
+    CommentContextKey k =
+        CommentContextKey.builder()
+            .project(proj)
+            .changeId(changeId)
+            .id("commentId")
+            .path("pathHash")
+            .patchset(1)
+            .build();
+    byte[] serialized = CommentContextKey.Serializer.INSTANCE.serialize(k);
+    assertThat(k).isEqualTo(CommentContextKey.Serializer.INSTANCE.deserialize(serialized));
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/BUILD b/javatests/com/google/gerrit/server/cache/serialize/entities/BUILD
index 7fe73d5..b84febb 100644
--- a/javatests/com/google/gerrit/server/cache/serialize/entities/BUILD
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/BUILD
@@ -7,6 +7,7 @@
         "//java/com/google/gerrit/common:server",
         "//java/com/google/gerrit/entities",
         "//java/com/google/gerrit/extensions:api",
+        "//java/com/google/gerrit/server",
         "//java/com/google/gerrit/server/cache/serialize",
         "//java/com/google/gerrit/server/cache/serialize/entities",
         "//java/com/google/gerrit/server/cache/testing",
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffCacheKeySerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffCacheKeySerializerTest.java
new file mode 100644
index 0000000..ecab07d
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffCacheKeySerializerTest.java
@@ -0,0 +1,50 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.server.patch.filediff.FileDiffCacheKey;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithm;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+/** Tests the protobuf serializer for the {@link FileDiffCacheKey}. */
+public class FileDiffCacheKeySerializerTest {
+  private static final ObjectId COMMIT_ID_1 =
+      ObjectId.fromString("123e9fa8a286255ac7d5ba11b598892735758391");
+  private static final ObjectId COMMIT_ID_2 =
+      ObjectId.fromString("d07a03a9818c120301cb5b4a969b035479400b5f");
+
+  @Test
+  public void roundTrip() {
+    FileDiffCacheKey key =
+        FileDiffCacheKey.builder()
+            .project(Project.nameKey("project/x"))
+            .oldCommit(COMMIT_ID_1)
+            .newCommit(COMMIT_ID_2)
+            .newFilePath("some_file.txt")
+            .renameScore(65)
+            .diffAlgorithm(DiffAlgorithm.HISTOGRAM)
+            .whitespace(Whitespace.IGNORE_ALL)
+            .build();
+
+    byte[] serialized = FileDiffCacheKey.Serializer.INSTANCE.serialize(key);
+
+    assertThat(FileDiffCacheKey.Serializer.INSTANCE.deserialize(serialized)).isEqualTo(key);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java
new file mode 100644
index 0000000..4307954
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java
@@ -0,0 +1,51 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.entities.Patch.PatchType;
+import com.google.gerrit.server.patch.filediff.Edit;
+import com.google.gerrit.server.patch.filediff.FileDiffOutput;
+import com.google.gerrit.server.patch.filediff.TaggedEdit;
+import java.util.Optional;
+import org.junit.Test;
+
+public class FileDiffOutputSerializerTest {
+  @Test
+  public void roundTrip() {
+    ImmutableList<TaggedEdit> edits =
+        ImmutableList.of(
+            TaggedEdit.create(Edit.create(1, 5, 3, 4), true),
+            TaggedEdit.create(Edit.create(21, 30, 150, 158), false));
+
+    FileDiffOutput fileDiff =
+        FileDiffOutput.builder()
+            .oldPath(Optional.of("old_file_path.txt"))
+            .newPath(Optional.empty())
+            .changeType(Optional.of(ChangeType.DELETED))
+            .patchType(Optional.of(PatchType.UNIFIED))
+            .size(23)
+            .sizeDelta(10)
+            .headerLines(ImmutableList.of("header line 1", "header line 2"))
+            .edits(edits)
+            .build();
+
+    byte[] serialized = FileDiffOutput.Serializer.INSTANCE.serialize(fileDiff);
+    assertThat(FileDiffOutput.Serializer.INSTANCE.deserialize(serialized)).isEqualTo(fileDiff);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffKeySerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffKeySerializerTest.java
new file mode 100644
index 0000000..12d8d00
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffKeySerializerTest.java
@@ -0,0 +1,49 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithm;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheKey;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+public class GitFileDiffKeySerializerTest {
+  private static final ObjectId TREE_ID_1 =
+      ObjectId.fromString("123e9fa8a286255ac7d5ba11b598892735758391");
+  private static final ObjectId TREE_ID_2 =
+      ObjectId.fromString("d07a03a9818c120301cb5b4a969b035479400b5f");
+
+  @Test
+  public void roundTrip() {
+    GitFileDiffCacheKey key =
+        GitFileDiffCacheKey.builder()
+            .project(Project.nameKey("project/x"))
+            .oldTree(TREE_ID_1)
+            .newTree(TREE_ID_2)
+            .newFilePath("some_file.txt")
+            .renameScore(65)
+            .diffAlgorithm(DiffAlgorithm.HISTOGRAM)
+            .whitespace(Whitespace.IGNORE_ALL)
+            .build();
+
+    byte[] serialized = GitFileDiffCacheKey.Serializer.INSTANCE.serialize(key);
+
+    assertThat(GitFileDiffCacheKey.Serializer.INSTANCE.deserialize(serialized)).isEqualTo(key);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java
new file mode 100644
index 0000000..8030818
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java
@@ -0,0 +1,59 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.entities.Patch.FileMode;
+import com.google.gerrit.entities.Patch.PatchType;
+import com.google.gerrit.server.patch.filediff.Edit;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiff;
+import com.google.gerrit.server.patch.gitfilediff.GitFileDiff.Serializer;
+import java.util.Optional;
+import org.eclipse.jgit.lib.AbbreviatedObjectId;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+public class GitFileDiffSerializerTest {
+  private static final ObjectId OLD_ID =
+      ObjectId.fromString("123e9fa8a286255ac7d5ba11b598892735758391");
+  private static final ObjectId NEW_ID =
+      ObjectId.fromString("d07a03a9818c120301cb5b4a969b035479400b5f");
+
+  @Test
+  public void roundTrip() {
+    ImmutableList<Edit> edits =
+        ImmutableList.of(Edit.create(1, 5, 3, 4), Edit.create(21, 30, 150, 158));
+
+    GitFileDiff gitFileDiff =
+        GitFileDiff.builder()
+            .edits(edits)
+            .fileHeader("file_header")
+            .oldPath(Optional.of("old_file_path.txt"))
+            .newPath(Optional.empty())
+            .oldId(AbbreviatedObjectId.fromObjectId(OLD_ID))
+            .newId(AbbreviatedObjectId.fromObjectId(NEW_ID))
+            .changeType(Optional.of(ChangeType.DELETED))
+            .patchType(Optional.of(PatchType.UNIFIED))
+            .oldMode(Optional.of(FileMode.REGULAR_FILE))
+            .newMode(Optional.of(FileMode.REGULAR_FILE))
+            .build();
+
+    byte[] serialized = Serializer.INSTANCE.serialize(gitFileDiff);
+    assertThat(Serializer.INSTANCE.deserialize(serialized)).isEqualTo(gitFileDiff);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/GitModifiedFilesCacheKeySerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/GitModifiedFilesCacheKeySerializerTest.java
new file mode 100644
index 0000000..caf1fbb
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/GitModifiedFilesCacheKeySerializerTest.java
@@ -0,0 +1,43 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheKey;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheKey.Serializer;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+public class GitModifiedFilesCacheKeySerializerTest {
+  private static final ObjectId TREE_ID_1 =
+      ObjectId.fromString("123e9fa8a286255ac7d5ba11b598892735758391");
+  private static final ObjectId TREE_ID_2 =
+      ObjectId.fromString("d07a03a9818c120301cb5b4a969b035479400b5f");
+
+  @Test
+  public void roundTrip() {
+    GitModifiedFilesCacheKey key =
+        GitModifiedFilesCacheKey.builder()
+            .project(Project.NameKey.parse("Project/X"))
+            .aTree(TREE_ID_1)
+            .bTree(TREE_ID_2)
+            .renameScore(65)
+            .build();
+    byte[] serialized = Serializer.INSTANCE.serialize(key);
+    assertThat(Serializer.INSTANCE.deserialize(serialized)).isEqualTo(key);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesCacheKeySerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesCacheKeySerializerTest.java
new file mode 100644
index 0000000..b39ba57
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesCacheKeySerializerTest.java
@@ -0,0 +1,42 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.server.patch.diff.ModifiedFilesCacheKey;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+public class ModifiedFilesCacheKeySerializerTest {
+  private static final ObjectId COMMIT_ID_1 =
+      ObjectId.fromString("123e9fa8a286255ac7d5ba11b598892735758391");
+  private static final ObjectId COMMIT_ID_2 =
+      ObjectId.fromString("d07a03a9818c120301cb5b4a969b035479400b5f");
+
+  @Test
+  public void roundTrip() {
+    ModifiedFilesCacheKey key =
+        ModifiedFilesCacheKey.builder()
+            .project(Project.NameKey.parse("Project/X"))
+            .aCommit(COMMIT_ID_1)
+            .bCommit(COMMIT_ID_2)
+            .renameScore(65)
+            .build();
+    byte[] serialized = ModifiedFilesCacheKey.Serializer.INSTANCE.serialize(key);
+    assertThat(ModifiedFilesCacheKey.Serializer.INSTANCE.deserialize(serialized)).isEqualTo(key);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesSerializerTest.java
new file mode 100644
index 0000000..bff0c5d
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/ModifiedFilesSerializerTest.java
@@ -0,0 +1,56 @@
+//  Copyright (C) 2020 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package com.google.gerrit.server.cache.serialize.entities;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.entities.Patch.ChangeType;
+import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheImpl.ValueSerializer;
+import com.google.gerrit.server.patch.gitdiff.ModifiedFile;
+import java.util.Optional;
+import org.junit.Test;
+
+public class ModifiedFilesSerializerTest {
+  @Test
+  public void roundTrip() {
+    ImmutableList.Builder<ModifiedFile> builder = ImmutableList.builder();
+
+    builder.add(
+        ModifiedFile.builder()
+            .changeType(ChangeType.DELETED)
+            .oldPath(Optional.of("file_1.txt"))
+            .newPath(Optional.of("file_2.txt"))
+            .build());
+    builder.add(
+        ModifiedFile.builder()
+            .changeType(ChangeType.ADDED)
+            .oldPath(Optional.empty())
+            .newPath(Optional.of("file_3.txt"))
+            .build());
+
+    // Note: the default value for strings in protocol buffers is the empty string, hence the
+    // serializer will not be able to differentiate between an empty optional and an optional
+    // with an empty string, i.e. if we serialize an optional with an empty string, the deserialized
+    // object will be an empty optional. That should not be problematic in this case because file
+    // paths cannot be empty anyway.
+
+    ImmutableList<ModifiedFile> modifiedFiles = builder.build();
+
+    byte[] serialized = ValueSerializer.INSTANCE.serialize(modifiedFiles);
+
+    assertThat(ValueSerializer.INSTANCE.deserialize(serialized)).isEqualTo(modifiedFiles);
+  }
+}
diff --git a/javatests/com/google/gerrit/server/git/receive/ReceivePackRefCacheTest.java b/javatests/com/google/gerrit/server/git/receive/ReceivePackRefCacheTest.java
index 698acd8..7eb6bc7 100644
--- a/javatests/com/google/gerrit/server/git/receive/ReceivePackRefCacheTest.java
+++ b/javatests/com/google/gerrit/server/git/receive/ReceivePackRefCacheTest.java
@@ -24,6 +24,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.RefNames;
 import java.util.Map;
 import org.eclipse.jgit.lib.ObjectId;
@@ -60,17 +61,18 @@
   }
 
   @Test
-  public void noCache_tipsFromObjectIdDelegatesToRefDbAndFiltersByPrefix() throws Exception {
+  public void noCache_tipsFromObjectIdDelegatesToRefDb() throws Exception {
     Ref refBla = newRef("refs/bla", "badc0feebadc0feebadc0feebadc0feebadc0fee");
-    Ref refheads = newRef(RefNames.REFS_HEADS, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
+    String patchSetRef = RefNames.REFS_CHANGES + "01/1/1";
+    Ref patchSet = newRef(patchSetRef, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
 
     RefDatabase mockRefDb = mock(RefDatabase.class);
     ReceivePackRefCache cache = ReceivePackRefCache.noCache(mockRefDb);
     when(mockRefDb.getTipsWithSha1(ObjectId.zeroId()))
-        .thenReturn(ImmutableSet.of(refBla, refheads));
+        .thenReturn(ImmutableSet.of(refBla, patchSet));
 
-    assertThat(cache.tipsFromObjectId(ObjectId.zeroId(), RefNames.REFS_HEADS))
-        .containsExactly(refheads);
+    assertThat(cache.patchSetIdsFromObjectId(ObjectId.zeroId()))
+        .containsExactly(PatchSet.Id.fromRef(patchSetRef));
     verify(mockRefDb).getTipsWithSha1(ObjectId.zeroId());
     verifyNoMoreInteractions(mockRefDb);
   }
@@ -107,25 +109,14 @@
   }
 
   @Test
-  public void advertisedRefs_tipsFromObjectIdWithNoPrefix() throws Exception {
+  public void advertisedRefs_patchSetIdsFromObjectId() throws Exception {
     Map<String, Ref> refs = setupTwoChanges();
     ReceivePackRefCache cache = ReceivePackRefCache.withAdvertisedRefs(() -> refs);
 
     assertThat(
-            cache.tipsFromObjectId(
-                ObjectId.fromString("badc0feebadc0feebadc0feebadc0feebadc0fee"), null))
-        .containsExactly(refs.get("refs/changes/01/1/1"));
-  }
-
-  @Test
-  public void advertisedRefs_tipsFromObjectIdWithPrefix() throws Exception {
-    Map<String, Ref> refs = setupTwoChanges();
-    ReceivePackRefCache cache = ReceivePackRefCache.withAdvertisedRefs(() -> refs);
-
-    assertThat(
-            cache.tipsFromObjectId(
-                ObjectId.fromString("badc0feebadc0feebadc0feebadc0feebadc0fee"), "/refs/some"))
-        .isEmpty();
+            cache.patchSetIdsFromObjectId(
+                ObjectId.fromString("badc0feebadc0feebadc0feebadc0feebadc0fee")))
+        .containsExactly(PatchSet.Id.fromRef("refs/changes/01/1/1"));
   }
 
   private static Ref newRef(String name, String sha1) {
diff --git a/javatests/com/google/gerrit/server/index/change/ChangeIndexRewriterTest.java b/javatests/com/google/gerrit/server/index/change/ChangeIndexRewriterTest.java
index f5d3bf7..e5b2ffb 100644
--- a/javatests/com/google/gerrit/server/index/change/ChangeIndexRewriterTest.java
+++ b/javatests/com/google/gerrit/server/index/change/ChangeIndexRewriterTest.java
@@ -107,6 +107,32 @@
   }
 
   @Test
+  public void threeLevelTreeWithMultipleSources() throws Exception {
+    Predicate<ChangeData> in = parse("-status:abandoned (foo:a OR file:b)");
+    Predicate<ChangeData> out = rewrite(in);
+    assertThat(out.getClass()).isSameInstanceAs(AndChangeSource.class);
+
+    Predicate<ChangeData> firstIndexedSubQuery = parse("-status:abandoned");
+
+    assertThat(out.getChild(0)).isEqualTo(query(firstIndexedSubQuery));
+
+    assertThat(out.getChild(1).getClass()).isSameInstanceAs(OrSource.class);
+    OrSource indexedSubTree = (OrSource) out.getChild(1);
+
+    Predicate<ChangeData> secondIndexedSubQuery = parse("foo:a OR file:b");
+    assertThat(indexedSubTree.getChildren())
+        .containsExactly(
+            query(secondIndexedSubQuery.getChild(1)), secondIndexedSubQuery.getChild(0))
+        .inOrder();
+
+    // Same at the assertions above, that were added for readability
+    assertThat(out.getChild(0)).isEqualTo(query(in.getChild(0)));
+    assertThat(indexedSubTree.getChildren())
+        .containsExactly(query(in.getChild(1).getChild(1)), in.getChild(1).getChild(0))
+        .inOrder();
+  }
+
+  @Test
   public void threeLevelTreeWithSomeIndexPredicates() throws Exception {
     Predicate<ChangeData> in = parse("-foo:a (file:b OR file:c)");
     Predicate<ChangeData> out = rewrite(in);
diff --git a/javatests/com/google/gerrit/server/logging/LoggingContextAwareExecutorServiceTest.java b/javatests/com/google/gerrit/server/logging/LoggingContextAwareExecutorServiceTest.java
index 733d784..8d019f3 100644
--- a/javatests/com/google/gerrit/server/logging/LoggingContextAwareExecutorServiceTest.java
+++ b/javatests/com/google/gerrit/server/logging/LoggingContextAwareExecutorServiceTest.java
@@ -24,8 +24,8 @@
 import com.google.inject.Guice;
 import com.google.inject.Inject;
 import com.google.inject.Injector;
-import java.util.SortedMap;
-import java.util.SortedSet;
+import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import org.eclipse.jgit.lib.Config;
@@ -76,7 +76,7 @@
       // Create a performance log record.
       TraceContext.newTimer("test").close();
 
-      SortedMap<String, SortedSet<Object>> tagMap = LoggingContext.getInstance().getTags().asMap();
+      Map<String, ? extends Set<Object>> tagMap = LoggingContext.getInstance().getTags().asMap();
       assertThat(tagMap.keySet()).containsExactly("foo");
       assertThat(tagMap.get("foo")).containsExactly("bar");
       assertForceLogging(true);
@@ -90,7 +90,7 @@
               () -> {
                 // Verify that the tags and force logging flag have been propagated to the new
                 // thread.
-                SortedMap<String, SortedSet<Object>> threadTagMap =
+                Map<String, ? extends Set<Object>> threadTagMap =
                     LoggingContext.getInstance().getTags().asMap();
                 expect.that(threadTagMap.keySet()).containsExactly("foo");
                 expect.that(threadTagMap.get("foo")).containsExactly("bar");
diff --git a/javatests/com/google/gerrit/server/logging/MutableTagsTest.java b/javatests/com/google/gerrit/server/logging/MutableTagsTest.java
index f6f3b46..200c49d 100644
--- a/javatests/com/google/gerrit/server/logging/MutableTagsTest.java
+++ b/javatests/com/google/gerrit/server/logging/MutableTagsTest.java
@@ -21,8 +21,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSetMultimap;
 import java.util.Map;
-import java.util.SortedMap;
-import java.util.SortedSet;
+import java.util.Set;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -157,7 +156,7 @@
   }
 
   private void assertTags(ImmutableMap<String, ImmutableSet<String>> expectedTagMap) {
-    SortedMap<String, SortedSet<Object>> actualTagMap = tags.getTags().asMap();
+    Map<String, ? extends Set<Object>> actualTagMap = tags.getTags().asMap();
     assertThat(actualTagMap.keySet()).containsExactlyElementsIn(expectedTagMap.keySet());
     for (Map.Entry<String, ImmutableSet<String>> expectedEntry : expectedTagMap.entrySet()) {
       assertThat(actualTagMap.get(expectedEntry.getKey()))
diff --git a/javatests/com/google/gerrit/server/logging/TraceContextTest.java b/javatests/com/google/gerrit/server/logging/TraceContextTest.java
index 13f2035..6a3632d 100644
--- a/javatests/com/google/gerrit/server/logging/TraceContextTest.java
+++ b/javatests/com/google/gerrit/server/logging/TraceContextTest.java
@@ -21,8 +21,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.server.logging.TraceContext.TraceIdConsumer;
 import java.util.Map;
-import java.util.SortedMap;
-import java.util.SortedSet;
+import java.util.Set;
 import org.junit.After;
 import org.junit.Test;
 
@@ -254,7 +253,7 @@
   }
 
   private void assertTags(ImmutableMap<String, ImmutableSet<String>> expectedTagMap) {
-    SortedMap<String, SortedSet<Object>> actualTagMap =
+    Map<String, ? extends Set<Object>> actualTagMap =
         LoggingContext.getInstance().getTags().asMap();
     assertThat(actualTagMap.keySet()).containsExactlyElementsIn(expectedTagMap.keySet());
     for (Map.Entry<String, ImmutableSet<String>> expectedEntry : expectedTagMap.entrySet()) {
diff --git a/javatests/com/google/gerrit/server/notedb/ChangeNotesStateTest.java b/javatests/com/google/gerrit/server/notedb/ChangeNotesStateTest.java
index dd3238f..6c5bc2e 100644
--- a/javatests/com/google/gerrit/server/notedb/ChangeNotesStateTest.java
+++ b/javatests/com/google/gerrit/server/notedb/ChangeNotesStateTest.java
@@ -634,6 +634,39 @@
   }
 
   @Test
+  public void serializeAllAttentionSetUpdates() throws Exception {
+    assertRoundTrip(
+        newBuilder()
+            .allAttentionSetUpdates(
+                ImmutableList.of(
+                    AttentionSetUpdate.createFromRead(
+                        Instant.EPOCH.plusSeconds(23),
+                        Account.id(1000),
+                        AttentionSetUpdate.Operation.ADD,
+                        "reason 1"),
+                    AttentionSetUpdate.createFromRead(
+                        Instant.EPOCH.plusSeconds(42),
+                        Account.id(2000),
+                        AttentionSetUpdate.Operation.REMOVE,
+                        "reason 2")))
+            .build(),
+        newProtoBuilder()
+            .addAllAttentionSetUpdate(
+                AttentionSetUpdateProto.newBuilder()
+                    .setTimestampMillis(23_000) // epoch millis
+                    .setAccount(1000)
+                    .setOperation("ADD")
+                    .setReason("reason 1"))
+            .addAllAttentionSetUpdate(
+                AttentionSetUpdateProto.newBuilder()
+                    .setTimestampMillis(42_000) // epoch millis
+                    .setAccount(2000)
+                    .setOperation("REMOVE")
+                    .setReason("reason 2"))
+            .build());
+  }
+
+  @Test
   public void serializeAssigneeUpdates() throws Exception {
     assertRoundTrip(
         newBuilder()
@@ -793,6 +826,9 @@
                     "attentionSet",
                     new TypeLiteral<ImmutableSet<AttentionSetUpdate>>() {}.getType())
                 .put(
+                    "allAttentionSetUpdates",
+                    new TypeLiteral<ImmutableList<AttentionSetUpdate>>() {}.getType())
+                .put(
                     "assigneeUpdates",
                     new TypeLiteral<ImmutableList<AssigneeStatusUpdate>>() {}.getType())
                 .put("submitRecords", new TypeLiteral<ImmutableList<SubmitRecord>>() {}.getType())
@@ -801,6 +837,7 @@
                     "publishedComments",
                     new TypeLiteral<ImmutableListMultimap<ObjectId, HumanComment>>() {}.getType())
                 .put("updateCount", int.class)
+                .put("mergedOn", Timestamp.class)
                 .build());
   }
 
@@ -941,6 +978,19 @@
   }
 
   @Test
+  public void serializeMergedOn() throws Exception {
+    assertRoundTrip(
+        newBuilder().mergedOn(new Timestamp(234567L)).build(),
+        ChangeNotesStateProto.newBuilder()
+            .setMetaId(SHA_BYTES)
+            .setChangeId(ID.get())
+            .setMergedOnMillis(234567L)
+            .setHasMergedOn(true)
+            .setColumns(colsProto.toBuilder())
+            .build());
+  }
+
+  @Test
   public void changeMessageFields() throws Exception {
     assertThatSerializedClass(ChangeMessage.Key.class)
         .hasAutoValueMethods(ImmutableMap.of("changeId", Change.Id.class, "uuid", String.class));
diff --git a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
index 938fffc..ae7727d 100644
--- a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
+++ b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
@@ -677,6 +677,74 @@
   }
 
   @Test
+  public void mergedOnEmptyIfNotSubmitted() throws Exception {
+    Change c = newChange();
+
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    // Make sure unrelevent update does not set mergedOn.
+    update.setTopic("topic");
+    update.commit();
+    assertThat(newNotes(c).getMergedOn()).isEmpty();
+  }
+
+  @Test
+  public void mergedOnSetWhenSubmitted() throws Exception {
+    Change c = newChange();
+
+    SubmissionId submissionId = new SubmissionId(c);
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.setSubjectForCommit("Update patch set 1");
+    update.merge(
+        submissionId,
+        ImmutableList.of(
+            submitRecord("OK", null, submitLabel("Code-Review", "OK", otherUser.getAccountId()))));
+    update.commit();
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getMergedOn()).isPresent();
+    Timestamp mergedOn = notes.getMergedOn().get();
+    assertThat(mergedOn).isEqualTo(notes.getChange().getLastUpdatedOn());
+
+    // Next update does not change mergedOn date.
+    update = newUpdate(c, changeOwner);
+    update.putApproval("Code-Review", (short) 1);
+    update.commit();
+    notes = newNotes(c);
+    assertThat(notes.getMergedOn().get()).isEqualTo(mergedOn);
+    assertThat(notes.getMergedOn().get()).isLessThan(notes.getChange().getLastUpdatedOn());
+  }
+
+  @Test
+  public void latestMergedOn() throws Exception {
+    Change c = newChange();
+    SubmissionId submissionId = new SubmissionId(c);
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.setSubjectForCommit("Update patch set 1");
+    update.merge(
+        submissionId,
+        ImmutableList.of(
+            submitRecord("OK", null, submitLabel("Code-Review", "OK", otherUser.getAccountId()))));
+    update.commit();
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getMergedOn()).isPresent();
+    Timestamp mergedOn = notes.getMergedOn().get();
+    assertThat(mergedOn).isEqualTo(notes.getChange().getLastUpdatedOn());
+
+    incrementPatchSet(c);
+    update = newUpdate(c, changeOwner);
+    update.setSubjectForCommit("Update patch set 2");
+    update.merge(
+        submissionId,
+        ImmutableList.of(
+            submitRecord(
+                "OK", null, submitLabel("Code-Review", "OK", changeOwner.getAccountId()))));
+    update.commit();
+
+    notes = newNotes(c);
+    assertThat(notes.getMergedOn().get()).isGreaterThan(mergedOn);
+    assertThat(notes.getMergedOn().get()).isEqualTo(notes.getChange().getLastUpdatedOn());
+  }
+
+  @Test
   public void emptyChangeUpdate() throws Exception {
     Change c = newChange();
     Ref initial = repo.exactRef(changeMetaRef(c.getId()));
@@ -699,6 +767,13 @@
   }
 
   @Test
+  public void defaultAttentionSetUpdatesIsEmpty() throws Exception {
+    Change c = newChange();
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getAttentionSetUpdates()).isEmpty();
+  }
+
+  @Test
   public void addAttentionStatus() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
@@ -712,6 +787,19 @@
   }
 
   @Test
+  public void addAllAttentionUpdates() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    AttentionSetUpdate attentionSetUpdate =
+        AttentionSetUpdate.createForWrite(changeOwner.getAccountId(), Operation.ADD, "test");
+    update.addToPlannedAttentionSetUpdates(ImmutableSet.of(attentionSetUpdate));
+    update.commit();
+
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getAttentionSetUpdates()).containsExactly(addTimestamp(attentionSetUpdate, c));
+  }
+
+  @Test
   public void filterLatestAttentionStatus() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
@@ -730,6 +818,28 @@
   }
 
   @Test
+  public void DoesNotFilterLatestAttentionSetUpdates() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    AttentionSetUpdate firstAttentionSetUpdate =
+        AttentionSetUpdate.createForWrite(changeOwner.getAccountId(), Operation.ADD, "test");
+    update.addToPlannedAttentionSetUpdates(ImmutableSet.of(firstAttentionSetUpdate));
+    update.commit();
+    update = newUpdate(c, changeOwner);
+    firstAttentionSetUpdate = addTimestamp(firstAttentionSetUpdate, c);
+
+    AttentionSetUpdate secondAttentionSetUpdate =
+        AttentionSetUpdate.createForWrite(changeOwner.getAccountId(), Operation.REMOVE, "test");
+    update.addToPlannedAttentionSetUpdates(ImmutableSet.of(secondAttentionSetUpdate));
+    update.commit();
+    secondAttentionSetUpdate = addTimestamp(secondAttentionSetUpdate, c);
+
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getAttentionSetUpdates())
+        .containsExactly(secondAttentionSetUpdate, firstAttentionSetUpdate);
+  }
+
+  @Test
   public void addAttentionStatus_rejectTimestamp() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
@@ -767,6 +877,8 @@
   public void addAttentionStatusForMultipleUsers() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
+    // put the user as cc to ensure that the user took part in this change.
+    update.putReviewer(otherUser.getAccount().id(), CC);
     AttentionSetUpdate attentionSetUpdate0 =
         AttentionSetUpdate.createForWrite(changeOwner.getAccountId(), Operation.ADD, "test");
     AttentionSetUpdate attentionSetUpdate1 =
@@ -3146,6 +3258,34 @@
   }
 
   @Test
+  public void resetCherryPickOf() throws Exception {
+    Change destinationChange = newChange();
+    Change cherryPickChange = newChange();
+    assertThat(newNotes(destinationChange).getChange().getCherryPickOf()).isNull();
+
+    ChangeUpdate update = newUpdate(destinationChange, changeOwner);
+    update.setCherryPickOf(
+        cherryPickChange.currentPatchSetId().getCommaSeparatedChangeAndPatchSetId());
+    update.commit();
+    assertThat(newNotes(destinationChange).getChange().getCherryPickOf())
+        .isEqualTo(cherryPickChange.currentPatchSetId());
+
+    update = newUpdate(destinationChange, changeOwner);
+    update.resetCherryPickOf();
+    update.commit();
+    assertThat(newNotes(destinationChange).getChange().getCherryPickOf()).isNull();
+
+    // Can set again after reset.
+    cherryPickChange = newChange();
+    update = newUpdate(destinationChange, changeOwner);
+    update.setCherryPickOf(
+        cherryPickChange.currentPatchSetId().getCommaSeparatedChangeAndPatchSetId());
+    update.commit();
+    assertThat(newNotes(destinationChange).getChange().getCherryPickOf())
+        .isEqualTo(cherryPickChange.currentPatchSetId());
+  }
+
+  @Test
   public void updateCount() throws Exception {
     Change c = newChange();
     assertThat(newNotes(c).getUpdateCount()).isEqualTo(1);
diff --git a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
index 6cfd9f2d..ededc42 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
@@ -61,8 +61,7 @@
             + "Reviewer: Gerrit User 1 <1@gerrit>\n"
             + "CC: Gerrit User 2 <2@gerrit>\n"
             + "Label: Code-Review=-1\n"
-            + "Label: Verified=+1\n"
-            + "Attention: {\"person_ident\":\"Gerrit User 1 \\u003c1@gerrit\\u003e\",\"operation\":\"ADD\",\"reason\":\"Reviewer was added\"}\n",
+            + "Label: Verified=+1\n",
         commit);
 
     PersonIdent author = commit.getAuthorIdent();
@@ -245,8 +244,7 @@
     update.commit();
 
     assertBodyEquals(
-        "Update patch set 1\n\nPatch-set: 1\nReviewer: Gerrit User 1 <1@gerrit>\n"
-            + "Attention: {\"person_ident\":\"Gerrit User 1 \\u003c1@gerrit\\u003e\",\"operation\":\"ADD\",\"reason\":\"Reviewer was added\"}\n",
+        "Update patch set 1\n\nPatch-set: 1\nReviewer: Gerrit User 1 <1@gerrit>\n",
         update.getResult());
   }
 
diff --git a/javatests/com/google/gerrit/server/project/GroupListTest.java b/javatests/com/google/gerrit/server/project/GroupListTest.java
index 7d4b7ca..853507d 100644
--- a/javatests/com/google/gerrit/server/project/GroupListTest.java
+++ b/javatests/com/google/gerrit/server/project/GroupListTest.java
@@ -26,6 +26,7 @@
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.GroupReference;
 import com.google.gerrit.entities.Project;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.git.ValidationError;
 import java.io.IOException;
 import java.util.Collection;
@@ -57,7 +58,7 @@
     GroupReference groupReference = groupList.byUUID(uuid);
 
     assertEquals(uuid, groupReference.getUUID());
-    assertEquals("Service Users", groupReference.getName());
+    assertEquals(ServiceUserClassifier.SERVICE_USERS, groupReference.getName());
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index 02f514a..e440be0 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -85,6 +85,7 @@
 import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.index.Schema;
+import com.google.gerrit.index.query.IndexPredicate;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.lifecycle.LifecycleManager;
@@ -110,6 +111,7 @@
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.index.change.ChangeIndexCollection;
 import com.google.gerrit.server.index.change.ChangeIndexer;
+import com.google.gerrit.server.index.change.IndexedChangeQuery;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.Sequences;
 import com.google.gerrit.server.project.ProjectCache;
@@ -1573,6 +1575,10 @@
     assertThat(nowMs - lastUpdatedMs(change2)).isEqualTo(thirtyHoursInMs);
     assertThat(TimeUtil.nowMs()).isEqualTo(nowMs);
 
+    // Change1 was last updated on 2009-09-30 21:00:00 -0000
+    // Change2 was last updated on 2009-10-02 03:00:00 -0000
+    // The endpoint is 2009-10-03 09:00:00 -0000
+
     assertQuery("-age:1d");
     assertQuery("-age:" + (30 * 60 - 1) + "m");
     assertQuery("-age:2d", change2);
@@ -1580,6 +1586,15 @@
     assertQuery("age:3d");
     assertQuery("age:2d", change1);
     assertQuery("age:1d", change2, change1);
+
+    // Same test as above, but using filter code path.
+    assertQuery(makeIndexedPredicateFilterQuery("-age:1d"));
+    assertQuery(makeIndexedPredicateFilterQuery("-age:" + (30 * 60 - 1) + "m"));
+    assertQuery(makeIndexedPredicateFilterQuery("-age:2d"), change2);
+    assertQuery(makeIndexedPredicateFilterQuery("-age:3d"), change2, change1);
+    assertQuery(makeIndexedPredicateFilterQuery("age:3d"));
+    assertQuery(makeIndexedPredicateFilterQuery("age:2d"), change1);
+    assertQuery(makeIndexedPredicateFilterQuery("age:1d"), change2, change1);
   }
 
   @Test
@@ -1592,6 +1607,9 @@
     Change change2 = insert(repo, newChange(repo), null, new Timestamp(startMs + thirtyHoursInMs));
     TestTimeUtil.setClockStep(0, MILLISECONDS);
 
+    // Change1 was last updated on 2009-09-30 21:00:00 -0000
+    // Change2 was last updated on 2009-10-02 03:00:00 -0000
+
     for (String predicate : Lists.newArrayList("before:", "until:")) {
       assertQuery(predicate + "2009-09-29");
       assertQuery(predicate + "2009-09-30");
@@ -1604,6 +1622,22 @@
       assertQuery(predicate + "2009-10-01", change1);
       assertQuery(predicate + "2009-10-03", change2, change1);
     }
+
+    // Same test as above, but using filter code path.
+    for (String predicate : Lists.newArrayList("before:", "until:")) {
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-09-29"));
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-09-30"));
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "\"2009-09-30 16:59:00 -0400\""));
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "\"2009-09-30 20:59:00 -0000\""));
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "\"2009-09-30 20:59:00\""));
+      assertQuery(
+          makeIndexedPredicateFilterQuery(predicate + "\"2009-09-30 17:02:00 -0400\""), change1);
+      assertQuery(
+          makeIndexedPredicateFilterQuery(predicate + "\"2009-10-01 21:02:00 -0000\""), change1);
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "\"2009-10-01 21:02:00\""), change1);
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-10-01"), change1);
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-10-03"), change2, change1);
+    }
   }
 
   @Test
@@ -1616,6 +1650,8 @@
     Change change2 = insert(repo, newChange(repo), null, new Timestamp(startMs + thirtyHoursInMs));
     TestTimeUtil.setClockStep(0, MILLISECONDS);
 
+    // Change1 was last updated on 2009-09-30 21:00:00 -0000
+    // Change2 was last updated on 2009-10-02 03:00:00 -0000
     for (String predicate : Lists.newArrayList("after:", "since:")) {
       assertQuery(predicate + "2009-10-03");
       assertQuery(predicate + "\"2009-10-01 20:59:59 -0400\"", change2);
@@ -1623,6 +1659,197 @@
       assertQuery(predicate + "2009-10-01", change2);
       assertQuery(predicate + "2009-09-30", change2, change1);
     }
+
+    // Same test as above, but using filter code path.
+    for (String predicate : Lists.newArrayList("after:", "since:")) {
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-10-03"));
+      assertQuery(
+          makeIndexedPredicateFilterQuery(predicate + "\"2009-10-01 20:59:59 -0400\""), change2);
+      assertQuery(
+          makeIndexedPredicateFilterQuery(predicate + "\"2009-10-01 20:59:59 -0000\""), change2);
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-10-01"), change2);
+      assertQuery(makeIndexedPredicateFilterQuery(predicate + "2009-09-30"), change2, change1);
+    }
+  }
+
+  @Test
+  public void mergedOperatorSupportedByIndexVersion() throws Exception {
+    if (getSchemaVersion() < 61) {
+      assertMissingField(ChangeField.MERGED_ON);
+      assertFailingQuery(
+          "mergedbefore:2009-10-01",
+          "'mergedbefore' operator is not supported by change index version");
+      assertFailingQuery(
+          "mergedafter:2009-10-01",
+          "'mergedafter' operator is not supported by change index version");
+    } else {
+      assertThat(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    }
+  }
+
+  @Test
+  public void byMergedBefore() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change3);
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    submit(change2);
+    TestTimeUtil.setClock(new Timestamp(startMs + 3 * thirtyHoursInMs));
+    // Put another approval on the change, just to update it.
+    approve(change1);
+    approve(change3);
+
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    // Verify that:
+    // 1. Change1 was not submitted and should be never returned.
+    // 2. Change2 was merged on 2009-10-02 03:00:00 -0000
+    // 3. Change3 was merged on 2009-10-03 09:00:00.0 -0000
+    assertQuery("mergedbefore:2009-10-01");
+    // Changes excluded on the date submitted.
+    assertQuery("mergedbefore:2009-10-02");
+    assertQuery("mergedbefore:\"2009-10-01 22:59:00 -0400\"");
+    assertQuery("mergedbefore:\"2009-10-01 02:59:00\"");
+    assertQuery("mergedbefore:\"2009-10-01 23:02:00 -0400\"", change3);
+    assertQuery("mergedbefore:\"2009-10-02 03:02:00 -0000\"", change3);
+    assertQuery("mergedbefore:\"2009-10-02 03:02:00\"", change3);
+    assertQuery("mergedbefore:2009-10-03", change3);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery("mergedbefore:2009-10-04", change3, change2);
+
+    // Same test as above, but using filter code path.
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-01"));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-02"));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 22:59:00 -0400\""));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 02:59:00\""));
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 23:02:00 -0400\""), change3);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-02 03:02:00 -0000\""), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-02 03:02:00\""), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-03"), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-04"), change3, change2);
+  }
+
+  @Test
+  public void byMergedAfter() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change3);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    submit(change2);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + 3 * thirtyHoursInMs));
+    // Put another approval on the change, just to update it.
+    approve(change1);
+    approve(change3);
+
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    // Verify that:
+    // 1. Change1 was not submitted and should be never returned.
+    // 2. Change2 was merged on 2009-10-02 03:00:00 -0000
+    // 3. Change3 was merged on 2009-10-03 09:00:00.0 -0000
+    assertQuery("mergedafter:2009-10-01", change3, change2);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery("mergedafter:\"2009-10-01 22:59:00 -0400\"", change3, change2);
+    assertQuery("mergedafter:\"2009-10-02 02:59:00 -0000\"", change3, change2);
+    assertQuery("mergedafter:\"2009-10-01 23:02:00 -0400\"", change2);
+    assertQuery("mergedafter:\"2009-10-02 03:02:00 -0000\"", change2);
+    // Changes included on the date submitted.
+    assertQuery("mergedafter:2009-10-02", change3, change2);
+    assertQuery("mergedafter:2009-10-03", change2);
+
+    // Same test as above, but using filter code path.
+
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-01"), change3, change2);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-01 22:59:00 -0400\""),
+        change3,
+        change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-02 02:59:00 -0000\""),
+        change3,
+        change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-01 23:02:00 -0400\""), change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-02 03:02:00 -0000\""), change2);
+    // Changes included on the date submitted.
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-02"), change3, change2);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-03"), change2);
+  }
+
+  @Test
+  public void updatedThenMergedOrder() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change2);
+    submit(change3);
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    // Approve post submit just to update lastUpdatedOn
+    approve(change3);
+    approve(change2);
+    submit(change1);
+
+    // All Changes were last updated at the same time.
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn, then by Id in reverse order.
+    // 1. Change3 and Change2 were merged at the same time, but Change3 ID > Change2 ID.
+    // 2. Change1 ID < Change3 ID & Change2 ID but it was merged last.
+    assertQuery("mergedbefore:2009-10-06", change1, change3, change2);
+    assertQuery("mergedafter:2009-09-30", change1, change3, change2);
+    assertQuery("status:merged", change1, change3, change2);
   }
 
   @Test
@@ -3055,6 +3282,14 @@
     gApi.changes().id(change.getChangeId()).addToAttentionSet(input);
     Account.Id user2Id =
         accountManager.authenticate(AuthRequest.forUser("anotheruser")).getAccountId();
+
+    // Add the second user as cc to ensure that user took part of the change and can be added to the
+    // attention set.
+    AddReviewerInput addReviewerInput = new AddReviewerInput();
+    addReviewerInput.reviewer = user2Id.toString();
+    addReviewerInput.state = ReviewerState.CC;
+    gApi.changes().id(change.getChangeId()).addReviewer(addReviewerInput);
+
     input = new AttentionSetInput(user2Id.toString(), "reason 2");
     gApi.changes().id(change.getChangeId()).addToAttentionSet(input);
 
@@ -3085,6 +3320,7 @@
     assertQuery("-assignee:" + user.getUserName().get(), change2);
   }
 
+  @GerritConfig(name = "accounts.visibility", value = "NONE")
   @Test
   public void userDestination() throws Exception {
     TestRepository<Repo> repo1 = createProject("repo1");
@@ -3096,6 +3332,8 @@
         .hasMessageThat()
         .isEqualTo("Unknown named destination: foo");
 
+    Account.Id anotherUserId =
+        accountManager.authenticate(AuthRequest.forUser("anotheruser")).getAccountId();
     String destination1 = "refs/heads/master\trepo1";
     String destination2 = "refs/heads/master\trepo2";
     String destination3 = "refs/heads/master\trepo1\nrefs/heads/master\trepo2";
@@ -3111,8 +3349,32 @@
       allUsers.branch(refsUsers).commit().add("destinations/destination4", destination4).create();
       allUsers.branch(refsUsers).commit().add("destinations/destination5", destination5).create();
 
+      String anotherRefsUsers = RefNames.refsUsers(anotherUserId);
+      allUsers
+          .branch(anotherRefsUsers)
+          .commit()
+          .add("destinations/destination6", destination1)
+          .create();
+      allUsers
+          .branch(anotherRefsUsers)
+          .commit()
+          .add("destinations/destination7", destination2)
+          .create();
+      allUsers
+          .branch(anotherRefsUsers)
+          .commit()
+          .add("destinations/destination8", destination3)
+          .create();
+      allUsers
+          .branch(anotherRefsUsers)
+          .commit()
+          .add("destinations/destination9", destination4)
+          .create();
+
       Ref userRef = allUsers.getRepository().exactRef(refsUsers);
+      Ref anotherUserRef = allUsers.getRepository().exactRef(anotherRefsUsers);
       assertThat(userRef).isNotNull();
+      assertThat(anotherUserRef).isNotNull();
     }
 
     assertQuery("destination:destination1", change1);
@@ -3120,38 +3382,87 @@
     assertQuery("destination:destination3", change2, change1);
     assertQuery("destination:destination4");
     assertQuery("destination:destination5");
+    assertQuery("destination:destination6,user=" + anotherUserId, change1);
+    assertQuery("destination:name=destination6,user=" + anotherUserId, change1);
+    assertQuery("destination:user=" + anotherUserId + ",destination7", change2);
+    assertQuery("destination:user=" + anotherUserId + ",name=destination8", change2, change1);
+    assertQuery("destination:destination9,user=" + anotherUserId);
+
+    assertThatQueryException("destination:destination3,user=" + anotherUserId)
+        .hasMessageThat()
+        .isEqualTo("Unknown named destination: destination3");
+    assertThatQueryException("destination:destination3,user=test")
+        .hasMessageThat()
+        .isEqualTo("Account 'test' not found");
+
+    requestContext.setContext(newRequestContext(anotherUserId));
+    // account 1000000 is not visible to 'anotheruser' as they are not an admin
+    assertThatQueryException("destination:destination3,user=" + userId)
+        .hasMessageThat()
+        .isEqualTo("Account '1000000' not found");
   }
 
+  @GerritConfig(name = "accounts.visibility", value = "NONE")
   @Test
   public void userQuery() throws Exception {
     TestRepository<Repo> repo = createProject("repo");
     Change change1 = insert(repo, newChange(repo));
     Change change2 = insert(repo, newChangeForBranch(repo, "stable"));
 
+    Account.Id anotherUserId =
+        accountManager.authenticate(AuthRequest.forUser("anotheruser")).getAccountId();
     String queryListText =
         "query1\tproject:repo\n"
             + "query2\tproject:repo status:open\n"
             + "query3\tproject:repo branch:stable\n"
             + "query4\tproject:repo branch:other";
+    String anotherQueryListText =
+        "query5\tproject:repo\n"
+            + "query6\tproject:repo status:merged\n"
+            + "query7\tproject:repo branch:stable\n"
+            + "query8\tproject:repo branch:other";
 
     try (TestRepository<Repo> allUsers =
             new TestRepository<>(repoManager.openRepository(allUsersName));
-        MetaDataUpdate md = metaDataUpdateFactory.create(allUsersName)) {
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsersName);
+        MetaDataUpdate anotherMd = metaDataUpdateFactory.create(allUsersName)) {
       VersionedAccountQueries queries = VersionedAccountQueries.forUser(userId);
       queries.load(md);
       queries.setQueryList(queryListText);
       queries.commit(md);
+      VersionedAccountQueries anotherQueries = VersionedAccountQueries.forUser(anotherUserId);
+      anotherQueries.load(anotherMd);
+      anotherQueries.setQueryList(anotherQueryListText);
+      anotherQueries.commit(anotherMd);
     }
 
     assertThatQueryException("query:foo").hasMessageThat().isEqualTo("Unknown named query: foo");
+    assertThatQueryException("query:query1,user=" + anotherUserId)
+        .hasMessageThat()
+        .isEqualTo("Unknown named query: query1");
+    assertThatQueryException("query:query1,user=test")
+        .hasMessageThat()
+        .isEqualTo("Account 'test' not found");
+
+    requestContext.setContext(newRequestContext(anotherUserId));
+    // account 1000000 is not visible to 'anotheruser' as they are not an admin
+    assertThatQueryException("query:query1,user=" + userId)
+        .hasMessageThat()
+        .isEqualTo("Account '1000000' not found");
+    requestContext.setContext(newRequestContext(userId));
 
     assertQuery("query:query1", change2, change1);
     assertQuery("query:query2", change2, change1);
+    assertQuery("query:name=query5,user=" + anotherUserId, change2, change1);
+    assertQuery("query:user=" + anotherUserId + ",name=query6");
     gApi.changes().id(change1.getChangeId()).current().review(ReviewInput.approve());
     gApi.changes().id(change1.getChangeId()).current().submit();
     assertQuery("query:query2", change2);
     assertQuery("query:query3", change2);
     assertQuery("query:query4");
+    assertQuery("query:query6,user=" + anotherUserId, change1);
+    assertQuery("query:user=" + anotherUserId + ",query7", change2);
+    assertQuery("query:query8,user=" + anotherUserId);
   }
 
   @Test
@@ -3505,6 +3816,62 @@
     return c.getLastUpdatedOn().getTime();
   }
 
+  // Get the last  updated time from ChangeApi
+  protected long lastUpdatedMsApi(Change c) throws Exception {
+    return gApi.changes().id(c.getChangeId()).get().updated.getTime();
+  }
+
+  protected void approve(Change change) throws Exception {
+    gApi.changes().id(change.getChangeId()).current().review(ReviewInput.approve());
+  }
+
+  protected void submit(Change change) throws Exception {
+    approve(change);
+    gApi.changes().id(change.getChangeId()).current().submit();
+  }
+
+  /**
+   * Generates a search query to test {@link com.google.gerrit.index.query.Matchable} implementation
+   * of change {@link IndexPredicate}
+   *
+   * <p>This code path requires triggering the condition, when
+   *
+   * <ol>
+   *   <li>The query is rewritten into multiple {@link IndexedChangeQuery} by {@link
+   *       com.google.gerrit.server.index.change.ChangeIndexRewriter#rewrite}
+   *   <li>The changes are returned from the index by the first {@link IndexedChangeQuery}
+   *   <li>Then constrained in {@link com.google.gerrit.index.query.AndSource#match} by applying all
+   *       parsed predicates from the search query
+   *   <li>Thus, the rest of {@link IndexedChangeQuery} work as filters on the index results, see
+   *       {@link IndexedChangeQuery#match}
+   * </ol>
+   *
+   * The constructed query only constrains by the passed searchTerm for the operator that is being
+   * tested (for all changes without a reviewer):
+   *
+   * <ul>
+   *   <li>The search term 'status:new OR status:merged OR status:abandoned' is used to return all
+   *       changes from the search index.
+   *   <li>The non-indexed search term 'reviewerin:"Empty Group"' is only used to make the right AND
+   *       operand work as a filter (not a data source).
+   *   <li>See how it is rewritten in {@link
+   *       com.google.gerrit.server.index.change.ChangeIndexRewriterTest#threeLevelTreeWithMultipleSources}
+   * </ul>
+   *
+   * @param searchTerm change search term that maps to {@link IndexPredicate} and needs to be tested
+   *     as filter
+   * @return a search query that allows to test the {@code searchTerm} as a filter.
+   */
+  protected String makeIndexedPredicateFilterQuery(String searchTerm) throws Exception {
+    String emptyGroupName = "Empty Group";
+    if (gApi.groups().query(emptyGroupName).get().isEmpty()) {
+      createGroup(emptyGroupName, "Administrators");
+    }
+    String queryPattern =
+        "(status:new OR status:merged OR status:abandoned) AND (reviewerin:\"%s\" OR %s)";
+    return String.format(queryPattern, emptyGroupName, searchTerm);
+  }
+
   private void addComment(int changeId, String message, Boolean unresolved) throws Exception {
     ReviewInput input = new ReviewInput();
     ReviewInput.CommentInput comment = new ReviewInput.CommentInput();
diff --git a/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java b/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
index d6c5b5a..e6a6497 100644
--- a/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
+++ b/javatests/com/google/gerrit/server/schema/AllProjectsCreatorTest.java
@@ -31,6 +31,7 @@
 import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.account.GroupUuid;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.notedb.Sequences;
@@ -88,7 +89,7 @@
     expectedConfig.fromText(getDefaultAllProjectsWithAllDefaultSections());
 
     GroupReference adminsGroup = createGroupReference("Administrators");
-    GroupReference batchUsersGroup = createGroupReference("Service Users");
+    GroupReference batchUsersGroup = createGroupReference(ServiceUserClassifier.SERVICE_USERS);
     AllProjectsInput allProjectsInput =
         AllProjectsInput.builder()
             .administratorsGroup(adminsGroup)
diff --git a/javatests/com/google/gerrit/server/schema/SchemaCreatorImplTest.java b/javatests/com/google/gerrit/server/schema/SchemaCreatorImplTest.java
index 01a44f3..fc6b412 100644
--- a/javatests/com/google/gerrit/server/schema/SchemaCreatorImplTest.java
+++ b/javatests/com/google/gerrit/server/schema/SchemaCreatorImplTest.java
@@ -23,6 +23,7 @@
 import com.google.gerrit.entities.LabelType;
 import com.google.gerrit.entities.LabelTypes;
 import com.google.gerrit.entities.LabelValue;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.GitRepositoryManager;
@@ -82,7 +83,7 @@
 
   @Test
   public void groupIsCreatedWhenSchemaIsCreated() throws Exception {
-    assertThat(hasGroup("Service Users")).isTrue();
+    assertThat(hasGroup(ServiceUserClassifier.SERVICE_USERS)).isTrue();
     assertThat(hasGroup("Non-Interactive Users")).isFalse();
   }
 
diff --git a/lib/auto/BUILD b/lib/auto/BUILD
index 1da7f50..18b9b91 100644
--- a/lib/auto/BUILD
+++ b/lib/auto/BUILD
@@ -27,6 +27,21 @@
     ],
 )
 
+java_plugin(
+    name = "auto-value-gson-plugin",
+    processor_class = "com.ryanharter.auto.value.gson.factory.AutoValueGsonAdapterFactoryProcessor",
+    deps = [
+        "@auto-value-annotations//jar",
+        "@auto-value-gson-extension//jar",
+        "@auto-value-gson-factory//jar",
+        "@auto-value-gson-runtime//jar",
+        "@auto-value//jar",
+        "@autotransient//jar",
+        "@gson//jar",
+        "@javapoet//jar",
+    ],
+)
+
 java_library(
     name = "auto-value",
     data = ["//lib:LICENSE-Apache2.0"],
@@ -50,3 +65,17 @@
     visibility = ["//visibility:public"],
     exports = ["@auto-value-annotations//jar"],
 )
+
+java_library(
+    name = "auto-value-gson",
+    data = ["//lib:LICENSE-Apache2.0"],
+    exported_plugins = [
+        ":auto-value-gson-plugin",
+    ],
+    visibility = ["//visibility:public"],
+    exports = [
+        "@auto-value-gson-extension//jar",
+        "@auto-value-gson-factory//jar",
+        "@auto-value-gson-runtime//jar",
+    ],
+)
diff --git a/lib/guava.bzl b/lib/guava.bzl
deleted file mode 100644
index 4de39cb..0000000
--- a/lib/guava.bzl
+++ /dev/null
@@ -1,5 +0,0 @@
-GUAVA_VERSION = "29.0-jre"
-
-GUAVA_BIN_SHA1 = "801142b4c3d0f0770dd29abea50906cacfddd447"
-
-GUAVA_DOC_URL = "https://google.github.io/guava/releases/" + GUAVA_VERSION + "/api/docs/"
diff --git a/lib/nongoogle_test.sh b/lib/nongoogle_test.sh
index 9ec19a3..bf53eb6 100755
--- a/lib/nongoogle_test.sh
+++ b/lib/nongoogle_test.sh
@@ -22,17 +22,23 @@
 flogger
 flogger-log4j-backend
 flogger-system-backend
+guava
+guice-assistedinject
+guice-library-no-aop
+guice-servlet
 httpasyncclient
 httpcore-nio
 j2objc
 jackson-annotations
 jackson-core
+jimfs
 jna
 jruby
 mina-core
 nekohtml
 objenesis
 openid-consumer
+soy
 sshd-mina
 sshd-osgi
 testcontainers
diff --git a/modules/jgit b/modules/jgit
index 5d925ec..415788d 160000
--- a/modules/jgit
+++ b/modules/jgit
@@ -1 +1 @@
-Subproject commit 5d925ecbb3d0977c586f0001baf20aff12823de9
+Subproject commit 415788df28bcfc1788bf17bc12f06d00d822afc2
diff --git a/package.json b/package.json
index 70f290b..91b8042 100644
--- a/package.json
+++ b/package.json
@@ -2,22 +2,26 @@
   "name": "gerrit",
   "version": "3.1.0-SNAPSHOT",
   "description": "Gerrit Code Review",
-  "dependencies": {},
+  "dependencies": {
+    "@bazel/rollup": "^3.0.0-rc.1",
+    "@bazel/terser": "^3.0.0-rc.1",
+    "@bazel/typescript": "^3.0.0-rc.1"
+  },
   "devDependencies": {
-    "@bazel/rollup": "^2.0.0",
-    "@bazel/terser": "^2.0.0",
-    "@bazel/typescript": "^2.0.0",
-    "eslint": "^6.6.0",
-    "eslint-config-google": "^0.13.0",
-    "eslint-plugin-html": "^6.0.0",
-    "eslint-plugin-import": "^2.20.1",
-    "eslint-plugin-jsdoc": "^19.2.0",
-    "eslint-plugin-prettier": "^3.1.3",
-    "gts": "^2.0.2",
+    "@typescript-eslint/eslint-plugin": "^4.11.0",
+    "eslint": "^7.16.0",
+    "eslint-config-google": "^0.14.0",
+    "eslint-plugin-html": "^6.1.1",
+    "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-jsdoc": "^30.7.9",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-prettier": "^3.3.0",
+    "gts": "^3.0.3",
     "polymer-cli": "^1.9.11",
     "prettier": "2.0.5",
+    "rollup": "^2.3.4",
     "terser": "^4.8.0",
-    "typescript": "3.9.5"
+    "typescript": "4.0.5"
   },
   "scripts": {
     "clean": "git clean -fdx && bazel clean --expunge",
@@ -29,8 +33,8 @@
     "eslint": "npm run safe_bazelisk test polygerrit-ui/app:lint_test",
     "eslintfix": "npm run safe_bazelisk run polygerrit-ui/app:lint_bin -- -- --fix $(pwd)/polygerrit-ui/app",
     "polylint": "npm run safe_bazelisk test polygerrit-ui/app:polylint_test",
-    "test:debug": "npm run safe_bazelisk run //polygerrit-ui:karma_bin -- -- start $(pwd)/polygerrit-ui/karma.conf.js --browsers ChromeDev --no-single-run --testFiles",
-    "test:single": "npm run safe_bazelisk run //polygerrit-ui:karma_bin -- -- start $(pwd)/polygerrit-ui/karma.conf.js --testFiles"
+    "test:debug": "npm run compile:local && npm run safe_bazelisk run //polygerrit-ui:karma_bin -- -- start $(pwd)/polygerrit-ui/karma.conf.js --browsers ChromeDev --no-single-run --testFiles",
+    "test:single": "npm run compile:local && npm run safe_bazelisk run //polygerrit-ui:karma_bin -- -- start $(pwd)/polygerrit-ui/karma.conf.js --testFiles"
   },
   "repository": {
     "type": "git",
diff --git a/plugins/codemirror-editor b/plugins/codemirror-editor
index 7357ab4..740c35a 160000
--- a/plugins/codemirror-editor
+++ b/plugins/codemirror-editor
@@ -1 +1 @@
-Subproject commit 7357ab473599d16ae33cc982bbd65472f08c2dd6
+Subproject commit 740c35ae36f44748b3c91e60ee7dcb2fb6e99549
diff --git a/plugins/delete-project b/plugins/delete-project
index 60ce67d..bfe159d 160000
--- a/plugins/delete-project
+++ b/plugins/delete-project
@@ -1 +1 @@
-Subproject commit 60ce67dd53ad64c33a2c34aae31e9ee823979109
+Subproject commit bfe159d3007db0f07e967473b53f679ba8f432df
diff --git a/plugins/download-commands b/plugins/download-commands
index 87e3930..5bd359c 160000
--- a/plugins/download-commands
+++ b/plugins/download-commands
@@ -1 +1 @@
-Subproject commit 87e3930cea7c06aea454998abdddf6515a9f103b
+Subproject commit 5bd359c08e10b93d2c08762f75cde01a14e45fc6
diff --git a/plugins/gitiles b/plugins/gitiles
index 584360d..b196dd5 160000
--- a/plugins/gitiles
+++ b/plugins/gitiles
@@ -1 +1 @@
-Subproject commit 584360d050f5adf8317ebc078a874da9c4316bd0
+Subproject commit b196dd5b6fcfd50518a6625a64cb93424c084620
diff --git a/plugins/replication b/plugins/replication
index 011c577..6185455 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit 011c577ef4ee2149d73db974e0ef2fcd3f66bfcf
+Subproject commit 6185455e0bbe184b9b7d7fb29d19335c2cdeb000
diff --git a/plugins/singleusergroup b/plugins/singleusergroup
index 58ee52a..a0c53c6 160000
--- a/plugins/singleusergroup
+++ b/plugins/singleusergroup
@@ -1 +1 @@
-Subproject commit 58ee52a8670e38f30785bfbb648ba27c61c3a202
+Subproject commit a0c53c6c5ad1ba8f8967ed6d2bcb18995f734cad
diff --git a/polygerrit-ui/FE_Style_Guide.md b/polygerrit-ui/FE_Style_Guide.md
index c9a5d9b..a636119 100644
--- a/polygerrit-ui/FE_Style_Guide.md
+++ b/polygerrit-ui/FE_Style_Guide.md
@@ -10,11 +10,20 @@
 Additionally to the rules above, Gerrit frontend uses the following rules (some of them have automated checks,
 some don't):
 
+- [Prefer null over undefined](#prefer-null)
 - [Use destructuring imports only](#destructuring-imports-only)
 - [Use classes and services for storing and manipulating global state](#services-for-global-state)
 - [Pass required services in the constructor for plain classes](#pass-dependencies-in-constructor)
 - [Assign required services in a HTML/Polymer element constructor](#assign-dependencies-in-html-element-constructor)
 
+## <a name="prefer-undefined"></a>Prefer `undefined` over `null`
+
+It is more confusing than helpful to work with both `null` and `undefined`. We prefer to only use `undefined` in
+our code base. Try to avoid `null`.
+
+Some browser and library APIs are using `null`, so we cannot remove `null` completely from our code base. But even
+then try to convert return values and leak as few `nulls` as possible.
+
 ## <a name="destructuring-imports-only"></a>Use destructuring imports only
 Always use destructuring import statement and specify all required names explicitly (e.g. `import {a,b,c} from '...'`)
 where possible.
diff --git a/polygerrit-ui/README.md b/polygerrit-ui/README.md
index 2266ba0..302551b 100644
--- a/polygerrit-ui/README.md
+++ b/polygerrit-ui/README.md
@@ -74,6 +74,14 @@
 
 More information for installing and using nodejs rules can be found here https://bazelbuild.github.io/rules_nodejs/install.html
 
+### Upgrade to @bazel-scoped packages
+
+It might be necessary to run this command to upgrade to major `rules_nodejs` release:
+
+```sh
+yarn remove @bazel/...
+```
+
 ## Setup typescript support in the IDE
 
 Modern IDE should automatically handle typescript settings from the 
@@ -187,6 +195,9 @@
 npm run test:debug async-foreach-behavior_test.js
 ```
 
+When converting a test file to typescript, the command for running tests is
+still using the .js suffix and not the new .ts suffix.
+
 Commands `test:debug` and `test:single` assumes that compiled code is located
 in the `./ts-out/polygerrit-ui/app` directory. It's up to you how to achieve it.
 For example, the following options are possible:
@@ -293,7 +304,7 @@
 existing helpers to create an object with all required properties:
 ```
 // Before:
-sinon.stub(element.$.restAPI, 'getPreferences').returns(
+sinon.stub(element.restApiService, 'getPreferences').returns(
     Promise.resolve({default_diff_view: 'UNIFIED'}));
 
 // After:
diff --git a/polygerrit-ui/app/.eslintignore b/polygerrit-ui/app/.eslintignore
index 16ea228..087a049 100644
--- a/polygerrit-ui/app/.eslintignore
+++ b/polygerrit-ui/app/.eslintignore
@@ -1,3 +1,4 @@
 **/node_modules
 **/rollup.config.js
 node_modules_licenses
+!.eslintrc-bazel.js
diff --git a/polygerrit-ui/app/.eslintrc-bazel.js b/polygerrit-ui/app/.eslintrc-bazel.js
index 977eb45..9a51242 100644
--- a/polygerrit-ui/app/.eslintrc-bazel.js
+++ b/polygerrit-ui/app/.eslintrc-bazel.js
@@ -20,7 +20,7 @@
 // for node_modules.
 
 function getBazelSettings() {
-  const runFilesDir = process.env["RUNFILES_DIR"];
+  const runFilesDir = process.env['RUNFILES_DIR'];
   if (!runFilesDir) {
     // eslint is executed with 'bazel run ...' to fix the source code. It runs
     // against real source code, no special paths for node_modules is set.
@@ -28,18 +28,18 @@
   }
   // eslint is executed with 'bazel test...'. Set path to required node_modules
   return {
-    "import/resolver": {
-      "node": {
-        "paths": [
+    'import/resolver': {
+      node: {
+        paths: [
           `${runFilesDir}/ui_npm/node_modules`,
-          `${runFilesDir}/ui_dev_npm/node_modules`
-        ]
-      }
-    }
+          `${runFilesDir}/ui_dev_npm/node_modules`,
+        ],
+      },
+    },
   };
 }
 
 module.exports = {
-  "extends": "./.eslintrc.js",
-  "settings": getBazelSettings(),
+  extends: './.eslintrc.js',
+  settings: getBazelSettings(),
 };
diff --git a/polygerrit-ui/app/.eslintrc.js b/polygerrit-ui/app/.eslintrc.js
index c5dde38..764d5e8 100644
--- a/polygerrit-ui/app/.eslintrc.js
+++ b/polygerrit-ui/app/.eslintrc.js
@@ -20,219 +20,224 @@
 const path = require('path');
 
 module.exports = {
-  "extends": ["eslint:recommended", "google"],
-  "parserOptions": {
-    "ecmaVersion": 9,
-    "sourceType": "module"
+  extends: ['eslint:recommended', 'google'],
+  parserOptions: {
+    ecmaVersion: 9,
+    sourceType: 'module',
   },
-  "env": {
-    "browser": true,
-    "es6": true
+  env: {
+    browser: true,
+    es6: true,
   },
-  "rules": {
+  rules: {
     // https://eslint.org/docs/rules/no-confusing-arrow
-    "no-confusing-arrow": "error",
+    'no-confusing-arrow': 'error',
     // https://eslint.org/docs/rules/newline-per-chained-call
-    "newline-per-chained-call": ["error", {"ignoreChainWithDepth": 2}],
+    'newline-per-chained-call': ['error', {ignoreChainWithDepth: 2}],
     // https://eslint.org/docs/rules/arrow-body-style
-    "arrow-body-style": ["error", "as-needed",
-      {"requireReturnForObjectLiteral": true}],
+    'arrow-body-style': ['error', 'as-needed',
+      {requireReturnForObjectLiteral: true}],
     // https://eslint.org/docs/rules/arrow-parens
-    "arrow-parens": ["error", "as-needed"],
+    'arrow-parens': ['error', 'as-needed'],
     // https://eslint.org/docs/rules/block-spacing
-    "block-spacing": ["error", "always"],
+    'block-spacing': ['error', 'always'],
     // https://eslint.org/docs/rules/brace-style
-    "brace-style": ["error", "1tbs", {"allowSingleLine": true}],
+    'brace-style': ['error', '1tbs', {allowSingleLine: true}],
     // https://eslint.org/docs/rules/camelcase
-    "camelcase": "off",
+    'camelcase': 'off',
     // https://eslint.org/docs/rules/comma-dangle
-    "comma-dangle": ["error", {
-      "arrays": "always-multiline",
-      "objects": "always-multiline",
-      "imports": "always-multiline",
-      "exports": "always-multiline",
-      "functions": "never"
+    'comma-dangle': ['error', {
+      arrays: 'always-multiline',
+      objects: 'always-multiline',
+      imports: 'always-multiline',
+      exports: 'always-multiline',
+      functions: 'never',
     }],
     // https://eslint.org/docs/rules/eol-last
-    "eol-last": "off",
+    'eol-last': 'off',
     // https://eslint.org/docs/rules/indent
-    "indent": ["error", 2, {
-      "MemberExpression": 2,
-      "FunctionDeclaration": {"body": 1, "parameters": 2},
-      "FunctionExpression": {"body": 1, "parameters": 2},
-      "CallExpression": {"arguments": 2},
-      "ArrayExpression": 1,
-      "ObjectExpression": 1,
-      "SwitchCase": 1
+    'indent': ['error', 2, {
+      MemberExpression: 2,
+      FunctionDeclaration: {body: 1, parameters: 2},
+      FunctionExpression: {body: 1, parameters: 2},
+      CallExpression: {arguments: 2},
+      ArrayExpression: 1,
+      ObjectExpression: 1,
+      SwitchCase: 1,
     }],
     // https://eslint.org/docs/rules/keyword-spacing
-    "keyword-spacing": ["error", {"after": true, "before": true}],
+    'keyword-spacing': ['error', {after: true, before: true}],
     // https://eslint.org/docs/rules/lines-between-class-members
-    "lines-between-class-members": ["error", "always"],
+    'lines-between-class-members': ['error', 'always'],
     // https://eslint.org/docs/rules/max-len
-    "max-len": [
-      "error",
+    'max-len': [
+      'error',
       80,
       2,
       {
-        "ignoreComments": true,
-        "ignorePattern": "^import .*;$"
-      }
+        ignoreComments: true,
+        ignorePattern: '^import .*;$',
+      },
     ],
     // https://eslint.org/docs/rules/new-cap
-    "new-cap": ["error", {
-      "capIsNewExceptions": ["Polymer", "GestureEventListeners"],
-      "capIsNewExceptionPattern": "^.*Mixin$"
+    'new-cap': ['error', {
+      capIsNewExceptions: ['Polymer', 'GestureEventListeners'],
+      capIsNewExceptionPattern: '^.*Mixin$',
     }],
     // https://eslint.org/docs/rules/no-console
-    "no-console": ["error", { allow: ["warn", "error", "info", "assert", "group", "groupEnd"] }],
+    'no-console': [
+      'error',
+      {allow: ['warn', 'error', 'info', 'assert', 'group', 'groupEnd']},
+    ],
     // https://eslint.org/docs/rules/no-multiple-empty-lines
-    "no-multiple-empty-lines": ["error", {"max": 1}],
+    'no-multiple-empty-lines': ['error', {max: 1}],
     // https://eslint.org/docs/rules/no-prototype-builtins
-    "no-prototype-builtins": "off",
+    'no-prototype-builtins': 'off',
     // https://eslint.org/docs/rules/no-redeclare
-    "no-redeclare": "off",
+    'no-redeclare': 'off',
     // https://eslint.org/docs/rules/no-trailing-spaces
-    "no-trailing-spaces": "error",
+    'no-trailing-spaces': 'error',
     // https://eslint.org/docs/rules/no-irregular-whitespace
-    "no-irregular-whitespace": "error",
+    'no-irregular-whitespace': 'error',
     // https://eslint.org/docs/rules/array-callback-return
-    "array-callback-return": ['error', { allowImplicit: true }],
+    'array-callback-return': ['error', {allowImplicit: true}],
     // https://eslint.org/docs/rules/no-restricted-syntax
-    "no-restricted-syntax": [
-      "error",
+    'no-restricted-syntax': [
+      'error',
       {
-        "selector": "ExpressionStatement > CallExpression > MemberExpression[object.name='test'][property.name='only']",
-        "message": "Remove test.only."
+        selector: 'ExpressionStatement > CallExpression > ' +
+            'MemberExpression[object.name=\'test\'][property.name=\'only\']',
+        message: 'Remove test.only.',
       },
       {
-        "selector": "ExpressionStatement > CallExpression > MemberExpression[object.name='suite'][property.name='only']",
-        "message": "Remove suite.only."
-      }
+        selector: 'ExpressionStatement > CallExpression > ' +
+            'MemberExpression[object.name=\'suite\'][property.name=\'only\']',
+        message: 'Remove suite.only.',
+      },
     ],
     // no-undef disables global variable.
     // "globals" declares allowed global variables.
     // https://eslint.org/docs/rules/no-undef
-    "no-undef": ["error"],
+    'no-undef': ['error'],
     // https://eslint.org/docs/rules/no-useless-escape
-    "no-useless-escape": "off",
+    'no-useless-escape': 'off',
     // https://eslint.org/docs/rules/no-var
-    "no-var": "error",
+    'no-var': 'error',
     // https://eslint.org/docs/rules/operator-linebreak
-    "operator-linebreak": "off",
+    'operator-linebreak': 'off',
     // https://eslint.org/docs/rules/object-shorthand
-    "object-shorthand": ["error", "always"],
+    'object-shorthand': ['error', 'always'],
     // https://eslint.org/docs/rules/padding-line-between-statements
-    "padding-line-between-statements": [
-      "error",
+    'padding-line-between-statements': [
+      'error',
       {
-        "blankLine": "always",
-        "prev": "class",
-        "next": "*"
+        blankLine: 'always',
+        prev: 'class',
+        next: '*',
       },
       {
-        "blankLine": "always",
-        "prev": "*",
-        "next": "class"
-      }
+        blankLine: 'always',
+        prev: '*',
+        next: 'class',
+      },
     ],
     // https://eslint.org/docs/rules/prefer-arrow-callback
-    "prefer-arrow-callback": "error",
+    'prefer-arrow-callback': 'error',
     // https://eslint.org/docs/rules/prefer-const
-    "prefer-const": "error",
+    'prefer-const': 'error',
     // https://eslint.org/docs/rules/prefer-promise-reject-errors
-    "prefer-promise-reject-errors": "error",
+    'prefer-promise-reject-errors': 'error',
     // https://eslint.org/docs/rules/prefer-spread
-    "prefer-spread": "error",
+    'prefer-spread': 'error',
     // https://eslint.org/docs/rules/prefer-object-spread
-    "prefer-object-spread": "error",
+    'prefer-object-spread': 'error',
     // https://eslint.org/docs/rules/quote-props
-    "quote-props": ["error", "consistent-as-needed"],
+    'quote-props': ['error', 'consistent-as-needed'],
     // https://eslint.org/docs/rules/semi
-    "semi": ["error", "always"],
+    'semi': ['error', 'always'],
     // https://eslint.org/docs/rules/template-curly-spacing
-    "template-curly-spacing": "error",
+    'template-curly-spacing': 'error',
 
     // https://eslint.org/docs/rules/require-jsdoc
-    "require-jsdoc": 0,
+    'require-jsdoc': 0,
     // https://eslint.org/docs/rules/valid-jsdoc
-    "valid-jsdoc": 0,
+    'valid-jsdoc': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-alignment
-    "jsdoc/check-alignment": 2,
+    'jsdoc/check-alignment': 2,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-examples
-    "jsdoc/check-examples": 0,
+    'jsdoc/check-examples': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-indentation
-    "jsdoc/check-indentation": 0,
+    'jsdoc/check-indentation': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-param-names
-    "jsdoc/check-param-names": 0,
+    'jsdoc/check-param-names': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-syntax
-    "jsdoc/check-syntax": 0,
+    'jsdoc/check-syntax': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-tag-names
-    "jsdoc/check-tag-names": 0,
+    'jsdoc/check-tag-names': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-check-types
-    "jsdoc/check-types": 0,
+    'jsdoc/check-types': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-implements-on-classes
-    "jsdoc/implements-on-classes": 2,
+    'jsdoc/implements-on-classes': 2,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-match-description
-    "jsdoc/match-description": 0,
+    'jsdoc/match-description': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-newline-after-description
-    "jsdoc/newline-after-description": 2,
+    'jsdoc/newline-after-description': 2,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-no-types
-    "jsdoc/no-types": 0,
+    'jsdoc/no-types': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-no-undefined-types
-    "jsdoc/no-undefined-types": 0,
+    'jsdoc/no-undefined-types': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-description
-    "jsdoc/require-description": 0,
+    'jsdoc/require-description': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-description-complete-sentence
-    "jsdoc/require-description-complete-sentence": 0,
+    'jsdoc/require-description-complete-sentence': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-example
-    "jsdoc/require-example": 0,
+    'jsdoc/require-example': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-hyphen-before-param-description
-    "jsdoc/require-hyphen-before-param-description": 0,
+    'jsdoc/require-hyphen-before-param-description': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-jsdoc
-    "jsdoc/require-jsdoc": 0,
+    'jsdoc/require-jsdoc': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-param
-    "jsdoc/require-param": 0,
+    'jsdoc/require-param': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-param-description
-    "jsdoc/require-param-description": 0,
+    'jsdoc/require-param-description': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-param-name
-    "jsdoc/require-param-name": 2,
+    'jsdoc/require-param-name': 2,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-returns
-    "jsdoc/require-returns": 0,
+    'jsdoc/require-returns': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-returns-check
-    "jsdoc/require-returns-check": 0,
+    'jsdoc/require-returns-check': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-returns-description
-    "jsdoc/require-returns-description": 0,
+    'jsdoc/require-returns-description': 0,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-valid-types
-    "jsdoc/valid-types": 2,
+    'jsdoc/valid-types': 2,
     // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-file-overview
-    "jsdoc/require-file-overview": ["error", {
-      "tags": {
-        "license": {
-          "mustExist": true,
-          "preventDuplicates": true
-        }
-      }
+    'jsdoc/require-file-overview': ['error', {
+      tags: {
+        license: {
+          mustExist: true,
+          preventDuplicates: true,
+        },
+      },
     }],
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-self-import.md
-    "import/no-self-import": 2,
+    'import/no-self-import': 2,
     // The no-cycle rule is slow, because it doesn't cache dependencies.
     // Disable it.
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-cycle.md
-    "import/no-cycle": 0,
+    'import/no-cycle': 0,
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-useless-path-segments.md
-    "import/no-useless-path-segments": 2,
+    'import/no-useless-path-segments': 2,
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-unused-modules.md
-    "import/no-unused-modules": 2,
+    'import/no-unused-modules': 2,
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-default-export.md
-    "import/no-default-export": 2,
+    'import/no-default-export': 2,
     // Prevents certain identifiers being used.
     // Prefer flush() over flushAsynchronousOperations().
-    "id-blacklist": ["error", "flushAsynchronousOperations"],
+    'id-blacklist': ['error', 'flushAsynchronousOperations'],
   },
 
   // List of allowed globals in all files
-  "globals": {
+  globals: {
     // Polygerrit global variables.
     // You must not add anything new in this list!
     // Instead export variables from modules
@@ -240,150 +245,168 @@
     // Global variables from 3rd party libraries.
     // You should not add anything in this list, always try to import
     // If import is not possible - you can extend this list
-    "ShadyCSS": "readonly",
-    "linkify": "readonly",
-    "security": "readonly",
+    ShadyCSS: 'readonly',
+    linkify: 'readonly',
+    security: 'readonly',
   },
-  "overrides": [
+  overrides: [
     {
-      // .js-only rules
-      "files": ["**/*.js"],
-      "rules": {
-        // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-param-type
-        "jsdoc/require-param-type": 2,
-        // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-returns-type
-        "jsdoc/require-returns-type": 2,
-        // The rule is required for .js files only, because typescript compiler
-        // always checks import.
-        "import/no-unresolved": 2,
-        "import/named": 2,
+      files: ['.eslintrc.js', '.eslintrc-bazel.js'],
+      env: {
+        browser: false,
+        es6: true,
+        node: true,
       },
-      "globals": {
-        "goog": "readonly",
-      }
     },
     {
-      "files": ["**/*.ts"],
-      "extends": [require.resolve("gts/.eslintrc.json")],
-      "rules": {
-        "no-restricted-imports": ["error", {
-          name: "@polymer/decorators/lib/decorators",
-          message: "Use @polymer/decorators instead",
+      // .js-only rules
+      files: ['**/*.js'],
+      rules: {
+        // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-param-type
+        'jsdoc/require-param-type': 2,
+        // https://github.com/gajus/eslint-plugin-jsdoc#eslint-plugin-jsdoc-rules-require-returns-type
+        'jsdoc/require-returns-type': 2,
+        // The rule is required for .js files only, because typescript compiler
+        // always checks import.
+        'import/no-unresolved': 2,
+        'import/named': 2,
+      },
+      globals: {
+        goog: 'readonly',
+      },
+    },
+    {
+      files: ['**/*.ts'],
+      extends: [require.resolve('gts/.eslintrc.json')],
+      rules: {
+        'no-restricted-imports': ['error', {
+          name: '@polymer/decorators/lib/decorators',
+          message: 'Use @polymer/decorators instead',
         }],
+        '@typescript-eslint/no-explicit-any': 'error',
         // See https://github.com/GoogleChromeLabs/shadow-selection-polyfill/issues/9
-        "@typescript-eslint/ban-ts-ignore": "off",
+        '@typescript-eslint/ban-ts-comment': 'off',
         // The following rules is required to match internal google rules
-        "@typescript-eslint/restrict-plus-operands": "error",
+        '@typescript-eslint/restrict-plus-operands': 'error',
+        '@typescript-eslint/no-unused-vars': [
+          'error',
+          {argsIgnorePattern: '^_'},
+        ],
         // https://github.com/mysticatea/eslint-plugin-node/blob/master/docs/rules/no-unsupported-features/node-builtins.md
-        "node/no-unsupported-features/node-builtins": "off",
+        'node/no-unsupported-features/node-builtins': 'off',
         // Disable no-invalid-this for ts files, because it incorrectly reports
         // errors in some cases (see https://github.com/typescript-eslint/typescript-eslint/issues/491)
         // At the same time, we are using typescript in a strict mode and
         // it catches almost all errors related to invalid usage of this.
-        "no-invalid-this": "off",
+        'no-invalid-this': 'off',
 
-        "node/no-extraneous-import": "off",
+        'node/no-extraneous-import': 'off',
 
         // Typescript already checks for undef
-        "no-undef": "off",
+        'no-undef': 'off',
 
-        "jsdoc/no-types": 2,
+        'jsdoc/no-types': 2,
       },
-      "parserOptions": {
-        "project": path.resolve(__dirname, "./tsconfig_eslint.json"),
-      }
-    },
-    {
-      "files": ["*.html", "test.js", "test-infra.js"],
-      "rules": {
-        "jsdoc/require-file-overview": "off"
+      parserOptions: {
+        project: path.resolve(__dirname, './tsconfig_eslint.json'),
       },
     },
     {
-      "files": [
-        "*.html",
-        "*_test.js",
-        "a11y-test-utils.js",
+      files: ['*_test.ts'],
+      rules: {
+        '@typescript-eslint/no-explicit-any': 'off',
+      },
+    },
+    {
+      files: ['*.html', 'test.js', 'test-infra.js'],
+      rules: {
+        'jsdoc/require-file-overview': 'off',
+      },
+    },
+    {
+      files: [
+        '*.html',
+        '*_test.js',
+        'a11y-test-utils.js',
       ],
       // Additional global variables allowed in tests
-      "globals": {
+      globals: {
         // Global variables from 3rd party test libraries/frameworks.
         // You can extend this list if you want to use other global
         // variables from these libraries and import is not possible
-        "MockInteractions": "readonly",
-        "_": "readonly",
-        "axs": "readonly",
-        "a11ySuite": "readonly",
-        "assert": "readonly",
-        "expect": "readonly",
-        "fixture": "readonly",
-        "flush": "readonly",
-        "flushAsynchronousOperations": "readonly",
-        "setup": "readonly",
-        "sinon": "readonly",
-        "stub": "readonly",
-        "suite": "readonly",
-        "suiteSetup": "readonly",
-        "suiteTeardown": "readonly",
-        "teardown": "readonly",
-        "test": "readonly",
-        "fixtureFromElement": "readonly",
-        "fixtureFromTemplate": "readonly",
-      }
+        MockInteractions: 'readonly',
+        _: 'readonly',
+        axs: 'readonly',
+        a11ySuite: 'readonly',
+        assert: 'readonly',
+        expect: 'readonly',
+        fixture: 'readonly',
+        flush: 'readonly',
+        setup: 'readonly',
+        sinon: 'readonly',
+        stub: 'readonly',
+        suite: 'readonly',
+        suiteSetup: 'readonly',
+        suiteTeardown: 'readonly',
+        teardown: 'readonly',
+        test: 'readonly',
+        fixtureFromElement: 'readonly',
+        fixtureFromTemplate: 'readonly',
+      },
     },
     {
-      "files": "import-href.js",
-      "globals": {
-        "HTMLImports": "readonly",
-      }
+      files: 'import-href.js',
+      globals: {
+        HTMLImports: 'readonly',
+      },
     },
     {
-      "files": ["samples/**/*.js"],
-      "globals": {
+      files: ['samples/**/*.js'],
+      globals: {
         // Settings for samples. You can add globals here if you want to use it
-        "Gerrit": "readonly",
-        "Polymer": "readonly",
-      }
+        Gerrit: 'readonly',
+        Polymer: 'readonly',
+      },
     },
     {
-      "files": ["test/functional/**/*.js"],
+      files: ['test/functional/**/*.js'],
       // Settings for functional tests. These scripts are node scripts.
       // Turn off "no-undef" to allow any global variable
-      "env": {
-        "browser": false,
-        "node": true,
-        "es6": false
+      env: {
+        browser: false,
+        node: true,
+        es6: false,
       },
-      "rules": {
-        "no-undef": "off",
-      }
+      rules: {
+        'no-undef': 'off',
+      },
     },
     {
-      "files": ["*_html.js", "gr-icons.js", "*-theme.js", "*-styles.js"],
-      "rules": {
-        "max-len": "off"
-      }
+      files: ['*_html.js', 'gr-icons.js', '*-theme.js', '*-styles.js'],
+      rules: {
+        'max-len': 'off',
+      },
     },
     {
-      "files": ["*_html.js"],
-      "rules": {
-        "prettier/prettier": ["error", {
-          "bracketSpacing": false,
-          "singleQuote": true,
-        }]
-      }
-    }
+      files: ['*_html.js'],
+      rules: {
+        'prettier/prettier': ['error', {
+          bracketSpacing: false,
+          singleQuote: true,
+        }],
+      },
+    },
   ],
-  "plugins": [
-    "html",
-    "jsdoc",
-    "import",
-    "prettier"
+  plugins: [
+    'html',
+    'jsdoc',
+    'import',
+    'prettier',
   ],
-  "settings": {
-    "html/report-bad-indent": "error",
-    "import/resolver": {
-      "node": {},
+  settings: {
+    'html/report-bad-indent': 'error',
+    'import/resolver': {
+      node: {},
       [path.resolve(__dirname, './.eslint-ts-resolver.js')]: {},
     },
   },
diff --git a/polygerrit-ui/app/constants/constants.ts b/polygerrit-ui/app/constants/constants.ts
index b64a7d1..061c5cd 100644
--- a/polygerrit-ui/app/constants/constants.ts
+++ b/polygerrit-ui/app/constants/constants.ts
@@ -21,10 +21,11 @@
 export enum PrimaryTab {
   FILES = 'files',
   /**
-   * When renaming this, the links in UrlFormatter must be updated.
+   * When renaming 'comments' or 'findings', UrlFormatter.java must be updated.
    */
   COMMENT_THREADS = 'comments',
   FINDINGS = 'findings',
+  CHECKS = 'checks',
 }
 
 /**
@@ -327,17 +328,6 @@
 }
 
 /**
- * Whether whitespace changes should be ignored and if yes, which whitespace changes should be ignored
- * https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#diff-preferences-input
- */
-export enum IgnoreWhitespaceType {
-  IGNORE_NONE = 'IGNORE_NONE',
-  IGNORE_TRAILING = 'IGNORE_TRAILING',
-  IGNORE_LEADING_AND_TRAILING = 'IGNORE_LEADING_AND_TRAILING',
-  IGNORE_ALL = 'IGNORE_ALL',
-}
-
-/**
  * how draft comments are handled
  */
 export enum DraftsAction {
diff --git a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.ts b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.ts
index 3c155f85..cbb3d95 100644
--- a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.ts
+++ b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-icons/gr-icons';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-permission/gr-permission';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -43,6 +42,7 @@
   LabelNameToLabelTypeInfoMap,
 } from '../../../types/common';
 import {PolymerDomRepeatEvent} from '../../../types/types';
+import {fireEvent} from '../../../utils/event-util';
 
 /**
  * Fired when the section has been modified or removed.
@@ -141,9 +141,7 @@
       // For a new section, this is not fired because new permissions and
       // rules have to be added in order to save, modifying the ref is not
       // enough.
-      this.dispatchEvent(
-        new CustomEvent('access-modified', {bubbles: true, composed: true})
-      );
+      fireEvent(this, 'access-modified');
     }
     this.section.value.updatedId = this.section.id;
   }
@@ -276,18 +274,11 @@
       return;
     }
     if (this.section.value.added) {
-      this.dispatchEvent(
-        new CustomEvent('added-section-removed', {
-          bubbles: true,
-          composed: true,
-        })
-      );
+      fireEvent(this, 'added-section-removed');
     }
     this._deleted = true;
     this.section.value.deleted = true;
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   _handleUndoRemove() {
diff --git a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_html.ts b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_html.ts
index 7c9f28b..46968eb 100644
--- a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_html.ts
@@ -153,5 +153,4 @@
     </div>
     <!-- end deletedContainer -->
   </fieldset>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
index 9d40e28..2c66a3e 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
@@ -20,7 +20,6 @@
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-list-view/gr-list-view';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-create-group-dialog/gr-create-group-dialog';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -32,8 +31,9 @@
 import {AppElementAdminParams} from '../../gr-app-types';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GroupId, GroupInfo, GroupName} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrCreateGroupDialog} from '../gr-create-group-dialog/gr-create-group-dialog';
+import {fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -45,7 +45,6 @@
   $: {
     createOverlay: GrOverlay;
     createNewModal: GrCreateGroupDialog;
-    restAPI: RestApiService & Element;
   };
 }
 
@@ -96,17 +95,13 @@
   @property({type: String})
   _filter = '';
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this._getCreateGroupCapability();
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Groups'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Groups');
     this._maybeOpenCreateOverlay(this.params);
   }
 
@@ -136,11 +131,11 @@
   }
 
   _getCreateGroupCapability() {
-    return this.$.restAPI.getAccount().then(account => {
+    return this.restApiService.getAccount().then(account => {
       if (!account) {
         return;
       }
-      return this.$.restAPI
+      return this.restApiService
         .getAccountCapabilities(['createGroup'])
         .then(capabilities => {
           if (capabilities?.createGroup) {
@@ -152,7 +147,7 @@
 
   _getGroups(filter: string, groupsPerPage: number, offset?: number) {
     this._groups = [];
-    return this.$.restAPI
+    return this.restApiService
       .getGroups(filter, groupsPerPage, offset)
       .then(groups => {
         if (!groups) {
@@ -168,7 +163,7 @@
   }
 
   _refreshGroupsList() {
-    this.$.restAPI.invalidateGroupsCache();
+    this.restApiService.invalidateGroupsCache();
     return this._getGroups(this._filter, this._groupsPerPage, this._offset);
   }
 
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_html.ts b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_html.ts
index 93de8b4..7574f79 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_html.ts
@@ -78,5 +78,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_test.js b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_test.js
index 93d41c3..77a2a41 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list_test.js
@@ -131,7 +131,7 @@
   suite('filter', () => {
     test('_paramsChanged', done => {
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getGroups')
           .callsFake(() => Promise.resolve(groups));
       const value = {
@@ -139,7 +139,7 @@
         offset: 25,
       };
       element._paramsChanged(value).then(() => {
-        assert.isTrue(element.$.restAPI.getGroups.lastCall
+        assert.isTrue(element.restApiService.getGroups.lastCall
             .calledWithExactly('test', 25, 25));
         done();
       });
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
index 7fb713f..2a607a7 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
@@ -21,7 +21,6 @@
 import '../../shared/gr-icons/gr-icons';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import '../../shared/gr-page-nav/gr-page-nav';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-admin-group-list/gr-admin-group-list';
 import '../gr-group/gr-group';
 import '../gr-group-audit-log/gr-group-audit-log';
@@ -40,7 +39,6 @@
 import {getBaseUrl} from '../../../utils/url-util';
 import {
   GerritNav,
-  GerritView,
   GroupDetailView,
   RepoDetailView,
 } from '../../core/gr-navigation/gr-navigation';
@@ -52,7 +50,6 @@
   SubsectionInterface,
 } from '../../../utils/admin-nav-util';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AppElementAdminParams,
   AppElementGroupParams,
@@ -67,12 +64,13 @@
 import {GroupNameChangedDetail} from '../gr-group/gr-group';
 import {ValueChangeDetail} from '../../shared/gr-dropdown-list/gr-dropdown-list';
 import {GrJsApiInterface} from '../../shared/gr-js-api-interface/gr-js-api-interface-element';
+import {appContext} from '../../../services/app-context';
+import {GerritView} from '../../../services/router/router-model';
 
 const INTERNAL_GROUP_REGEX = /^[\da-f]{40}$/;
 
 export interface GrAdminView {
   $: {
-    restAPI: RestApiService & Element;
     jsAPI: GrJsApiInterface;
   };
 }
@@ -183,6 +181,8 @@
   @property({type: Boolean})
   _showPluginList?: boolean;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
@@ -191,7 +191,7 @@
 
   reload() {
     const promises: [Promise<AccountDetailInfo | undefined>, Promise<void>] = [
-      this.$.restAPI.getAccount(),
+      this.restApiService.getAccount(),
       getPluginLoader().awaitPluginsLoaded(),
     ];
     return Promise.all(promises).then(result => {
@@ -212,7 +212,7 @@
       return getAdminLinks(
         this._account,
         () =>
-          this.$.restAPI.getAccountCapabilities().then(capabilities => {
+          this.restApiService.getAccountCapabilities().then(capabilities => {
             if (!capabilities) {
               throw new Error('getAccountCapabilities returns undefined');
             }
@@ -423,7 +423,7 @@
     if (!groupId) return;
 
     const promises: Array<Promise<void>> = [];
-    this.$.restAPI.getGroupConfig(groupId).then(group => {
+    this.restApiService.getGroupConfig(groupId).then(group => {
       if (!group || !group.name) {
         return;
       }
@@ -433,13 +433,13 @@
       this.reload();
 
       promises.push(
-        this.$.restAPI.getIsAdmin().then(isAdmin => {
+        this.restApiService.getIsAdmin().then(isAdmin => {
           this._isAdmin = !!isAdmin;
         })
       );
 
       promises.push(
-        this.$.restAPI.getIsGroupOwner(group.name).then(isOwner => {
+        this.restApiService.getIsGroupOwner(group.name).then(isOwner => {
           this._groupOwner = isOwner;
         })
       );
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_html.ts b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_html.ts
index 5e85a93..4dacd38 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_html.ts
@@ -178,6 +178,5 @@
       <gr-repo-dashboards repo="[[params.repo]]"></gr-repo-dashboards>
     </main>
   </template>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_test.js b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_test.js
index 44fd4d6..cac409d 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view_test.js
@@ -18,9 +18,10 @@
 import '../../../test/common-test-setup-karma.js';
 import './gr-admin-view.js';
 import {dom} from '@polymer/polymer/lib/legacy/polymer.dom.js';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation.js';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';
 import {stubBaseUrl} from '../../../test/test-utils.js';
+import {GerritView} from '../../../services/router/router-model.js';
 
 const basicFixture = fixtureFromElement('gr-admin-view');
 
@@ -83,11 +84,11 @@
   });
 
   test('_filteredLinks admin', done => {
-    sinon.stub(element.$.restAPI, 'getAccount').returns(Promise.resolve({
+    sinon.stub(element.restApiService, 'getAccount').returns(Promise.resolve({
       name: 'test-user',
     }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -111,11 +112,11 @@
   });
 
   test('_filteredLinks non admin authenticated', done => {
-    sinon.stub(element.$.restAPI, 'getAccount').returns(Promise.resolve({
+    sinon.stub(element.restApiService, 'getAccount').returns(Promise.resolve({
       name: 'test-user',
     }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({})
         );
@@ -171,11 +172,11 @@
 
   test('Repo shows up in nav', done => {
     element._repoName = 'Test Repo';
-    sinon.stub(element.$.restAPI, 'getAccount').returns(Promise.resolve({
+    sinon.stub(element.restApiService, 'getAccount').returns(Promise.resolve({
       name: 'test-user',
     }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -202,11 +203,11 @@
     element._groupIsInternal = true;
     element._isAdmin = true;
     element._groupOwner = false;
-    sinon.stub(element.$.restAPI, 'getAccount').returns(Promise.resolve({
+    sinon.stub(element.restApiService, 'getAccount').returns(Promise.resolve({
       name: 'test-user',
     }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -232,7 +233,7 @@
 
   test('Nav is reloaded when repo changes', () => {
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -240,7 +241,7 @@
           viewPlugins: true,
         }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccount')
         .callsFake(() => Promise.resolve({_id: 1}));
     sinon.stub(element, 'reload');
@@ -254,7 +255,7 @@
   test('Nav is reloaded when group changes', () => {
     sinon.stub(element, '_computeGroupName');
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -262,7 +263,7 @@
           viewPlugins: true,
         }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccount')
         .callsFake(() => Promise.resolve({_id: 1}));
     sinon.stub(element, 'reload');
@@ -321,7 +322,7 @@
       detail: GerritNav.RepoDetailView.ACCESS,
     };
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccountCapabilities')
         .callsFake(() => Promise.resolve({
           createGroup: true,
@@ -329,7 +330,7 @@
           viewPlugins: true,
         }));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getAccount')
         .callsFake(() => Promise.resolve({_id: 1}));
     flush();
@@ -484,7 +485,7 @@
   suite('_computeSelectedClass', () => {
     setup(() => {
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getAccountCapabilities')
           .callsFake(() => Promise.resolve({
             createGroup: true,
@@ -492,7 +493,7 @@
             viewPlugins: true,
           }));
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getAccount')
           .callsFake(() => Promise.resolve({_id: 1}));
 
@@ -576,12 +577,12 @@
           _loadGroupDetails: () => {},
         });
 
-        sinon.stub(element.$.restAPI, 'getGroupConfig')
+        sinon.stub(element.restApiService, 'getGroupConfig')
             .returns(Promise.resolve({
               name: 'foo',
               id: 'c0f83e941ce90caea30e6ad88f0d4ea0e841a7a9',
             }));
-        sinon.stub(element.$.restAPI, 'getIsGroupOwner')
+        sinon.stub(element.restApiService, 'getIsGroupOwner')
             .returns(Promise.resolve(true));
         return element.reload();
       });
@@ -619,8 +620,8 @@
       });
 
       test('external group', () => {
-        element.$.restAPI.getGroupConfig.restore();
-        sinon.stub(element.$.restAPI, 'getGroupConfig')
+        element.restApiService.getGroupConfig.restore();
+        sinon.stub(element.restApiService, 'getGroupConfig')
             .returns(Promise.resolve({
               name: 'foo',
               id: 'external-id',
diff --git a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.ts b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.ts
index 2a6c7a8..0b1e27e 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -36,16 +35,15 @@
 } from '../../../types/common';
 import {InheritedBooleanInfoConfiguredValue} from '../../../constants/constants';
 import {hasOwnProperty} from '../../../utils/common-util';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrAutocomplete} from '../../shared/gr-autocomplete/gr-autocomplete';
 import {IronAutogrowTextareaElement} from '@polymer/iron-autogrow-textarea/iron-autogrow-textarea';
+import {appContext} from '../../../services/app-context';
 
 const SUGGESTIONS_LIMIT = 15;
 const REF_PREFIX = 'refs/heads/';
 
 export interface GrCreateChangeDialog {
   $: {
-    restAPI: RestApiService & Element;
     privateChangeCheckBox: HTMLInputElement;
     branchInput: GrAutocomplete;
     tagNameInput: HTMLInputElement;
@@ -93,6 +91,8 @@
   @property({type: Boolean})
   _privateChangesEnabled?: boolean;
 
+  restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = (input: string) => this._getRepoBranchesSuggestions(input);
@@ -108,14 +108,14 @@
     const promises = [];
 
     promises.push(
-      this.$.restAPI.getProjectConfig(this.repoName).then(config => {
+      this.restApiService.getProjectConfig(this.repoName).then(config => {
         if (!config) return;
         this.privateByDefault = config.private_by_default;
       })
     );
 
     promises.push(
-      this.$.restAPI.getConfig().then(config => {
+      this.restApiService.getConfig().then(config => {
         if (!config) {
           return;
         }
@@ -143,7 +143,7 @@
     }
     const isPrivate = this.$.privateChangeCheckBox.checked;
     const isWip = true;
-    return this.$.restAPI
+    return this.restApiService
       .createChange(
         this.repoName,
         this.branch,
@@ -169,7 +169,7 @@
     if (input.startsWith(REF_PREFIX)) {
       input = input.substring(REF_PREFIX.length);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getRepoBranches(input, this.repoName, SUGGESTIONS_LIMIT)
       .then(response => {
         if (!response) return [];
diff --git a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_html.ts b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_html.ts
index 77e2c3b..47f3818 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_html.ts
@@ -113,5 +113,4 @@
       </span>
     </section>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_test.ts b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_test.ts
index e529730..0a4e23d 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_test.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog_test.ts
@@ -68,7 +68,7 @@
     };
 
     const saveStub = sinon
-      .stub(element.$.restAPI, 'createChange')
+      .stub(element.restApiService, 'createChange')
       .callsFake(() => Promise.resolve(createChange()));
 
     element.branch = 'test-branch' as BranchName;
@@ -104,7 +104,7 @@
     };
 
     const saveStub = sinon
-      .stub(element.$.restAPI, 'createChange')
+      .stub(element.restApiService, 'createChange')
       .callsFake(() => Promise.resolve(createChange()));
 
     element.branch = 'test-branch' as BranchName;
diff --git a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.ts b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.ts
index 1d8b7db..5902717 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-input/iron-input';
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -25,14 +24,8 @@
 import {encodeURL, getBaseUrl} from '../../../utils/url-util';
 import {page} from '../../../utils/page-wrapper-utils';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GroupName} from '../../../types/common';
-
-export interface GrCreateGroupDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 @customElement('gr-create-group-dialog')
 export class GrCreateGroupDialog extends GestureEventListeners(
@@ -51,6 +44,8 @@
   @property({type: Boolean})
   _groupCreated = false;
 
+  private restApiService = appContext.restApiService;
+
   _computeGroupUrl(groupId: string) {
     return getBaseUrl() + '/admin/groups/' + encodeURL(groupId, true);
   }
@@ -62,12 +57,12 @@
 
   handleCreateGroup() {
     const name = this._name as GroupName;
-    return this.$.restAPI.createGroup({name}).then(groupRegistered => {
+    return this.restApiService.createGroup({name}).then(groupRegistered => {
       if (groupRegistered.status !== 201) {
         return;
       }
       this._groupCreated = true;
-      return this.$.restAPI.getGroupConfig(name).then(group => {
+      return this.restApiService.getGroupConfig(name).then(group => {
         // TODO(TS): should group always defined ?
         page.show(this._computeGroupUrl(group!.group_id!));
       });
diff --git a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_html.ts b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_html.ts
index d4ecc5d..daf8780 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_html.ts
@@ -38,5 +38,4 @@
       </section>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_test.js b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_test.js
index d32ff30..bf0c244 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog_test.js
@@ -47,10 +47,10 @@
   });
 
   test('test for redirecting to group on successful creation', done => {
-    sinon.stub(element.$.restAPI, 'createGroup')
+    sinon.stub(element.restApiService, 'createGroup')
         .returns(Promise.resolve({status: 201}));
 
-    sinon.stub(element.$.restAPI, 'getGroupConfig')
+    sinon.stub(element.restApiService, 'getGroupConfig')
         .returns(Promise.resolve({group_id: 551}));
 
     const showStub = sinon.stub(page, 'show');
@@ -62,10 +62,10 @@
   });
 
   test('test for unsuccessful group creation', done => {
-    sinon.stub(element.$.restAPI, 'createGroup')
+    sinon.stub(element.restApiService, 'createGroup')
         .returns(Promise.resolve({status: 409}));
 
-    sinon.stub(element.$.restAPI, 'getGroupConfig')
+    sinon.stub(element.restApiService, 'getGroupConfig')
         .returns(Promise.resolve({group_id: 551}));
 
     const showStub = sinon.stub(page, 'show');
diff --git a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.ts b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.ts
index e0a5042..d50d7c5 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.ts
@@ -18,7 +18,6 @@
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -28,19 +27,13 @@
 import {page} from '../../../utils/page-wrapper-utils';
 import {customElement, property, observe} from '@polymer/decorators';
 import {BranchName, RepoName} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 enum DetailType {
   branches = 'branches',
   tags = 'tags',
 }
 
-export interface GrCreatePointerDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-create-pointer-dialog')
 export class GrCreatePointerDialog extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -75,6 +68,8 @@
     this.hasNewItemName = !!name;
   }
 
+  private restApiService = appContext.restApiService;
+
   handleCreateItem() {
     if (!this.repoName) {
       throw new Error('repoName name is not set');
@@ -85,7 +80,7 @@
     const USE_HEAD = this._itemRevision ? this._itemRevision : 'HEAD';
     const url = `${getBaseUrl()}/admin/repos/${encodeURL(this.repoName, true)}`;
     if (this.itemDetail === DetailType.branches) {
-      return this.$.restAPI
+      return this.restApiService
         .createRepoBranch(this.repoName, this._itemName, {revision: USE_HEAD})
         .then(itemRegistered => {
           if (itemRegistered.status === 201) {
@@ -93,7 +88,7 @@
           }
         });
     } else if (this.itemDetail === DetailType.tags) {
-      return this.$.restAPI
+      return this.restApiService
         .createRepoTag(this.repoName, this._itemName, {
           revision: USE_HEAD,
           message: this._itemAnnotation || undefined,
diff --git a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_html.ts b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_html.ts
index 0b3d81ae..452aab7 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_html.ts
@@ -80,5 +80,4 @@
       </section>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_test.js b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_test.js
index 79a18d5..9c281b1 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog_test.js
@@ -36,7 +36,7 @@
 
   test('branch created', done => {
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'createRepoBranch')
         .callsFake(() => Promise.resolve({}));
 
@@ -58,7 +58,7 @@
 
   test('tag created', done => {
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'createRepoTag')
         .callsFake(() => Promise.resolve({}));
 
@@ -80,7 +80,7 @@
 
   test('tag created with annotations', done => {
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'createRepoTag')
         .callsFake(() => Promise.resolve({}));
 
diff --git a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.ts b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.ts
index 6f0ac19..d3ce98a 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -28,10 +27,10 @@
 import {encodeURL, getBaseUrl} from '../../../utils/url-util';
 import {page} from '../../../utils/page-wrapper-utils';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {ProjectInput, RepoName} from '../../../types/common';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {AutocompleteQuery} from '../../shared/gr-autocomplete/gr-autocomplete';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -39,12 +38,6 @@
   }
 }
 
-export interface GrCreateRepoDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-create-repo-dialog')
 export class GrCreateRepoDialog extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -78,6 +71,8 @@
   @property({type: Object})
   _queryGroups: AutocompleteQuery;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = (input: string) => this._getRepoSuggestions(input);
@@ -103,16 +98,18 @@
   }
 
   handleCreateRepo() {
-    return this.$.restAPI.createRepo(this._repoConfig).then(repoRegistered => {
-      if (repoRegistered.status === 201) {
-        this._repoCreated = true;
-        page.show(this._computeRepoUrl(this._repoConfig.name));
-      }
-    });
+    return this.restApiService
+      .createRepo(this._repoConfig)
+      .then(repoRegistered => {
+        if (repoRegistered.status === 201) {
+          this._repoCreated = true;
+          page.show(this._computeRepoUrl(this._repoConfig.name));
+        }
+      });
   }
 
   _getRepoSuggestions(input: string) {
-    return this.$.restAPI.getSuggestedProjects(input).then(response => {
+    return this.restApiService.getSuggestedProjects(input).then(response => {
       const repos = [];
       for (const key in response) {
         if (!hasOwnProperty(response, key)) {
@@ -120,7 +117,7 @@
         }
         repos.push({
           name: key,
-          value: response[key],
+          value: response[key].id,
         });
       }
       return repos;
@@ -128,7 +125,7 @@
   }
 
   _getGroupSuggestions(input: string) {
-    return this.$.restAPI.getSuggestedGroups(input).then(response => {
+    return this.restApiService.getSuggestedGroups(input).then(response => {
       const groups = [];
       for (const key in response) {
         if (!hasOwnProperty(response, key)) {
diff --git a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_html.ts b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_html.ts
index 02aabfe..070ee86 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_html.ts
@@ -99,5 +99,4 @@
       </section>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_test.js b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_test.js
index 1e1fb0e..0af2e23 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog_test.js
@@ -44,7 +44,7 @@
       owners: ['testId'],
     };
 
-    const saveStub = sinon.stub(element.$.restAPI,
+    const saveStub = sinon.stub(element.restApiService,
         'createRepo').callsFake(() => Promise.resolve({}));
 
     assert.isFalse(element.hasNewRepoName);
diff --git a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
index f7cffac..536c5c3 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
@@ -18,7 +18,6 @@
 import '../../../styles/gr-table-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-account-link/gr-account-link';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -27,24 +26,18 @@
 import {ListViewMixin} from '../../../mixins/gr-list-view-mixin/gr-list-view-mixin';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property} from '@polymer/decorators';
-import {
-  ErrorCallback,
-  RestApiService,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   GroupInfo,
   AccountInfo,
   EncodedGroupId,
   GroupAuditEventInfo,
 } from '../../../types/common';
+import {firePageError, fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const GROUP_EVENTS = ['ADD_GROUP', 'REMOVE_GROUP'];
 
-export interface GrGroupAuditLog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-group-audit-log')
 export class GrGroupAuditLog extends ListViewMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -62,16 +55,12 @@
   @property({type: Boolean})
   _loading = true;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Audit Log'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Audit Log');
   }
 
   /** @override */
@@ -86,16 +75,10 @@
     }
 
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
-    return this.$.restAPI
+    return this.restApiService
       .getGroupAuditLog(this.groupId, errFn)
       .then(auditLog => {
         if (!auditLog) {
diff --git a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_html.ts b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_html.ts
index 1212685..32db13f 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_html.ts
@@ -66,5 +66,4 @@
       </template>
     </tbody>
   </table>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_test.js b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_test.js
index 1bbfcae..ce4e4c3 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log_test.js
@@ -80,7 +80,7 @@
 
       const response = {status: 404};
       sinon.stub(
-          element.$.restAPI, 'getGroupAuditLog')
+          element.restApiService, 'getGroupAuditLog')
           .callsFake((group, errFn) => {
             errFn(response);
           });
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
index ae10c03..b152e3c 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
@@ -23,7 +23,6 @@
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-confirm-delete-item-dialog/gr-confirm-delete-item-dialog';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -31,10 +30,7 @@
 import {htmlTemplate} from './gr-group-members_html';
 import {getBaseUrl} from '../../../utils/url-util';
 import {customElement, property} from '@polymer/decorators';
-import {
-  RestApiService,
-  ErrorCallback,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {
   GroupId,
@@ -46,6 +42,12 @@
 import {AutocompleteQuery} from '../../shared/gr-autocomplete/gr-autocomplete';
 import {PolymerDomRepeatEvent} from '../../../types/types';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {
+  fireAlert,
+  firePageError,
+  fireTitleChange,
+} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const SUGGESTIONS_LIMIT = 15;
 const SAVING_ERROR_TEXT =
@@ -55,7 +57,6 @@
 
 export interface GrGroupMembers {
   $: {
-    restAPI: RestApiService & Element;
     overlay: GrOverlay;
   };
 }
@@ -114,6 +115,8 @@
 
   _itemId?: AccountId | GroupId;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._queryMembers = input => this._getAccountSuggestions(input);
@@ -125,13 +128,7 @@
     super.attached();
     this._loadGroupDetails();
 
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Members'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Members');
   }
 
   _loadGroupDetails() {
@@ -142,50 +139,48 @@
     const promises: Promise<void>[] = [];
 
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
-    return this.$.restAPI.getGroupConfig(this.groupId, errFn).then(config => {
-      if (!config || !config.name) {
-        return Promise.resolve();
-      }
+    return this.restApiService
+      .getGroupConfig(this.groupId, errFn)
+      .then(config => {
+        if (!config || !config.name) {
+          return Promise.resolve();
+        }
 
-      this._groupName = config.name;
+        this._groupName = config.name;
 
-      promises.push(
-        this.$.restAPI.getIsAdmin().then(isAdmin => {
-          this._isAdmin = !!isAdmin;
-        })
-      );
+        promises.push(
+          this.restApiService.getIsAdmin().then(isAdmin => {
+            this._isAdmin = !!isAdmin;
+          })
+        );
 
-      promises.push(
-        this.$.restAPI.getIsGroupOwner(this._groupName).then(isOwner => {
-          this._groupOwner = !!isOwner;
-        })
-      );
+        promises.push(
+          this.restApiService.getIsGroupOwner(this._groupName).then(isOwner => {
+            this._groupOwner = !!isOwner;
+          })
+        );
 
-      promises.push(
-        this.$.restAPI.getGroupMembers(this._groupName).then(members => {
-          this._groupMembers = members;
-        })
-      );
+        promises.push(
+          this.restApiService.getGroupMembers(this._groupName).then(members => {
+            this._groupMembers = members;
+          })
+        );
 
-      promises.push(
-        this.$.restAPI.getIncludedGroup(this._groupName).then(includedGroup => {
-          this._includedGroups = includedGroup;
-        })
-      );
+        promises.push(
+          this.restApiService
+            .getIncludedGroup(this._groupName)
+            .then(includedGroup => {
+              this._includedGroups = includedGroup;
+            })
+        );
 
-      return Promise.all(promises).then(() => {
-        this._loading = false;
+        return Promise.all(promises).then(() => {
+          this._loading = false;
+        });
       });
-    });
   }
 
   _computeLoadingClass(loading: boolean) {
@@ -217,13 +212,13 @@
     if (!this._groupName) {
       return Promise.reject(new Error('group name undefined'));
     }
-    return this.$.restAPI
+    return this.restApiService
       .saveGroupMember(this._groupName, this._groupMemberSearchId as AccountId)
       .then(config => {
         if (!config || !this._groupName) {
           return;
         }
-        this.$.restAPI.getGroupMembers(this._groupName).then(members => {
+        this.restApiService.getGroupMembers(this._groupName).then(members => {
           this._groupMembers = members;
         });
         this._groupMemberSearchName = '';
@@ -237,24 +232,26 @@
     }
     this.$.overlay.close();
     if (this._itemType === 'member') {
-      return this.$.restAPI
+      return this.restApiService
         .deleteGroupMember(this._groupName, this._itemId! as AccountId)
         .then(itemDeleted => {
           if (itemDeleted.status === 204 && this._groupName) {
-            this.$.restAPI.getGroupMembers(this._groupName).then(members => {
-              this._groupMembers = members;
-            });
+            this.restApiService
+              .getGroupMembers(this._groupName)
+              .then(members => {
+                this._groupMembers = members;
+              });
           }
         });
     } else if (this._itemType === 'includedGroup') {
-      return this.$.restAPI
+      return this.restApiService
         .deleteIncludedGroup(this._groupName, this._itemId! as GroupId)
         .then(itemDeleted => {
           if (
             (itemDeleted.status === 204 || itemDeleted.status === 205) &&
             this._groupName
           ) {
-            this.$.restAPI
+            this.restApiService
               .getIncludedGroup(this._groupName)
               .then(includedGroup => {
                 this._includedGroups = includedGroup;
@@ -290,20 +287,14 @@
         new Error('group name or includedGroupSearchId undefined')
       );
     }
-    return this.$.restAPI
+    return this.restApiService
       .saveIncludedGroup(
         this._groupName,
         this._includedGroupSearchId.replace(/\+/g, ' ') as GroupId,
         (errResponse, err) => {
           if (errResponse) {
             if (errResponse.status === 404) {
-              this.dispatchEvent(
-                new CustomEvent('show-alert', {
-                  detail: {message: SAVING_ERROR_TEXT},
-                  bubbles: true,
-                  composed: true,
-                })
-              );
+              fireAlert(this, SAVING_ERROR_TEXT);
               return errResponse;
             }
             throw Error(errResponse.statusText);
@@ -315,9 +306,11 @@
         if (!config || !this._groupName) {
           return;
         }
-        this.$.restAPI.getIncludedGroup(this._groupName).then(includedGroup => {
-          this._includedGroups = includedGroup;
-        });
+        this.restApiService
+          .getIncludedGroup(this._groupName)
+          .then(includedGroup => {
+            this._includedGroups = includedGroup;
+          });
         this._includedGroupSearchName = '';
         this._includedGroupSearchId = '';
       });
@@ -343,7 +336,7 @@
     if (input.length === 0) {
       return Promise.resolve([]);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getSuggestedAccounts(input, SUGGESTIONS_LIMIT)
       .then(accounts => {
         const accountSuggestions = [];
@@ -362,7 +355,7 @@
           }
           accountSuggestions.push({
             name: nameAndEmail,
-            value: accounts[key]._account_id,
+            value: accounts[key]._account_id?.toString(),
           });
         }
         return accountSuggestions;
@@ -370,7 +363,7 @@
   }
 
   _getGroupSuggestions(input: string) {
-    return this.$.restAPI.getSuggestedGroups(input).then(response => {
+    return this.restApiService.getSuggestedGroups(input).then(response => {
       const groups = [];
       for (const key in response) {
         if (!hasOwnProperty(response, key)) {
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_html.ts b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_html.ts
index 2d3f8fc..6b6cb31 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_html.ts
@@ -180,5 +180,4 @@
       item-type="[[_itemType]]"
     ></gr-confirm-delete-item-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.js b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.js
index b5d2217..59820b8 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.js
@@ -139,7 +139,7 @@
     stubBaseUrl('https://test/site');
     element.groupId = 1;
     groupStub = sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getGroupConfig')
         .callsFake(() => Promise.resolve(groups));
     return element._loadGroupDetails();
@@ -162,7 +162,7 @@
 
     const memberName = 'test-admin';
 
-    const saveStub = sinon.stub(element.$.restAPI, 'saveGroupMember')
+    const saveStub = sinon.stub(element.restApiService, 'saveGroupMember')
         .callsFake(() => Promise.resolve({}));
 
     const button = element.$.saveGroupMember;
@@ -188,7 +188,7 @@
     const includedGroupName = 'testName';
 
     const saveIncludedGroupStub = sinon.stub(
-        element.$.restAPI, 'saveIncludedGroup')
+        element.restApiService, 'saveIncludedGroup')
         .callsFake(() => Promise.resolve({}));
 
     const button = element.$.saveIncludedGroups;
@@ -219,7 +219,7 @@
       status: 404,
       ok: false,
     };
-    sinon.stub(element.$.restAPI._restApiHelper, 'fetch').callsFake(
+    sinon.stub(element.restApiService._restApiHelper, 'fetch').callsFake(
         () => Promise.resolve(errorResponse));
 
     element.$.groupMemberSearchInput.text = memberName;
@@ -237,7 +237,7 @@
     const alertStub = sinon.stub();
     element.addEventListener('show-alert', alertStub);
     const err = new Error();
-    sinon.stub(element.$.restAPI._restApiHelper, 'fetch').callsFake(
+    sinon.stub(element.restApiService._restApiHelper, 'fetch').callsFake(
         () => Promise.reject(err));
 
     element.$.groupMemberSearchInput.text = memberName;
@@ -367,7 +367,7 @@
 
     const response = {status: 404};
     sinon.stub(
-        element.$.restAPI, 'getGroupConfig')
+        element.restApiService, 'getGroupConfig')
         .callsFake((group, errFn) => {
           errFn(response);
         });
diff --git a/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts b/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
index 511bf5c..f5170ed 100644
--- a/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
@@ -21,7 +21,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-copy-clipboard/gr-copy-clipboard';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -33,11 +32,14 @@
   AutocompleteQuery,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
 import {GroupId, GroupInfo, GroupName} from '../../../types/common';
-import {
-  ErrorCallback,
-  RestApiService,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {
+  fireEvent,
+  firePageError,
+  fireTitleChange,
+} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const INTERNAL_GROUP_REGEX = /^[\da-f]{40}$/;
 
@@ -54,7 +56,6 @@
 
 export interface GrGroup {
   $: {
-    restAPI: RestApiService & Element;
     loading: HTMLDivElement;
   };
 }
@@ -126,6 +127,8 @@
   @property({type: Boolean})
   _isAdmin = false;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = (input: string) => this._getGroupSuggestions(input);
@@ -145,56 +148,46 @@
     const promises: Promise<unknown>[] = [];
 
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
-    return this.$.restAPI.getGroupConfig(this.groupId, errFn).then(config => {
-      if (!config || !config.name) {
-        return Promise.resolve();
-      }
+    return this.restApiService
+      .getGroupConfig(this.groupId, errFn)
+      .then(config => {
+        if (!config || !config.name) {
+          return Promise.resolve();
+        }
 
-      this._groupName = config.name;
-      this._groupIsInternal = !!config.id.match(INTERNAL_GROUP_REGEX);
+        this._groupName = config.name;
+        this._groupIsInternal = !!config.id.match(INTERNAL_GROUP_REGEX);
 
-      promises.push(
-        this.$.restAPI.getIsAdmin().then(isAdmin => {
-          this._isAdmin = !!isAdmin;
-        })
-      );
+        promises.push(
+          this.restApiService.getIsAdmin().then(isAdmin => {
+            this._isAdmin = !!isAdmin;
+          })
+        );
 
-      promises.push(
-        this.$.restAPI.getIsGroupOwner(config.name).then(isOwner => {
-          this._groupOwner = !!isOwner;
-        })
-      );
+        promises.push(
+          this.restApiService.getIsGroupOwner(config.name).then(isOwner => {
+            this._groupOwner = !!isOwner;
+          })
+        );
 
-      // If visible to all is undefined, set to false. If it is defined
-      // as false, setting to false is fine. If any optional values
-      // are added with a default of true, then this would need to be an
-      // undefined check and not a truthy/falsy check.
-      if (config.options && !config.options.visible_to_all) {
-        config.options.visible_to_all = false;
-      }
-      this._groupConfig = config;
+        // If visible to all is undefined, set to false. If it is defined
+        // as false, setting to false is fine. If any optional values
+        // are added with a default of true, then this would need to be an
+        // undefined check and not a truthy/falsy check.
+        if (config.options && !config.options.visible_to_all) {
+          config.options.visible_to_all = false;
+        }
+        this._groupConfig = config;
 
-      this.dispatchEvent(
-        new CustomEvent('title-change', {
-          detail: {title: config.name},
-          composed: true,
-          bubbles: true,
-        })
-      );
+        fireTitleChange(this, config.name);
 
-      return Promise.all(promises).then(() => {
-        this._loading = false;
+        return Promise.all(promises).then(() => {
+          this._loading = false;
+        });
       });
-    });
   }
 
   _computeLoadingClass(loading: boolean) {
@@ -211,7 +204,7 @@
       return Promise.reject(new Error('invalid groupId or config name'));
     }
     const groupName = groupConfig.name;
-    return this.$.restAPI
+    return this.restApiService
       .saveGroupName(this.groupId, groupName)
       .then(config => {
         if (config.status === 200) {
@@ -220,6 +213,7 @@
             name: groupName,
             external: !this._groupIsInternal,
           };
+          fireEvent(this, 'name-changed');
           this.dispatchEvent(
             new CustomEvent('name-changed', {
               detail,
@@ -239,7 +233,7 @@
       owner = decodeURIComponent(this._groupConfigOwner);
     }
     if (!owner) return;
-    return this.$.restAPI.saveGroupOwner(this.groupId, owner).then(() => {
+    return this.restApiService.saveGroupOwner(this.groupId, owner).then(() => {
       this._owner = false;
     });
   }
@@ -247,7 +241,7 @@
   _handleSaveDescription() {
     if (!this.groupId || !this._groupConfig || !this._groupConfig.description)
       return;
-    return this.$.restAPI
+    return this.restApiService
       .saveGroupDescription(this.groupId, this._groupConfig.description)
       .then(() => {
         this._description = false;
@@ -261,9 +255,11 @@
 
     const options = {visible_to_all: visible};
 
-    return this.$.restAPI.saveGroupOptions(this.groupId, options).then(() => {
-      this._options = false;
-    });
+    return this.restApiService
+      .saveGroupOptions(this.groupId, options)
+      .then(() => {
+        this._options = false;
+      });
   }
 
   @observe('_groupConfig.name')
@@ -303,7 +299,7 @@
   }
 
   _getGroupSuggestions(input: string) {
-    return this.$.restAPI.getSuggestedGroups(input).then(response => {
+    return this.restApiService.getSuggestedGroups(input).then(response => {
       const groups: AutocompleteSuggestion[] = [];
       for (const key in response) {
         if (!hasOwnProperty(response, key)) {
diff --git a/polygerrit-ui/app/elements/admin/gr-group/gr-group_html.ts b/polygerrit-ui/app/elements/admin/gr-group/gr-group_html.ts
index aed73bf..4dcc1b8 100644
--- a/polygerrit-ui/app/elements/admin/gr-group/gr-group_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group/gr-group_html.ts
@@ -165,5 +165,4 @@
       </div>
     </div>
   </main>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-group/gr-group_test.js b/polygerrit-ui/app/elements/admin/gr-group/gr-group_test.js
index 34f6b6a..c006251 100644
--- a/polygerrit-ui/app/elements/admin/gr-group/gr-group_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-group/gr-group_test.js
@@ -41,7 +41,7 @@
     });
     element = basicFixture.instantiate();
     groupStub = sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getGroupConfig')
         .callsFake(() => Promise.resolve(group));
   });
@@ -56,7 +56,7 @@
 
   test('default values are populated with internal group', done => {
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getIsGroupOwner')
         .callsFake(() => Promise.resolve(true));
     element.groupId = 1;
@@ -72,11 +72,11 @@
     groupExternal.id = 'external-group-id';
     groupStub.restore();
     groupStub = sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getGroupConfig')
         .callsFake(() => Promise.resolve(groupExternal));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getIsGroupOwner')
         .callsFake(() => Promise.resolve(true));
     element.groupId = 1;
@@ -97,12 +97,12 @@
     element._groupName = groupName;
 
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getIsGroupOwner')
         .callsFake(() => Promise.resolve(true));
 
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'saveGroupName')
         .callsFake(() => Promise.resolve({status: 200}));
 
@@ -136,7 +136,7 @@
     element._groupOwner = true;
 
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getIsGroupOwner')
         .callsFake(() => Promise.resolve({status: 200}));
 
@@ -163,7 +163,7 @@
     groupStub.restore();
 
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getGroupConfig')
         .callsFake(() => Promise.resolve({}));
 
@@ -189,7 +189,7 @@
       name: 'test-group',
     };
     element.groupId = 'gg';
-    sinon.stub(element.$.restAPI, 'saveGroupName')
+    sinon.stub(element.restApiService, 'saveGroupName')
         .returns(Promise.resolve({status: 200}));
 
     const showStub = sinon.stub(element, 'dispatchEvent');
@@ -240,7 +240,7 @@
 
     const response = {status: 404};
     sinon.stub(
-        element.$.restAPI, 'getGroupConfig').callsFake((group, errFn) => {
+        element.restApiService, 'getGroupConfig').callsFake((group, errFn) => {
       errFn(response);
     });
 
diff --git a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission.ts b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission.ts
index c998cd8..65a3b00 100644
--- a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission.ts
+++ b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission.ts
@@ -21,7 +21,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-rule-editor/gr-rule-editor';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -34,7 +33,6 @@
   PermissionArray,
 } from '../../../utils/access-util';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {
   LabelNameToLabelTypeInfoMap,
@@ -56,6 +54,8 @@
   EditableProjectAccessGroups,
 } from '../gr-repo-access/gr-repo-access-interfaces';
 import {PolymerDomRepeatEvent} from '../../../types/types';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
 const MAX_AUTOCOMPLETE_RESULTS = 20;
 
@@ -65,7 +65,6 @@
 
 export interface GrPermission {
   $: {
-    restAPI: RestApiService & Element;
     groupAutocomplete: GrAutocomplete;
   };
 }
@@ -142,6 +141,8 @@
   @property({type: Boolean})
   _originalExclusiveValue?: boolean;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = () => this._getGroupSuggestions();
@@ -222,9 +223,7 @@
     }
     this.permission.value.modified = true;
     // Allows overall access page to know a change has been made.
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   _handleRemovePermission() {
@@ -232,18 +231,11 @@
       return;
     }
     if (this.permission.value.added) {
-      this.dispatchEvent(
-        new CustomEvent('added-permission-removed', {
-          bubbles: true,
-          composed: true,
-        })
-      );
+      fireEvent(this, 'added-permission-removed');
     }
     this._deleted = true;
     this.permission.value.deleted = true;
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   @observe('_rules.splices')
@@ -337,7 +329,7 @@
   }
 
   _getGroupSuggestions(): Promise<AutocompleteSuggestion[]> {
-    return this.$.restAPI
+    return this.restApiService
       .getSuggestedGroups(this._groupFilter || '', MAX_AUTOCOMPLETE_RESULTS)
       .then(response => {
         const groups: GroupSuggestion[] = [];
@@ -407,9 +399,7 @@
     value.added = true;
     // See comment above for why we cannot use "this.set(...)" here.
     this.permission.value.rules[groupId] = value;
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   _computeHasRange(name: string) {
diff --git a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_html.ts b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_html.ts
index 9795c92..6ae982b 100644
--- a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_html.ts
@@ -140,5 +140,4 @@
     </div>
     <!-- end deletedContainer -->
   </section>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_test.js b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_test.js
index 32430ec..c9b0131 100644
--- a/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-permission/gr-permission_test.js
@@ -25,7 +25,7 @@
 
   setup(() => {
     element = basicFixture.instantiate();
-    sinon.stub(element.$.restAPI, 'getSuggestedGroups').returns(
+    sinon.stub(element.restApiService, 'getSuggestedGroups').returns(
         Promise.resolve({
           'Administrators': {
             id: '4c97682e6ce61b7247f3381b6f1789356666de7f',
diff --git a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
index 5039972..fe3d9ff 100644
--- a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
@@ -17,7 +17,6 @@
 import '../../../styles/gr-table-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-list-view/gr-list-view';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -27,18 +26,15 @@
   ListViewParams,
 } from '../../../mixins/gr-list-view-mixin/gr-list-view-mixin';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {PluginInfo} from '../../../types/common';
+import {firePageError} from '../../../utils/event-util';
+import {fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 interface PluginInfoWithName extends PluginInfo {
   name: string;
 }
-export interface GrPluginList {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-plugin-list')
 export class GrPluginList extends ListViewMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -81,16 +77,12 @@
   @property({type: String})
   _filter = '';
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Plugins'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Plugins');
   }
 
   _paramsChanged(params: ListViewParams) {
@@ -103,15 +95,9 @@
 
   _getPlugins(filter: string, pluginsPerPage: number, offset?: number) {
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
-    return this.$.restAPI
+    return this.restApiService
       .getPlugins(filter, pluginsPerPage, offset, errFn)
       .then(plugins => {
         if (!plugins) {
diff --git a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_html.ts b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_html.ts
index d5318b5..eeca478 100644
--- a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_html.ts
@@ -78,5 +78,4 @@
       </tbody>
     </table>
   </gr-list-view>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_test.js b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_test.js
index 7303748..6aa247f 100644
--- a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list_test.js
@@ -131,7 +131,7 @@
   suite('filter', () => {
     test('_paramsChanged', done => {
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getPlugins')
           .callsFake(() => Promise.resolve(plugins));
       const value = {
@@ -139,11 +139,11 @@
         offset: 25,
       };
       element._paramsChanged(value).then(() => {
-        assert.equal(element.$.restAPI.getPlugins.lastCall.args[0],
+        assert.equal(element.restApiService.getPlugins.lastCall.args[0],
             'test');
-        assert.equal(element.$.restAPI.getPlugins.lastCall.args[1],
+        assert.equal(element.restApiService.getPlugins.lastCall.args[1],
             25);
-        assert.equal(element.$.restAPI.getPlugins.lastCall.args[2],
+        assert.equal(element.restApiService.getPlugins.lastCall.args[2],
             25);
         done();
       });
@@ -168,7 +168,7 @@
   suite('404', () => {
     test('fires page-error', done => {
       const response = {status: 404};
-      sinon.stub(element.$.restAPI, 'getPlugins').callsFake(
+      sinon.stub(element.restApiService, 'getPlugins').callsFake(
           (filter, pluginsPerPage, opt_offset, errFn) => {
             errFn(response);
           });
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
index b96ec2c..b46a905 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
@@ -17,7 +17,6 @@
 import '../../../styles/gr-menu-page-styles';
 import '../../../styles/gr-subpage-styles';
 import '../../../styles/shared-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-access-section/gr-access-section';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -38,7 +37,6 @@
   UrlEncodedRepoName,
   ProjectAccessGroups,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrAccessSection} from '../gr-access-section/gr-access-section';
@@ -52,17 +50,13 @@
   PropertyTreeNode,
   PrimitiveValue,
 } from './gr-repo-access-interfaces';
+import {firePageError, fireAlert} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const NOTHING_TO_SAVE = 'No changes to save.';
 
 const MAX_AUTOCOMPLETE_RESULTS = 50;
 
-export interface GrRepoAccess {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 /**
  * Fired when save is a no-op
  *
@@ -126,6 +120,8 @@
 
   private _originalInheritsFrom?: ProjectInfo | null;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = () => this._getInheritFromSuggestions();
@@ -155,20 +151,14 @@
 
   _reload(repo: RepoName) {
     const errFn = (response?: Response | null) => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
     this._editing = false;
 
     // Always reset sections when a project changes.
     this._sections = [];
-    const sectionsPromises = this.$.restAPI
+    const sectionsPromises = this.restApiService
       .getRepoAccessRights(repo, errFn)
       .then(res => {
         if (!res) {
@@ -204,7 +194,7 @@
         return toSortedPermissionsArray(this._local);
       });
 
-    const capabilitiesPromises = this.$.restAPI
+    const capabilitiesPromises = this.restApiService
       .getCapabilities(errFn)
       .then(res => {
         if (!res) {
@@ -214,13 +204,15 @@
         return res;
       });
 
-    const labelsPromises = this.$.restAPI.getRepo(repo, errFn).then(res => {
-      if (!res) {
-        return Promise.resolve(undefined);
-      }
+    const labelsPromises = this.restApiService
+      .getRepo(repo, errFn)
+      .then(res => {
+        if (!res) {
+          return Promise.resolve(undefined);
+        }
 
-      return res.labels;
-    });
+        return res.labels;
+      });
 
     return Promise.all([
       sectionsPromises,
@@ -252,7 +244,7 @@
   }
 
   _getInheritFromSuggestions(): Promise<AutocompleteSuggestion[]> {
-    return this.$.restAPI
+    return this.restApiService
       .getRepos(this._inheritFromFilter, MAX_AUTOCOMPLETE_RESULTS)
       .then(response => {
         const projects: AutocompleteSuggestion[] = [];
@@ -516,13 +508,7 @@
       !Object.keys(addRemoveObj.remove).length &&
       !addRemoveObj.parent
     ) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: NOTHING_TO_SAVE},
-          bubbles: true,
-          composed: true,
-        })
-      );
+      fireAlert(this, NOTHING_TO_SAVE);
       return;
     }
     const obj: ProjectAccessInput = ({
@@ -548,7 +534,7 @@
     if (!repo) {
       return Promise.resolve();
     }
-    return this.$.restAPI
+    return this.restApiService
       .setRepoAccessRights(repo, obj)
       .then(() => {
         this._reload(repo);
@@ -573,7 +559,7 @@
     if (!this.repo) {
       return;
     }
-    return this.$.restAPI
+    return this.restApiService
       .setRepoAccessRightsForReview(this.repo, obj)
       .then(change => {
         GerritNav.navigateToChange(change);
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_html.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_html.ts
index 4e76360..a16ad28 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_html.ts
@@ -143,5 +143,4 @@
       </div>
     </div>
   </main>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_test.js b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_test.js
index d3204e1..2af4b6f1 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access_test.js
@@ -104,7 +104,7 @@
     stub('gr-rest-api-interface', {
       getAccount() { return Promise.resolve(null); },
     });
-    repoStub = sinon.stub(element.$.restAPI, 'getRepo').returns(
+    repoStub = sinon.stub(element.restApiService, 'getRepo').returns(
         Promise.resolve(repoRes));
     element._loading = false;
     element._ownerOf = [];
@@ -118,14 +118,14 @@
   });
 
   test('_repoChanged', done => {
-    const accessStub = sinon.stub(element.$.restAPI,
+    const accessStub = sinon.stub(element.restApiService,
         'getRepoAccessRights');
 
     accessStub.withArgs('New Repo').returns(
         Promise.resolve(JSON.parse(JSON.stringify(accessRes))));
     accessStub.withArgs('Another New Repo')
         .returns(Promise.resolve(JSON.parse(JSON.stringify(accessRes2))));
-    const capabilitiesStub = sinon.stub(element.$.restAPI,
+    const capabilitiesStub = sinon.stub(element.restApiService,
         'getCapabilities');
     capabilitiesStub.returns(Promise.resolve(capabilitiesRes));
 
@@ -160,9 +160,9 @@
         name: 'Access Database',
       },
     };
-    const accessStub = sinon.stub(element.$.restAPI, 'getRepoAccessRights')
+    const accessStub = sinon.stub(element.restApiService, 'getRepoAccessRights')
         .returns(Promise.resolve(JSON.parse(JSON.stringify(accessRes2))));
-    const capabilitiesStub = sinon.stub(element.$.restAPI,
+    const capabilitiesStub = sinon.stub(element.restApiService,
         'getCapabilities').returns(Promise.resolve(capabilitiesRes));
 
     element._repoChanged().then(() => {
@@ -241,7 +241,7 @@
     const response = {status: 404};
 
     sinon.stub(
-        element.$.restAPI, 'getRepoAccessRights')
+        element.restApiService, 'getRepoAccessRights')
         .callsFake((repoName, errFn) => {
           errFn(response);
         });
@@ -378,7 +378,7 @@
 
     test('_handleSaveForReview', () => {
       const saveStub =
-          sinon.stub(element.$.restAPI, 'setRepoAccessRightsForReview');
+          sinon.stub(element.restApiService, 'setRepoAccessRightsForReview');
       sinon.stub(element, '_computeAddAndRemove').returns({
         add: {},
         remove: {},
@@ -1161,11 +1161,11 @@
           },
         },
       };
-      sinon.stub(element.$.restAPI, 'getRepoAccessRights').returns(
+      sinon.stub(element.restApiService, 'getRepoAccessRights').returns(
           Promise.resolve(JSON.parse(JSON.stringify(accessRes))));
       sinon.stub(GerritNav, 'navigateToChange');
       let resolver;
-      const saveStub = sinon.stub(element.$.restAPI,
+      const saveStub = sinon.stub(element.restApiService,
           'setRepoAccessRights')
           .returns(new Promise(r => resolver = r));
 
@@ -1208,11 +1208,11 @@
           },
         },
       };
-      sinon.stub(element.$.restAPI, 'getRepoAccessRights').returns(
+      sinon.stub(element.restApiService, 'getRepoAccessRights').returns(
           Promise.resolve(JSON.parse(JSON.stringify(accessRes))));
       sinon.stub(GerritNav, 'navigateToChange');
       let resolver;
-      const saveForReviewStub = sinon.stub(element.$.restAPI,
+      const saveForReviewStub = sinon.stub(element.restApiService,
           'setRepoAccessRightsForReview')
           .returns(new Promise(r => resolver = r));
 
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
index a74f4bb..0145b9f 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
@@ -22,7 +22,6 @@
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-create-change-dialog/gr-create-change-dialog';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -30,10 +29,7 @@
 import {htmlTemplate} from './gr-repo-commands_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property} from '@polymer/decorators';
-import {
-  ErrorCallback,
-  RestApiService,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   BranchName,
   ConfigInfo,
@@ -42,6 +38,12 @@
 } from '../../../types/common';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GrCreateChangeDialog} from '../gr-create-change-dialog/gr-create-change-dialog';
+import {
+  fireAlert,
+  firePageError,
+  fireTitleChange,
+} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const GC_MESSAGE = 'Garbage collection completed successfully.';
 const CONFIG_BRANCH = 'refs/meta/config' as BranchName;
@@ -53,7 +55,6 @@
 
 export interface GrRepoCommands {
   $: {
-    restAPI: RestApiService & Element;
     createChangeOverlay: GrOverlay;
     createNewChangeModal: GrCreateChangeDialog;
   };
@@ -90,18 +91,14 @@
   @property({type: Boolean})
   _runningGC = false;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this._loadRepo();
 
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Repo Commands'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Repo Commands');
   }
 
   _loadRepo() {
@@ -109,16 +106,10 @@
       // Do not process the error, if the component is not attached to the DOM
       // anymore, which at least in tests can happen.
       if (!this.isConnected) return;
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
-    this.$.restAPI.getProjectConfig(this.repo, errFn).then(config => {
+    this.restApiService.getProjectConfig(this.repo, errFn).then(config => {
       if (!config) return;
       // Do not process the response, if the component is not attached to the
       // DOM anymore, which at least in tests can happen.
@@ -137,18 +128,13 @@
   }
 
   _handleRunningGC() {
+    if (!this.repo) return;
     this._runningGC = true;
-    return this.$.restAPI
+    return this.restApiService
       .runRepoGC(this.repo)
       .then(response => {
         if (response?.status === 200) {
-          this.dispatchEvent(
-            new CustomEvent('show-alert', {
-              detail: {message: GC_MESSAGE},
-              bubbles: true,
-              composed: true,
-            })
-          );
+          fireAlert(this, GC_MESSAGE);
         }
       })
       .finally(() => {
@@ -177,7 +163,7 @@
    */
   _handleEditRepoConfig() {
     this._editingConfig = true;
-    return this.$.restAPI
+    return this.restApiService
       .createChange(
         this.repo,
         CONFIG_BRANCH,
@@ -190,13 +176,7 @@
         const message = change
           ? CREATE_CHANGE_SUCCEEDED_MESSAGE
           : CREATE_CHANGE_FAILED_MESSAGE;
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message},
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireAlert(this, message);
         if (!change) {
           return;
         }
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_html.ts b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_html.ts
index 3880e4a..d69692d 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_html.ts
@@ -88,5 +88,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_test.js b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_test.js
index efe4012..60d5f20 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands_test.js
@@ -31,7 +31,7 @@
     // Note that this probably does not achieve what it is supposed to, because
     // getProjectConfig() is called as soon as the element is attached, so
     // stubbing it here has not effect anymore.
-    repoStub = sinon.stub(element.$.restAPI, 'getProjectConfig')
+    repoStub = sinon.stub(element.restApiService, 'getProjectConfig')
         .returns(Promise.resolve({}));
   });
 
@@ -68,7 +68,7 @@
     let alertStub;
 
     setup(() => {
-      createChangeStub = sinon.stub(element.$.restAPI, 'createChange');
+      createChangeStub = sinon.stub(element.restApiService, 'createChange');
       urlStub = sinon.stub(GerritNav, 'getEditUrlForDiff');
       sinon.stub(GerritNav, 'navigateToRelativeUrl');
       handleSpy = sinon.spy(element, '_handleEditRepoConfig');
@@ -119,7 +119,7 @@
 
       const response = {status: 404};
       sinon.stub(
-          element.$.restAPI, 'getProjectConfig')
+          element.restApiService, 'getProjectConfig')
           .callsFake((repo, errFn) => {
             errFn(response);
           });
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards.ts b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards.ts
index d9d8560..e72170b 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards.ts
@@ -16,7 +16,6 @@
  */
 
 import '../../../styles/shared-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -24,20 +23,16 @@
 import {htmlTemplate} from './gr-repo-dashboards_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {RepoName, DashboardId, DashboardInfo} from '../../../types/common';
 import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {firePageError} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 interface DashboardRef {
   section: string;
   dashboards: DashboardInfo[];
 }
 
-export interface GrRepoDashboards {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-repo-dashboards')
 export class GrRepoDashboards extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -55,6 +50,8 @@
   @property({type: Array})
   _dashboards?: DashboardRef[];
 
+  private restApiService = appContext.restApiService;
+
   _repoChanged(repo?: RepoName) {
     this._loading = true;
     if (!repo) {
@@ -62,16 +59,10 @@
     }
 
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
-    return this.$.restAPI
+    return this.restApiService
       .getRepoDashboards(repo, errFn)
       .then((res?: DashboardInfo[]) => {
         if (!res) {
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_html.ts b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_html.ts
index 7cdd10e..51ea417 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_html.ts
@@ -67,5 +67,4 @@
       </template>
     </tbody>
   </table>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_test.js b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_test.js
index b4d3575..f5d4365 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo-dashboards/gr-repo-dashboards_test.js
@@ -30,7 +30,7 @@
 
   suite('dashboard table', () => {
     setup(() => {
-      sinon.stub(element.$.restAPI, 'getRepoDashboards').returns(
+      sinon.stub(element.restApiService, 'getRepoDashboards').returns(
           Promise.resolve([
             {
               id: 'default:contributor',
@@ -124,7 +124,7 @@
     test('fires page-error', done => {
       const response = {status: 404};
       sinon.stub(
-          element.$.restAPI, 'getRepoDashboards')
+          element.restApiService, 'getRepoDashboards')
           .callsFake((repo, errFn) => {
             errFn(response);
           });
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.ts b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.ts
index 2fce6e1..644e9b1 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.ts
@@ -25,7 +25,6 @@
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-list-view/gr-list-view';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-create-pointer-dialog/gr-create-pointer-dialog';
 import '../gr-confirm-delete-item-dialog/gr-confirm-delete-item-dialog';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
@@ -36,10 +35,7 @@
 import {ListViewMixin} from '../../../mixins/gr-list-view-mixin/gr-list-view-mixin';
 import {encodeURL} from '../../../utils/url-util';
 import {customElement, property} from '@polymer/decorators';
-import {
-  ErrorCallback,
-  RestApiService,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GrCreatePointerDialog} from '../gr-create-pointer-dialog/gr-create-pointer-dialog';
 import {
@@ -53,12 +49,13 @@
 import {AppElementRepoParams} from '../../gr-app-types';
 import {PolymerDomRepeatEvent} from '../../../types/types';
 import {RepoDetailView} from '../../core/gr-navigation/gr-navigation';
+import {firePageError} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const PGP_START = '-----BEGIN PGP SIGNATURE-----';
 
 export interface GrRepoDetailList {
   $: {
-    restAPI: RestApiService & Element;
     overlay: GrOverlay;
     createOverlay: GrOverlay;
     createNewModal: GrCreatePointerDialog;
@@ -120,8 +117,10 @@
   @property({type: String})
   _revisedRef?: GitRef;
 
+  private readonly restApiService = appContext.restApiService;
+
   _determineIfOwner(repo: RepoName) {
-    return this.$.restAPI
+    return this.restApiService
       .getRepoAccess(repo)
       .then(access => (this._isOwner = !!access && !!access[repo].is_owner));
   }
@@ -182,16 +181,11 @@
     this._items = [];
     flush();
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
+
     if (detailType === RepoDetailView.BRANCHES) {
-      return this.$.restAPI
+      return this.restApiService
         .getRepoBranches(filter, repo, itemsPerPage, offset, errFn)
         .then(items => {
           if (!items) {
@@ -201,7 +195,7 @@
           this._loading = false;
         });
     } else if (detailType === RepoDetailView.TAGS) {
-      return this.$.restAPI
+      return this.restApiService
         .getRepoTags(filter, repo, itemsPerPage, offset, errFn)
         .then(items => {
           if (!items) {
@@ -249,7 +243,7 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _computeEditingClass(isEditing: boolean) {
@@ -277,7 +271,7 @@
   }
 
   _setRepoHead(repo: RepoName, ref: GitRef, e: PolymerDomRepeatEvent<GitRef>) {
-    return this.$.restAPI.setRepoHead(repo, ref).then(res => {
+    return this.restApiService.setRepoHead(repo, ref).then(res => {
       if (res.status < 400) {
         this._isEditing = false;
         e.model.set('item.revision', ref);
@@ -309,7 +303,7 @@
       return Promise.reject(new Error('undefined repo or refName'));
     }
     if (this.detailType === RepoDetailView.BRANCHES) {
-      return this.$.restAPI
+      return this.restApiService
         .deleteRepoBranches(this._repo, this._refName)
         .then(itemDeleted => {
           if (itemDeleted.status === 204) {
@@ -323,7 +317,7 @@
           }
         });
     } else if (this.detailType === RepoDetailView.TAGS) {
-      return this.$.restAPI
+      return this.restApiService
         .deleteRepoTags(this._repo, this._refName)
         .then(itemDeleted => {
           if (itemDeleted.status === 204) {
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_html.ts b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_html.ts
index 196797f..4435d3a 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_html.ts
@@ -220,5 +220,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_test.js b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_test.js
index 7727821..f20fd1e 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list_test.js
@@ -118,7 +118,7 @@
 
       test('Edit HEAD button not admin', done => {
         sinon.stub(element, '_getLoggedIn').returns(Promise.resolve(true));
-        sinon.stub(element.$.restAPI, 'getRepoAccess').returns(
+        sinon.stub(element.restApiService, 'getRepoAccess').returns(
             Promise.resolve({
               test: {is_owner: false},
             }));
@@ -142,7 +142,7 @@
             .querySelector('.revisionWithEditing');
 
         sinon.stub(element, '_getLoggedIn').returns(Promise.resolve(true));
-        sinon.stub(element.$.restAPI, 'getRepoAccess').returns(
+        sinon.stub(element.restApiService, 'getRepoAccess').returns(
             Promise.resolve({
               test: {is_owner: true},
             }));
@@ -219,7 +219,7 @@
       test('_handleSaveRevision with invalid rev', done => {
         const event = {model: {set: sinon.stub()}};
         element._isEditing = true;
-        sinon.stub(element.$.restAPI, 'setRepoHead').returns(
+        sinon.stub(element.restApiService, 'setRepoHead').returns(
             Promise.resolve({
               status: 400,
             })
@@ -235,7 +235,7 @@
       test('_handleSaveRevision with valid rev', done => {
         const event = {model: {set: sinon.stub()}};
         element._isEditing = true;
-        sinon.stub(element.$.restAPI, 'setRepoHead').returns(
+        sinon.stub(element.restApiService, 'setRepoHead').returns(
             Promise.resolve({
               status: 200,
             })
@@ -280,7 +280,7 @@
     suite('filter', () => {
       test('_paramsChanged', done => {
         sinon.stub(
-            element.$.restAPI,
+            element.restApiService,
             'getRepoBranches')
             .callsFake(() => Promise.resolve(branches));
         const params = {
@@ -290,13 +290,13 @@
           offset: 25,
         };
         element._paramsChanged(params).then(() => {
-          assert.equal(element.$.restAPI.getRepoBranches.lastCall.args[0],
+          assert.equal(element.restApiService.getRepoBranches.lastCall.args[0],
               'test');
-          assert.equal(element.$.restAPI.getRepoBranches.lastCall.args[1],
+          assert.equal(element.restApiService.getRepoBranches.lastCall.args[1],
               'test');
-          assert.equal(element.$.restAPI.getRepoBranches.lastCall.args[2],
+          assert.equal(element.restApiService.getRepoBranches.lastCall.args[2],
               25);
-          assert.equal(element.$.restAPI.getRepoBranches.lastCall.args[3],
+          assert.equal(element.restApiService.getRepoBranches.lastCall.args[3],
               25);
           done();
         });
@@ -306,7 +306,7 @@
     suite('404', () => {
       test('fires page-error', done => {
         const response = {status: 404};
-        sinon.stub(element.$.restAPI, 'getRepoBranches').callsFake(
+        sinon.stub(element.restApiService, 'getRepoBranches').callsFake(
             (filter, repo, reposBranchesPerPage, opt_offset, errFn) => {
               errFn(response);
             });
@@ -458,7 +458,7 @@
     suite('filter', () => {
       test('_paramsChanged', done => {
         sinon.stub(
-            element.$.restAPI,
+            element.restApiService,
             'getRepoTags')
             .callsFake(() => Promise.resolve(tags));
         const params = {
@@ -468,13 +468,13 @@
           offset: 25,
         };
         element._paramsChanged(params).then(() => {
-          assert.equal(element.$.restAPI.getRepoTags.lastCall.args[0],
+          assert.equal(element.restApiService.getRepoTags.lastCall.args[0],
               'test');
-          assert.equal(element.$.restAPI.getRepoTags.lastCall.args[1],
+          assert.equal(element.restApiService.getRepoTags.lastCall.args[1],
               'test');
-          assert.equal(element.$.restAPI.getRepoTags.lastCall.args[2],
+          assert.equal(element.restApiService.getRepoTags.lastCall.args[2],
               25);
-          assert.equal(element.$.restAPI.getRepoTags.lastCall.args[3],
+          assert.equal(element.restApiService.getRepoTags.lastCall.args[3],
               25);
           done();
         });
@@ -520,7 +520,7 @@
     suite('404', () => {
       test('fires page-error', done => {
         const response = {status: 404};
-        sinon.stub(element.$.restAPI, 'getRepoTags').callsFake(
+        sinon.stub(element.restApiService, 'getRepoTags').callsFake(
             (filter, repo, reposTagsPerPage, opt_offset, errFn) => {
               errFn(response);
             });
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
index ba2d850..6f6f926 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
@@ -19,7 +19,6 @@
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-list-view/gr-list-view';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-create-repo-dialog/gr-create-repo-dialog';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -29,11 +28,12 @@
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property, observe, computed} from '@polymer/decorators';
 import {AppElementAdminParams} from '../../gr-app-types';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {RepoName, ProjectInfoWithName} from '../../../types/common';
 import {GrCreateRepoDialog} from '../gr-create-repo-dialog/gr-create-repo-dialog';
 import {ProjectState} from '../../../constants/constants';
+import {fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -43,7 +43,6 @@
 
 export interface GrRepoList {
   $: {
-    restAPI: RestApiService & Element;
     createOverlay: GrOverlay;
     createNewModal: GrCreateRepoDialog;
   };
@@ -89,17 +88,13 @@
     return this.computeShownItems(this._repos);
   }
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this._getCreateRepoCapability();
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Repos'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Repos');
     this._maybeOpenCreateOverlay(this.params);
   }
 
@@ -130,11 +125,11 @@
   }
 
   _getCreateRepoCapability() {
-    return this.$.restAPI.getAccount().then(account => {
+    return this.restApiService.getAccount().then(account => {
       if (!account) {
         return;
       }
-      return this.$.restAPI
+      return this.restApiService
         .getAccountCapabilities(['createProject'])
         .then(capabilities => {
           if (capabilities?.createProject) {
@@ -146,18 +141,20 @@
 
   _getRepos(filter: string, reposPerPage: number, offset?: number) {
     this._repos = [];
-    return this.$.restAPI.getRepos(filter, reposPerPage, offset).then(repos => {
-      // Late response.
-      if (filter !== this._filter || !repos) {
-        return;
-      }
-      this._repos = repos;
-      this._loading = false;
-    });
+    return this.restApiService
+      .getRepos(filter, reposPerPage, offset)
+      .then(repos => {
+        // Late response.
+        if (filter !== this._filter || !repos) {
+          return;
+        }
+        this._repos = repos;
+        this._loading = false;
+      });
   }
 
   _refreshReposList() {
-    this.$.restAPI.invalidateReposCache();
+    this.restApiService.invalidateReposCache();
     return this._getRepos(this._filter, this._reposPerPage, this._offset);
   }
 
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_html.ts b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_html.ts
index 4889845..20c72f9 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_html.ts
@@ -115,5 +115,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_test.js b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_test.js
index e2a29f2..baa33a7 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_test.js
@@ -109,21 +109,21 @@
     });
 
     test('_paramsChanged', done => {
-      sinon.stub(element.$.restAPI, 'getRepos')
+      sinon.stub(element.restApiService, 'getRepos')
           .callsFake( () => Promise.resolve(repos));
       const value = {
         filter: 'test',
         offset: 25,
       };
       element._paramsChanged(value).then(() => {
-        assert.isTrue(element.$.restAPI.getRepos.lastCall
+        assert.isTrue(element.restApiService.getRepos.lastCall
             .calledWithExactly('test', 25, 25));
         done();
       });
     });
 
     test('latest repos requested are always set', done => {
-      const repoStub = sinon.stub(element.$.restAPI, 'getRepos');
+      const repoStub = sinon.stub(element.restApiService, 'getRepos');
       repoStub.withArgs('test').returns(Promise.resolve(repos));
       repoStub.withArgs('filter').returns(Promise.resolve(reposFiltered));
       element._filter = 'test';
diff --git a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
index 101c77a..d8481ad 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
@@ -19,7 +19,6 @@
 import '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
 import '../../shared/gr-download-commands/gr-download-commands';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import '../../../styles/gr-form-styles';
 import '../../../styles/gr-subpage-styles';
@@ -31,10 +30,7 @@
 import {htmlTemplate} from './gr-repo_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property, observe} from '@polymer/decorators';
-import {
-  RestApiService,
-  ErrorCallback,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   ConfigInfo,
   RepoName,
@@ -48,6 +44,8 @@
 import {ProjectState} from '../../../constants/constants';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {firePageError, fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const STATES = {
   active: {value: ProjectState.ACTIVE, label: 'Active'},
@@ -83,11 +81,6 @@
   },
 };
 
-export interface GrRepo {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-repo')
 export class GrRepo extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -144,18 +137,14 @@
   @property({type: Object})
   _schemesObj?: SchemesInfoMap;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this._loadRepo();
 
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: this.repo},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, `${this.repo}`);
   }
 
   _computePluginData(
@@ -182,13 +171,7 @@
     const promises = [];
 
     const errFn: ErrorCallback = response => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
 
     promises.push(
@@ -197,7 +180,7 @@
         if (loggedIn) {
           const repo = this.repo;
           if (!repo) throw new Error('undefined repo');
-          this.$.restAPI.getRepoAccess(repo).then(access => {
+          this.restApiService.getRepoAccess(repo).then(access => {
             if (!access || this.repo !== repo) {
               return;
             }
@@ -210,7 +193,7 @@
     );
 
     promises.push(
-      this.$.restAPI.getProjectConfig(this.repo, errFn).then(config => {
+      this.restApiService.getProjectConfig(this.repo, errFn).then(config => {
         if (!config) {
           return;
         }
@@ -232,7 +215,7 @@
     );
 
     promises.push(
-      this.$.restAPI.getConfig().then(config => {
+      this.restApiService.getConfig().then(config => {
         if (!config) {
           return;
         }
@@ -256,7 +239,7 @@
     if (!_loggedIn) {
       return;
     }
-    this.$.restAPI.getPreferences().then(prefs => {
+    this.restApiService.getPreferences().then(prefs => {
       if (prefs?.download_scheme) {
         // Note (issue 5180): normalize the download scheme with lower-case.
         this._selectedScheme = prefs.download_scheme.toLowerCase();
@@ -324,7 +307,7 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _formatRepoConfigForSave(repoConfig: ConfigInfo): ConfigInput {
@@ -340,12 +323,14 @@
       if (key === 'plugin_config') {
         configInputObj.plugin_config_values = repoConfig.plugin_config;
       } else if (typeof repoConfig[key] === 'object') {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
         const repoConfigObj: any = repoConfig[key];
         if (repoConfigObj.configured_value) {
           configInputObj[key as keyof ConfigInput] =
             repoConfigObj.configured_value;
         }
       } else {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
         configInputObj[key as keyof ConfigInput] = repoConfig[key] as any;
       }
     }
@@ -355,7 +340,7 @@
   _handleSaveRepoConfig() {
     if (!this._repoConfig || !this.repo)
       return Promise.reject(new Error('undefined repoConfig or repo'));
-    return this.$.restAPI
+    return this.restApiService
       .saveRepoConfig(
         this.repo,
         this._formatRepoConfigForSave(this._repoConfig)
diff --git a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_html.ts b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_html.ts
index 2e86758..5bfb7e6 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_html.ts
@@ -436,5 +436,4 @@
       </div>
     </div>
   </main>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_test.js b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_test.js
index 93a9d64..29a83941 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo_test.js
@@ -106,7 +106,7 @@
     });
     element = basicFixture.instantiate();
     repoStub = sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getProjectConfig')
         .callsFake(() => Promise.resolve(repoConf));
   });
@@ -171,7 +171,7 @@
     element.repo = REPO;
     sinon.stub(element, '_getLoggedIn').callsFake(() => Promise.resolve(true));
     sinon.stub(
-        element.$.restAPI,
+        element.restApiService,
         'getRepoAccess')
         .callsFake(() => Promise.resolve({'test-repo': {}}));
     element._loadRepo().then(() => {
@@ -247,7 +247,7 @@
 
     const response = {status: 404};
     sinon.stub(
-        element.$.restAPI, 'getProjectConfig').callsFake((repo, errFn) => {
+        element.restApiService, 'getProjectConfig').callsFake((repo, errFn) => {
       errFn(response);
     });
     element.addEventListener('page-error', e => {
@@ -264,7 +264,7 @@
       sinon.stub(element, '_getLoggedIn')
           .callsFake(() => Promise.resolve(true));
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getRepoAccess')
           .callsFake(() => Promise.resolve({'test-repo': {is_owner: true}}));
     });
@@ -322,7 +322,7 @@
         enable_reviewer_by_email: 'TRUE',
       };
 
-      const saveStub = sinon.stub(element.$.restAPI, 'saveRepoConfig')
+      const saveStub = sinon.stub(element.restApiService, 'saveRepoConfig')
           .callsFake(() => Promise.resolve({}));
 
       const button = element.root.querySelector('gr-button');
diff --git a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor.ts b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor.ts
index 8843933..13d0e50 100644
--- a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor.ts
+++ b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-select/gr-select';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -27,6 +26,7 @@
 import {encodeURL, getBaseUrl} from '../../../utils/url-util';
 import {AccessPermissionId} from '../../../utils/access-util';
 import {property, customElement, observe} from '@polymer/decorators';
+import {fireEvent} from '../../../utils/event-util';
 
 /**
  * Fired when the rule has been modified or removed.
@@ -268,15 +268,11 @@
   _handleRemoveRule() {
     if (!this.rule) return;
     if (this.rule.value.added) {
-      this.dispatchEvent(
-        new CustomEvent('added-rule-removed', {bubbles: true, composed: true})
-      );
+      fireEvent(this, 'added-rule-removed');
     }
     this._deleted = true;
     this.rule.value.deleted = true;
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   _handleUndoRemove() {
@@ -305,9 +301,7 @@
     }
     this.rule.value.modified = true;
     // Allows overall access page to know a change has been made.
-    this.dispatchEvent(
-      new CustomEvent('access-modified', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'access-modified');
   }
 
   _setOriginalRuleValues(value: RuleValue) {
diff --git a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_html.ts b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_html.ts
index 98403e0..c4d7688 100644
--- a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_html.ts
+++ b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_html.ts
@@ -156,5 +156,4 @@
       >Undo</gr-button
     >
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item.ts
index d70e891..558037d 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item.ts
@@ -49,6 +49,7 @@
   Timestamp,
 } from '../../../types/common';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {pluralize} from '../../../utils/string-util';
 
 enum ChangeSize {
   XS = 10,
@@ -152,15 +153,18 @@
     if (!label || category === LabelCategory.NOT_APPLICABLE) {
       return 'Label not applicable';
     }
+    const titleParts: string[] = [];
     if (category === LabelCategory.UNRESOLVED_COMMENTS) {
       const num = change?.unresolved_comment_count ?? 0;
-      const plural = num > 1 ? 's' : '';
-      return `${num} unresolved comment${plural}`;
+      titleParts.push(pluralize(num, 'unresolved comment'));
     }
     const significantLabel =
       label.rejected || label.approved || label.disliked || label.recommended;
-    if (significantLabel && significantLabel.name) {
-      return `${labelName}\nby ${significantLabel.name}`;
+    if (significantLabel?.name) {
+      titleParts.push(`${labelName} by ${significantLabel.name}`);
+    }
+    if (titleParts.length > 0) {
+      return titleParts.join(',\n');
     }
     return labelName;
   }
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item_test.js b/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item_test.js
index d3274f3..38cc772 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item_test.js
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-item/gr-change-list-item_test.js
@@ -88,35 +88,35 @@
         'Label not applicable');
     assert.equal(element._computeLabelTitle(
         {labels: {Verified: {approved: {name: 'Diffy'}}}}, 'Verified'),
-    'Verified\nby Diffy');
+    'Verified by Diffy');
     assert.equal(element._computeLabelTitle(
         {labels: {Verified: {approved: {name: 'Diffy'}}}}, 'Code-Review'),
     'Label not applicable');
     assert.equal(element._computeLabelTitle(
         {labels: {Verified: {rejected: {name: 'Diffy'}}}}, 'Verified'),
-    'Verified\nby Diffy');
+    'Verified by Diffy');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {disliked: {name: 'Diffy'}, value: -1}}},
-        'Code-Review'), 'Code-Review\nby Diffy');
+        'Code-Review'), 'Code-Review by Diffy');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {recommended: {name: 'Diffy'}, value: 1}}},
-        'Code-Review'), 'Code-Review\nby Diffy');
+        'Code-Review'), 'Code-Review by Diffy');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {recommended: {name: 'Diffy'},
           rejected: {name: 'Admin'}}}}, 'Code-Review'),
-    'Code-Review\nby Admin');
+    'Code-Review by Admin');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {approved: {name: 'Diffy'},
           rejected: {name: 'Admin'}}}}, 'Code-Review'),
-    'Code-Review\nby Admin');
+    'Code-Review by Admin');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {recommended: {name: 'Diffy'},
           disliked: {name: 'Admin'}, value: -1}}}, 'Code-Review'),
-    'Code-Review\nby Admin');
+    'Code-Review by Admin');
     assert.equal(element._computeLabelTitle(
         {labels: {'Code-Review': {approved: {name: 'Diffy'},
           disliked: {name: 'Admin'}, value: -1}}}, 'Code-Review'),
-    'Code-Review\nby Diffy');
+    'Code-Review by Diffy');
     assert.equal(element._computeLabelTitle(
         {
           labels: {'Code-Review': {approved: true, value: 1}},
@@ -125,6 +125,12 @@
     '1 unresolved comment');
     assert.equal(element._computeLabelTitle(
         {
+          labels: {'Code-Review': {approved: {name: 'Diffy'}, value: 1}},
+          unresolved_comment_count: 1,
+        }, 'Code-Review'),
+    '1 unresolved comment,\nCode-Review by Diffy');
+    assert.equal(element._computeLabelTitle(
+        {
           labels: {'Code-Review': {approved: true, value: 1}},
           unresolved_comment_count: 2,
         }, 'Code-Review'),
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
index 927d32f..973ccc8 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
@@ -16,7 +16,6 @@
  */
 
 import '../../shared/gr-icons/gr-icons';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-change-list/gr-change-list';
 import '../gr-repo-header/gr-repo-header';
 import '../gr-user-header/gr-user-header';
@@ -26,7 +25,7 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-change-list-view_html';
 import {page} from '../../../utils/page-wrapper-utils';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property} from '@polymer/decorators';
 import {AppElementParams} from '../../gr-app-types';
 import {
@@ -36,11 +35,13 @@
   EmailAddress,
   PreferencesInput,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {ChangeListToggleReviewedDetail} from '../gr-change-list-item/gr-change-list-item';
 import {ChangeStarToggleStarDetail} from '../../shared/gr-change-star/gr-change-star';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {ChangeListViewState} from '../../../types/types';
+import {fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
+import {GerritView} from '../../../services/router/router-model';
 
 const LookupQueryPatterns = {
   CHANGE_ID: /^\s*i?[0-9a-f]{7,40}\s*$/i,
@@ -56,7 +57,6 @@
 
 export interface GrChangeListView {
   $: {
-    restAPI: RestApiService & Element;
     prevArrow: HTMLAnchorElement;
     nextArrow: HTMLAnchorElement;
   };
@@ -112,6 +112,8 @@
   @property({type: String})
   _repo: string | null = null;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   created() {
     super.created();
@@ -143,17 +145,9 @@
 
     // NOTE: This method may be called before attachment. Fire title-change
     // in an async so that attachment to the DOM can take place first.
-    this.async(() =>
-      this.dispatchEvent(
-        new CustomEvent('title-change', {
-          detail: {title: this._query},
-          composed: true,
-          bubbles: true,
-        })
-      )
-    );
+    this.async(() => fireTitleChange(this, this._query));
 
-    this.$.restAPI
+    this.restApiService
       .getPreferences()
       .then(prefs => {
         if (!prefs) {
@@ -190,9 +184,9 @@
   }
 
   _loadPreferences() {
-    return this.$.restAPI.getLoggedIn().then(loggedIn => {
+    return this.restApiService.getLoggedIn().then(loggedIn => {
       if (loggedIn) {
-        this.$.restAPI.getPreferences().then(preferences => {
+        this.restApiService.getPreferences().then(preferences => {
           this.preferences = preferences;
         });
       } else {
@@ -202,7 +196,7 @@
   }
 
   _getChanges() {
-    return this.$.restAPI.getChanges(
+    return this.restApiService.getChanges(
       this._changesPerPage,
       this._query,
       this._offset
@@ -289,11 +283,14 @@
   }
 
   _handleToggleStar(e: CustomEvent<ChangeStarToggleStarDetail>) {
-    this.$.restAPI.saveChangeStarred(e.detail.change._number, e.detail.starred);
+    this.restApiService.saveChangeStarred(
+      e.detail.change._number,
+      e.detail.starred
+    );
   }
 
   _handleToggleReviewed(e: CustomEvent<ChangeListToggleReviewedDetail>) {
-    this.$.restAPI.saveChangeReviewed(
+    this.restApiService.saveChangeReviewed(
       e.detail.change._number,
       e.detail.reviewed
     );
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view_html.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view_html.ts
index 0e8f843..9914e70 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view_html.ts
@@ -98,5 +98,4 @@
       </a>
     </nav>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.ts b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.ts
index 3acdaf9..c45e801 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.ts
@@ -17,7 +17,6 @@
 
 import '../../../styles/gr-change-list-styles';
 import '../../shared/gr-cursor-manager/gr-cursor-manager';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-change-list-item/gr-change-list-item';
 import '../../../styles/shared-styles';
 import '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
@@ -43,7 +42,6 @@
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {changeIsOpen, isOwner} from '../../../utils/change-util';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrCursorManager} from '../../shared/gr-cursor-manager/gr-cursor-manager';
 import {
   AccountInfo,
@@ -56,6 +54,7 @@
   isAttentionSetEnabled,
 } from '../../../utils/attention-set-util';
 import {CustomKeyboardEvent} from '../../../types/events';
+import {fireEvent} from '../../../utils/event-util';
 
 const NUMBER_FIXED_COLUMNS = 3;
 const CLOSED_STATUS = ['MERGED', 'ABANDONED'];
@@ -69,7 +68,6 @@
 }
 export interface GrChangeList {
   $: {
-    restAPI: RestApiService & Element;
     cursor: GrCursorManager;
   };
 }
@@ -147,6 +145,8 @@
 
   flagsService = appContext.flagsService;
 
+  private restApiService = appContext.restApiService;
+
   keyboardShortcuts() {
     return {
       [Shortcut.CURSOR_NEXT_CHANGE]: '_nextChange',
@@ -169,7 +169,7 @@
   /** @override */
   ready() {
     super.ready();
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this._config = config;
     });
   }
@@ -227,7 +227,9 @@
         preferences && preferences.legacycid_in_change_table
       );
       if (preferences.change_table && preferences.change_table.length > 0) {
-        const prefColumns = this.getVisibleColumns(preferences.change_table);
+        const prefColumns = this.renameProjectToRepoColumn(
+          preferences.change_table
+        );
         this.visibleChangeTableColumns = this.getEnabledColumns(
           prefColumns,
           config,
@@ -424,12 +426,7 @@
     }
 
     e.preventDefault();
-    this.dispatchEvent(
-      new CustomEvent('next-page', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'next-page');
   }
 
   _prevPage(e: CustomKeyboardEvent) {
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list_html.ts b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list_html.ts
index 06957d9..990525c 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list_html.ts
@@ -163,5 +163,4 @@
     scroll-mode="keep-visible"
     focus-on-move=""
   ></gr-cursor-manager>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help.ts b/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help.ts
index 35f3aeb..f320296 100644
--- a/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help.ts
@@ -23,6 +23,7 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {customElement} from '@polymer/decorators';
 import {htmlTemplate} from './gr-create-change-help_html';
+import {fireEvent} from '../../../utils/event-util';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -43,8 +44,6 @@
    */
   _handleCreateTap(e: Event) {
     e.preventDefault();
-    this.dispatchEvent(
-      new CustomEvent('create-tap', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'create-tap');
   }
 }
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
index 57d3dd9..0a87503 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
@@ -19,7 +19,6 @@
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-create-commands-dialog/gr-create-commands-dialog';
 import '../gr-create-change-help/gr-create-change-help';
 import '../gr-create-destination-dialog/gr-create-destination-dialog';
@@ -30,7 +29,6 @@
 import {htmlTemplate} from './gr-dashboard-view_html';
 import {
   GerritNav,
-  GerritView,
   UserDashboard,
   YOUR_TURN,
 } from '../../core/gr-navigation/gr-navigation';
@@ -47,7 +45,6 @@
   RepoName,
 } from '../../../types/common';
 import {AppElementDashboardParams, AppElementParams} from '../../gr-app-types';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrDialog} from '../../shared/gr-dialog/gr-dialog';
 import {GrCreateCommandsDialog} from '../gr-create-commands-dialog/gr-create-commands-dialog';
 import {
@@ -58,12 +55,13 @@
 import {ChangeListToggleReviewedDetail} from '../gr-change-list-item/gr-change-list-item';
 import {ChangeStarToggleStarDetail} from '../../shared/gr-change-star/gr-change-star';
 import {DashboardViewState} from '../../../types/types';
+import {firePageError, fireTitleChange} from '../../../utils/event-util';
+import {GerritView} from '../../../services/router/router-model';
 
 const PROJECT_PLACEHOLDER_PATTERN = /\$\{project\}/g;
 
 export interface GrDashboardView {
   $: {
-    restAPI: RestApiService & Element;
     confirmDeleteDialog: GrDialog;
     commandsDialog: GrCreateCommandsDialog;
     destinationDialog: GrCreateDestinationDialog;
@@ -119,6 +117,8 @@
 
   private reporting = appContext.reportingService;
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
   }
@@ -134,9 +134,9 @@
   }
 
   _loadPreferences() {
-    return this.$.restAPI.getLoggedIn().then(loggedIn => {
+    return this.restApiService.getLoggedIn().then(loggedIn => {
       if (loggedIn) {
-        this.$.restAPI.getPreferences().then(preferences => {
+        this.restApiService.getPreferences().then(preferences => {
           this.preferences = preferences;
         });
       } else {
@@ -150,15 +150,9 @@
     dashboard: DashboardId
   ): Promise<UserDashboard | undefined> {
     const errFn = (response?: Response | null) => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      firePageError(this, response);
     };
-    return this.$.restAPI
+    return this.restApiService
       .getDashboard(project, dashboard, errFn)
       .then(response => {
         if (!response) {
@@ -211,7 +205,7 @@
     const {project, dashboard, title, user, sections} = params;
     const dashboardPromise: Promise<UserDashboard | undefined> = project
       ? this._getProjectDashboard(project, dashboard)
-      : this.$.restAPI
+      : this.restApiService
           .getConfig()
           .then(config =>
             Promise.resolve(
@@ -224,17 +218,13 @@
             )
           );
 
-    const checkForNewUser = !project && user === 'self';
+    // Checking `this.account` to make sure that the user is logged in.
+    // Otherwise sending a query for 'owner:self' will result in an error.
+    const checkForNewUser = !project && !!this.account && user === 'self';
     return dashboardPromise
       .then(res => {
         if (res && res.title) {
-          this.dispatchEvent(
-            new CustomEvent('title-change', {
-              detail: {title: res.title},
-              composed: true,
-              bubbles: true,
-            })
-          );
+          fireTitleChange(this, res.title);
         }
         return this._fetchDashboardChanges(res, checkForNewUser);
       })
@@ -243,15 +233,7 @@
         this.reporting.dashboardDisplayed();
       })
       .catch(err => {
-        this.dispatchEvent(
-          new CustomEvent('title-change', {
-            detail: {
-              title: title || this._computeTitle(user),
-            },
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireTitleChange(this, title || this._computeTitle(user));
         console.warn(err);
       })
       .then(() => {
@@ -289,7 +271,7 @@
       }
     }
 
-    return this.$.restAPI.getChanges(undefined, queries).then(changes => {
+    return this.restApiService.getChanges(undefined, queries).then(changes => {
       if (!changes) {
         throw new Error('getChanges returns undefined');
       }
@@ -368,11 +350,14 @@
   }
 
   _handleToggleStar(e: CustomEvent<ChangeStarToggleStarDetail>) {
-    this.$.restAPI.saveChangeStarred(e.detail.change._number, e.detail.starred);
+    this.restApiService.saveChangeStarred(
+      e.detail.change._number,
+      e.detail.starred
+    );
   }
 
   _handleToggleReviewed(e: CustomEvent<ChangeListToggleReviewedDetail>) {
-    this.$.restAPI.saveChangeReviewed(
+    this.restApiService.saveChangeReviewed(
       e.detail.change._number,
       e.detail.reviewed
     );
@@ -419,7 +404,7 @@
 
   _handleConfirmDelete() {
     this.$.confirmDeleteDialog.disabled = true;
-    return this.$.restAPI.deleteDraftComments('-is:open').then(() => {
+    return this.restApiService.deleteDraftComments('-is:open').then(() => {
       this._closeConfirmDeleteOverlay();
       this._reload(this.params);
     });
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_html.ts b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_html.ts
index 6dae176..c23a1cc 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_html.ts
@@ -125,5 +125,4 @@
     on-confirm="_handleDestinationConfirm"
   ></gr-create-destination-dialog>
   <gr-create-commands-dialog id="commandsDialog"></gr-create-commands-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.js b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.js
index 44f203d..1f5d519 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.js
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.js
@@ -18,9 +18,11 @@
 import '../../../test/common-test-setup-karma.js';
 import './gr-dashboard-view.js';
 import {isHidden} from '../../../test/test-utils.js';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation.js';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
+import {GerritView} from '../../../services/router/router-model.js';
 import {changeIsOpen} from '../../../utils/change-util.js';
 import {ChangeStatus} from '../../../constants/constants.js';
+import {createAccountWithId} from '../../../test/test-data-generators.js';
 
 const basicFixture = fixtureFromElement('gr-dashboard-view');
 
@@ -38,7 +40,7 @@
     });
     element = basicFixture.instantiate();
 
-    getChangesStub = sinon.stub(element.$.restAPI, 'getChanges').callsFake(
+    getChangesStub = sinon.stub(element.restApiService, 'getChanges').callsFake(
         (_, qs) => Promise.resolve(qs.map(() => [])));
 
     let resolver;
@@ -123,14 +125,14 @@
       const deleteDraftCommentsPromise = new Promise(resolve => {
         deleteDraftCommentsPromiseResolver = resolve;
       });
-      sinon.stub(element.$.restAPI, 'deleteDraftComments')
+      sinon.stub(element.restApiService, 'deleteDraftComments')
           .returns(deleteDraftCommentsPromise);
 
       // Open confirmation dialog and tap confirm button.
       await element.$.confirmDeleteOverlay.open();
       MockInteractions.tap(element.$.confirmDeleteDialog.$.confirm);
       flush();
-      assert.isTrue(element.$.restAPI.deleteDraftComments
+      assert.isTrue(element.restApiService.deleteDraftComments
           .calledWithExactly('-is:open'));
       assert.isTrue(element.$.confirmDeleteDialog.disabled);
       assert.equal(element._reload.callCount, 0);
@@ -201,9 +203,23 @@
         user: 'self',
       };
       return paramsChangedPromise.then(() => {
-        assert.isTrue(
-            getChangesStub.calledWith(undefined,
-                ['1', '2', 'owner:self limit:1']));
+        assert.isTrue(getChangesStub.calledWith(undefined, ['1', '2']));
+      });
+    });
+
+    test('viewing dashboard when logged in includes owner:self query', () => {
+      element.account = createAccountWithId(1);
+      element.params = {
+        view: GerritNav.View.DASHBOARD,
+        sections: [
+          {query: '1'},
+          {query: '2', selfOnly: true},
+        ],
+        user: 'self',
+      };
+      return paramsChangedPromise.then(() => {
+        assert.isTrue(getChangesStub.calledWith(undefined,
+            ['1', '2', 'owner:self limit:1']));
       });
     });
 
@@ -239,7 +255,7 @@
 
   suite('_getProjectDashboard', () => {
     test('dashboard with foreach', () => {
-      sinon.stub(element.$.restAPI, 'getDashboard')
+      sinon.stub(element.restApiService, 'getDashboard')
           .callsFake( () => Promise.resolve({
             title: 'title',
             foreach: 'foreach for ${project}',
@@ -265,7 +281,7 @@
     });
 
     test('dashboard without foreach', () => {
-      sinon.stub(element.$.restAPI, 'getDashboard').callsFake(
+      sinon.stub(element.restApiService, 'getDashboard').callsFake(
           () => Promise.resolve({
             title: 'title',
             sections: [
@@ -293,7 +309,7 @@
       {name: 'test2', query: 'test2', hideIfEmpty: true},
     ];
     getChangesStub.restore();
-    sinon.stub(element.$.restAPI, 'getChanges')
+    sinon.stub(element.restApiService, 'getChanges')
         .returns(Promise.resolve([[], ['nonempty']]));
 
     return element._fetchDashboardChanges({sections}, false).then(() => {
@@ -308,7 +324,7 @@
       {name: 'test2', query: 'test2'},
     ];
     getChangesStub.restore();
-    sinon.stub(element.$.restAPI, 'getChanges')
+    sinon.stub(element.restApiService, 'getChanges')
         .returns(Promise.resolve([[], []]));
 
     return element._fetchDashboardChanges({sections}, false).then(() => {
@@ -359,7 +375,7 @@
 
   test('404 page', done => {
     const response = {status: 404};
-    sinon.stub(element.$.restAPI, 'getDashboard').callsFake(
+    sinon.stub(element.restApiService, 'getDashboard').callsFake(
         async (project, dashboard, errFn) => {
           errFn(response);
         });
diff --git a/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header.ts b/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header.ts
index e501cfd..35a2a7f 100644
--- a/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header.ts
@@ -18,7 +18,6 @@
 import '../../../styles/dashboard-header-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
diff --git a/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header_html.ts b/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header_html.ts
index d1221d15..2dd2913 100644
--- a/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-repo-header/gr-repo-header_html.ts
@@ -30,5 +30,4 @@
     <hr />
     <div><span>Detail:</span> <a href$="[[_repoUrl]]">Repo settings</a></div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header.ts b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header.ts
index 055c82c..10f65a5 100644
--- a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header.ts
@@ -20,7 +20,6 @@
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
 import '../../shared/gr-avatar/gr-avatar';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/dashboard-header-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -28,15 +27,9 @@
 import {htmlTemplate} from './gr-user-header_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {AccountDetailInfo, AccountId} from '../../../types/common';
 import {getDisplayName} from '../../../utils/display-name-util';
-
-export interface GrUserHeader {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 @customElement('gr-user-header')
 export class GrUserHeader extends GestureEventListeners(
@@ -61,6 +54,8 @@
   @property({type: String})
   _status = '';
 
+  private restApiService = appContext.restApiService;
+
   _accountChanged(userId?: AccountId) {
     if (!userId) {
       this._accountDetails = null;
@@ -68,7 +63,7 @@
       return;
     }
 
-    this.$.restAPI.getAccountDetails(userId).then(details => {
+    this.restApiService.getAccountDetails(userId).then(details => {
       this._accountDetails = details ?? null;
       this._status = details?.status ?? '';
     });
diff --git a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_html.ts b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_html.ts
index 002a4ba..a8a6a56 100644
--- a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_html.ts
@@ -66,5 +66,4 @@
       <a href$="[[_computeDashboardUrl(_accountDetails)]]">View dashboard</a>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_test.js b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_test.js
index a808f3c..78560907 100644
--- a/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_test.js
+++ b/polygerrit-ui/app/elements/change-list/gr-user-header/gr-user-header_test.js
@@ -28,7 +28,7 @@
   });
 
   test('loads and clears account info', done => {
-    sinon.stub(element.$.restAPI, 'getAccountDetails')
+    sinon.stub(element.restApiService, 'getAccountDetails')
         .returns(Promise.resolve({
           name: 'foo',
           email: 'bar',
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
index 3f6dd23..fdf2811 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
@@ -21,7 +21,6 @@
 import '../../shared/gr-icons/gr-icons';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-confirm-abandon-dialog/gr-confirm-abandon-dialog';
 import '../gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog';
 import '../gr-confirm-cherrypick-conflict-dialog/gr-confirm-cherrypick-conflict-dialog';
@@ -39,12 +38,10 @@
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {appContext} from '../../../services/app-context';
-import {
-  fetchChangeUpdates,
-  patchNumEquals,
-} from '../../../utils/patch-set-util';
+import {fetchChangeUpdates, CURRENT} from '../../../utils/patch-set-util';
 import {
   changeIsOpen,
+  isOwner,
   ListChangesOption,
   listChangesOptionsToHex,
 } from '../../../utils/change-util';
@@ -54,16 +51,19 @@
   HttpMethod,
   NotifyType,
 } from '../../../constants/constants';
-import {EventType, TargetElement} from '../../plugins/gr-plugin-types';
+import {
+  EventType as PluginEventType,
+  TargetElement,
+} from '../../plugins/gr-plugin-types';
 import {customElement, observe, property} from '@polymer/decorators';
 import {GrJsApiInterface} from '../../shared/gr-js-api-interface/gr-js-api-interface-element';
 import {
   ActionPriority,
   ActionType,
   ErrorCallback,
-  RestApiService,
 } from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
+  AccountInfo,
   ActionInfo,
   ActionNameToActionInfoMap,
   BranchName,
@@ -110,6 +110,12 @@
   RevisionActions,
   UIActionInfo,
 } from '../../shared/gr-js-api-interface/gr-change-actions-js-api';
+import {fireAlert} from '../../../utils/event-util';
+import {
+  CODE_REVIEW,
+  getApprovalInfo,
+  getVotingRange,
+} from '../../../utils/label-util';
 
 const ERR_BRANCH_EMPTY = 'The destination branch can’t be empty.';
 const ERR_COMMIT_EMPTY = 'The commit message can’t be empty.';
@@ -317,7 +323,6 @@
 export interface GrChangeActions {
   $: {
     jsAPI: GrJsApiInterface;
-    restAPI: RestApiService & Element;
     mainContent: Element;
     overlay: GrOverlay;
     confirmRebase: GrConfirmRebaseDialog;
@@ -399,6 +404,9 @@
   @property({type: Boolean})
   _hideQuickApproveAction = false;
 
+  @property({type: Object})
+  account?: AccountInfo;
+
   @property({type: String})
   changeNum?: NumericChangeId;
 
@@ -543,6 +551,8 @@
   @property({type: Object})
   _config?: ServerInfo;
 
+  private restApiService = appContext.restApiService;
+
   /** @override */
   created() {
     super.created();
@@ -558,7 +568,7 @@
   ready() {
     super.ready();
     this.$.jsAPI.addElement(TargetElement.CHANGE_ACTIONS, this);
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this._config = config;
     });
     this._handleLoadingComplete();
@@ -594,7 +604,7 @@
     const change = this.change;
 
     this._loading = true;
-    return this.$.restAPI
+    return this.restApiService
       .getChangeRevisionActions(this.changeNum, this.latestPatchNum)
       .then(revisionActions => {
         if (!revisionActions) {
@@ -609,13 +619,7 @@
         this._handleLoadingComplete();
       })
       .catch(err => {
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message: ERR_REVISION_ACTIONS},
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireAlert(this, ERR_REVISION_ACTIONS);
         this._loading = false;
         throw err;
       });
@@ -631,7 +635,7 @@
     change: ChangeInfo;
     revisionActions: ActionNameToActionInfoMap;
   }) {
-    this.$.jsAPI.handleEvent(EventType.SHOW_REVISION_ACTIONS, detail);
+    this.$.jsAPI.handleEvent(PluginEventType.SHOW_REVISION_ACTIONS, detail);
   }
 
   @observe('change')
@@ -926,6 +930,9 @@
     if (!this.change || !this.change.labels || !this.change.permitted_labels) {
       return null;
     }
+    if (this.change && this.change.status === ChangeStatus.MERGED) {
+      return null;
+    }
     let result;
     for (const label in this.change.labels) {
       if (!(label in this.change.permitted_labels)) {
@@ -949,18 +956,39 @@
         return null;
       }
     }
+    // Allow the user to use quick approve to vote the max score on code review
+    // even if it is already granted by someone else. Does not apply if the
+    // user owns the change or has already granted the max score themselves.
+    const codeReviewLabel = this.change.labels[CODE_REVIEW];
+    const codeReviewPermittedValues = this.change.permitted_labels[CODE_REVIEW];
+    if (
+      !result &&
+      codeReviewLabel &&
+      codeReviewPermittedValues &&
+      this.account?._account_id &&
+      isDetailedLabelInfo(codeReviewLabel) &&
+      this._getLabelStatus(codeReviewLabel) === LabelStatus.OK &&
+      !isOwner(this.change, this.account) &&
+      getApprovalInfo(codeReviewLabel, this.account)?.value !==
+        getVotingRange(codeReviewLabel)?.max
+    ) {
+      result = CODE_REVIEW;
+    }
+
     if (result) {
-      const score = this.change.permitted_labels[result].slice(-1)[0];
       const labelInfo = this.change.labels[result];
       if (!isDetailedLabelInfo(labelInfo)) {
         return null;
       }
-      const maxScore = Object.keys(labelInfo.values).slice(-1)[0];
-      if (score === maxScore) {
+      const permittedValues = this.change.permitted_labels[result];
+      const usersMaxPermittedScore =
+        permittedValues[permittedValues.length - 1];
+      const maxScoreForLabel = getVotingRange(labelInfo)?.max;
+      if (Number(usersMaxPermittedScore) === maxScoreForLabel) {
         // Allow quick approve only for maximal score.
         return {
           label: result,
-          score,
+          score: usersMaxPermittedScore,
         };
       }
     }
@@ -1074,7 +1102,7 @@
     if (!this.changeNum) {
       return;
     }
-    this.$.restAPI
+    this.restApiService
       .getChangeActionURL(this.changeNum, patchNum, '/' + action.__key)
       .then(url => (action.__url = url));
   }
@@ -1121,7 +1149,7 @@
 
   _getRevision(change: ChangeViewChangeInfo, patchNum?: PatchSetNum) {
     for (const rev of Object.values(change.revisions)) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         return rev;
       }
     }
@@ -1136,9 +1164,9 @@
     /* A chromium plugin expects that the modifyRevertMsg hook will only
     be called after the revert button is pressed, hence we populate the
     revert dialog after revert button is pressed. */
-    this.$.restAPI.getChanges(0, query).then(changes => {
+    this.restApiService.getChanges(0, query).then(changes => {
       if (!changes) {
-        console.error('changes is undefined');
+        this.reporting.error(new Error('changes is undefined'));
         return;
       }
       this.$.confirmRevertDialog.populate(change, this.commitMessage, changes);
@@ -1150,9 +1178,9 @@
     const change = this.change;
     if (!change) return;
     const query = `submissionid:${change.submission_id}`;
-    this.$.restAPI.getChanges(0, query).then(changes => {
+    this.restApiService.getChanges(0, query).then(changes => {
       if (!changes) {
-        console.error('changes is undefined');
+        this.reporting.error(new Error('changes is undefined'));
         return;
       }
       this.$.confirmRevertSubmissionDialog._populateRevertSubmissionMessage(
@@ -1370,23 +1398,11 @@
   _handleCherryPickRestApi(conflicts: boolean) {
     const el = this.$.confirmCherrypick;
     if (!el.branch) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_BRANCH_EMPTY},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_BRANCH_EMPTY);
       return;
     }
     if (!el.message) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_COMMIT_EMPTY},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_COMMIT_EMPTY);
       return;
     }
     this.$.overlay.close();
@@ -1407,13 +1423,7 @@
   _handleMoveConfirm() {
     const el = this.$.confirmMove;
     if (!el.branch) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_BRANCH_EMPTY},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_BRANCH_EMPTY);
       return;
     }
     this.$.overlay.close();
@@ -1448,7 +1458,7 @@
         );
         break;
       default:
-        console.error('invalid revert type');
+        this.reporting.error(new Error('invalid revert type'));
     }
   }
 
@@ -1600,14 +1610,14 @@
     if (!labels) {
       return Promise.resolve(undefined);
     }
-    return this.$.restAPI.saveChangeReview(newChangeId, 'current', {labels});
+    return this.restApiService.saveChangeReview(newChangeId, CURRENT, {labels});
   }
 
   _handleResponse(action: UIActionInfo, response?: Response) {
     if (!response) {
       return;
     }
-    return this.$.restAPI.getResponseObject(response).then(obj => {
+    return this.restApiService.getResponseObject(response).then(obj => {
       switch (action.__key) {
         case ChangeActions.REVERT: {
           const revertChangeInfo: ChangeInfo = (obj as unknown) as ChangeInfo;
@@ -1735,7 +1745,7 @@
         new Error('Properties change and changeNum must be set.')
       );
     }
-    return fetchChangeUpdates(change, this.$.restAPI).then(result => {
+    return fetchChangeUpdates(change, this.restApiService).then(result => {
       if (!result.isLatest) {
         this.dispatchEvent(
           new CustomEvent('show-alert', {
@@ -1766,7 +1776,7 @@
         return Promise.resolve(undefined);
       }
       const patchNum = revisionAction ? this.latestPatchNum : undefined;
-      return this.$.restAPI
+      return this.restApiService
         .executeChangeAction(
           changeNum,
           method,
@@ -1796,14 +1806,16 @@
       ListChangesOption.MESSAGES,
       ListChangesOption.ALL_REVISIONS
     );
-    this.$.restAPI.getChanges(0, query, undefined, options).then(changes => {
-      if (!changes) {
-        console.error('getChanges returns undefined');
-        return;
-      }
-      this.$.confirmCherrypick.updateChanges(changes);
-      this._showActionDialog(this.$.confirmCherrypick);
-    });
+    this.restApiService
+      .getChanges(0, query, undefined, options)
+      .then(changes => {
+        if (!changes) {
+          this.reporting.error(new Error('getChanges returns undefined'));
+          return;
+        }
+        this.$.confirmCherrypick.updateChanges(changes);
+        this._showActionDialog(this.$.confirmCherrypick);
+      });
   }
 
   _handleMoveTap() {
@@ -2058,7 +2070,7 @@
       const check = () => {
         attempsRemaining--;
         // Pass a no-op error handler to avoid the "not found" error toast.
-        this.$.restAPI
+        this.restApiService
           .getChange(changeNum, () => {})
           .then(response => {
             // If the response is 404, the response will be undefined.
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_html.ts b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_html.ts
index 4e315af..0a3e536 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_html.ts
@@ -270,5 +270,4 @@
     </gr-dialog>
   </gr-overlay>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
index ae49a57..f7bca82 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
@@ -21,10 +21,14 @@
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';
 import {
+  createAccountWithId,
+  createApproval,
   createChange,
   createChangeMessages,
   createRevisions,
 } from '../../../test/test-data-generators.js';
+import {appContext} from '../../../services/app-context.js';
+import {ChangeStatus} from '../../../constants/constants.js';
 
 const basicFixture = fixtureFromElement('gr-change-actions');
 
@@ -104,10 +108,11 @@
           enabled: true,
         },
       };
-      sinon.stub(element.$.confirmCherrypick.$.restAPI,
-          'getRepoBranches').returns(Promise.resolve([]));
-      sinon.stub(element.$.confirmMove.$.restAPI,
-          'getRepoBranches').returns(Promise.resolve([]));
+      element.account = {
+        _account_id: 123,
+      };
+      sinon.stub(appContext.restApiService, 'getRepoBranches').returns(
+          Promise.resolve([]));
 
       return element.reload();
     });
@@ -143,14 +148,14 @@
     });
 
     test('plugin revision actions', done => {
-      sinon.stub(element.$.restAPI, 'getChangeActionURL').returns(
+      sinon.stub(element.restApiService, 'getChangeActionURL').returns(
           Promise.resolve('the-url'));
       element.revisionActions = {
         'plugin~action': {},
       };
       assert.isOk(element.revisionActions['plugin~action']);
       flush(() => {
-        assert.isTrue(element.$.restAPI.getChangeActionURL.calledWith(
+        assert.isTrue(element.restApiService.getChangeActionURL.calledWith(
             element.changeNum, element.latestPatchNum, '/plugin~action'));
         assert.equal(element.revisionActions['plugin~action'].__url, 'the-url');
         done();
@@ -158,14 +163,14 @@
     });
 
     test('plugin change actions', async () => {
-      sinon.stub(element.$.restAPI, 'getChangeActionURL').returns(
+      sinon.stub(element.restApiService, 'getChangeActionURL').returns(
           Promise.resolve('the-url'));
       element.actions = {
         'plugin~action': {},
       };
       assert.isOk(element.actions['plugin~action']);
       await flush();
-      assert.isTrue(element.$.restAPI.getChangeActionURL.calledWith(
+      assert.isTrue(element.restApiService.getChangeActionURL.calledWith(
           element.changeNum, undefined, '/plugin~action'));
       assert.equal(element.actions['plugin~action'].__url, 'the-url');
     });
@@ -253,7 +258,7 @@
           rev2: revObj,
         },
       };
-      assert.deepEqual(element._getRevision(change, '2'), revObj);
+      assert.deepEqual(element._getRevision(change, 2), revObj);
     });
 
     test('_actionComparator sort order', () => {
@@ -273,7 +278,7 @@
 
     test('submit change', () => {
       const showSpy = sinon.spy(element, '_showActionDialog');
-      sinon.stub(element.$.restAPI, 'getFromProjectLookup')
+      sinon.stub(element.restApiService, 'getFromProjectLookup')
           .returns(Promise.resolve('test'));
       sinon.stub(element.$.overlay, 'open').returns(Promise.resolve());
       element.change = {
@@ -295,7 +300,7 @@
 
     test('submit change, tap on icon', done => {
       sinon.stub(element.$.confirmSubmitDialog, 'resetFocus').callsFake( done);
-      sinon.stub(element.$.restAPI, 'getFromProjectLookup')
+      sinon.stub(element.restApiService, 'getFromProjectLookup')
           .returns(Promise.resolve('test'));
       sinon.stub(element.$.overlay, 'open').returns(Promise.resolve());
       element.change = {
@@ -399,7 +404,7 @@
 
     test('rebase change fires reload event', done => {
       const eventStub = sinon.stub(element, 'dispatchEvent');
-      sinon.stub(element.$.restAPI, 'getResponseObject').returns(
+      sinon.stub(element.restApiService, 'getResponseObject').returns(
           Promise.resolve({}));
       element._handleResponse({__key: 'rebase'}, {});
       flush(() => {
@@ -429,24 +434,21 @@
       });
     });
 
-    test('two dialogs are not shown at the same time', done => {
+    test('two dialogs are not shown at the same time', async () => {
       element._hasKnownChainState = true;
-      flush(() => {
-        const rebaseButton = element.shadowRoot
-            .querySelector('gr-button[data-action-key="rebase"]');
-        assert.ok(rebaseButton);
-        MockInteractions.tap(rebaseButton);
-        flush();
-        assert.isFalse(element.$.confirmRebase.hidden);
-        sinon.stub(element.$.restAPI, 'getChanges')
-            .returns(Promise.resolve([]));
-        element._handleCherrypickTap();
-        flush(() => {
-          assert.isTrue(element.$.confirmRebase.hidden);
-          assert.isFalse(element.$.confirmCherrypick.hidden);
-          done();
-        });
-      });
+      await flush();
+      const rebaseButton = element.shadowRoot
+          .querySelector('gr-button[data-action-key="rebase"]');
+      assert.ok(rebaseButton);
+      MockInteractions.tap(rebaseButton);
+      await flush();
+      assert.isFalse(element.$.confirmRebase.hidden);
+      sinon.stub(element.restApiService, 'getChanges')
+          .returns(Promise.resolve([]));
+      element._handleCherrypickTap();
+      await flush();
+      assert.isTrue(element.$.confirmRebase.hidden);
+      assert.isFalse(element.$.confirmCherrypick.hidden);
     });
 
     test('fullscreen-overlay-opened hides content', () => {
@@ -473,7 +475,7 @@
       const labels = {'Foo': 1, 'Bar-Baz': -2};
       const changeId = 1234;
       sinon.stub(element.$.jsAPI, 'getLabelValuesPostRevert').returns(labels);
-      const saveStub = sinon.stub(element.$.restAPI, 'saveChangeReview')
+      const saveStub = sinon.stub(element.restApiService, 'saveChangeReview')
           .returns(Promise.resolve());
       return element._setLabelValuesOnRevert(changeId).then(() => {
         assert.isTrue(saveStub.calledOnce);
@@ -740,15 +742,15 @@
         const changes = [
           {
             change_id: '12345678901234', topic: 'T', subject: 'random',
-            project: 'A',
+            project: 'A', status: 'MERGED',
           },
           {
             change_id: '23456', topic: 'T', subject: 'a'.repeat(100),
-            project: 'B',
+            project: 'B', status: 'NEW',
           },
         ];
         setup(done => {
-          sinon.stub(element.$.restAPI, 'getChanges')
+          sinon.stub(element.restApiService, 'getChanges')
               .returns(Promise.resolve(changes));
           element._handleCherrypickTap();
           flush(() => {
@@ -767,8 +769,8 @@
           flush(() => {
             const changesTable = dialog.shadowRoot.querySelector('table');
             const headers = Array.from(changesTable.querySelectorAll('th'));
-            const expectedHeadings = ['Change', 'Subject', 'Project',
-              'Status', ''];
+            const expectedHeadings = ['', 'Change', 'Status', 'Subject',
+              'Project', 'Progress', ''];
             const headings = headers.map(header => header.innerText);
             assert.equal(headings.length, expectedHeadings.length);
             for (let i = 0; i < headings.length; i++) {
@@ -777,7 +779,7 @@
             const changeRows = changesTable.querySelectorAll('tbody > tr');
             const change = Array.from(changeRows[0].querySelectorAll('td'))
                 .map(e => e.innerText);
-            const expectedChange = ['1234567890', 'random', 'A',
+            const expectedChange = ['', '1234567890', 'MERGED', 'random', 'A',
               'NOT STARTED', ''];
             for (let i = 0; i < change.length; i++) {
               assert.equal(change[i].trim(), expectedChange[i]);
@@ -994,7 +996,7 @@
         element.change = {
           current_revision: 'abc1234',
         };
-        sinon.stub(element.$.restAPI, 'getChanges')
+        sinon.stub(element.restApiService, 'getChanges')
             .returns(Promise.resolve([
               {change_id: '12345678901234', topic: 'T', subject: 'random'},
               {change_id: '23456', topic: 'T', subject: 'a'.repeat(100)},
@@ -1019,7 +1021,7 @@
             submission_id: '199 0',
             current_revision: '2000',
           };
-          getChangesStub = sinon.stub(element.$.restAPI, 'getChanges')
+          getChangesStub = sinon.stub(element.restApiService, 'getChanges')
               .returns(Promise.resolve([
                 {change_id: '12345678901234', topic: 'T', subject: 'random'},
                 {change_id: '23456', topic: 'T', subject: 'a'.repeat(100)},
@@ -1129,7 +1131,7 @@
             submission_id: '199',
             current_revision: '2000',
           };
-          sinon.stub(element.$.restAPI, 'getChanges')
+          sinon.stub(element.restApiService, 'getChanges')
               .returns(Promise.resolve([
                 {change_id: '12345678901234', topic: 'T', subject: 'random'},
               ]));
@@ -1529,9 +1531,6 @@
       setup(() => {
         element.change = {
           current_revision: 'abc1234',
-        };
-        element.change = {
-          current_revision: 'abc1234',
           labels: {
             foo: {
               values: {
@@ -1578,6 +1577,16 @@
         assert.equal(approveButton.getAttribute('data-label'), 'foo+1');
       });
 
+      test('not added when change is merged', () => {
+        element.change.status = ChangeStatus.MERGED;
+        flush(() => {
+          const approveButton =
+          element.shadowRoot
+              .querySelector('gr-button[data-action-key=\'review\']');
+          assert.isNull(approveButton);
+        });
+      });
+
       test('not added when already approved', () => {
         element.change = {
           current_revision: 'abc1234',
@@ -1717,6 +1726,87 @@
                 .querySelector('gr-button[data-action-key=\'review\']');
         assert.equal(approveButton.getAttribute('data-label'), 'bar+2');
       });
+
+      test('added when can approve an already-approved code review label',
+          () => {
+            element.change = {
+              current_revision: 'abc1234',
+              labels: {
+                'Code-Review': {
+                  approved: {},
+                  values: {
+                    ' 0': '',
+                    '+1': '',
+                    '+2': '',
+                  },
+                },
+              },
+              permitted_labels: {
+                'Code-Review': [' 0', '+1', '+2'],
+              },
+            };
+            flush();
+            const approveButton =
+                element.shadowRoot
+                    .querySelector('gr-button[data-action-key=\'review\']');
+            assert.isNotNull(approveButton);
+          });
+
+      test('not added when the user has already approved', () => {
+        const vote = {
+          ...createApproval(),
+          _account_id: 123,
+          name: 'name',
+          value: 2,
+        };
+        element.change = {
+          current_revision: 'abc1234',
+          labels: {
+            'Code-Review': {
+              approved: {},
+              values: {
+                ' 0': '',
+                '+1': '',
+                '+2': '',
+              },
+              all: [vote],
+            },
+          },
+          permitted_labels: {
+            'Code-Review': [' 0', '+1', '+2'],
+          },
+        };
+        flush();
+        const approveButton =
+            element.shadowRoot
+                .querySelector('gr-button[data-action-key=\'review\']');
+        assert.isNull(approveButton);
+      });
+
+      test('not added when user owns the change', () => {
+        element.change = {
+          current_revision: 'abc1234',
+          owner: createAccountWithId(123),
+          labels: {
+            'Code-Review': {
+              approved: {},
+              values: {
+                ' 0': '',
+                '+1': '',
+                '+2': '',
+              },
+            },
+          },
+          permitted_labels: {
+            'Code-Review': [' 0', '+1', '+2'],
+          },
+        };
+        flush();
+        const approveButton =
+            element.shadowRoot
+                .querySelector('gr-button[data-action-key=\'review\']');
+        assert.isNull(approveButton);
+      });
     });
 
     test('adds download revision action', () => {
@@ -1785,7 +1875,7 @@
         };
 
         test('succeed', () => {
-          sinon.stub(element.$.restAPI, 'getChange')
+          sinon.stub(element.restApiService, 'getChange')
               .callsFake( makeGetChange(5));
           return element._waitForChangeReachable(123).then(success => {
             assert.isTrue(success);
@@ -1793,7 +1883,7 @@
         });
 
         test('fail', () => {
-          sinon.stub(element.$.restAPI, 'getChange')
+          sinon.stub(element.restApiService, 'getChange')
               .callsFake( makeGetChange(6));
           return element._waitForChangeReachable(123).then(success => {
             assert.isFalse(success);
@@ -1830,16 +1920,16 @@
       suite('happy path', () => {
         let sendStub;
         setup(() => {
-          sinon.stub(element.$.restAPI, 'getChangeDetail')
+          sinon.stub(element.restApiService, 'getChangeDetail')
               .returns(Promise.resolve({
                 ...createChange(),
                 // element has latest info
                 revisions: createRevisions(element.latestPatchNum),
                 messages: createChangeMessages(1),
               }));
-          sendStub = sinon.stub(element.$.restAPI, 'executeChangeAction')
+          sendStub = sinon.stub(element.restApiService, 'executeChangeAction')
               .returns(Promise.resolve({}));
-          getResponseObjectStub = sinon.stub(element.$.restAPI,
+          getResponseObjectStub = sinon.stub(element.restApiService,
               'getResponseObject');
           sinon.stub(GerritNav,
               'navigateToChange').returns(Promise.resolve(true));
@@ -1857,7 +1947,7 @@
           setup(() => {
             element.change.submission_id = '199';
             element.change.current_revision = '2000';
-            sinon.stub(element.$.restAPI, 'getChanges')
+            sinon.stub(element.restApiService, 'getChanges')
                 .returns(Promise.resolve([
                   {change_id: '12345678901234', topic: 'T', subject: 'random'},
                   {change_id: '23456', topic: 'T', subject: 'a'.repeat(100)},
@@ -1949,14 +2039,14 @@
 
       suite('failure modes', () => {
         test('non-latest', () => {
-          sinon.stub(element.$.restAPI, 'getChangeDetail')
+          sinon.stub(element.restApiService, 'getChangeDetail')
               .returns(Promise.resolve({
                 ...createChange(),
                 // new patchset was uploaded
                 revisions: createRevisions(element.latestPatchNum + 1),
                 messages: createChangeMessages(1),
               }));
-          const sendStub = sinon.stub(element.$.restAPI,
+          const sendStub = sinon.stub(element.restApiService,
               'executeChangeAction');
 
           return element._send('DELETE', payload, '/endpoint', true, cleanup)
@@ -1969,14 +2059,14 @@
         });
 
         test('send fails', () => {
-          sinon.stub(element.$.restAPI, 'getChangeDetail')
+          sinon.stub(element.restApiService, 'getChangeDetail')
               .returns(Promise.resolve({
                 ...createChange(),
                 // element has latest info
                 revisions: createRevisions(element.latestPatchNum),
                 messages: createChangeMessages(1),
               }));
-          const sendStub = sinon.stub(element.$.restAPI,
+          const sendStub = sinon.stub(element.restApiService,
               'executeChangeAction').callsFake(
               (num, method, patchNum, endpoint, payload, onErr) => {
                 onErr();
@@ -2037,10 +2127,8 @@
       element.changeNum = '42';
       element.latestPatchNum = '2';
 
-      sinon.stub(element.$.confirmCherrypick.$.restAPI,
-          'getRepoBranches').returns(Promise.resolve([]));
-      sinon.stub(element.$.confirmMove.$.restAPI,
-          'getRepoBranches').returns(Promise.resolve([]));
+      sinon.stub(appContext.restApiService, 'getRepoBranches').returns(
+          Promise.resolve([]));
       return element.reload();
     });
 
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
index f8a5940..36ef429 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
@@ -28,7 +28,6 @@
 import '../../shared/gr-limited-text/gr-limited-text';
 import '../../shared/gr-linked-chip/gr-linked-chip';
 import '../../shared/gr-tooltip-content/gr-tooltip-content';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-change-requirements/gr-change-requirements';
 import '../gr-commit-info/gr-commit-info';
 import '../gr-reviewer-list/gr-reviewer-list';
@@ -73,9 +72,16 @@
   TopicName,
 } from '../../../types/common';
 import {assertNever} from '../../../utils/common-util';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrEditableLabel} from '../../shared/gr-editable-label/gr-editable-label';
 import {GrLinkedChip} from '../../shared/gr-linked-chip/gr-linked-chip';
+import {appContext} from '../../../services/app-context';
+import {KnownExperimentId} from '../../../services/flags/flags';
+import {
+  Metadata,
+  isSectionSet,
+  DisplayRules,
+} from '../../../utils/change-metadata-util';
+import {fireEvent} from '../../../utils/event-util';
 
 const HASHTAG_ADD_MESSAGE = 'Add Hashtag';
 
@@ -102,7 +108,7 @@
 
 const NOT_CURRENT_MESSAGE = 'Not current - rebase possible';
 
-interface PushCertifacteValidationInfo {
+interface PushCertificateValidationInfo {
   class: string;
   icon: string;
   message: string;
@@ -110,7 +116,7 @@
 
 export interface GrChangeMetadata {
   $: {
-    restAPI: RestApiService & Element;
+    webLinks: HTMLElement;
   };
 }
 
@@ -171,7 +177,7 @@
     type: Object,
     computed: '_computePushCertificateValidation(serverConfig, change)',
   })
-  _pushCertificateValidation: PushCertifacteValidationInfo | null = null;
+  _pushCertificateValidation?: PushCertificateValidationInfo;
 
   @property({type: Boolean, computed: '_computeShowRequirements(change)'})
   _showRequirements = false;
@@ -194,9 +200,30 @@
   @property({type: Object})
   _CHANGE_ROLE = ChangeRole;
 
+  @property({type: Object})
+  _SECTION = Metadata;
+
+  @property({type: Boolean})
+  _showAllSections = false;
+
+  @property({type: Boolean})
+  _isNewChangeSummaryUiEnabled = false;
+
+  flagsService = appContext.flagsService;
+
+  restApiService = appContext.restApiService;
+
+  /** @override */
+  ready() {
+    super.ready();
+    this._isNewChangeSummaryUiEnabled = this.flagsService.isEnabled(
+      KnownExperimentId.NEW_CHANGE_SUMMARY_UI
+    );
+  }
+
   @observe('change.labels')
   _labelsChanged(labels?: LabelNameToInfoMap) {
-    this.labels = {...labels} || null;
+    this.labels = {...labels};
   }
 
   @observe('change')
@@ -223,13 +250,13 @@
         return;
       }
       this.set(['change', 'assignee'], acct);
-      this.$.restAPI.setAssignee(this.change._number, acct._account_id);
+      this.restApiService.setAssignee(this.change._number, acct._account_id);
     } else {
       if (!this.change.assignee) {
         return;
       }
       this.set(['change', 'assignee'], undefined);
-      this.$.restAPI.deleteAssignee(this.change._number);
+      this.restApiService.deleteAssignee(this.change._number);
     }
   }
 
@@ -238,7 +265,7 @@
   }
 
   /**
-   * @return If array is empty, returns null instead so
+   * @return If array is empty, returns undefined instead so
    * an existential check can be used to hide or show the webLinks
    * section.
    */
@@ -246,9 +273,7 @@
     commitInfo?: CommitInfoWithRequiredCommit,
     serverConfig?: ServerInfo
   ) {
-    if (!commitInfo) {
-      return null;
-    }
+    if (!commitInfo) return undefined;
     const weblinks = GerritNav.getChangeWeblinks(
       this.change ? this.change.project : ('' as RepoName),
       commitInfo.commit,
@@ -257,15 +282,11 @@
         config: serverConfig,
       }
     );
-    return weblinks.length ? weblinks : null;
+    return weblinks.length ? weblinks : undefined;
   }
 
   _isAssigneeEnabled(serverConfig?: ServerInfo) {
-    return (
-      serverConfig &&
-      serverConfig.change &&
-      !!serverConfig.change.enable_assignee
-    );
+    return !!serverConfig?.change?.enable_assignee;
   }
 
   _computeStrategy(change?: ParsedChangeInfo) {
@@ -285,54 +306,43 @@
       throw new Error('change must be set');
     }
     const lastTopic = this.change.topic;
-    const topic = e.detail.length ? e.detail : null;
+    const topic = e.detail.length ? e.detail : undefined;
     this._settingTopic = true;
     const topicChangedForChangeNumber = this.change._number;
-    this.$.restAPI
+    this.restApiService
       .setChangeTopic(topicChangedForChangeNumber, topic)
       .then(newTopic => {
-        if (
-          !this.change ||
-          this.change._number !== topicChangedForChangeNumber
-        ) {
-          return;
-        }
+        if (this.change?._number !== topicChangedForChangeNumber) return;
         this._settingTopic = false;
         this.set(['change', 'topic'], newTopic);
         if (newTopic !== lastTopic) {
-          this.dispatchEvent(
-            new CustomEvent('topic-changed', {bubbles: true, composed: true})
-          );
+          fireEvent(this, 'topic-changed');
         }
       });
   }
 
   _showAddTopic(
-    changeRecord: ElementPropertyDeepChange<GrChangeMetadata, 'change'>,
+    changeRecord?: ElementPropertyDeepChange<GrChangeMetadata, 'change'>,
     settingTopic?: boolean
   ) {
-    const hasTopic =
-      !!changeRecord && !!changeRecord.base && !!changeRecord.base.topic;
+    const hasTopic = !!changeRecord?.base?.topic;
     return !hasTopic && !settingTopic;
   }
 
   _showTopicChip(
-    changeRecord: ElementPropertyDeepChange<GrChangeMetadata, 'change'>,
+    changeRecord?: ElementPropertyDeepChange<GrChangeMetadata, 'change'>,
     settingTopic?: boolean
   ) {
-    const hasTopic =
-      !!changeRecord && !!changeRecord.base && !!changeRecord.base.topic;
+    const hasTopic = !!changeRecord?.base?.topic;
     return hasTopic && !settingTopic;
   }
 
   _showCherryPickOf(
-    changeRecord: ElementPropertyDeepChange<GrChangeMetadata, 'change'>
+    changeRecord?: ElementPropertyDeepChange<GrChangeMetadata, 'change'>
   ) {
     const hasCherryPickOf =
-      !!changeRecord &&
-      !!changeRecord.base &&
-      !!changeRecord.base.cherry_pick_of_change &&
-      !!changeRecord.base.cherry_pick_of_patch_set;
+      !!changeRecord?.base?.cherry_pick_of_change &&
+      !!changeRecord?.base?.cherry_pick_of_patch_set;
     return hasCherryPickOf;
   }
 
@@ -345,47 +355,24 @@
     }
     const newHashtag = this._newHashtag;
     this._newHashtag = '' as Hashtag;
-    this.$.restAPI
+    this.restApiService
       .setChangeHashtag(this.change._number, {add: [newHashtag]})
       .then(newHashtag => {
         this.set(['change', 'hashtags'], newHashtag);
-        this.dispatchEvent(
-          new CustomEvent('hashtag-changed', {
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireEvent(this, 'hashtag-changed');
       });
   }
 
   _computeTopicReadOnly(mutable?: boolean, change?: ParsedChangeInfo) {
-    return (
-      !mutable ||
-      !change ||
-      !change.actions ||
-      !change.actions.topic ||
-      !change.actions.topic.enabled
-    );
+    return !mutable || !change?.actions?.topic?.enabled;
   }
 
   _computeHashtagReadOnly(mutable?: boolean, change?: ParsedChangeInfo) {
-    return (
-      !mutable ||
-      !change ||
-      !change.actions ||
-      !change.actions.hashtags ||
-      !change.actions.hashtags.enabled
-    );
+    return !mutable || !change?.actions?.hashtags?.enabled;
   }
 
   _computeAssigneeReadOnly(mutable?: boolean, change?: ParsedChangeInfo) {
-    return (
-      !mutable ||
-      !change ||
-      !change.actions ||
-      !change.actions.assignee ||
-      !change.actions.assignee.enabled
-    );
+    return !mutable || !change?.actions?.assignee?.enabled;
   }
 
   _computeTopicPlaceholder(_topicReadOnly?: boolean) {
@@ -419,17 +406,11 @@
   _computePushCertificateValidation(
     serverConfig?: ServerInfo,
     change?: ParsedChangeInfo
-  ): PushCertifacteValidationInfo | null {
-    if (
-      !change ||
-      !serverConfig ||
-      !serverConfig.receive ||
-      !serverConfig.receive.enable_signed_push
-    ) {
-      return null;
-    }
+  ): PushCertificateValidationInfo | undefined {
+    if (!change || !serverConfig?.receive?.enable_signed_push) return undefined;
+
     const rev = change.revisions[change.current_revision];
-    if (!rev.push_certificate || !rev.push_certificate.key) {
+    if (!rev.push_certificate?.key) {
       return {
         class: 'help',
         icon: 'gr-icons:help',
@@ -472,7 +453,7 @@
   }
 
   _problems(msg: string, key: GpgKeyInfo) {
-    if (!key || !key.problems || key.problems.length === 0) {
+    if (!key?.problems || key.problems.length === 0) {
       return msg;
     }
 
@@ -524,18 +505,15 @@
     }
     const target = (dom(e) as EventApi).rootTarget as GrLinkedChip;
     target.disabled = true;
-    this.$.restAPI
-      .setChangeTopic(this.change._number, null)
+    this.restApiService
+      .setChangeTopic(this.change._number)
       .then(() => {
         target.disabled = false;
         this.set(['change', 'topic'], '');
-        this.dispatchEvent(
-          new CustomEvent('topic-changed', {bubbles: true, composed: true})
-        );
+        fireEvent(this, 'topic-changed');
       })
       .catch(() => {
         target.disabled = false;
-        return;
       });
   }
 
@@ -546,7 +524,7 @@
     }
     const target = (dom(e) as EventApi).rootTarget as GrLinkedChip;
     target.disabled = true;
-    this.$.restAPI
+    this.restApiService
       .setChangeHashtag(this.change._number, {remove: [target.text as Hashtag]})
       .then(newHashtags => {
         target.disabled = false;
@@ -554,35 +532,55 @@
       })
       .catch(() => {
         target.disabled = false;
-        return;
       });
   }
 
   _computeIsWip(change?: ParsedChangeInfo) {
-    return change && !!change.work_in_progress;
+    return !!change?.work_in_progress;
   }
 
   _computeShowRoleClass(change?: ParsedChangeInfo, role?: ChangeRole) {
     return this._getNonOwnerRole(change, role) ? '' : 'hideDisplay';
   }
 
+  _computeDisplayState(
+    showAllSections: boolean,
+    change: ParsedChangeInfo | undefined,
+    section: Metadata
+  ) {
+    if (
+      !this._isNewChangeSummaryUiEnabled ||
+      showAllSections ||
+      DisplayRules.ALWAYS_SHOW.includes(section) ||
+      (DisplayRules.SHOW_IF_SET.includes(section) &&
+        isSectionSet(section, change))
+    ) {
+      return '';
+    }
+    return 'hideDisplay';
+  }
+
+  _computeShowAllLabelText(showAllSections: boolean) {
+    if (showAllSections) {
+      return 'Show less';
+    } else {
+      return 'Show all';
+    }
+  }
+
+  _onShowAllClick() {
+    this._showAllSections = !this._showAllSections;
+  }
+
   /**
-   * Get the user with the specified role on the change. Returns null if the
+   * Get the user with the specified role on the change. Returns undefined if the
    * user with that role is the same as the owner.
    */
   _getNonOwnerRole(change?: ParsedChangeInfo, role?: ChangeRole) {
-    if (
-      !change ||
-      !change.current_revision ||
-      !change.revisions[change.current_revision]
-    ) {
-      return null;
-    }
+    if (!change?.revisions?.[change.current_revision]) return undefined;
 
     const rev = change.revisions[change.current_revision];
-    if (!rev) {
-      return null;
-    }
+    if (!rev) return undefined;
 
     if (
       role === ChangeRole.UPLOADER &&
@@ -611,7 +609,7 @@
       return rev.commit.committer;
     }
 
-    return null;
+    return undefined;
   }
 
   _computeParents(
@@ -670,7 +668,7 @@
       return undefined;
     }
     const provider = GrReviewerSuggestionsProvider.create(
-      this.$.restAPI,
+      this.restApiService,
       change._number,
       SUGGESTIONS_PROVIDERS_USERS_TYPES.ANY
     );
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
index f1d1127..3b89a33 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
@@ -49,7 +49,15 @@
       pointer-events: none;
     }
     .hashtagChip {
-      margin-bottom: var(--spacing-m);
+      padding-bottom: var(--spacing-s);
+    }
+    /* consistent with section .title, .value */
+    .hashtagChip.new-change-summary-true:not(last-of-type) {
+      padding-bottom: var(--spacing-s);
+    }
+    .hashtagChip.new-change-summary-true:last-of-type {
+      display: inline;
+      vertical-align: top;
     }
     #externalStyle {
       display: block;
@@ -94,18 +102,59 @@
       --account-max-length: 120px;
       max-width: 285px;
     }
+    .metadata-title {
+      font-weight: var(--font-weight-bold);
+      color: var(--deemphasized-text-color);
+      padding-left: var(--metadata-horizontal-padding);
+    }
+    .metadata-header {
+      display: flex;
+      justify-content: space-between;
+    }
   </style>
   <gr-external-style id="externalStyle" name="change-metadata">
-    <section>
+    <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
+      <div class="metadata-header">
+        <h3 class="metadata-title">Change Info</h3>
+        <gr-button
+          class="show-all-button"
+          on-click="_onShowAllClick"
+          no-uppercase=""
+          >[[_computeShowAllLabelText(_showAllSections)]]</gr-button
+        >
+      </div>
+    </template>
+    <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
+      <template is="dom-if" if="[[change.submitted]]">
+        <section
+          class$="[[_computeDisplayState(_showAllSections, change, _SECTION.SUBMITTED)]]"
+        >
+          <span class="title">Submitted</span>
+          <span class="value">
+            <gr-date-formatter
+              has-tooltip=""
+              date-str="[[change.submitted]]"
+              show-yesterday=""
+            ></gr-date-formatter>
+          </span>
+        </section>
+      </template>
+    </template>
+    <section
+      class$="[[_computeDisplayState(_showAllSections, change, _SECTION.UPDATED)]]"
+    >
       <span class="title">Updated</span>
       <span class="value">
         <gr-date-formatter
           has-tooltip=""
           date-str="[[change.updated]]"
+          show-yesterday=""
         ></gr-date-formatter>
       </span>
     </section>
-    <section>
+    <section
+      class$="[[_computeDisplayState(_showAllSections, change, _SECTION.OWNER)]]"
+    >
       <span class="title">Owner</span>
       <span class="value">
         <gr-account-chip
@@ -156,7 +205,9 @@
       </span>
     </section>
     <template is="dom-if" if="[[_isAssigneeEnabled(serverConfig)]]">
-      <section class="assignee">
+      <section
+        class$="assignee [[_computeDisplayState(_showAllSections, change, _SECTION.ASSIGNEE)]]"
+      >
         <span class="title">Assignee</span>
         <span class="value">
           <gr-account-list
@@ -172,7 +223,9 @@
         </span>
       </section>
     </template>
-    <section>
+    <section
+      class$="[[_computeDisplayState(_showAllSections, change, _SECTION.REVIEWERS)]]"
+    >
       <span class="title">Reviewers</span>
       <span class="value">
         <gr-reviewer-list
@@ -183,7 +236,9 @@
         ></gr-reviewer-list>
       </span>
     </section>
-    <section>
+    <section
+      class$="[[_computeDisplayState(_showAllSections, change, _SECTION.CC)]]"
+    >
       <span class="title">CC</span>
       <span class="value">
         <gr-reviewer-list
@@ -198,7 +253,9 @@
       is="dom-if"
       if="[[_computeShowRepoBranchTogether(change.project, change.branch)]]"
     >
-      <section>
+      <section
+        class$="[[_computeDisplayState(_showAllSections, change, _SECTION.REPO_BRANCH)]]"
+      >
         <span class="title">Repo | Branch</span>
         <span class="value">
           <a href$="[[_computeProjectUrl(change.project)]]"
@@ -215,7 +272,9 @@
       is="dom-if"
       if="[[!_computeShowRepoBranchTogether(change.project, change.branch)]]"
     >
-      <section>
+      <section
+        class$="[[_computeDisplayState(_showAllSections, change, _SECTION.REPO_BRANCH)]]"
+      >
         <span class="title">Repo</span>
         <span class="value">
           <a href$="[[_computeProjectUrl(change.project)]]">
@@ -226,7 +285,9 @@
           </a>
         </span>
       </section>
-      <section>
+      <section
+        class$="[[_computeDisplayState(_showAllSections, change, _SECTION.REPO_BRANCH)]]"
+      >
         <span class="title">Branch</span>
         <span class="value">
           <a href$="[[_computeBranchUrl(change.project, change.branch)]]">
@@ -238,7 +299,9 @@
         </span>
       </section>
     </template>
-    <section>
+    <section
+      class$="[[_computeDisplayState(_showAllSections, change, _SECTION.PARENT)]]"
+    >
       <span class="title">[[_computeParentsLabel(_currentParents)]]</span>
       <span class="value">
         <ol
@@ -262,7 +325,9 @@
         </ol>
       </span>
     </section>
-    <section class="topic">
+    <section
+      class$="topic [[_computeDisplayState(_showAllSections, change, _SECTION.TOPIC)]]"
+    >
       <span class="title">Topic</span>
       <span class="value">
         <template is="dom-if" if="[[_showTopicChip(change.*, _settingTopic)]]">
@@ -283,12 +348,15 @@
             placeholder="[[_computeTopicPlaceholder(_topicReadOnly)]]"
             read-only="[[_topicReadOnly]]"
             on-changed="_handleTopicChanged"
+            show-as-edit-pencil="[[_isNewChangeSummaryUiEnabled]]"
           ></gr-editable-label>
         </template>
       </span>
     </section>
     <template is="dom-if" if="[[_showCherryPickOf(change.*)]]">
-      <section>
+      <section
+        class$="[[_computeDisplayState(_showAllSections, change, _SECTION.CHERRY_PICK_OF)]]"
+      >
         <span class="title">Cherry pick of</span>
         <span class="value">
           <a
@@ -304,19 +372,21 @@
       </section>
     </template>
     <section
-      class="strategy"
+      class$="strategy [[_computeDisplayState(_showAllSections, change, _SECTION.STRATEGY)]]"
       hidden$="[[_computeHideStrategy(change)]]"
       hidden=""
     >
       <span class="title">Strategy</span>
       <span class="value">[[_computeStrategy(change)]]</span>
     </section>
-    <section class="hashtag">
+    <section
+      class$="hashtag [[_computeDisplayState(_showAllSections, change, _SECTION.HASHTAGS)]]"
+    >
       <span class="title">Hashtags</span>
       <span class="value">
         <template is="dom-repeat" items="[[change.hashtags]]">
           <gr-linked-chip
-            class="hashtagChip"
+            class$="hashtagChip new-change-summary-[[_isNewChangeSummaryUiEnabled]]"
             text="[[item]]"
             href="[[_computeHashtagUrl(item)]]"
             removable="[[!_hashtagReadOnly]]"
@@ -333,6 +403,7 @@
             placeholder="[[_computeHashtagPlaceholder(_hashtagReadOnly)]]"
             read-only="[[_hashtagReadOnly]]"
             on-changed="_handleHashtagChanged"
+            show-as-edit-pencil="[[_isNewChangeSummaryUiEnabled]]"
           ></gr-editable-label>
         </template>
       </span>
@@ -371,5 +442,4 @@
       ></gr-endpoint-param>
     </gr-endpoint-decorator>
   </gr-external-style>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.js b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.js
deleted file mode 100644
index 5bdf105..0000000
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.js
+++ /dev/null
@@ -1,782 +0,0 @@
-/**
- * @license
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import '../../../test/common-test-setup-karma.js';
-import '../../core/gr-router/gr-router.js';
-import './gr-change-metadata.js';
-import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
-import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';
-import {_testOnly_initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit.js';
-
-const basicFixture = fixtureFromElement('gr-change-metadata');
-
-const pluginApi = _testOnly_initGerritPluginApi();
-
-suite('gr-change-metadata tests', () => {
-  let element;
-
-  setup(() => {
-    stub('gr-rest-api-interface', {
-      getConfig() { return Promise.resolve({}); },
-      getLoggedIn() { return Promise.resolve(false); },
-    });
-
-    element = basicFixture.instantiate();
-  });
-
-  test('computed fields', () => {
-    assert.isFalse(element._computeHideStrategy({status: 'NEW'}));
-    assert.isTrue(element._computeHideStrategy({status: 'MERGED'}));
-    assert.isTrue(element._computeHideStrategy({status: 'ABANDONED'}));
-    assert.equal(element._computeStrategy({submit_type: 'CHERRY_PICK'}),
-        'Cherry Pick');
-    assert.equal(element._computeStrategy({submit_type: 'REBASE_ALWAYS'}),
-        'Rebase Always');
-  });
-
-  test('computed fields requirements', () => {
-    assert.isFalse(element._computeShowRequirements({status: 'MERGED'}));
-    assert.isFalse(element._computeShowRequirements({status: 'ABANDONED'}));
-
-    // No labels and no requirements: submit status is useless
-    assert.isFalse(element._computeShowRequirements({
-      status: 'NEW',
-      labels: {},
-    }));
-
-    // Work in Progress: submit status should be present
-    assert.isTrue(element._computeShowRequirements({
-      status: 'NEW',
-      labels: {},
-      work_in_progress: true,
-    }));
-
-    // We have at least one reason to display Submit Status
-    assert.isTrue(element._computeShowRequirements({
-      status: 'NEW',
-      labels: {
-        Verified: {
-          approved: false,
-        },
-      },
-      requirements: [],
-    }));
-    assert.isTrue(element._computeShowRequirements({
-      status: 'NEW',
-      labels: {},
-      requirements: [{
-        fallback_text: 'Resolve all comments',
-        status: 'OK',
-      }],
-    }));
-  });
-
-  test('show strategy for open change', () => {
-    element.change = {status: 'NEW', submit_type: 'CHERRY_PICK', labels: {}};
-    flush();
-    const strategy = element.shadowRoot
-        .querySelector('.strategy');
-    assert.ok(strategy);
-    assert.isFalse(strategy.hasAttribute('hidden'));
-    assert.equal(strategy.children[1].innerHTML, 'Cherry Pick');
-  });
-
-  test('hide strategy for closed change', () => {
-    element.change = {status: 'MERGED', labels: {}};
-    flush();
-    assert.isTrue(element.shadowRoot
-        .querySelector('.strategy').hasAttribute('hidden'));
-  });
-
-  test('weblinks use GerritNav interface', () => {
-    const weblinksStub = sinon.stub(GerritNav, '_generateWeblinks')
-        .returns([{name: 'stubb', url: '#s'}]);
-    element.commitInfo = {};
-    element.serverConfig = {};
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isTrue(weblinksStub.called);
-    assert.isFalse(webLinks.hasAttribute('hidden'));
-    assert.equal(element._computeWebLinks(element.commitInfo).length, 1);
-  });
-
-  test('weblinks hidden when no weblinks', () => {
-    element.commitInfo = {};
-    element.serverConfig = {};
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isTrue(webLinks.hasAttribute('hidden'));
-  });
-
-  test('weblinks hidden when only gitiles weblink', () => {
-    element.commitInfo = {web_links: [{name: 'gitiles', url: '#'}]};
-    element.serverConfig = {};
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isTrue(webLinks.hasAttribute('hidden'));
-    assert.equal(element._computeWebLinks(element.commitInfo), null);
-  });
-
-  test('weblinks hidden when sole weblink is set as primary', () => {
-    const browser = 'browser';
-    element.commitInfo = {web_links: [{name: browser, url: '#'}]};
-    element.serverConfig = {
-      gerrit: {
-        primary_weblink_name: browser,
-      },
-    };
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isTrue(webLinks.hasAttribute('hidden'));
-  });
-
-  test('weblinks are visible when other weblinks', () => {
-    const router = document.createElement('gr-router');
-    sinon.stub(GerritNav, '_generateWeblinks').callsFake(
-        router._generateWeblinks.bind(router));
-
-    element.commitInfo = {web_links: [{name: 'test', url: '#'}]};
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isFalse(webLinks.hasAttribute('hidden'));
-    assert.equal(element._computeWebLinks(element.commitInfo).length, 1);
-    // With two non-gitiles weblinks, there are two returned.
-    element.commitInfo = {
-      web_links: [{name: 'test', url: '#'}, {name: 'test2', url: '#'}]};
-    assert.equal(element._computeWebLinks(element.commitInfo).length, 2);
-  });
-
-  test('weblinks are visible when gitiles and other weblinks', () => {
-    const router = document.createElement('gr-router');
-    sinon.stub(GerritNav, '_generateWeblinks').callsFake(
-        router._generateWeblinks.bind(router));
-
-    element.commitInfo = {
-      web_links: [{name: 'test', url: '#'}, {name: 'gitiles', url: '#'}]};
-    flush();
-    const webLinks = element.$.webLinks;
-    assert.isFalse(webLinks.hasAttribute('hidden'));
-    // Only the non-gitiles weblink is returned.
-    assert.equal(element._computeWebLinks(element.commitInfo).length, 1);
-  });
-
-  suite('_getNonOwnerRole', () => {
-    let change;
-
-    setup(() => {
-      change = {
-        owner: {
-          email: 'abc@def',
-          _account_id: 1019328,
-        },
-        revisions: {
-          rev1: {
-            _number: 1,
-            uploader: {
-              email: 'ghi@def',
-              _account_id: 1011123,
-            },
-            commit: {
-              author: {email: 'jkl@def'},
-              committer: {email: 'ghi@def'},
-            },
-          },
-        },
-        current_revision: 'rev1',
-      };
-    });
-
-    suite('role=uploader', () => {
-      test('_getNonOwnerRole for uploader', () => {
-        assert.deepEqual(
-            element._getNonOwnerRole(change, element._CHANGE_ROLE.UPLOADER),
-            {email: 'ghi@def', _account_id: 1011123});
-      });
-
-      test('_getNonOwnerRole that it does not return uploader', () => {
-        // Set the uploader email to be the same as the owner.
-        change.revisions.rev1.uploader._account_id = 1019328;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.UPLOADER));
-      });
-
-      test('_getNonOwnerRole null for uploader with no current rev', () => {
-        delete change.current_revision;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.UPLOADER));
-      });
-
-      test('_computeShowRoleClass show uploader', () => {
-        assert.equal(element._computeShowRoleClass(
-            change, element._CHANGE_ROLE.UPLOADER), '');
-      });
-
-      test('_computeShowRoleClass hide uploader', () => {
-        // Set the uploader email to be the same as the owner.
-        change.revisions.rev1.uploader._account_id = 1019328;
-        assert.equal(element._computeShowRoleClass(change,
-            element._CHANGE_ROLE.UPLOADER), 'hideDisplay');
-      });
-    });
-
-    suite('role=committer', () => {
-      test('_getNonOwnerRole for committer', () => {
-        change.revisions.rev1.uploader.email = 'ghh@def';
-        assert.deepEqual(
-            element._getNonOwnerRole(change, element._CHANGE_ROLE.COMMITTER),
-            {email: 'ghi@def'});
-      });
-
-      test('_getNonOwnerRole is null if committer is same as uploader', () => {
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.COMMITTER));
-      });
-
-      test('_getNonOwnerRole that it does not return committer', () => {
-        // Set the committer email to be the same as the owner.
-        change.revisions.rev1.commit.committer.email = 'abc@def';
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.COMMITTER));
-      });
-
-      test('_getNonOwnerRole null for committer with no current rev', () => {
-        delete change.current_revision;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.COMMITTER));
-      });
-
-      test('_getNonOwnerRole null for committer with no commit', () => {
-        delete change.revisions.rev1.commit;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.COMMITTER));
-      });
-
-      test('_getNonOwnerRole null for committer with no committer', () => {
-        delete change.revisions.rev1.commit.committer;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.COMMITTER));
-      });
-    });
-
-    suite('role=author', () => {
-      test('_getNonOwnerRole for author', () => {
-        assert.deepEqual(
-            element._getNonOwnerRole(change, element._CHANGE_ROLE.AUTHOR),
-            {email: 'jkl@def'});
-      });
-
-      test('_getNonOwnerRole that it does not return author', () => {
-        // Set the author email to be the same as the owner.
-        change.revisions.rev1.commit.author.email = 'abc@def';
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.AUTHOR));
-      });
-
-      test('_getNonOwnerRole null for author with no current rev', () => {
-        delete change.current_revision;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.AUTHOR));
-      });
-
-      test('_getNonOwnerRole null for author with no commit', () => {
-        delete change.revisions.rev1.commit;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.AUTHOR));
-      });
-
-      test('_getNonOwnerRole null for author with no author', () => {
-        delete change.revisions.rev1.commit.author;
-        assert.isNotOk(element._getNonOwnerRole(change,
-            element._CHANGE_ROLE.AUTHOR));
-      });
-    });
-  });
-
-  test('Push Certificate Validation test BAD', () => {
-    const serverConfig = {
-      receive: {
-        enable_signed_push: true,
-      },
-    };
-    const change = {
-      change_id: 'Iad9dc96274af6946f3632be53b106ef80f7ba6ca',
-      owner: {
-        _account_id: 1019328,
-      },
-      revisions: {
-        rev1: {
-          _number: 1,
-          push_certificate: {
-            key: {
-              status: 'BAD',
-              problems: [
-                'No public keys found for key ID E5E20E52',
-              ],
-            },
-          },
-        },
-      },
-      current_revision: 'rev1',
-      status: 'NEW',
-      labels: {},
-      mergeable: true,
-    };
-    const result =
-        element._computePushCertificateValidation(serverConfig, change);
-    assert.equal(result.message,
-        'Push certificate is invalid:\n' +
-        'No public keys found for key ID E5E20E52');
-    assert.equal(result.icon, 'gr-icons:close');
-    assert.equal(result.class, 'invalid');
-  });
-
-  test('Push Certificate Validation test TRUSTED', () => {
-    const serverConfig = {
-      receive: {
-        enable_signed_push: true,
-      },
-    };
-    const change = {
-      change_id: 'Iad9dc96274af6946f3632be53b106ef80f7ba6ca',
-      owner: {
-        _account_id: 1019328,
-      },
-      revisions: {
-        rev1: {
-          _number: 1,
-          push_certificate: {
-            key: {
-              status: 'TRUSTED',
-            },
-          },
-        },
-      },
-      current_revision: 'rev1',
-      status: 'NEW',
-      labels: {},
-      mergeable: true,
-    };
-    const result =
-        element._computePushCertificateValidation(serverConfig, change);
-    assert.equal(result.message,
-        'Push certificate is valid and key is trusted');
-    assert.equal(result.icon, 'gr-icons:check');
-    assert.equal(result.class, 'trusted');
-  });
-
-  test('Push Certificate Validation is missing test', () => {
-    const serverConfig = {
-      receive: {
-        enable_signed_push: true,
-      },
-    };
-    const change = {
-      change_id: 'Iad9dc96274af6946f3632be53b106ef80f7ba6ca',
-      owner: {
-        _account_id: 1019328,
-      },
-      revisions: {
-        rev1: {
-          _number: 1,
-        },
-      },
-      current_revision: 'rev1',
-      status: 'NEW',
-      labels: {},
-      mergeable: true,
-    };
-    const result =
-        element._computePushCertificateValidation(serverConfig, change);
-    assert.equal(result.message,
-        'This patch set was created without a push certificate');
-    assert.equal(result.icon, 'gr-icons:help');
-    assert.equal(result.class, 'help');
-  });
-
-  test('_computeParents', () => {
-    const parents = [{commit: '123', subject: 'abc'}];
-    const revision = {commit: {parents}};
-    assert.deepEqual(element._computeParents({}, {}), []);
-    assert.equal(element._computeParents(null, revision), parents);
-    const change = current_revision => {
-      return {current_revision, revisions: {456: revision}};
-    };
-    assert.deepEqual(element._computeParents(change(null), null), []);
-    const change_bad_revision = change('789');
-    assert.deepEqual(element._computeParents(change_bad_revision, {}), []);
-    const change_no_commit = {current_revision: '456', revisions: {456: {}}};
-    assert.deepEqual(element._computeParents(change_no_commit, null), []);
-    const change_good = change('456');
-    assert.equal(element._computeParents(change_good, null), parents);
-  });
-
-  test('_currentParents', () => {
-    const revision = parent => {
-      return {commit: {parents: [{commit: parent, subject: 'abc'}]}};
-    };
-    element.change = {
-      current_revision: '456',
-      revisions: {456: revision('111')},
-      owner: {},
-    };
-    element.revision = revision('222');
-    assert.equal(element._currentParents[0].commit, '222');
-    element.revision = revision('333');
-    assert.equal(element._currentParents[0].commit, '333');
-    element.revision = null;
-    assert.equal(element._currentParents[0].commit, '111');
-    element.change = {current_revision: null};
-    assert.deepEqual(element._currentParents, []);
-  });
-
-  test('_computeParentsLabel', () => {
-    const parent = {commit: 'abc123', subject: 'My parent commit'};
-    assert.equal(element._computeParentsLabel([parent]), 'Parent');
-    assert.equal(element._computeParentsLabel([parent, parent]),
-        'Parents');
-  });
-
-  test('_computeParentListClass', () => {
-    const parent = {commit: 'abc123', subject: 'My parent commit'};
-    assert.equal(element._computeParentListClass([parent], true),
-        'parentList nonMerge current');
-    assert.equal(element._computeParentListClass([parent], false),
-        'parentList nonMerge notCurrent');
-    assert.equal(element._computeParentListClass([parent, parent], false),
-        'parentList merge notCurrent');
-    assert.equal(element._computeParentListClass([parent, parent], true),
-        'parentList merge current');
-  });
-
-  test('_showAddTopic', () => {
-    assert.isTrue(element._showAddTopic(null, false));
-    assert.isTrue(element._showAddTopic({base: {topic: null}}, false));
-    assert.isFalse(element._showAddTopic({base: {topic: null}}, true));
-    assert.isFalse(element._showAddTopic({base: {topic: 'foo'}}, true));
-    assert.isFalse(element._showAddTopic({base: {topic: 'foo'}}, false));
-  });
-
-  test('_showTopicChip', () => {
-    assert.isFalse(element._showTopicChip(null, false));
-    assert.isFalse(element._showTopicChip({base: {topic: null}}, false));
-    assert.isFalse(element._showTopicChip({base: {topic: null}}, true));
-    assert.isFalse(element._showTopicChip({base: {topic: 'foo'}}, true));
-    assert.isTrue(element._showTopicChip({base: {topic: 'foo'}}, false));
-  });
-
-  test('_showCherryPickOf', () => {
-    assert.isFalse(element._showCherryPickOf(null));
-    assert.isFalse(element._showCherryPickOf({
-      base: {
-        cherry_pick_of_change: null,
-        cherry_pick_of_patch_set: null,
-      },
-    }));
-    assert.isTrue(element._showCherryPickOf({
-      base: {
-        cherry_pick_of_change: 123,
-        cherry_pick_of_patch_set: 1,
-      },
-    }));
-  });
-
-  suite('Topic removal', () => {
-    let change;
-    setup(() => {
-      change = {
-        _number: 'the number',
-        actions: {
-          topic: {enabled: false},
-        },
-        change_id: 'the id',
-        topic: 'the topic',
-        status: 'NEW',
-        submit_type: 'CHERRY_PICK',
-        labels: {
-          test: {
-            all: [{_account_id: 1, name: 'bojack', value: 1}],
-            default_value: 0,
-            values: [],
-          },
-        },
-        removable_reviewers: [],
-      };
-    });
-
-    test('_computeTopicReadOnly', () => {
-      let mutable = false;
-      assert.isTrue(element._computeTopicReadOnly(mutable, change));
-      mutable = true;
-      assert.isTrue(element._computeTopicReadOnly(mutable, change));
-      change.actions.topic.enabled = true;
-      assert.isFalse(element._computeTopicReadOnly(mutable, change));
-      mutable = false;
-      assert.isTrue(element._computeTopicReadOnly(mutable, change));
-    });
-
-    test('topic read only hides delete button', () => {
-      element.account = {};
-      element.change = change;
-      flush();
-      const button = element.shadowRoot
-          .querySelector('gr-linked-chip').shadowRoot
-          .querySelector('gr-button');
-      assert.isTrue(button.hasAttribute('hidden'));
-    });
-
-    test('topic not read only does not hide delete button', () => {
-      element.account = {test: true};
-      change.actions.topic.enabled = true;
-      element.change = change;
-      flush();
-      const button = element.shadowRoot
-          .querySelector('gr-linked-chip').shadowRoot
-          .querySelector('gr-button');
-      assert.isFalse(button.hasAttribute('hidden'));
-    });
-  });
-
-  suite('Hashtag removal', () => {
-    let change;
-    setup(() => {
-      change = {
-        _number: 'the number',
-        actions: {
-          hashtags: {enabled: false},
-        },
-        change_id: 'the id',
-        hashtags: ['test-hashtag'],
-        status: 'NEW',
-        submit_type: 'CHERRY_PICK',
-        labels: {
-          test: {
-            all: [{_account_id: 1, name: 'bojack', value: 1}],
-            default_value: 0,
-            values: [],
-          },
-        },
-        removable_reviewers: [],
-      };
-    });
-
-    test('_computeHashtagReadOnly', () => {
-      flush();
-      let mutable = false;
-      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
-      mutable = true;
-      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
-      change.actions.hashtags.enabled = true;
-      assert.isFalse(element._computeHashtagReadOnly(mutable, change));
-      mutable = false;
-      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
-    });
-
-    test('hashtag read only hides delete button', () => {
-      flush();
-      element.account = {};
-      element.change = change;
-      flush();
-      const button = element.shadowRoot
-          .querySelector('gr-linked-chip').shadowRoot
-          .querySelector('gr-button');
-      assert.isTrue(button.hasAttribute('hidden'));
-    });
-
-    test('hashtag not read only does not hide delete button', () => {
-      flush();
-      element.account = {test: true};
-      change.actions.hashtags.enabled = true;
-      element.change = change;
-      flush();
-      const button = element.shadowRoot
-          .querySelector('gr-linked-chip').shadowRoot
-          .querySelector('gr-button');
-      assert.isFalse(button.hasAttribute('hidden'));
-    });
-  });
-
-  suite('remove reviewer votes', () => {
-    setup(() => {
-      sinon.stub(element, '_computeTopicReadOnly').returns(true);
-      element.change = {
-        _number: 42,
-        change_id: 'the id',
-        actions: [],
-        topic: 'the topic',
-        status: 'NEW',
-        submit_type: 'CHERRY_PICK',
-        labels: {
-          test: {
-            all: [{_account_id: 1, name: 'bojack', value: 1}],
-            default_value: 0,
-            values: [],
-          },
-        },
-        removable_reviewers: [],
-      };
-      flush();
-    });
-
-    suite('assignee field', () => {
-      const dummyAccount = {
-        _account_id: 1,
-        name: 'bojack',
-      };
-      const change = {
-        actions: {
-          assignee: {enabled: false},
-        },
-        assignee: dummyAccount,
-      };
-      let deleteStub;
-      let setStub;
-
-      setup(() => {
-        deleteStub = sinon.stub(element.$.restAPI, 'deleteAssignee');
-        setStub = sinon.stub(element.$.restAPI, 'setAssignee');
-        element.serverConfig = {
-          change: {
-            enable_assignee: true,
-          },
-        };
-      });
-
-      test('changing change recomputes _assignee', () => {
-        assert.isFalse(!!element._assignee.length);
-        const change = element.change;
-        change.assignee = dummyAccount;
-        element._changeChanged(change);
-        assert.deepEqual(element._assignee[0], dummyAccount);
-      });
-
-      test('modifying _assignee calls API', () => {
-        assert.isFalse(!!element._assignee.length);
-        element.set('_assignee', [dummyAccount]);
-        assert.isTrue(setStub.calledOnce);
-        assert.deepEqual(element.change.assignee, dummyAccount);
-        element.set('_assignee', [dummyAccount]);
-        assert.isTrue(setStub.calledOnce);
-        element.set('_assignee', []);
-        assert.isTrue(deleteStub.calledOnce);
-        assert.equal(element.change.assignee, undefined);
-        element.set('_assignee', []);
-        assert.isTrue(deleteStub.calledOnce);
-      });
-
-      test('_computeAssigneeReadOnly', () => {
-        let mutable = false;
-        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
-        mutable = true;
-        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
-        change.actions.assignee.enabled = true;
-        assert.isFalse(element._computeAssigneeReadOnly(mutable, change));
-        mutable = false;
-        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
-      });
-    });
-
-    test('changing topic', () => {
-      const newTopic = 'the new topic';
-      sinon.stub(element.$.restAPI, 'setChangeTopic').returns(
-          Promise.resolve(newTopic));
-      element._handleTopicChanged({detail: newTopic});
-      const topicChangedSpy = sinon.spy();
-      element.addEventListener('topic-changed', topicChangedSpy);
-      assert.isTrue(element.$.restAPI.setChangeTopic.calledWith(
-          42, newTopic));
-      return element.$.restAPI.setChangeTopic.lastCall.returnValue
-          .then(() => {
-            assert.equal(element.change.topic, newTopic);
-            assert.isTrue(topicChangedSpy.called);
-          });
-    });
-
-    test('topic removal', () => {
-      sinon.stub(element.$.restAPI, 'setChangeTopic').returns(
-          Promise.resolve());
-      const chip = element.shadowRoot
-          .querySelector('gr-linked-chip');
-      const remove = chip.$.remove;
-      const topicChangedSpy = sinon.spy();
-      element.addEventListener('topic-changed', topicChangedSpy);
-      MockInteractions.tap(remove);
-      assert.isTrue(chip.disabled);
-      assert.isTrue(element.$.restAPI.setChangeTopic.calledWith(
-          42, null));
-      return element.$.restAPI.setChangeTopic.lastCall.returnValue
-          .then(() => {
-            assert.isFalse(chip.disabled);
-            assert.equal(element.change.topic, '');
-            assert.isTrue(topicChangedSpy.called);
-          });
-    });
-
-    test('changing hashtag', () => {
-      flush();
-      element._newHashtag = 'new hashtag';
-      const newHashtag = ['new hashtag'];
-      sinon.stub(element.$.restAPI, 'setChangeHashtag').returns(
-          Promise.resolve(newHashtag));
-      element._handleHashtagChanged({}, 'new hashtag');
-      assert.isTrue(element.$.restAPI.setChangeHashtag.calledWith(
-          42, {add: ['new hashtag']}));
-      return element.$.restAPI.setChangeHashtag.lastCall.returnValue
-          .then(() => {
-            assert.equal(element.change.hashtags, newHashtag);
-          });
-    });
-  });
-
-  test('editTopic', () => {
-    element.account = {test: true};
-    element.change = {actions: {topic: {enabled: true}}};
-    flush();
-
-    const label = element.shadowRoot
-        .querySelector('.topicEditableLabel');
-    assert.ok(label);
-    sinon.stub(label, 'open');
-    element.editTopic();
-    flush();
-
-    assert.isTrue(label.open.called);
-  });
-
-  suite('plugin endpoints', () => {
-    test('endpoint params', done => {
-      element.change = {labels: {}};
-      element.revision = {};
-      let hookEl;
-      let plugin;
-      pluginApi.install(
-          p => {
-            plugin = p;
-            plugin.hook('change-metadata-item').getLastAttached()
-                .then(el => hookEl = el);
-          },
-          '0.1',
-          'http://some/plugins/url.html');
-      getPluginLoader().loadPlugins([]);
-      flush(() => {
-        assert.strictEqual(hookEl.plugin, plugin);
-        assert.strictEqual(hookEl.change, element.change);
-        assert.strictEqual(hookEl.revision, element.revision);
-        done();
-      });
-    });
-  });
-});
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.ts
new file mode 100644
index 0000000..ab7d09b
--- /dev/null
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.ts
@@ -0,0 +1,956 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../../test/common-test-setup-karma';
+import '../../core/gr-router/gr-router';
+import './gr-change-metadata';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
+import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
+import {_testOnly_initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit';
+import {GrChangeMetadata} from './gr-change-metadata';
+import {
+  createServerInfo,
+  createUserConfig,
+  createParsedChange,
+  createAccountWithId,
+  createRequirement,
+  createCommitInfoWithRequiredCommit,
+  createWebLinkInfo,
+  createGerritInfo,
+  createGitPerson,
+  createCommit,
+  createRevision,
+  createAccountDetailWithId,
+  createChangeConfig,
+} from '../../../test/test-data-generators';
+import {
+  ChangeStatus,
+  SubmitType,
+  RequirementStatus,
+  GpgKeyInfoStatus,
+} from '../../../constants/constants';
+import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
+import {
+  EmailAddress,
+  AccountId,
+  CommitId,
+  ServerInfo,
+  RevisionInfo,
+  ParentCommitInfo,
+  TopicName,
+  ElementPropertyDeepChange,
+  PatchSetNum,
+  NumericChangeId,
+  LabelValueToDescriptionMap,
+  Hashtag,
+} from '../../../types/common';
+import {SinonStubbedMember} from 'sinon/pkg/sinon-esm';
+import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {tap} from '@polymer/iron-test-helpers/mock-interactions';
+import {GrEditableLabel} from '../../shared/gr-editable-label/gr-editable-label';
+import {PluginApi} from '../../plugins/gr-plugin-types';
+import {GrEndpointDecorator} from '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
+
+const basicFixture = fixtureFromElement('gr-change-metadata');
+
+const pluginApi = _testOnly_initGerritPluginApi();
+
+suite('gr-change-metadata tests', () => {
+  let element: GrChangeMetadata;
+
+  setup(() => {
+    stub('gr-rest-api-interface', {
+      getConfig() {
+        return Promise.resolve({
+          ...createServerInfo(),
+          user: {
+            ...createUserConfig(),
+            anonymous_coward_name: 'test coward name',
+          },
+        });
+      },
+      getLoggedIn() {
+        return Promise.resolve(false);
+      },
+    });
+
+    element = basicFixture.instantiate();
+  });
+
+  test('computed fields', () => {
+    assert.isFalse(
+      element._computeHideStrategy({
+        ...createParsedChange(),
+        status: ChangeStatus.NEW,
+      })
+    );
+    assert.isTrue(
+      element._computeHideStrategy({
+        ...createParsedChange(),
+        status: ChangeStatus.MERGED,
+      })
+    );
+    assert.isTrue(
+      element._computeHideStrategy({
+        ...createParsedChange(),
+        status: ChangeStatus.ABANDONED,
+      })
+    );
+    assert.equal(
+      element._computeStrategy({
+        ...createParsedChange(),
+        submit_type: SubmitType.CHERRY_PICK,
+      }),
+      'Cherry Pick'
+    );
+    assert.equal(
+      element._computeStrategy({
+        ...createParsedChange(),
+        submit_type: SubmitType.REBASE_ALWAYS,
+      }),
+      'Rebase Always'
+    );
+  });
+
+  test('computed fields requirements', () => {
+    assert.isFalse(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.MERGED,
+      })
+    );
+    assert.isFalse(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.ABANDONED,
+      })
+    );
+
+    // No labels and no requirements: submit status is useless
+    assert.isFalse(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.NEW,
+        labels: {},
+      })
+    );
+
+    // Work in Progress: submit status should be present
+    assert.isTrue(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.NEW,
+        labels: {},
+        work_in_progress: true,
+      })
+    );
+
+    // We have at least one reason to display Submit Status
+    assert.isTrue(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.NEW,
+        labels: {
+          Verified: {
+            approved: createAccountWithId(),
+          },
+        },
+        requirements: [],
+      })
+    );
+    assert.isTrue(
+      element._computeShowRequirements({
+        ...createParsedChange(),
+        status: ChangeStatus.NEW,
+        labels: {},
+        requirements: [
+          {
+            ...createRequirement(),
+            fallbackText: 'Resolve all comments',
+            status: RequirementStatus.OK,
+          },
+        ],
+      })
+    );
+  });
+
+  test('show strategy for open change', () => {
+    element.change = {
+      ...createParsedChange(),
+      status: ChangeStatus.NEW,
+      submit_type: SubmitType.CHERRY_PICK,
+      labels: {},
+    };
+    flush();
+    const strategy = element.shadowRoot?.querySelector('.strategy');
+    assert.ok(strategy);
+    assert.isFalse(strategy?.hasAttribute('hidden'));
+    assert.equal(strategy?.children[1].innerHTML, 'Cherry Pick');
+  });
+
+  test('hide strategy for closed change', () => {
+    element.change = {
+      ...createParsedChange(),
+      status: ChangeStatus.MERGED,
+      labels: {},
+    };
+    flush();
+    assert.isTrue(
+      element.shadowRoot?.querySelector('.strategy')?.hasAttribute('hidden')
+    );
+  });
+
+  test('weblinks use GerritNav interface', () => {
+    const weblinksStub = sinon
+      .stub(GerritNav, '_generateWeblinks')
+      .returns([{name: 'stubb', url: '#s'}]);
+    element.commitInfo = createCommitInfoWithRequiredCommit();
+    element.serverConfig = createServerInfo();
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isTrue(weblinksStub.called);
+    assert.isFalse(webLinks.hasAttribute('hidden'));
+    assert.equal(element._computeWebLinks(element.commitInfo)?.length, 1);
+  });
+
+  test('weblinks hidden when no weblinks', () => {
+    element.commitInfo = createCommitInfoWithRequiredCommit();
+    element.serverConfig = createServerInfo();
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isTrue(webLinks.hasAttribute('hidden'));
+  });
+
+  test('weblinks hidden when only gitiles weblink', () => {
+    element.commitInfo = {
+      ...createCommitInfoWithRequiredCommit(),
+      web_links: [{...createWebLinkInfo(), name: 'gitiles', url: '#'}],
+    };
+    element.serverConfig = createServerInfo();
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isTrue(webLinks.hasAttribute('hidden'));
+    assert.equal(element._computeWebLinks(element.commitInfo), null);
+  });
+
+  test('weblinks hidden when sole weblink is set as primary', () => {
+    const browser = 'browser';
+    element.commitInfo = {
+      ...createCommitInfoWithRequiredCommit(),
+      web_links: [{...createWebLinkInfo(), name: browser, url: '#'}],
+    };
+    element.serverConfig = {
+      ...createServerInfo(),
+      gerrit: {
+        ...createGerritInfo(),
+        primary_weblink_name: browser,
+      },
+    };
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isTrue(webLinks.hasAttribute('hidden'));
+  });
+
+  test('weblinks are visible when other weblinks', () => {
+    const router = document.createElement('gr-router');
+    sinon
+      .stub(GerritNav, '_generateWeblinks')
+      .callsFake(router._generateWeblinks.bind(router));
+
+    element.commitInfo = {
+      ...createCommitInfoWithRequiredCommit(),
+      web_links: [{...createWebLinkInfo(), name: 'test', url: '#'}],
+    };
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isFalse(webLinks.hasAttribute('hidden'));
+    assert.equal(element._computeWebLinks(element.commitInfo)?.length, 1);
+    // With two non-gitiles weblinks, there are two returned.
+    element.commitInfo = {
+      ...createCommitInfoWithRequiredCommit(),
+      web_links: [
+        {...createWebLinkInfo(), name: 'test', url: '#'},
+        {...createWebLinkInfo(), name: 'test2', url: '#'},
+      ],
+    };
+    assert.equal(element._computeWebLinks(element.commitInfo)?.length, 2);
+  });
+
+  test('weblinks are visible when gitiles and other weblinks', () => {
+    const router = document.createElement('gr-router');
+    sinon
+      .stub(GerritNav, '_generateWeblinks')
+      .callsFake(router._generateWeblinks.bind(router));
+
+    element.commitInfo = {
+      ...createCommitInfoWithRequiredCommit(),
+      web_links: [
+        {...createWebLinkInfo(), name: 'test', url: '#'},
+        {...createWebLinkInfo(), name: 'gitiles', url: '#'},
+      ],
+    };
+    flush();
+    const webLinks = element.$.webLinks;
+    assert.isFalse(webLinks.hasAttribute('hidden'));
+    // Only the non-gitiles weblink is returned.
+    assert.equal(element._computeWebLinks(element.commitInfo)?.length, 1);
+  });
+
+  suite('_getNonOwnerRole', () => {
+    let change: ParsedChangeInfo | undefined;
+
+    setup(() => {
+      change = {
+        ...createParsedChange(),
+        owner: {
+          ...createAccountWithId(),
+          email: 'abc@def' as EmailAddress,
+          _account_id: 1019328 as AccountId,
+        },
+        revisions: {
+          rev1: {
+            ...createRevision(),
+            uploader: {
+              ...createAccountWithId(),
+              email: 'ghi@def' as EmailAddress,
+              _account_id: 1011123 as AccountId,
+            },
+            commit: {
+              ...createCommit(),
+              author: {...createGitPerson(), email: 'jkl@def'},
+              committer: {...createGitPerson(), email: 'ghi@def'},
+            },
+          },
+        },
+        current_revision: 'rev1' as CommitId,
+      };
+    });
+
+    suite('role=uploader', () => {
+      test('_getNonOwnerRole for uploader', () => {
+        assert.deepEqual(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.UPLOADER),
+          {
+            ...createAccountWithId(),
+            email: 'ghi@def' as EmailAddress,
+            _account_id: 1011123 as AccountId,
+          }
+        );
+      });
+
+      test('_getNonOwnerRole that it does not return uploader', () => {
+        // Set the uploader email to be the same as the owner.
+        change!.revisions.rev1.uploader!._account_id = 1019328 as AccountId;
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.UPLOADER)
+        );
+      });
+
+      test('_computeShowRoleClass show uploader', () => {
+        assert.equal(
+          element._computeShowRoleClass(change, element._CHANGE_ROLE.UPLOADER),
+          ''
+        );
+      });
+
+      test('_computeShowRoleClass hide uploader', () => {
+        // Set the uploader email to be the same as the owner.
+        change!.revisions.rev1.uploader!._account_id = 1019328 as AccountId;
+        assert.equal(
+          element._computeShowRoleClass(change, element._CHANGE_ROLE.UPLOADER),
+          'hideDisplay'
+        );
+      });
+    });
+
+    suite('role=committer', () => {
+      test('_getNonOwnerRole for committer', () => {
+        change!.revisions.rev1.uploader!.email = 'ghh@def' as EmailAddress;
+        assert.deepEqual(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.COMMITTER),
+          {...createGitPerson(), email: 'ghi@def'}
+        );
+      });
+
+      test('_getNonOwnerRole is null if committer is same as uploader', () => {
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.COMMITTER)
+        );
+      });
+
+      test('_getNonOwnerRole that it does not return committer', () => {
+        // Set the committer email to be the same as the owner.
+        change!.revisions.rev1.commit!.committer.email = 'abc@def';
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.COMMITTER)
+        );
+      });
+
+      test('_getNonOwnerRole null for committer with no commit', () => {
+        delete change!.revisions.rev1.commit;
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.COMMITTER)
+        );
+      });
+    });
+
+    suite('role=author', () => {
+      test('_getNonOwnerRole for author', () => {
+        assert.deepEqual(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.AUTHOR),
+          {...createGitPerson(), email: 'jkl@def'}
+        );
+      });
+
+      test('_getNonOwnerRole that it does not return author', () => {
+        // Set the author email to be the same as the owner.
+        change!.revisions.rev1.commit!.author.email = 'abc@def';
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.AUTHOR)
+        );
+      });
+
+      test('_getNonOwnerRole null for author with no commit', () => {
+        delete change!.revisions.rev1.commit;
+        assert.isNotOk(
+          element._getNonOwnerRole(change, element._CHANGE_ROLE.AUTHOR)
+        );
+      });
+    });
+  });
+
+  suite('Push Certificate Validation', () => {
+    let serverConfig: ServerInfo | undefined;
+    let change: ParsedChangeInfo | undefined;
+
+    setup(() => {
+      serverConfig = {
+        ...createServerInfo(),
+        receive: {
+          enable_signed_push: 'true',
+        },
+      };
+      change = {
+        ...createParsedChange(),
+        revisions: {
+          rev1: {
+            ...createRevision(1),
+            push_certificate: {
+              certificate: 'Push certificate',
+              key: {
+                status: GpgKeyInfoStatus.BAD,
+                problems: ['No public keys found for key ID E5E20E52'],
+              },
+            },
+          },
+        },
+        current_revision: 'rev1' as CommitId,
+        status: ChangeStatus.NEW,
+        labels: {},
+        mergeable: true,
+      };
+    });
+
+    test('Push Certificate Validation test BAD', () => {
+      change!.revisions.rev1!.push_certificate = {
+        certificate: 'Push certificate',
+        key: {
+          status: GpgKeyInfoStatus.BAD,
+          problems: ['No public keys found for key ID E5E20E52'],
+        },
+      };
+      const result = element._computePushCertificateValidation(
+        serverConfig,
+        change
+      );
+      assert.equal(
+        result?.message,
+        'Push certificate is invalid:\n' +
+          'No public keys found for key ID E5E20E52'
+      );
+      assert.equal(result?.icon, 'gr-icons:close');
+      assert.equal(result?.class, 'invalid');
+    });
+
+    test('Push Certificate Validation test TRUSTED', () => {
+      change!.revisions.rev1!.push_certificate = {
+        certificate: 'Push certificate',
+        key: {
+          status: GpgKeyInfoStatus.TRUSTED,
+        },
+      };
+      const result = element._computePushCertificateValidation(
+        serverConfig,
+        change
+      );
+      assert.equal(
+        result?.message,
+        'Push certificate is valid and key is trusted'
+      );
+      assert.equal(result?.icon, 'gr-icons:check');
+      assert.equal(result?.class, 'trusted');
+    });
+
+    test('Push Certificate Validation is missing test', () => {
+      change!.revisions.rev1! = createRevision(1);
+      const result = element._computePushCertificateValidation(
+        serverConfig,
+        change
+      );
+      assert.equal(
+        result?.message,
+        'This patch set was created without a push certificate'
+      );
+      assert.equal(result?.icon, 'gr-icons:help');
+      assert.equal(result?.class, 'help');
+    });
+  });
+
+  test('_computeParents', () => {
+    const parents: ParentCommitInfo[] = [
+      {...createCommit(), commit: '123' as CommitId, subject: 'abc'},
+    ];
+    const revision: RevisionInfo = {
+      ...createRevision(1),
+      commit: {...createCommit(), parents},
+    };
+    assert.equal(element._computeParents(undefined, revision), parents);
+    const change = (current_revision: CommitId): ParsedChangeInfo => {
+      return {
+        ...createParsedChange(),
+        current_revision,
+        revisions: {456: revision},
+      };
+    };
+    const change_bad_revision = change('789' as CommitId);
+    assert.deepEqual(
+      element._computeParents(change_bad_revision, createRevision()),
+      []
+    );
+    const change_no_commit: ParsedChangeInfo = {
+      ...createParsedChange(),
+      current_revision: '456' as CommitId,
+      revisions: {456: createRevision()},
+    };
+    assert.deepEqual(element._computeParents(change_no_commit, undefined), []);
+    const change_good = change('456' as CommitId);
+    assert.equal(element._computeParents(change_good, undefined), parents);
+  });
+
+  test('_currentParents', () => {
+    const revision = (parent: CommitId): RevisionInfo => {
+      return {
+        ...createRevision(),
+        commit: {
+          ...createCommit(),
+          parents: [{...createCommit(), commit: parent, subject: 'abc'}],
+        },
+      };
+    };
+    element.change = {
+      ...createParsedChange(),
+      current_revision: '456' as CommitId,
+      revisions: {456: revision('111' as CommitId)},
+      owner: {},
+    };
+    element.revision = revision('222' as CommitId);
+    assert.equal(element._currentParents[0].commit, '222');
+    element.revision = revision('333' as CommitId);
+    assert.equal(element._currentParents[0].commit, '333');
+    element.revision = undefined;
+    assert.equal(element._currentParents[0].commit, '111');
+    element.change = createParsedChange();
+    assert.deepEqual(element._currentParents, []);
+  });
+
+  test('_computeParentsLabel', () => {
+    const parent: ParentCommitInfo = {
+      ...createCommit(),
+      commit: 'abc123' as CommitId,
+      subject: 'My parent commit',
+    };
+    assert.equal(element._computeParentsLabel([parent]), 'Parent');
+    assert.equal(element._computeParentsLabel([parent, parent]), 'Parents');
+  });
+
+  test('_computeParentListClass', () => {
+    const parent: ParentCommitInfo = {
+      ...createCommit(),
+      commit: 'abc123' as CommitId,
+      subject: 'My parent commit',
+    };
+    assert.equal(
+      element._computeParentListClass([parent], true),
+      'parentList nonMerge current'
+    );
+    assert.equal(
+      element._computeParentListClass([parent], false),
+      'parentList nonMerge notCurrent'
+    );
+    assert.equal(
+      element._computeParentListClass([parent, parent], false),
+      'parentList merge notCurrent'
+    );
+    assert.equal(
+      element._computeParentListClass([parent, parent], true),
+      'parentList merge current'
+    );
+  });
+
+  test('_showAddTopic', () => {
+    const changeRecord: ElementPropertyDeepChange<
+      GrChangeMetadata,
+      'change'
+    > = {
+      base: {...createParsedChange()},
+      path: '',
+      value: undefined,
+    };
+    assert.isTrue(element._showAddTopic(undefined, false));
+    assert.isTrue(element._showAddTopic(changeRecord, false));
+    assert.isFalse(element._showAddTopic(changeRecord, true));
+    changeRecord.base!.topic = 'foo' as TopicName;
+    assert.isFalse(element._showAddTopic(changeRecord, true));
+    assert.isFalse(element._showAddTopic(changeRecord, false));
+  });
+
+  test('_showTopicChip', () => {
+    const changeRecord: ElementPropertyDeepChange<
+      GrChangeMetadata,
+      'change'
+    > = {
+      base: {...createParsedChange()},
+      path: '',
+      value: undefined,
+    };
+    assert.isFalse(element._showTopicChip(undefined, false));
+    assert.isFalse(element._showTopicChip(changeRecord, false));
+    assert.isFalse(element._showTopicChip(changeRecord, true));
+    changeRecord.base!.topic = 'foo' as TopicName;
+    assert.isFalse(element._showTopicChip(changeRecord, true));
+    assert.isTrue(element._showTopicChip(changeRecord, false));
+  });
+
+  test('_showCherryPickOf', () => {
+    const changeRecord: ElementPropertyDeepChange<
+      GrChangeMetadata,
+      'change'
+    > = {
+      base: {...createParsedChange()},
+      path: '',
+      value: undefined,
+    };
+    assert.isFalse(element._showCherryPickOf(undefined));
+    assert.isFalse(element._showCherryPickOf(changeRecord));
+    changeRecord.base!.cherry_pick_of_change = 123 as NumericChangeId;
+    changeRecord.base!.cherry_pick_of_patch_set = 1 as PatchSetNum;
+    assert.isTrue(element._showCherryPickOf(changeRecord));
+  });
+
+  suite('Topic removal', () => {
+    let change: ParsedChangeInfo;
+    setup(() => {
+      change = {
+        ...createParsedChange(),
+        actions: {
+          topic: {enabled: false},
+        },
+        topic: 'the topic' as TopicName,
+        status: ChangeStatus.NEW,
+        submit_type: SubmitType.CHERRY_PICK,
+        labels: {
+          test: {
+            all: [{_account_id: 1 as AccountId, name: 'bojack', value: 1}],
+            default_value: 0,
+            values: ([] as unknown) as LabelValueToDescriptionMap,
+          },
+        },
+        removable_reviewers: [],
+      };
+    });
+
+    test('_computeTopicReadOnly', () => {
+      let mutable = false;
+      assert.isTrue(element._computeTopicReadOnly(mutable, change));
+      mutable = true;
+      assert.isTrue(element._computeTopicReadOnly(mutable, change));
+      change!.actions!.topic!.enabled = true;
+      assert.isFalse(element._computeTopicReadOnly(mutable, change));
+      mutable = false;
+      assert.isTrue(element._computeTopicReadOnly(mutable, change));
+    });
+
+    test('topic read only hides delete button', () => {
+      element.account = createAccountDetailWithId();
+      element.change = change;
+      flush();
+      const button = element!
+        .shadowRoot!.querySelector('gr-linked-chip')!
+        .shadowRoot!.querySelector('gr-button');
+      assert.isTrue(button?.hasAttribute('hidden'));
+    });
+
+    test('topic not read only does not hide delete button', () => {
+      element.account = createAccountDetailWithId();
+      change.actions!.topic!.enabled = true;
+      element.change = change;
+      flush();
+      const button = element!
+        .shadowRoot!.querySelector('gr-linked-chip')!
+        .shadowRoot!.querySelector('gr-button');
+      assert.isFalse(button?.hasAttribute('hidden'));
+    });
+  });
+
+  suite('Hashtag removal', () => {
+    let change: ParsedChangeInfo;
+    setup(() => {
+      change = {
+        ...createParsedChange(),
+        actions: {
+          hashtags: {enabled: false},
+        },
+        hashtags: ['test-hashtag' as Hashtag],
+        labels: {
+          test: {
+            all: [{_account_id: 1 as AccountId, name: 'bojack', value: 1}],
+            default_value: 0,
+            values: ([] as unknown) as LabelValueToDescriptionMap,
+          },
+        },
+        removable_reviewers: [],
+      };
+    });
+
+    test('_computeHashtagReadOnly', () => {
+      flush();
+      let mutable = false;
+      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
+      mutable = true;
+      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
+      change!.actions!.hashtags!.enabled = true;
+      assert.isFalse(element._computeHashtagReadOnly(mutable, change));
+      mutable = false;
+      assert.isTrue(element._computeHashtagReadOnly(mutable, change));
+    });
+
+    test('hashtag read only hides delete button', () => {
+      flush();
+      element.account = createAccountDetailWithId();
+      element.change = change;
+      flush();
+      const button = element!
+        .shadowRoot!.querySelector('gr-linked-chip')!
+        .shadowRoot!.querySelector('gr-button');
+      assert.isTrue(button?.hasAttribute('hidden'));
+    });
+
+    test('hashtag not read only does not hide delete button', () => {
+      flush();
+      element.account = createAccountDetailWithId();
+      change!.actions!.hashtags!.enabled = true;
+      element.change = change;
+      flush();
+      const button = element!
+        .shadowRoot!.querySelector('gr-linked-chip')!
+        .shadowRoot!.querySelector('gr-button');
+      assert.isFalse(button?.hasAttribute('hidden'));
+    });
+  });
+
+  suite('remove reviewer votes', () => {
+    setup(() => {
+      sinon.stub(element, '_computeTopicReadOnly').returns(true);
+      element.change = {
+        ...createParsedChange(),
+        topic: 'the topic' as TopicName,
+        labels: {
+          test: {
+            all: [{_account_id: 1 as AccountId, name: 'bojack', value: 1}],
+            default_value: 0,
+            values: ([] as unknown) as LabelValueToDescriptionMap,
+          },
+        },
+        removable_reviewers: [],
+      };
+      flush();
+    });
+
+    suite('assignee field', () => {
+      const dummyAccount = createAccountWithId();
+      const change: ParsedChangeInfo = {
+        ...createParsedChange(),
+        actions: {
+          assignee: {enabled: false},
+        },
+        assignee: dummyAccount,
+      };
+      let deleteStub: SinonStubbedMember<RestApiService['deleteAssignee']>;
+      let setStub: SinonStubbedMember<RestApiService['setAssignee']>;
+
+      setup(() => {
+        deleteStub = sinon.stub(element.restApiService, 'deleteAssignee');
+        setStub = sinon.stub(element.restApiService, 'setAssignee');
+        element.serverConfig = {
+          ...createServerInfo(),
+          change: {
+            ...createChangeConfig(),
+            enable_assignee: true,
+          },
+        };
+      });
+
+      test('changing change recomputes _assignee', () => {
+        assert.isFalse(!!element._assignee?.length);
+        const change = element.change;
+        change!.assignee = dummyAccount;
+        element._changeChanged(change);
+        assert.deepEqual(element?._assignee?.[0], dummyAccount);
+      });
+
+      test('modifying _assignee calls API', () => {
+        assert.isFalse(!!element._assignee?.length);
+        element.set('_assignee', [dummyAccount]);
+        assert.isTrue(setStub.calledOnce);
+        assert.deepEqual(element.change!.assignee, dummyAccount);
+        element.set('_assignee', [dummyAccount]);
+        assert.isTrue(setStub.calledOnce);
+        element.set('_assignee', []);
+        assert.isTrue(deleteStub.calledOnce);
+        assert.equal(element.change!.assignee, undefined);
+        element.set('_assignee', []);
+        assert.isTrue(deleteStub.calledOnce);
+      });
+
+      test('_computeAssigneeReadOnly', () => {
+        let mutable = false;
+        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
+        mutable = true;
+        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
+        change.actions!.assignee!.enabled = true;
+        assert.isFalse(element._computeAssigneeReadOnly(mutable, change));
+        mutable = false;
+        assert.isTrue(element._computeAssigneeReadOnly(mutable, change));
+      });
+    });
+
+    test('changing topic', () => {
+      const newTopic = 'the new topic' as TopicName;
+      const setChangeTopicStub = sinon
+        .stub(element.restApiService, 'setChangeTopic')
+        .returns(Promise.resolve(newTopic));
+      element._handleTopicChanged(new CustomEvent('test', {detail: newTopic}));
+      const topicChangedSpy = sinon.spy();
+      element.addEventListener('topic-changed', topicChangedSpy);
+      assert.isTrue(
+        setChangeTopicStub.calledWith(42 as NumericChangeId, newTopic)
+      );
+      return setChangeTopicStub.lastCall.returnValue.then(() => {
+        assert.equal(element.change!.topic, newTopic);
+        assert.isTrue(topicChangedSpy.called);
+      });
+    });
+
+    test('topic removal', () => {
+      const newTopic = 'the new topic' as TopicName;
+      const setChangeTopicStub = sinon
+        .stub(element.restApiService, 'setChangeTopic')
+        .returns(Promise.resolve(newTopic));
+      const chip = element.shadowRoot!.querySelector('gr-linked-chip');
+      const remove = chip!.$.remove;
+      const topicChangedSpy = sinon.spy();
+      element.addEventListener('topic-changed', topicChangedSpy);
+      tap(remove);
+      assert.isTrue(chip?.disabled);
+      assert.isTrue(setChangeTopicStub.calledWith(42 as NumericChangeId));
+      return setChangeTopicStub.lastCall.returnValue.then(() => {
+        assert.isFalse(chip?.disabled);
+        assert.equal(element.change!.topic, '' as TopicName);
+        assert.isTrue(topicChangedSpy.called);
+      });
+    });
+
+    test('changing hashtag', () => {
+      flush();
+      element._newHashtag = 'new hashtag' as Hashtag;
+      const newHashtag: Hashtag[] = ['new hashtag' as Hashtag];
+      const setChangeHashtagStub = sinon
+        .stub(element.restApiService, 'setChangeHashtag')
+        .returns(Promise.resolve(newHashtag));
+      element._handleHashtagChanged();
+      assert.isTrue(
+        setChangeHashtagStub.calledWith(42 as NumericChangeId, {
+          add: ['new hashtag' as Hashtag],
+        })
+      );
+      return setChangeHashtagStub.lastCall.returnValue.then(() => {
+        assert.equal(element.change!.hashtags, newHashtag);
+      });
+    });
+  });
+
+  test('editTopic', () => {
+    element.account = createAccountDetailWithId();
+    element.change = {
+      ...createParsedChange(),
+      actions: {topic: {enabled: true}},
+    };
+    flush();
+
+    const label = element.shadowRoot!.querySelector(
+      '.topicEditableLabel'
+    ) as GrEditableLabel;
+    assert.ok(label);
+    const openStub = sinon.stub(label, 'open');
+    element.editTopic();
+    flush();
+
+    assert.isTrue(openStub.called);
+  });
+
+  suite('plugin endpoints', () => {
+    test('endpoint params', done => {
+      element.change = createParsedChange();
+      element.revision = createRevision();
+      interface MetadataGrEndpointDecorator extends GrEndpointDecorator {
+        plugin: PluginApi;
+        change: ParsedChangeInfo;
+        revision: RevisionInfo;
+      }
+      let hookEl: MetadataGrEndpointDecorator;
+      let plugin: PluginApi;
+      pluginApi.install(
+        p => {
+          plugin = p;
+          plugin
+            .hook('change-metadata-item')
+            .getLastAttached()
+            .then(el => (hookEl = el as MetadataGrEndpointDecorator));
+        },
+        '0.1',
+        'http://some/plugins/url.html'
+      );
+      getPluginLoader().loadPlugins([]);
+      flush(() => {
+        assert.strictEqual(hookEl!.plugin, plugin);
+        assert.strictEqual(hookEl!.change, element.change);
+        assert.strictEqual(hookEl!.revision, element.revision);
+        done();
+      });
+    });
+  });
+});
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index 8504df4..126d017 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -28,7 +28,6 @@
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import '../../shared/gr-linked-text/gr-linked-text';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-tooltip-content/gr-tooltip-content';
 import '../gr-change-actions/gr-change-actions';
 import '../gr-change-metadata/gr-change-metadata';
@@ -43,6 +42,7 @@
 import '../gr-reply-dialog/gr-reply-dialog';
 import '../gr-thread-list/gr-thread-list';
 import '../gr-upload-help-dialog/gr-upload-help-dialog';
+import '../../checks/gr-checks-tab';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -53,9 +53,9 @@
   Shortcut,
 } from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 import {GrEditConstants} from '../../edit/gr-edit-constants';
-import {GrCountStringFormatter} from '../../shared/gr-count-string-formatter/gr-count-string-formatter';
+import {pluralize} from '../../../utils/string-util';
 import {getComputedStyleValue} from '../../../utils/dom-util';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {getPluginEndpoints} from '../../shared/gr-js-api-interface/gr-plugin-endpoints';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {RevisionInfo as RevisionInfoClass} from '../../shared/revision-info/revision-info';
@@ -69,13 +69,11 @@
   fetchChangeUpdates,
   hasEditBasedOnCurrentPatchSet,
   hasEditPatchsetLoaded,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {changeStatuses, changeStatusString} from '../../../utils/change-util';
-import {EventType} from '../../plugins/gr-plugin-types';
+import {EventType as PluginEventType} from '../../plugins/gr-plugin-types';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrJsApiInterface} from '../../shared/gr-js-api-interface/gr-js-api-interface-element';
 import {GrApplyFixDialog} from '../../diff/gr-apply-fix-dialog/gr-apply-fix-dialog';
 import {GrFileListHeader} from '../gr-file-list-header/gr-file-list-header';
@@ -98,7 +96,6 @@
   ConfigInfo,
   PreferencesInfo,
   CommitInfo,
-  DiffPreferencesInfo,
   RevisionInfo,
   EditInfo,
   LabelNameToInfoMap,
@@ -107,6 +104,7 @@
   ApprovalInfo,
   ElementPropertyDeepChange,
 } from '../../../types/common';
+import {DiffPreferencesInfo} from '../../../types/diff';
 import {GrReplyDialog, FocusTarget} from '../gr-reply-dialog/gr-reply-dialog';
 import {GrIncludedInDialog} from '../gr-included-in-dialog/gr-included-in-dialog';
 import {GrDownloadDialog} from '../gr-download-dialog/gr-download-dialog';
@@ -145,12 +143,16 @@
   CustomKeyboardEvent,
   EditableContentSaveEvent,
   OpenFixPreviewEvent,
-  ShowAlertEventDetail,
   SwitchTabEvent,
+  ThreadListModifiedEvent,
 } from '../../../types/events';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrMessagesList} from '../gr-messages-list/gr-messages-list';
 import {GrThreadList} from '../gr-thread-list/gr-thread-list';
+import {fireAlert, fireEvent, firePageError} from '../../../utils/event-util';
+import {KnownExperimentId} from '../../../services/flags/flags';
+import {fireTitleChange} from '../../../utils/event-util';
+import {GerritView} from '../../../services/router/router-model';
 
 const CHANGE_ID_ERROR = {
   MISMATCH: 'mismatch',
@@ -201,7 +203,6 @@
 
 export interface GrChangeView {
   $: {
-    restAPI: RestApiService & Element;
     jsAPI: GrJsApiInterface;
     commentAPI: GrCommentApi;
     applyFixDialog: GrApplyFixDialog;
@@ -261,6 +262,8 @@
 
   reporting = appContext.reportingService;
 
+  flagsService = appContext.flagsService;
+
   /**
    * URL params passed from the router.
    */
@@ -530,6 +533,10 @@
 
   _throttledToggleChangeStar?: EventListener;
 
+  _isChecksEnabled = false;
+
+  restApiService = appContext.restApiService;
+
   keyboardShortcuts() {
     return {
       [Shortcut.SEND_REPLY]: null, // DOC_ONLY binding
@@ -554,6 +561,14 @@
   }
 
   /** @override */
+  ready() {
+    super.ready();
+    this._isChecksEnabled = this.flagsService.isEnabled(
+      KnownExperimentId.CI_REBOOT_CHECKS
+    );
+  }
+
+  /** @override */
   connectedCallback() {
     super.connectedCallback();
     this._throttledToggleChangeStar = this._throttleWrap(e =>
@@ -585,6 +600,11 @@
       this._handleReloadCommentThreads()
     );
 
+    this.addEventListener(
+      'thread-list-modified',
+      (e: ThreadListModifiedEvent) => this._handleReloadDiffComments(e)
+    );
+
     this.addEventListener('open-reply-dialog', () => this._openReplyDialog());
   }
 
@@ -599,7 +619,7 @@
     this._getLoggedIn().then(loggedIn => {
       this._loggedIn = loggedIn;
       if (loggedIn) {
-        this.$.restAPI.getAccount().then(acct => {
+        this.restApiService.getAccount().then(acct => {
           this._account = acct;
         });
       }
@@ -831,7 +851,7 @@
     this.$.jsAPI.handleCommitMessage(this._change, message);
 
     this.$.commitMessageEditor.disabled = true;
-    this.$.restAPI
+    this.restApiService
       .putChangeCommitMessage(this._changeNum, message)
       .then(resp => {
         this.$.commitMessageEditor.disabled = false;
@@ -918,8 +938,7 @@
     const commentCount = this._robotCommentCountPerPatchSet(commentThreads);
     const commentCnt = commentCount[patch._number] || 0;
     if (commentCnt === 0) return `Patchset ${patch._number}`;
-    const findingsText = commentCnt === 1 ? 'finding' : 'findings';
-    return `Patchset ${patch._number} (${commentCnt} ${findingsText})`;
+    return `Patchset ${patch._number} (${pluralize(commentCnt, 'finding')})`;
   }
 
   _computeRobotCommentsPatchSetDropdownItems(
@@ -1008,14 +1027,9 @@
   ) {
     if (!changeComments) return undefined;
     const draftCount = changeComments.computeDraftCount();
-    const unresolvedString = GrCountStringFormatter.computeString(
-      unresolvedCount,
-      'unresolved'
-    );
-    const draftString = GrCountStringFormatter.computePluralString(
-      draftCount,
-      'draft'
-    );
+    const unresolvedString =
+      unresolvedCount === 0 ? '' : `${unresolvedCount} unresolved`;
+    const draftString = pluralize(draftCount, 'draft');
 
     return (
       unresolvedString +
@@ -1226,7 +1240,7 @@
     }
 
     if (value.changeNum && value.project) {
-      this.$.restAPI.setInProjectLookup(value.changeNum, value.project);
+      this.restApiService.setInProjectLookup(value.changeNum, value.project);
     }
 
     const patchChanged =
@@ -1296,7 +1310,7 @@
   _sendShowChangeEvent() {
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    this.$.jsAPI.handleEvent(EventType.SHOW_CHANGE, {
+    this.$.jsAPI.handleEvent(PluginEventType.SHOW_CHANGE, {
       change: this._change,
       patchNum: this._patchRange.patchNum,
       info: {mergeable: this._mergeable},
@@ -1473,13 +1487,7 @@
     this.set('_patchRange.basePatchNum', parent);
 
     const title = change.subject + ' (' + change.change_id.substr(0, 9) + ')';
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, title);
   }
 
   /**
@@ -1613,12 +1621,7 @@
     }
     this._getLoggedIn().then(isLoggedIn => {
       if (!isLoggedIn) {
-        this.dispatchEvent(
-          new CustomEvent('show-auth-required', {
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireEvent(this, 'show-auth-required');
         return;
       }
 
@@ -1652,16 +1655,8 @@
     if (!this._change) throw new Error('missing required change property');
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Base is already selected.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
+      fireAlert(this, 'Base is already selected.');
       return;
     }
     GerritNav.navigateToChange(this._change, this._patchRange.patchNum);
@@ -1674,16 +1669,8 @@
     if (!this._change) throw new Error('missing required change property');
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Left is already base.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
+      fireAlert(this, 'Left is already base.');
       return;
     }
     GerritNav.navigateToChange(this._change, this._patchRange.basePatchNum);
@@ -1697,17 +1684,8 @@
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
-      const detail: ShowAlertEventDetail = {
-        message: 'Latest is already selected.',
-      };
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail,
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.patchNum === latestPatchNum) {
+      fireAlert(this, 'Latest is already selected.');
       return;
     }
     GerritNav.navigateToChange(
@@ -1725,16 +1703,8 @@
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Right is already latest.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.patchNum === latestPatchNum) {
+      fireAlert(this, 'Right is already latest.');
       return;
     }
     GerritNav.navigateToChange(
@@ -1753,18 +1723,10 @@
       throw new Error('missing required _patchRange property');
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (
-      patchNumEquals(this._patchRange.patchNum, latestPatchNum) &&
-      patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)
+      this._patchRange.patchNum === latestPatchNum &&
+      this._patchRange.basePatchNum === ParentPatchSetNum
     ) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Already diffing base against latest.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'Already diffing base against latest.');
       return;
     }
     GerritNav.navigateToChange(this._change, latestPatchNum);
@@ -1872,7 +1834,7 @@
         changeRecord.path
       );
     }
-    this.$.jsAPI.handleEvent(EventType.LABEL_CHANGE, {
+    this.$.jsAPI.handleEvent(PluginEventType.LABEL_CHANGE, {
       change: this._change,
     });
   }
@@ -1888,26 +1850,20 @@
   }
 
   _handleGetChangeDetailError(response?: Response | null) {
-    this.dispatchEvent(
-      new CustomEvent('page-error', {
-        detail: {response},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    firePageError(this, response);
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _getServerConfig() {
-    return this.$.restAPI.getConfig();
+    return this.restApiService.getConfig();
   }
 
   _getProjectConfig() {
     if (!this._change) throw new Error('missing required change property');
-    return this.$.restAPI
+    return this.restApiService
       .getProjectConfig(this._change.project)
       .then(config => {
         this._projectConfig = config;
@@ -1915,7 +1871,7 @@
   }
 
   _getPreferences() {
-    return this.$.restAPI.getPreferences();
+    return this.restApiService.getPreferences();
   }
 
   _prepareCommitMsgForLinkify(msg: string) {
@@ -1965,8 +1921,9 @@
   _getChangeDetail() {
     if (!this._changeNum)
       throw new Error('missing required changeNum property');
-    const detailCompletes = this.$.restAPI.getChangeDetail(this._changeNum, r =>
-      this._handleGetChangeDetailError(r)
+    const detailCompletes = this.restApiService.getChangeDetail(
+      this._changeNum,
+      r => this._handleGetChangeDetailError(r)
     );
     const editCompletes = this._getEdit();
     const prefCompletes = this._getPreferences();
@@ -2009,7 +1966,7 @@
         if (
           !this._patchRange ||
           !this._patchRange.patchNum ||
-          patchNumEquals(this._patchRange.patchNum, currentRevision._number)
+          this._patchRange.patchNum === currentRevision._number
         ) {
           // CommitInfo.commit is optional, and may need patching.
           if (currentRevision.commit && !currentRevision.commit.commit) {
@@ -2055,7 +2012,7 @@
   _getEdit() {
     if (!this._changeNum)
       return Promise.reject(new Error('missing required changeNum property'));
-    return this.$.restAPI.getChangeEdit(this._changeNum, true);
+    return this.restApiService.getChangeEdit(this._changeNum, true);
   }
 
   _getLatestCommitMessage() {
@@ -2064,7 +2021,7 @@
     const lastpatchNum = computeLatestPatchNum(this._allPatchSets);
     if (lastpatchNum === undefined)
       throw new Error('missing lastPatchNum property');
-    return this.$.restAPI
+    return this.restApiService
       .getChangeCommitInfo(this._changeNum, lastpatchNum)
       .then(commitInfo => {
         if (!commitInfo) return;
@@ -2102,7 +2059,7 @@
       throw new Error('missing required _patchRange property');
     if (this._patchRange.patchNum === undefined)
       throw new Error('missing required patchNum property');
-    return this.$.restAPI
+    return this.restApiService
       .getChangeCommitInfo(this._changeNum, this._patchRange.patchNum)
       .then(commitInfo => {
         this._commitInfo = commitInfo;
@@ -2127,9 +2084,12 @@
     this._robotCommentThreads = undefined;
     if (!this._changeNum)
       throw new Error('missing required changeNum property');
+
     return this.$.commentAPI
-      .loadAll(this._changeNum)
-      .then(comments => this._recomputeComments(comments));
+      .loadAll(this._changeNum, this._patchRange?.patchNum)
+      .then(comments => {
+        this._recomputeComments(comments);
+      });
   }
 
   /**
@@ -2201,12 +2161,7 @@
     const loadingFlagSet = detailCompletes
       .then(() => {
         this._loading = false;
-        this.dispatchEvent(
-          new CustomEvent('change-details-loaded', {
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireEvent(this, 'change-details-loaded');
       })
       .then(() => {
         this.reporting.timeEnd(CHANGE_RELOAD_TIMING_LABEL);
@@ -2329,11 +2284,13 @@
     }
 
     this._mergeable = null;
-    return this.$.restAPI.getMergeable(this._changeNum).then(mergableInfo => {
-      if (mergableInfo) {
-        this._mergeable = mergableInfo.mergeable;
-      }
-    });
+    return this.restApiService
+      .getMergeable(this._changeNum)
+      .then(mergableInfo => {
+        if (mergableInfo) {
+          this._mergeable = mergableInfo.mergeable;
+        }
+      });
   }
 
   _computeCanStartReview(change: ChangeInfo) {
@@ -2516,7 +2473,7 @@
     this._updateCheckTimerHandle = this.async(() => {
       if (!this._change) throw new Error('missing required change property');
       const change = this._change;
-      fetchChangeUpdates(change, this.$.restAPI).then(result => {
+      fetchChangeUpdates(change, this.restApiService).then(result => {
         let toastMessage = null;
         if (!result.isLatest) {
           toastMessage = ReloadToastMessage.NEWER_REVISION;
@@ -2609,7 +2566,7 @@
     }
 
     const patchRange = patchRangeRecord.base || {};
-    return patchNumEquals(patchRange.patchNum, EditPatchSetNum);
+    return patchRange.patchNum === EditPatchSetNum;
   }
 
   _handleFileActionTap(e: CustomEvent<{path: string; action: string}>) {
@@ -2693,10 +2650,7 @@
       throw new Error('missing required _patchRange property');
     let patchNum;
     if (
-      !patchNumEquals(
-        this._patchRange.patchNum,
-        computeLatestPatchNum(this._allPatchSets)
-      )
+      !(this._patchRange.patchNum === computeLatestPatchNum(this._allPatchSets))
     ) {
       patchNum = this._patchRange.patchNum;
     }
@@ -2715,7 +2669,10 @@
   }
 
   _handleToggleStar(e: CustomEvent<{change: ChangeInfo; starred: boolean}>) {
-    this.$.restAPI.saveChangeStarred(e.detail.change._number, e.detail.starred);
+    this.restApiService.saveChangeStarred(
+      e.detail.change._number,
+      e.detail.starred
+    );
   }
 
   _getRevisionInfo(change: ChangeInfo | ParsedChangeInfo) {
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
index efc86bc..4fcc9fe 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
@@ -405,6 +405,7 @@
             has-parent="[[hasParent]]"
             actions="[[_change.actions]]"
             revision-actions="{{_currentRevisionActions}}"
+            account="[[_account]]"
             change-num="[[_changeNum]]"
             change-status="[[_change.status]]"
             commit-num="[[_commitInfo.commit]]"
@@ -558,6 +559,11 @@
           <span>Comments</span></gr-tooltip-content
         >
       </paper-tab>
+      <template is="dom-if" if="[[_isChecksEnabled]]">
+        <paper-tab data-name$="[[_constants.PrimaryTab.CHECKS]]"
+          >Checks</paper-tab
+        >
+      </template>
       <template
         is="dom-repeat"
         items="[[_dynamicTabHeaderEndpoints]]"
@@ -617,9 +623,7 @@
           change-num="[[_changeNum]]"
           patch-range="{{_patchRange}}"
           change-comments="[[_changeComments]]"
-          drafts="[[_diffDrafts]]"
           revisions="[[_change.revisions]]"
-          project-config="[[_projectConfig]]"
           selected-index="{{viewState.selectedFileIndex}}"
           diff-view-mode="[[viewState.diffMode]]"
           edit-mode="[[_editMode]]"
@@ -642,12 +646,17 @@
           change-num="[[_changeNum]]"
           logged-in="[[_loggedIn]]"
           only-show-robot-comments-with-human-reply=""
-          on-thread-list-modified="_handleReloadDiffComments"
           unresolved-only
         ></gr-thread-list>
       </template>
       <template
         is="dom-if"
+        if="[[_isTabActive(_constants.PrimaryTab.CHECKS, _activeTabs)]]"
+      >
+        <gr-checks-tab id="checksTab"></gr-checks-tab>
+      </template>
+      <template
+        is="dom-if"
         if="[[_isTabActive(_constants.PrimaryTab.FINDINGS, _activeTabs)]]"
       >
         <gr-dropdown-list
@@ -664,7 +673,6 @@
           logged-in="[[_loggedIn]]"
           hide-toggle-buttons
           empty-thread-msg="[[_messages.NO_ROBOT_COMMENTS_THREADS_MSG]]"
-          on-thread-list-modified="_handleReloadDiffComments"
         >
         </gr-thread-list>
         <template is="dom-if" if="[[_showRobotCommentsButton]]">
@@ -782,6 +790,5 @@
     </gr-reply-dialog>
   </gr-overlay>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-comment-api id="commentAPI"></gr-comment-api>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
index 8d06a03..5cb84b4 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
@@ -30,7 +30,7 @@
 import {GrEditConstants} from '../../edit/gr-edit-constants';
 import {_testOnly_resetEndpoints} from '../../shared/gr-js-api-interface/gr-plugin-endpoints';
 import {getComputedStyleValue} from '../../../utils/dom-util';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {_testOnly_initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit';
 import {EventType, PluginApi} from '../../plugins/gr-plugin-types';
@@ -102,6 +102,7 @@
 import 'lodash/lodash';
 import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
 import {ChangeComments} from '../../diff/gr-comment-api/gr-comment-api';
+import {GerritView} from '../../../services/router/router-model';
 
 const pluginApi = _testOnly_initGerritPluginApi();
 const fixture = fixtureFromElement('gr-change-view');
@@ -144,7 +145,7 @@
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -159,7 +160,7 @@
           unresolved: true,
         },
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -190,11 +191,12 @@
       path: '/COMMIT_MSG',
       line: 5,
       rootId: 'ecf0b9fa_fe1a5f62' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -209,7 +211,7 @@
           unresolved: true,
         },
         {
-          __path: 'test.txt',
+          path: 'test.txt',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -231,7 +233,7 @@
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -249,11 +251,12 @@
       path: '/COMMIT_MSG',
       line: 4,
       rootId: '8caddf38_44770ec1' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -271,6 +274,7 @@
       path: '/COMMIT_MSG',
       line: 4,
       rootId: 'scaddf38_44770ec1' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
     {
       comments: [
@@ -291,11 +295,12 @@
       path: '/COMMIT_MSG',
       line: 6,
       rootId: 'zcf0b9fa_fe1a5f62' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -314,11 +319,12 @@
       path: '/COMMIT_MSG',
       line: 5,
       rootId: 'rc1' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
     {
       comments: [
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -333,7 +339,7 @@
           robot_id: 'rc2' as RobotId,
         },
         {
-          __path: '/COMMIT_MSG',
+          path: '/COMMIT_MSG',
           author: {
             _account_id: 1000000 as AccountId,
             name: 'user',
@@ -351,6 +357,7 @@
       path: '/COMMIT_MSG',
       line: 5,
       rootId: 'rc2' as UrlEncodedCommentId,
+      commentSide: CommentSide.REVISION,
     },
   ];
 
@@ -698,7 +705,7 @@
         messages: createChangeMessages(1),
       };
       element._change.labels = {};
-      sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+      sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
         Promise.resolve({
           ...createChange(),
           // element has latest info
@@ -1468,7 +1475,7 @@
 
   test('diffMode defaults to side by side without preferences', done => {
     sinon
-      .stub(element.$.restAPI, 'getPreferences')
+      .stub(element.restApiService, 'getPreferences')
       .returns(Promise.resolve(createPreferences()));
     // No user prefs or diff view mode set.
 
@@ -1479,7 +1486,7 @@
   });
 
   test('diffMode defaults to preference when not already set', done => {
-    sinon.stub(element.$.restAPI, 'getPreferences').returns(
+    sinon.stub(element.restApiService, 'getPreferences').returns(
       Promise.resolve({
         ...createPreferences(),
         default_diff_view: DiffViewMode.UNIFIED,
@@ -1494,7 +1501,7 @@
 
   test('existing diffMode overrides preference', done => {
     element.viewState.diffMode = DiffViewMode.SIDE_BY_SIDE;
-    sinon.stub(element.$.restAPI, 'getPreferences').returns(
+    sinon.stub(element.restApiService, 'getPreferences').returns(
       Promise.resolve({
         ...createPreferences(),
         default_diff_view: DiffViewMode.UNIFIED,
@@ -1641,7 +1648,7 @@
     element._change = createChange();
     // Response code is 500, because we want to avoid window reloading
     const putStub = sinon
-      .stub(element.$.restAPI, 'putChangeCommitMessage')
+      .stub(element.restApiService, 'putChangeCommitMessage')
       .returns(Promise.resolve(new Response(null, {status: 500})));
 
     const mockEvent = (content: string) => {
@@ -1758,7 +1765,7 @@
 
   test('topic is coalesced to null', done => {
     sinon.stub(element, '_changeChanged');
-    sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+    sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
       Promise.resolve({
         ...createChange(),
         labels: {},
@@ -1775,7 +1782,7 @@
 
   test('commit sha is populated from getChangeDetail', done => {
     sinon.stub(element, '_changeChanged');
-    sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+    sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
       Promise.resolve({
         ...createChange(),
         labels: {},
@@ -1793,7 +1800,7 @@
   test('edit is added to change', () => {
     sinon.stub(element, '_changeChanged');
     const changeRevision = createRevision();
-    sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+    sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
       Promise.resolve({
         ...createChange(),
         labels: {},
@@ -1951,7 +1958,7 @@
 
   test('revert dialog opened with revert param', done => {
     sinon
-      .stub(element.$.restAPI, 'getLoggedIn')
+      .stub(element.restApiService, 'getLoggedIn')
       .callsFake(() => Promise.resolve(true));
     const awaitPluginsLoadedStub = sinon
       .stub(getPluginLoader(), 'awaitPluginsLoaded')
@@ -2028,7 +2035,7 @@
         messages: createChangeMessages(1),
       };
       element._change.labels = {};
-      sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+      sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
         Promise.resolve({
           ...createChange(),
           // element has latest info
@@ -2120,7 +2127,7 @@
         messages: createChangeMessages(1),
       };
       element._change.labels = {};
-      sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+      sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
         Promise.resolve({
           ...createChange(),
           // new patchset was uploaded
@@ -2300,7 +2307,7 @@
 
       test('_startUpdateCheckTimer negative delay', () => {
         const getChangeDetailStub = sinon
-          .stub(element.$.restAPI, 'getChangeDetail')
+          .stub(element.restApiService, 'getChangeDetail')
           .callsFake(() =>
             Promise.resolve({
               ...createChange(),
@@ -2322,7 +2329,7 @@
 
       test('_startUpdateCheckTimer up-to-date', async () => {
         const getChangeDetailStub = sinon
-          .stub(element.$.restAPI, 'getChangeDetail')
+          .stub(element.restApiService, 'getChangeDetail')
           .callsFake(() =>
             Promise.resolve({
               ...createChange(),
@@ -2345,7 +2352,7 @@
       });
 
       test('_startUpdateCheckTimer out-of-date shows an alert', done => {
-        sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+        sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
           Promise.resolve({
             ...createChange(),
             // new patchset was uploaded
@@ -2368,7 +2375,7 @@
       });
 
       test('_startUpdateCheckTimer respects _loading', async () => {
-        sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+        sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
           Promise.resolve({
             ...createChange(),
             // new patchset was uploaded
@@ -2390,7 +2397,7 @@
       });
 
       test('_startUpdateCheckTimer new status shows an alert', done => {
-        sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+        sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
           Promise.resolve({
             ...createChange(),
             // element has latest info
@@ -2412,7 +2419,7 @@
       });
 
       test('_startUpdateCheckTimer new messages shows an alert', done => {
-        sinon.stub(element.$.restAPI, 'getChangeDetail').callsFake(() =>
+        sinon.stub(element.restApiService, 'getChangeDetail').callsFake(() =>
           Promise.resolve({
             ...createChange(),
             revisions: {rev1: createRevision()},
@@ -2654,7 +2661,7 @@
   test('_selectedRevision updates when patchNum is changed', () => {
     const revision1: RevisionInfo = createRevision(1);
     const revision2: RevisionInfo = createRevision(2);
-    sinon.stub(element.$.restAPI, 'getChangeDetail').returns(
+    sinon.stub(element.restApiService, 'getChangeDetail').returns(
       Promise.resolve({
         ...createChange(),
         revisions: {
@@ -2683,7 +2690,7 @@
     const revision1 = createRevision(1);
     const revision2 = createRevision(2);
     const revision3 = createEditRevision();
-    sinon.stub(element.$.restAPI, 'getChangeDetail').returns(
+    sinon.stub(element.restApiService, 'getChangeDetail').returns(
       Promise.resolve({
         ...createChange(),
         revisions: {
@@ -2833,7 +2840,7 @@
     setup(() => {
       element._change = {...createChange(), labels: {}};
       getMergeableStub = sinon
-        .stub(element.$.restAPI, 'getMergeable')
+        .stub(element.restApiService, 'getMergeable')
         .returns(Promise.resolve({...createMergeable(), mergeable: true}));
     });
 
@@ -2867,7 +2874,7 @@
   test('_paramsChanged sets in projectLookup', () => {
     sinon.stub(element.$.relatedChanges, 'reload');
     sinon.stub(element, '_reload').returns(Promise.resolve([]));
-    const setStub = sinon.stub(element.$.restAPI, 'setInProjectLookup');
+    const setStub = sinon.stub(element.restApiService, 'setInProjectLookup');
     element._paramsChanged({
       view: GerritNav.View.CHANGE,
       changeNum: 101 as NumericChangeId,
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
index e05bac0..c4526bb 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-dialog/gr-dialog';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -32,16 +31,17 @@
   RepoName,
   BranchName,
   CommitId,
+  ChangeInfoId,
 } from '../../../types/common';
 import {ReportingService} from '../../../services/gr-reporting/gr-reporting';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   GrAutocomplete,
   AutocompleteSuggestion,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
 import {HttpMethod, ChangeStatus} from '../../../constants/constants';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 
 const SUGGESTIONS_LIMIT = 15;
 const CHANGE_SUBJECT_LIMIT = 50;
@@ -50,11 +50,18 @@
   TOPIC,
 }
 
+// These values are directly displayed in the dialog to show progress of change
+enum ProgressStatus {
+  RUNNING = 'RUNNING',
+  FAILED = 'FAILED',
+  NOT_STARTED = 'NOT STARTED',
+  SUCCESSFUL = 'SUCCESSFUL',
+}
+
 type Statuses = {[changeId: string]: Status};
 
-// TODO(TS): maybe convert status to an enum
 interface Status {
-  status: string;
+  status: ProgressStatus;
   msg?: string;
 }
 
@@ -68,7 +75,6 @@
 // is converted
 export interface GrConfirmCherrypickDialog {
   $: {
-    restAPI: RestApiService & Element;
     branchInput: GrAutocomplete;
   };
 }
@@ -142,6 +148,10 @@
   @property({type: Object})
   reporting: ReportingService;
 
+  private selectedChangeIds = new Set<ChangeInfoId>();
+
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._statuses = {};
@@ -155,6 +165,7 @@
     const projects: {[projectName: string]: boolean} = {};
     this._duplicateProjectChanges = false;
     changes.forEach(change => {
+      this.selectedChangeIds.add(change.id);
       if (projects[change.project]) {
         this._duplicateProjectChanges = true;
       }
@@ -172,6 +183,19 @@
     );
   }
 
+  _isChangeSelected(changeId: ChangeInfoId) {
+    return this.selectedChangeIds.has(changeId);
+  }
+
+  _toggleChangeSelected(e: Event) {
+    const changeId = ((dom(e) as EventApi).localTarget as HTMLElement).dataset[
+      'item'
+    ]! as ChangeInfoId;
+    if (this.selectedChangeIds.has(changeId))
+      this.selectedChangeIds.delete(changeId);
+    else this.selectedChangeIds.add(changeId);
+  }
+
   _computeTopicErrorMessage(duplicateProjectChanges: boolean) {
     if (duplicateProjectChanges) {
       return 'Two changes cannot be of the same project';
@@ -184,18 +208,19 @@
   }
 
   _computeStatus(change: ChangeInfo, statuses: Statuses) {
-    if (!change || !statuses || !statuses[change.id]) return 'NOT STARTED';
+    if (!change || !statuses || !statuses[change.id])
+      return ProgressStatus.NOT_STARTED;
     return statuses[change.id].status;
   }
 
   _computeStatusClass(change: ChangeInfo, statuses: Statuses) {
     if (!change || !statuses || !statuses[change.id]) return '';
-    return statuses[change.id].status === 'FAILED' ? 'error' : '';
+    return statuses[change.id].status === ProgressStatus.FAILED ? 'error' : '';
   }
 
   _computeError(change: ChangeInfo, statuses: Statuses) {
     if (!change || !statuses || !statuses[change.id]) return '';
-    if (statuses[change.id].status === 'FAILED') {
+    if (statuses[change.id].status === ProgressStatus.FAILED) {
       return statuses[change.id].msg;
     }
     return '';
@@ -213,7 +238,7 @@
 
   _computeCancelLabel(statuses: Statuses) {
     const isRunningChange = Object.values(statuses).some(
-      v => v.status === 'RUNNING'
+      v => v.status === ProgressStatus.RUNNING
     );
     return isRunningChange ? 'Close' : 'Cancel';
   }
@@ -221,14 +246,16 @@
   _computeDisableCherryPick(
     cherryPickType: CherryPickType,
     duplicateProjectChanges: boolean,
-    statuses: Statuses
+    statuses: Statuses,
+    branch?: BranchName
   ) {
+    if (!branch) return true;
     const duplicateProject =
       cherryPickType === CherryPickType.TOPIC && duplicateProjectChanges;
     if (duplicateProject) return true;
     if (!statuses) return false;
     const isRunningChange = Object.values(statuses).some(
-      v => v.status === 'RUNNING'
+      v => v.status === ProgressStatus.RUNNING
     );
     return isRunningChange;
   }
@@ -281,14 +308,22 @@
   _handleCherryPickFailed(change: ChangeInfo, response?: Response | null) {
     if (!response) return;
     response.text().then((errText: string) => {
-      this.updateStatus(change, {status: 'FAILED', msg: errText});
+      this.updateStatus(change, {status: ProgressStatus.FAILED, msg: errText});
     });
   }
 
   _handleCherryPickTopic() {
-    const topic = this._generateRandomCherryPickTopic(this.changes[0]);
-    this.changes.forEach(change => {
-      this.updateStatus(change, {status: 'RUNNING'});
+    const changes = this.changes.filter(change =>
+      this.selectedChangeIds.has(change.id)
+    );
+    if (!changes.length) {
+      const errorSpan = this.shadowRoot?.querySelector('.error-message');
+      errorSpan!.innerHTML = 'No change selected';
+      return;
+    }
+    const topic = this._generateRandomCherryPickTopic(changes[0]);
+    changes.forEach(change => {
+      this.updateStatus(change, {status: ProgressStatus.RUNNING});
       const payload = {
         destination: this.branch,
         base: null,
@@ -301,7 +336,7 @@
       };
       // revisions and current_revision must exist hence casting
       const patchNum = change.revisions![change.current_revision!]._number;
-      this.$.restAPI
+      this.restApiService
         .executeChangeAction(
           change._number,
           HttpMethod.POST,
@@ -311,9 +346,9 @@
           handleError
         )
         .then(() => {
-          this.updateStatus(change, {status: 'SUCCESSFUL'});
+          this.updateStatus(change, {status: ProgressStatus.SUCCESSFUL});
           const failedOrPending = Object.values(this._statuses).find(
-            v => v.status !== 'SUCCESSFUL'
+            v => v.status !== ProgressStatus.SUCCESSFUL
           );
           if (!failedOrPending) {
             /* This needs some more work, as the new topic may not always be
@@ -360,13 +395,13 @@
     input: string
   ): Promise<AutocompleteSuggestion[]> {
     if (!this.project) {
-      console.error('no project specified');
+      this.reporting.error(new Error('no project specified'));
       return Promise.resolve([]);
     }
     if (input.startsWith('refs/heads/')) {
       input = input.substring('refs/heads/'.length);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getRepoBranches(input, this.project, SUGGESTIONS_LIMIT)
       .then((response: BranchInfo[] | undefined) => {
         const branches = [];
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
index 072f110..4de395c 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
@@ -85,7 +85,7 @@
   <gr-dialog
     confirm-label="Cherry Pick"
     cancel-label="[[_computeCancelLabel(_statuses)]]"
-    disabled$="[[_computeDisableCherryPick(_cherryPickType, _duplicateProjectChanges, _statuses)]]"
+    disabled$="[[_computeDisableCherryPick(_cherryPickType, _duplicateProjectChanges, _statuses, branch)]]"
     on-confirm="_handleConfirmTap"
     on-cancel="_handleCancelTap"
   >
@@ -179,10 +179,12 @@
         <table>
           <thead>
             <tr>
+              <th></th>
               <th>Change</th>
+              <th>Status</th>
               <th>Subject</th>
               <th>Project</th>
-              <th>Status</th>
+              <th>Progress</th>
               <!-- Error Message -->
               <th></th>
             </tr>
@@ -190,7 +192,16 @@
           <tbody>
             <template is="dom-repeat" items="[[changes]]">
               <tr>
+                <td>
+                  <input
+                    type="checkbox"
+                    data-item$="[[item.id]]"
+                    on-change="_toggleChangeSelected"
+                    checked="[[_isChangeSelected(item.id)]]"
+                  />
+                </td>
                 <td><span> [[_getChangeId(item)]] </span></td>
+                <td><span> [[item.status]] </span></td>
                 <td>
                   <span> [[_getTrimmedChangeSubject(item.subject)]] </span>
                 </td>
@@ -212,5 +223,4 @@
       </template>
     </div>
   </gr-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
index 07f8f63..5564fcf 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
@@ -88,6 +88,7 @@
   suite('cherry pick topic', () => {
     const changes = [
       {
+        id: '1234',
         change_id: '12345678901234', topic: 'T', subject: 'random',
         project: 'A',
         _number: 1,
@@ -97,6 +98,7 @@
         current_revision: 'a',
       },
       {
+        id: '5678',
         change_id: '23456', topic: 'T', subject: 'a'.repeat(100),
         project: 'B',
         _number: 2,
@@ -109,11 +111,12 @@
     setup(() => {
       element.updateChanges(changes);
       element._cherryPickType = CHERRY_PICK_TYPES.TOPIC;
+      flush();
     });
 
     test('cherry pick topic submit', done => {
       element.branch = 'master';
-      const executeChangeActionStub = sinon.stub(element.$.restAPI,
+      const executeChangeActionStub = sinon.stub(element.restApiService,
           'executeChangeAction').returns(Promise.resolve([]));
       MockInteractions.tap(element.shadowRoot.
           querySelector('gr-dialog').$.confirm);
@@ -129,6 +132,38 @@
       });
     });
 
+    test('deselecting a change removes it from being cherry picked', () => {
+      element.branch = 'master';
+      const executeChangeActionStub = sinon.stub(element.restApiService,
+          'executeChangeAction').returns(Promise.resolve([]));
+      const checkboxes = element.shadowRoot.querySelectorAll(
+          'input[type="checkbox"]');
+      assert.equal(checkboxes.length, 2);
+      assert.isTrue(checkboxes[0].checked);
+      MockInteractions.tap(checkboxes[0]);
+      MockInteractions.tap(element.shadowRoot.
+          querySelector('gr-dialog').$.confirm);
+      flush();
+      assert.equal(executeChangeActionStub.callCount, 1);
+    });
+
+    test('deselecting all change shows error message', () => {
+      element.branch = 'master';
+      const executeChangeActionStub = sinon.stub(element.restApiService,
+          'executeChangeAction').returns(Promise.resolve([]));
+      const checkboxes = element.shadowRoot.querySelectorAll(
+          'input[type="checkbox"]');
+      assert.equal(checkboxes.length, 2);
+      MockInteractions.tap(checkboxes[0]);
+      MockInteractions.tap(checkboxes[1]);
+      MockInteractions.tap(element.shadowRoot.
+          querySelector('gr-dialog').$.confirm);
+      flush();
+      assert.equal(executeChangeActionStub.callCount, 0);
+      assert.equal(element.shadowRoot.querySelector('.error-message').innerText
+          , 'No change selected');
+    });
+
     test('_computeStatusClass', () => {
       assert.equal(element._computeStatusClass({id: 1}, {1: {status: 'RUNNING'},
       }), '');
@@ -139,6 +174,9 @@
     test('submit button is blocked while cherry picks is running', done => {
       const confirmButton = element.shadowRoot.querySelector('gr-dialog').$
           .confirm;
+      assert.isTrue(confirmButton.hasAttribute('disabled'));
+      element.branch = 'b';
+      flush();
       assert.isFalse(confirmButton.hasAttribute('disabled'));
       element.updateStatus(changes[0], {status: 'RUNNING'});
       flush(() => {
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog.ts
index e9cf19e..ff61de9 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog.ts
@@ -17,24 +17,18 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-dialog/gr-dialog';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-confirm-move-dialog_html';
 import {KeyboardShortcutMixin} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {RepoName, BranchName} from '../../../types/common';
 import {AutocompleteSuggestion} from '../../shared/gr-autocomplete/gr-autocomplete';
+import {appContext} from '../../../services/app-context';
 
 const SUGGESTIONS_LIMIT = 15;
 
-export interface GrConfirmMoveDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-confirm-move-dialog')
 export class GrConfirmMoveDialog extends KeyboardShortcutMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -73,6 +67,8 @@
     };
   }
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = () => this._getProjectBranchesSuggestions();
@@ -108,7 +104,7 @@
     if (input.startsWith('refs/heads/')) {
       input = input.substring('refs/heads/'.length);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getRepoBranches(input, this.project, SUGGESTIONS_LIMIT)
       .then(response => {
         const branches: AutocompleteSuggestion[] = [];
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog_html.ts
index b5b46d6..de75a39 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-move-dialog/gr-confirm-move-dialog_html.ts
@@ -79,5 +79,4 @@
       ></iron-autogrow-textarea>
     </div>
   </gr-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
index db0e1ff..9e7bdb4 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
@@ -16,7 +16,6 @@
  */
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-dialog/gr-dialog';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -30,7 +29,7 @@
   AutocompleteQuery,
   AutocompleteSuggestion,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 interface RebaseChange {
   name: string;
@@ -43,7 +42,6 @@
 
 export interface GrConfirmRebaseDialog {
   $: {
-    restAPI: RestApiService & Element;
     parentInput: GrAutocomplete;
     rebaseOnParentInput: HTMLInputElement;
     rebaseOnOtherInput: HTMLInputElement;
@@ -92,6 +90,8 @@
   @property({type: Array})
   _recentChanges?: RebaseChange[];
 
+  private restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = input => this._getChangeSuggestions(input);
@@ -104,7 +104,7 @@
   // in case there are new/updated changes in the generic query since the
   // last time it was run.
   fetchRecentChanges() {
-    return this.$.restAPI
+    return this.restApiService
       .getChanges(undefined, 'is:open -age:90d')
       .then(response => {
         if (!response) return [];
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_html.ts
index 687d31f..7d28de6 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_html.ts
@@ -127,5 +127,4 @@
       </div>
     </div>
   </gr-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.js b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.js
index 8bce572..8b3b73a 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.js
@@ -118,7 +118,7 @@
         },
       ];
 
-      sinon.stub(element.$.restAPI, 'getChanges').returns(Promise.resolve(
+      sinon.stub(element.restApiService, 'getChanges').returns(Promise.resolve(
           [
             {
               _number: 123,
@@ -141,13 +141,13 @@
       return element._getRecentChanges()
           .then(() => {
             assert.deepEqual(element._recentChanges, recentChanges);
-            assert.equal(element.$.restAPI.getChanges.callCount, 1);
+            assert.equal(element.restApiService.getChanges.callCount, 1);
             // When called a second time, should not re-request recent changes.
             element._getRecentChanges();
           })
           .then(() => {
             assert.equal(element._getRecentChanges.callCount, 2);
-            assert.equal(element.$.restAPI.getChanges.callCount, 1);
+            assert.equal(element.restApiService.getChanges.callCount, 1);
           });
     });
 
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-revert-dialog/gr-confirm-revert-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-revert-dialog/gr-confirm-revert-dialog.ts
index 5c0b19f..3facde1 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-revert-dialog/gr-confirm-revert-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-revert-dialog/gr-confirm-revert-dialog.ts
@@ -25,6 +25,7 @@
 import {customElement, property} from '@polymer/decorators';
 import {JsApiService} from '../../shared/gr-js-api-interface/gr-js-api-types';
 import {ChangeInfo, CommitId} from '../../../types/common';
+import {fireAlert} from '../../../utils/event-util';
 
 const ERR_COMMIT_NOT_FOUND = 'Unable to find the commit hash of this change.';
 const CHANGE_SUBJECT_LIMIT = 50;
@@ -124,13 +125,7 @@
     const originalTitle = (commitMessage || '').split('\n')[0];
     const revertTitle = `Revert "${originalTitle}"`;
     if (!commitHash) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_COMMIT_NOT_FOUND},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_COMMIT_NOT_FOUND);
       return;
     }
     const revertCommitText = `This reverts commit ${commitHash}.`;
@@ -168,13 +163,7 @@
     // Follow the same convention of the revert
     const commitHash = change.current_revision;
     if (!commitHash) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_COMMIT_NOT_FOUND},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_COMMIT_NOT_FOUND);
       return;
     }
     if (!changes || changes.length <= 1) return;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-revert-submission-dialog/gr-confirm-revert-submission-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-revert-submission-dialog/gr-confirm-revert-submission-dialog.ts
index 9754e89..ac52664 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-revert-submission-dialog/gr-confirm-revert-submission-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-revert-submission-dialog/gr-confirm-revert-submission-dialog.ts
@@ -24,6 +24,7 @@
 import {customElement, property} from '@polymer/decorators';
 import {JsApiService} from '../../shared/gr-js-api-interface/gr-js-api-types';
 import {ChangeInfo} from '../../../types/common';
+import {fireAlert} from '../../../utils/event-util';
 
 const ERR_COMMIT_NOT_FOUND = 'Unable to find the commit hash of this change.';
 const CHANGE_SUBJECT_LIMIT = 50;
@@ -86,13 +87,7 @@
     // Follow the same convention of the revert
     const commitHash = change.current_revision;
     if (!commitHash) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_COMMIT_NOT_FOUND},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_COMMIT_NOT_FOUND);
       return;
     }
     const revertTitle = `Revert submission ${change.submission_id}`;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
index 666f95d..6e2e595 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-icon/iron-icon';
 import '../../shared/gr-icons/gr-icons';
 import '../../shared/gr-dialog/gr-dialog';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
 import '../../../styles/shared-styles';
@@ -28,6 +27,7 @@
 import {customElement, property} from '@polymer/decorators';
 import {ChangeInfo, ActionInfo} from '../../../types/common';
 import {GrDialog} from '../../shared/gr-dialog/gr-dialog';
+import {pluralize} from '../../../utils/string-util';
 
 export interface GrConfirmSubmitDialog {
   $: {
@@ -74,8 +74,8 @@
 
   _computeUnresolvedCommentsWarning(change: ChangeInfo) {
     const unresolvedCount = change.unresolved_comment_count;
-    const plural = unresolvedCount && unresolvedCount > 1 ? 's' : '';
-    return `Heads Up! ${unresolvedCount} unresolved comment${plural}.`;
+    if (!unresolvedCount) throw new Error('unresolved comments undefined or 0');
+    return `Heads Up! ${pluralize(unresolvedCount, 'unresolved comment')}.`;
   }
 
   _handleConfirmTap(e: MouseEvent) {
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
index 84668ed..6c7b1c2 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
@@ -81,5 +81,4 @@
       </gr-endpoint-decorator>
     </div>
   </gr-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
index 27d9756..5949513 100644
--- a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
@@ -20,7 +20,6 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-download-dialog_html';
-import {patchNumEquals} from '../../../utils/patch-set-util';
 import {changeBaseURL} from '../../../utils/change-util';
 import {customElement, property, computed, observe} from '@polymer/decorators';
 import {ChangeInfo, ServerInfo, PatchSetNum} from '../../../types/common';
@@ -72,7 +71,7 @@
     }
 
     for (const rev of Object.values(this.change.revisions || {})) {
-      if (patchNumEquals(rev._number, this.patchNum)) {
+      if (rev._number === this.patchNum) {
         const fetch = rev.fetch;
         if (fetch) {
           return Object.keys(fetch).sort();
@@ -113,7 +112,7 @@
     if (!change || !selectedScheme) return [];
     for (const rev of Object.values(change.revisions || {})) {
       if (
-        patchNumEquals(rev._number, patchNum) &&
+        rev._number === patchNum &&
         rev &&
         rev.fetch &&
         hasOwnProperty(rev.fetch, selectedScheme)
@@ -171,7 +170,7 @@
 
     let shortRev = '';
     for (const rev in change.revisions) {
-      if (patchNumEquals(change.revisions[rev]._number, patchNum)) {
+      if (change.revisions[rev]._number === patchNum) {
         shortRev = rev.substr(0, 7);
         break;
       }
@@ -185,7 +184,7 @@
       return false;
     }
     for (const rev of Object.values(change.revisions || {})) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         const parentLength =
           rev.commit && rev.commit.parents ? rev.commit.parents.length : 0;
         return parentLength === 0 || parentLength > 1;
diff --git a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.js b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.ts
similarity index 65%
rename from polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.js
rename to polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.ts
index 7401026..52ec8af 100644
--- a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog_test.ts
@@ -15,29 +15,46 @@
  * limitations under the License.
  */
 
-import '../../../test/common-test-setup-karma.js';
-import './gr-download-dialog.js';
+import '../../../test/common-test-setup-karma';
+import {tap} from '@polymer/iron-test-helpers/mock-interactions';
+import {
+  createChange,
+  createCommit,
+  createRevision,
+  createRevisions,
+  createServerInfo,
+} from '../../../test/test-data-generators';
+import {
+  CommitId,
+  NumericChangeId,
+  PatchSetNum,
+  RepoName,
+} from '../../../types/common';
+import {GrDownloadDialog} from './gr-download-dialog';
 
 const basicFixture = fixtureFromElement('gr-download-dialog');
 
 function getChangeObject() {
   return {
-    current_revision: '34685798fe548b6d17d1e8e5edc43a26d055cc72',
+    ...createChange(),
+    current_revision: '34685798fe548b6d17d1e8e5edc43a26d055cc72' as CommitId,
     revisions: {
       '34685798fe548b6d17d1e8e5edc43a26d055cc72': {
-        _number: 1,
-        commit: {
-          parents: [],
-        },
+        ...createRevision(),
+        commit: createCommit(),
         fetch: {
           repo: {
+            url: 'my.url',
+            ref: 'refs/changes/5/6/1',
             commands: {
               repo: 'repo download test-project 5/1',
             },
           },
           ssh: {
+            url: 'my.url',
+            ref: 'refs/changes/5/6/1',
             commands: {
-              'Checkout':
+              Checkout:
                 'git fetch ' +
                 'ssh://andybons@localhost:29418/test-project ' +
                 'refs/changes/05/5/1 && git checkout FETCH_HEAD',
@@ -50,15 +67,17 @@
                 'ssh://andybons@localhost:29418/test-project ' +
                 'refs/changes/05/5/1 ' +
                 '&& git format-patch -1 --stdout FETCH_HEAD',
-              'Pull':
+              Pull:
                 'git pull ' +
                 'ssh://andybons@localhost:29418/test-project ' +
                 'refs/changes/05/5/1',
             },
           },
           http: {
+            url: 'my.url',
+            ref: 'refs/changes/5/6/1',
             commands: {
-              'Checkout':
+              Checkout:
                 'git fetch ' +
                 'http://andybons@localhost:8080/a/test-project ' +
                 'refs/changes/05/5/1 && git checkout FETCH_HEAD',
@@ -71,7 +90,7 @@
                 'http://andybons@localhost:8080/a/test-project ' +
                 'refs/changes/05/5/1 && ' +
                 'git format-patch -1 --stdout FETCH_HEAD',
-              'Pull':
+              Pull:
                 'git pull ' +
                 'http://andybons@localhost:8080/a/test-project ' +
                 'refs/changes/05/5/1',
@@ -85,41 +104,24 @@
 
 function getChangeObjectNoFetch() {
   return {
-    current_revision: '34685798fe548b6d17d1e8e5edc43a26d055cc72',
-    revisions: {
-      '34685798fe548b6d17d1e8e5edc43a26d055cc72': {
-        _number: 1,
-        commit: {
-          parents: [],
-        },
-        fetch: {},
-      },
-    },
+    ...createChange(),
+    current_revision: '34685798fe548b6d17d1e8e5edc43a26d055cc72' as CommitId,
+    revisions: createRevisions(1),
   };
 }
 
 suite('gr-download-dialog', () => {
-  let element;
+  let element: GrDownloadDialog;
 
   setup(() => {
     element = basicFixture.instantiate();
-    element.patchNum = '1';
-    element.config = {
-      schemes: {
-        'anonymous http': {},
-        'http': {},
-        'repo': {},
-        'ssh': {},
-      },
-      archives: ['tgz', 'tar', 'tbz2', 'txz'],
-    };
-
+    element.patchNum = 1 as PatchSetNum;
+    element.config = createServerInfo();
     flush();
   });
 
   test('anchors use download attribute', () => {
-    const anchors = Array.from(
-        element.root.querySelectorAll('a'));
+    const anchors = Array.from(element.root!.querySelectorAll('a'));
     assert.isTrue(!anchors.some(a => !a.hasAttribute('download')));
   });
 
@@ -152,17 +154,28 @@
     });
 
     test('computed fields', () => {
-      assert.equal(element._computeArchiveDownloadLink(
-          {project: 'test/project', _number: 123}, 2, 'tgz'),
-      '/changes/test%2Fproject~123/revisions/2/archive?format=tgz');
+      assert.equal(
+        element._computeArchiveDownloadLink(
+          {
+            ...createChange(),
+            project: 'test/project' as RepoName,
+            _number: 123 as NumericChangeId,
+          },
+          2 as PatchSetNum,
+          'tgz'
+        ),
+        '/changes/test%2Fproject~123/revisions/2/archive?format=tgz'
+      );
     });
 
     test('close event', done => {
       element.addEventListener('close', () => {
         done();
       });
-      MockInteractions.tap(element.shadowRoot
-          .querySelector('.closeButtonContainer gr-button'));
+      const closeButton = element.shadowRoot!.querySelector(
+        '.closeButtonContainer gr-button'
+      );
+      tap(closeButton!);
     });
   });
 
@@ -172,35 +185,49 @@
   });
 
   test('_computeHidePatchFile', () => {
-    const patchNum = '1';
+    const patchNum = 1 as PatchSetNum;
 
     const changeWithNoParent = {
+      ...createChange(),
       revisions: {
-        r1: {_number: 1, commit: {parents: []}},
+        r1: {...createRevision(), commit: createCommit()},
       },
     };
     assert.isTrue(element._computeHidePatchFile(changeWithNoParent, patchNum));
 
     const changeWithOneParent = {
+      ...createChange(),
       revisions: {
-        r1: {_number: 1, commit: {parents: [
-          {commit: 'p1'},
-        ]}},
+        r1: {
+          ...createRevision(),
+          commit: {
+            ...createCommit(),
+            parents: [{commit: 'p1' as CommitId, subject: 'subject1'}],
+          },
+        },
       },
     };
     assert.isFalse(
-        element._computeHidePatchFile(changeWithOneParent, patchNum));
+      element._computeHidePatchFile(changeWithOneParent, patchNum)
+    );
 
     const changeWithMultipleParents = {
+      ...createChange(),
       revisions: {
-        r1: {_number: 1, commit: {parents: [
-          {commit: 'p1'},
-          {commit: 'p2'},
-        ]}},
+        r1: {
+          ...createRevision(),
+          commit: {
+            ...createCommit(),
+            parents: [
+              {commit: 'p1' as CommitId, subject: 'subject1'},
+              {commit: 'p2' as CommitId, subject: 'subject2'},
+            ],
+          },
+        },
       },
     };
     assert.isTrue(
-        element._computeHidePatchFile(changeWithMultipleParents, patchNum));
+      element._computeHidePatchFile(changeWithMultipleParents, patchNum)
+    );
   });
 });
-
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
index b86dd90..146b3e2 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
@@ -20,7 +20,6 @@
 import '../../edit/gr-edit-controls/gr-edit-controls';
 import '../../shared/gr-editable-label/gr-editable-label';
 import '../../shared/gr-linked-chip/gr-linked-chip';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-icons/gr-icons';
@@ -36,7 +35,6 @@
 import {
   computeLatestPatchNum,
   getRevisionByPatchNum,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {property, computed, observe, customElement} from '@polymer/decorators';
@@ -46,15 +44,16 @@
   PatchSetNum,
   CommitInfo,
   ServerInfo,
-  DiffPreferencesInfo,
   RevisionInfo,
   NumericChangeId,
 } from '../../../types/common';
+import {DiffPreferencesInfo} from '../../../types/diff';
 import {ChangeComments} from '../../diff/gr-comment-api/gr-comment-api';
 import {GrDiffModeSelector} from '../../diff/gr-diff-mode-selector/gr-diff-mode-selector';
 import {DiffViewMode} from '../../../constants/constants';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrButton} from '../../shared/gr-button/gr-button';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
 // Maximum length for patch set descriptions.
 const PATCH_DESC_MAX_LENGTH = 500;
@@ -69,7 +68,6 @@
 export interface GrFileListHeader {
   $: {
     modeSelect: GrDiffModeSelector;
-    restAPI: RestApiService & Element;
     expandBtn: GrButton;
     collapseBtn: GrButton;
   };
@@ -169,6 +167,8 @@
   @property({type: Object})
   revisionInfo?: RevisionInfo;
 
+  private readonly restApiService = appContext.restApiService;
+
   @computed('loggedIn', 'change', 'account')
   get _descriptionReadOnly(): boolean {
     if (
@@ -190,21 +190,11 @@
   }
 
   _expandAllDiffs() {
-    this.dispatchEvent(
-      new CustomEvent('expand-diffs', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'expand-diffs');
   }
 
   _collapseAllDiffs() {
-    this.dispatchEvent(
-      new CustomEvent('collapse-diffs', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'collapse-diffs');
   }
 
   _computeExpandedClass(filesExpanded: FilesExpandedState) {
@@ -294,7 +284,7 @@
       this.patchNum
     )!;
     const sha = this._getPatchsetHash(this.change.revisions, rev);
-    return this.$.restAPI
+    return this.restApiService
       .setDescription(this.changeNum, this.patchNum, desc)
       .then((res: Response) => {
         if (res.ok) {
@@ -330,8 +320,7 @@
   _handlePatchChange(e: CustomEvent) {
     const {basePatchNum, patchNum} = e.detail;
     if (
-      (patchNumEquals(basePatchNum, this.basePatchNum) &&
-        patchNumEquals(patchNum, this.patchNum)) ||
+      (basePatchNum === this.basePatchNum && patchNum === this.patchNum) ||
       !this.change
     ) {
       return;
@@ -341,22 +330,12 @@
 
   _handlePrefsTap(e: Event) {
     e.preventDefault();
-    this.dispatchEvent(
-      new CustomEvent('open-diff-prefs', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'open-diff-prefs');
   }
 
   _handleIncludedInTap(e: Event) {
     e.preventDefault();
-    this.dispatchEvent(
-      new CustomEvent('open-included-in-dialog', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'open-included-in-dialog');
   }
 
   _handleDownloadTap(e: Event) {
@@ -373,7 +352,7 @@
 
   _computePatchInfoClass(patchNum?: PatchSetNum, allPatchSets?: PatchSet[]) {
     const latestNum = computeLatestPatchNum(allPatchSets);
-    if (patchNumEquals(patchNum, latestNum)) {
+    if (patchNum === latestNum) {
       return '';
     }
     return 'patchInfoOldPatchSet';
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
index 1355412..1e72ae9 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
@@ -29,7 +29,6 @@
     }
     .patchInfo-header {
       align-items: center;
-      border-top: 1px solid var(--border-color);
       display: flex;
       padding: var(--spacing-s) var(--spacing-l);
     }
@@ -273,5 +272,4 @@
       </div>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
index 3469b3a..b8670c0 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
@@ -86,7 +86,7 @@
   });
 
   test('description editing', () => {
-    const putDescStub = sinon.stub(element.$.restAPI, 'setDescription')
+    const putDescStub = sinon.stub(element.restApiService, 'setDescription')
         .returns(Promise.resolve({ok: true}));
 
     element.changeNum = '42';
@@ -249,11 +249,11 @@
 
   test('class is applied to file list on old patch set', () => {
     const allPatchSets = [{num: 4}, {num: 2}, {num: 1}];
-    assert.equal(element._computePatchInfoClass('1', allPatchSets),
+    assert.equal(element._computePatchInfoClass(1, allPatchSets),
         'patchInfoOldPatchSet');
-    assert.equal(element._computePatchInfoClass('2', allPatchSets),
+    assert.equal(element._computePatchInfoClass(2, allPatchSets),
         'patchInfoOldPatchSet');
-    assert.equal(element._computePatchInfoClass('4', allPatchSets), '');
+    assert.equal(element._computePatchInfoClass(4, allPatchSets), '');
   });
 
   suite('editMode behavior', () => {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
index e188254..c062188 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
@@ -23,10 +23,10 @@
 import '../../shared/gr-cursor-manager/gr-cursor-manager';
 import '../../shared/gr-icons/gr-icons';
 import '../../shared/gr-linked-text/gr-linked-text';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import '../../shared/gr-tooltip-content/gr-tooltip-content';
 import '../../shared/gr-copy-clipboard/gr-copy-clipboard';
+import '../../shared/gr-file-status-chip/gr-file-status-chip';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -39,7 +39,7 @@
   Shortcut,
 } from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 import {FilesExpandedState} from '../gr-file-list-constants';
-import {GrCountStringFormatter} from '../../shared/gr-count-string-formatter/gr-count-string-formatter';
+import {pluralize} from '../../../utils/string-util';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {getPluginEndpoints} from '../../shared/gr-js-api-interface/gr-plugin-endpoints';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
@@ -54,10 +54,7 @@
   specialFilePathCompare,
 } from '../../../utils/path-list-util';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
-  ConfigInfo,
-  DiffPreferencesInfo,
   ElementPropertyDeepChange,
   FileInfo,
   FileNameToFileInfoMap,
@@ -67,6 +64,7 @@
   RevisionInfo,
   UrlEncodedCommentId,
 } from '../../../types/common';
+import {DiffPreferencesInfo} from '../../../types/diff';
 import {GrDiffHost} from '../../diff/gr-diff-host/gr-diff-host';
 import {GrDiffPreferencesDialog} from '../../diff/gr-diff-preferences-dialog/gr-diff-preferences-dialog';
 import {hasOwnProperty} from '../../../utils/common-util';
@@ -74,10 +72,9 @@
 import {GrCursorManager} from '../../shared/gr-cursor-manager/gr-cursor-manager';
 import {PolymerSpliceChange} from '@polymer/polymer/interfaces';
 import {ChangeComments} from '../../diff/gr-comment-api/gr-comment-api';
-import {UIDraft} from '../../../utils/comment-util';
 import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
-import {PatchSetFile} from '../../../types/types';
 import {CustomKeyboardEvent} from '../../../types/events';
+import {PatchSetFile} from '../../../types/types';
 
 export const DEFAULT_NUM_FILES_SHOWN = 200;
 
@@ -93,21 +90,10 @@
 const EXPAND_ALL_TIMING_LABEL = 'ExpandAllDiffs';
 const EXPAND_ALL_AVG_TIMING_LABEL = 'ExpandAllPerDiff';
 
-const FileStatus = {
-  A: 'Added',
-  C: 'Copied',
-  D: 'Deleted',
-  M: 'Modified',
-  R: 'Renamed',
-  W: 'Rewritten',
-  U: 'Unchanged',
-};
-
 const FILE_ROW_CLASS = 'file-row';
 
 export interface GrFileList {
   $: {
-    restAPI: RestApiService & Element;
     diffPreferencesDialog: GrDiffPreferencesDialog;
     diffCursor: GrDiffCursor;
     fileCursor: GrCursorManager;
@@ -117,7 +103,7 @@
 interface ReviewedFileInfo extends FileInfo {
   isReviewed?: boolean;
 }
-interface NormalizedFileInfo extends ReviewedFileInfo {
+export interface NormalizedFileInfo extends ReviewedFileInfo {
   __path: string;
 }
 
@@ -209,15 +195,9 @@
   @property({type: Object})
   changeComments?: ChangeComments;
 
-  @property({type: Object})
-  drafts?: {[path: string]: UIDraft[]};
-
   @property({type: Array})
   revisions?: {[revisionId: string]: RevisionInfo};
 
-  @property({type: Object})
-  projectConfig?: ConfigInfo;
-
   @property({type: Number, notify: true})
   selectedIndex = -1;
 
@@ -334,6 +314,8 @@
 
   private readonly reporting = appContext.reportingService;
 
+  private readonly restApiService = appContext.restApiService;
+
   get keyBindings() {
     return {
       esc: '_handleEscKey',
@@ -457,7 +439,7 @@
     const promises = [];
 
     promises.push(
-      this.$.restAPI
+      this.restApiService
         .getChangeOrEditFiles(changeNum, patchRange)
         .then(filesByPath => {
           this._filesByPath = filesByPath;
@@ -544,11 +526,11 @@
   }
 
   _getDiffPreferences() {
-    return this.$.restAPI.getDiffPreferences();
+    return this.restApiService.getDiffPreferences();
   }
 
   _getPreferences() {
-    return this.$.restAPI.getPreferences();
+    return this.restApiService.getPreferences();
   }
 
   private _toggleFileExpanded(file: PatchSetFile) {
@@ -619,49 +601,16 @@
   _computeCommentsString(
     changeComments?: ChangeComments,
     patchRange?: PatchRange,
-    path?: string
+    file?: NormalizedFileInfo
   ) {
     if (
       changeComments === undefined ||
       patchRange === undefined ||
-      path === undefined
+      file?.__path === undefined
     ) {
       return '';
     }
-    const unresolvedCount =
-      changeComments.computeUnresolvedNum({
-        patchNum: patchRange.basePatchNum,
-        path,
-      }) +
-      changeComments.computeUnresolvedNum({
-        patchNum: patchRange.patchNum,
-        path,
-      });
-    const commentThreadCount =
-      changeComments.computeCommentThreadCount({
-        patchNum: patchRange.basePatchNum,
-        path,
-      }) +
-      changeComments.computeCommentThreadCount({
-        patchNum: patchRange.patchNum,
-        path,
-      });
-    const commentString = GrCountStringFormatter.computePluralString(
-      commentThreadCount,
-      'comment'
-    );
-    const unresolvedString = GrCountStringFormatter.computeString(
-      unresolvedCount,
-      'unresolved'
-    );
-
-    return (
-      commentString +
-      // Add a space if both comments and unresolved
-      (commentString && unresolvedString ? ' ' : '') +
-      // Add parentheses around unresolved if it exists.
-      (unresolvedString ? `(${unresolvedString})` : '')
-    );
+    return changeComments.computeCommentsString(patchRange, file.__path, file);
   }
 
   /**
@@ -688,7 +637,7 @@
         patchNum: patchRange.patchNum,
         path,
       });
-    return GrCountStringFormatter.computePluralString(draftCount, 'draft');
+    return pluralize(draftCount, 'draft');
   }
 
   /**
@@ -715,7 +664,7 @@
         patchNum: patchRange.patchNum,
         path,
       });
-    return GrCountStringFormatter.computeShortString(draftCount, 'd');
+    return draftCount === 0 ? '' : `${draftCount}d`;
   }
 
   /**
@@ -742,7 +691,7 @@
         patchNum: patchRange.patchNum,
         path,
       });
-    return GrCountStringFormatter.computeShortString(commentThreadCount, 'c');
+    return commentThreadCount === 0 ? '' : `${commentThreadCount}c`;
   }
 
   private _reviewFile(path: string, reviewed?: boolean) {
@@ -765,7 +714,7 @@
       throw new Error('changeNum and patchRange must be set');
     }
 
-    return this.$.restAPI.saveFileReviewed(
+    return this.restApiService.saveFileReviewed(
       this.changeNum,
       this.patchRange.patchNum,
       path,
@@ -774,14 +723,14 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _getReviewedFiles(changeNum: NumericChangeId, patchRange: PatchRange) {
     if (this.editMode) {
       return Promise.resolve([]);
     }
-    return this.$.restAPI.getReviewedFiles(changeNum, patchRange.patchNum);
+    return this.restApiService.getReviewedFiles(changeNum, patchRange.patchNum);
   }
 
   _normalizeChangeFilesResponse(
@@ -998,6 +947,7 @@
       return;
     }
     e.preventDefault();
+    this.classList.remove('hideComments');
     this.$.diffCursor.createCommentInPlace();
   }
 
@@ -1164,12 +1114,6 @@
     );
   }
 
-  _computeFileStatus(
-    status?: keyof typeof FileStatus
-  ): keyof typeof FileStatus {
-    return status || 'M';
-  }
-
   _computeDiffURL(
     change?: ParsedChangeInfo,
     patchRange?: PatchRange,
@@ -1244,12 +1188,6 @@
     return classes.join(' ');
   }
 
-  _computeStatusClass(file?: NormalizedFileInfo) {
-    if (!file) return '';
-    const classStr = this._computeClass('status', file.__path);
-    return `${classStr} ${this._computeFileStatus(file.status)}`;
-  }
-
   _computePathClass(
     path: string | undefined,
     expandedFilesRecord: ElementPropertyDeepChange<GrFileList, '_expandedFiles'>
@@ -1405,17 +1343,6 @@
   }
 
   /**
-   * Get a descriptive label for use in the status indicator's tooltip and
-   * ARIA label.
-   */
-  _computeFileStatusLabel(status?: keyof typeof FileStatus) {
-    const statusCode = this._computeFileStatus(status);
-    return hasOwnProperty(FileStatus, statusCode)
-      ? FileStatus[statusCode]
-      : 'Status Unknown';
-  }
-
-  /**
    * Converts any boolean-like variable to the string 'true' or 'false'
    *
    * This method is useful when you bind aria-checked attribute to a boolean
@@ -1557,10 +1484,10 @@
             'changeComments, patchRange and diffPrefs must be set'
           );
         }
-        diffElem.comments = this.changeComments.getCommentsBySideForFile(
+
+        diffElem.threads = this.changeComments.getThreadsBySideForFile(
           file,
-          this.patchRange,
-          this.projectConfig
+          this.patchRange
         );
         const promises: Array<Promise<unknown>> = [diffElem.reload()];
         if (this._loggedIn && !this.diffPrefs.manual_review) {
@@ -1647,14 +1574,9 @@
       return;
     }
 
-    // Comments are not returned with the commentSide attribute from
-    // the api, but it's necessary to be stored on the diff's
-    // comments due to use in the _handleCommentUpdate function.
-    // The comment thread already has a side associated with it, so
-    // set the comment's side to match.
-    threadEl.comments = newComments.map(c =>
-      Object.assign(c, {__commentSide: threadEl.commentSide})
-    );
+    threadEl.comments = newComments.map(c => {
+      return {...c};
+    });
     flush();
   }
 
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
index d93ce68..ec985af 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
@@ -80,27 +80,6 @@
       text-align: left;
       width: 1.5em;
     }
-    .status {
-      display: inline-block;
-      border-radius: var(--border-radius);
-      margin-left: var(--spacing-s);
-      padding: 0 var(--spacing-m);
-      color: var(--primary-text-color);
-      font-size: var(--font-size-small);
-      background-color: var(--dark-add-highlight-color);
-    }
-    .status.invisible,
-    .status.M {
-      display: none;
-    }
-    .status.D,
-    .status.R,
-    .status.W {
-      background-color: var(--dark-remove-highlight-color);
-    }
-    .status.U {
-      background-color: var(--comment-background-color);
-    }
     .file-row {
       cursor: pointer;
     }
@@ -421,14 +400,7 @@
               >
                 [[_computeTruncatedPath(file.__path)]]
               </span>
-              <span
-                class$="[[_computeStatusClass(file)]]"
-                tabindex="0"
-                title$="[[_computeFileStatusLabel(file.status)]]"
-                aria-label$="[[_computeFileStatusLabel(file.status)]]"
-              >
-                [[_computeFileStatusLabel(file.status)]]
-              </span>
+              <gr-file-status-chip file="[[file]]"></gr-file-status-chip>
               <gr-copy-clipboard
                 hide-input=""
                 text="[[file.__path]]"
@@ -456,8 +428,7 @@
               >
               <span
                 ><!--
-              -->[[_computeCommentsString(changeComments, patchRange,
-                file.__path)]]<!--
+              -->[[_computeCommentsString(changeComments, patchRange, file)]]<!--
            --></span
               >
               <span class="noCommentsScreenReaderText">
@@ -763,7 +734,6 @@
     on-reload-diff-preference="_handleReloadingDiffPreference"
   >
   </gr-diff-preferences-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
   <gr-diff-cursor id="diffCursor"></gr-diff-cursor>
   <gr-cursor-manager
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
index d85ae4d..d0ae833 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
@@ -28,7 +28,8 @@
 import {html} from '@polymer/polymer/lib/utils/html-tag.js';
 import {TestKeyboardShortcutBinder} from '../../../test/test-utils.js';
 import {Shortcut} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.js';
-import {ChangeComments} from '../../diff/gr-comment-api/gr-comment-api.js';
+import {createCommentThreads} from '../../../utils/comment-util.js';
+import {createChangeComments} from '../../../test/test-data-generators.js';
 
 const commentApiMock = createCommentApiMockWithTemplateElement(
     'gr-file-list-comment-api-mock', html`
@@ -106,8 +107,6 @@
       // been initialized.
       commentApiWrapper.loadComments().then(() => {
         sinon.stub(element.changeComments, 'getPaths').returns({});
-        sinon.stub(element.changeComments, 'getCommentsBySideForPath')
-            .returns({meta: {}, left: [], right: []});
         done();
       });
       element._loading = false;
@@ -353,101 +352,7 @@
     });
 
     test('comment filtering', () => {
-      const comments = {
-        '/COMMIT_MSG': [
-          {
-            patch_set: 1,
-            message: 'Done',
-            updated: '2017-02-08 16:40:49',
-            id: '1',
-          },
-          {
-            patch_set: 1,
-            message: 'oh hay',
-            updated: '2017-02-09 16:40:49',
-            id: '2',
-          },
-          {
-            patch_set: 2,
-            message: 'hello',
-            updated: '2017-02-10 16:40:49',
-            id: '3',
-          },
-        ],
-        'myfile.txt': [
-          {
-            patch_set: 1,
-            message: 'good news!',
-            updated: '2017-02-08 16:40:49',
-            id: '4',
-          },
-          {
-            patch_set: 2,
-            message: 'wat!?',
-            updated: '2017-02-09 16:40:49',
-            id: '5',
-          },
-          {
-            patch_set: 2,
-            message: 'hi',
-            updated: '2017-02-10 16:40:49',
-            id: '6',
-          },
-        ],
-        'unresolved.file': [
-          {
-            patch_set: 2,
-            message: 'wat!?',
-            updated: '2017-02-09 16:40:49',
-            id: '7',
-            unresolved: true,
-          },
-          {
-            patch_set: 2,
-            message: 'hi',
-            updated: '2017-02-10 16:40:49',
-            id: '8',
-            in_reply_to: '7',
-            unresolved: false,
-          },
-          {
-            patch_set: 2,
-            message: 'good news!',
-            updated: '2017-02-08 16:40:49',
-            id: '9',
-            unresolved: true,
-          },
-        ],
-      };
-      const drafts = {
-        '/COMMIT_MSG': [
-          {
-            patch_set: 1,
-            message: 'hi',
-            updated: '2017-02-15 16:40:49',
-            id: '10',
-            unresolved: true,
-          },
-          {
-            patch_set: 1,
-            message: 'fyi',
-            updated: '2017-02-15 16:40:49',
-            id: '11',
-            unresolved: false,
-          },
-        ],
-        'unresolved.file': [
-          {
-            patch_set: 1,
-            message: 'hi',
-            updated: '2017-02-11 16:40:49',
-            id: '12',
-            unresolved: false,
-          },
-        ],
-      };
-      element.changeComments = new ChangeComments(comments, {}, drafts, 123);
-
+      element.changeComments = createChangeComments();
       const parentTo1 = {
         basePatchNum: 'PARENT',
         patchNum: 1,
@@ -464,12 +369,6 @@
       };
 
       assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo1,
-              '/COMMIT_MSG', 'comment'), '2 comments (1 unresolved)');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              '/COMMIT_MSG', 'comment'), '3 comments (1 unresolved)');
-      assert.equal(
           element._computeCommentsStringMobile(element.changeComments, parentTo1
               , '/COMMIT_MSG'), '2c');
       assert.equal(
@@ -488,12 +387,6 @@
           element._computeDraftsStringMobile(element.changeComments, _1To2,
               'unresolved.file'), '1d');
       assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo1,
-              'myfile.txt', 'comment'), '1 comment');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              'myfile.txt', 'comment'), '3 comments');
-      assert.equal(
           element._computeCommentsStringMobile(
               element.changeComments,
               parentTo1,
@@ -515,12 +408,6 @@
           element._computeDraftsStringMobile(element.changeComments, _1To2,
               'myfile.txt'), '');
       assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo1,
-              'file_added_in_rev2.txt', 'comment'), '');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              'file_added_in_rev2.txt', 'comment'), '');
-      assert.equal(
           element._computeCommentsStringMobile(
               element.changeComments,
               parentTo1,
@@ -542,12 +429,6 @@
           element._computeDraftsStringMobile(element.changeComments, _1To2,
               'file_added_in_rev2.txt'), '');
       assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo2,
-              '/COMMIT_MSG', 'comment'), '1 comment');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              '/COMMIT_MSG', 'comment'), '3 comments (1 unresolved)');
-      assert.equal(
           element._computeCommentsStringMobile(
               element.changeComments,
               parentTo2,
@@ -572,12 +453,6 @@
           element._computeDraftsStringMobile(element.changeComments, _1To2,
               '/COMMIT_MSG'), '2d');
       assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo2,
-              'myfile.txt', 'comment'), '2 comments');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              'myfile.txt', 'comment'), '3 comments');
-      assert.equal(
           element._computeCommentsStringMobile(
               element.changeComments,
               parentTo2,
@@ -592,18 +467,6 @@
       assert.equal(
           element._computeDraftsStringMobile(element.changeComments, _1To2,
               'myfile.txt'), '');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo2,
-              'file_added_in_rev2.txt', 'comment'), '');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              'file_added_in_rev2.txt', 'comment'), '');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, parentTo2,
-              'unresolved.file', 'comment'), '2 comments (1 unresolved)');
-      assert.equal(
-          element._computeCommentsString(element.changeComments, _1To2,
-              'unresolved.file', 'comment'), '2 comments (1 unresolved)');
     });
 
     test('_reviewedTitle', () => {
@@ -836,16 +699,6 @@
       });
     });
 
-    test('computed properties', () => {
-      assert.equal(element._computeFileStatus('A'), 'A');
-      assert.equal(element._computeFileStatus(undefined), 'M');
-      assert.equal(element._computeFileStatus(null), 'M');
-
-      assert.equal(element._computeClass('clazz', '/foo/bar/baz'), 'clazz');
-      assert.equal(element._computeClass('clazz', '/COMMIT_MSG'),
-          'clazz invisible');
-    });
-
     test('file review status', () => {
       element._reviewed = ['/COMMIT_MSG', 'myfile.txt'];
       element._filesByPath = {
@@ -898,11 +751,6 @@
       assert.isFalse(toggleExpandSpy.called);
     });
 
-    test('_computeFileStatusLabel', () => {
-      assert.equal(element._computeFileStatusLabel('A'), 'Added');
-      assert.equal(element._computeFileStatusLabel('M'), 'Modified');
-    });
-
     test('_handleFileListClick', () => {
       element._filesByPath = {
         '/COMMIT_MSG': {},
@@ -1498,6 +1346,7 @@
     const commitMsgComments = [
       {
         patch_set: 2,
+        path: '/p',
         id: 'ecf0b9fa_fe1a5f62',
         line: 20,
         updated: '2018-02-08 18:49:18.000000000',
@@ -1506,6 +1355,7 @@
       },
       {
         patch_set: 2,
+        path: '/p',
         id: '503008e2_0ab203ee',
         line: 10,
         updated: '2018-02-14 22:07:43.000000000',
@@ -1514,6 +1364,7 @@
       },
       {
         patch_set: 2,
+        path: '/p',
         id: 'cc788d2c_cb1d728c',
         line: 20,
         in_reply_to: 'ecf0b9fa_fe1a5f62',
@@ -1524,17 +1375,8 @@
     ];
 
     async function setupDiff(diff) {
-      diff.comments = {
-        left: diff.path === '/COMMIT_MSG' ? commitMsgComments : [],
-        right: [],
-        meta: {
-          changeNum: 1,
-          patchRange: {
-            basePatchNum: 'PARENT',
-            patchNum: 2,
-          },
-        },
-      };
+      diff.threads = diff.path === '/COMMIT_MSG' ?
+        createCommentThreads(commitMsgComments) : [];
       diff.prefs = {
         context: 10,
         tab_size: 8,
@@ -1553,7 +1395,7 @@
       };
       diff.diff = getMockDiffResponse();
       commentApiWrapper.loadComments().then(() => {
-        sinon.stub(element.changeComments, 'getCommentsBySideForPath')
+        sinon.stub(element.changeComments, 'getCommentsForPath')
             .withArgs('/COMMIT_MSG', {
               basePatchNum: 'PARENT',
               patchNum: 2,
@@ -1605,8 +1447,6 @@
       // been initialized.
       commentApiWrapper.loadComments().then(() => {
         sinon.stub(element.changeComments, 'getPaths').returns({});
-        sinon.stub(element.changeComments, 'getCommentsBySideForPath')
-            .returns({meta: {}, left: [], right: []});
         done();
       });
       element._loading = false;
@@ -1834,7 +1674,7 @@
       });
 
       test('_getReviewedFiles does not call API', () => {
-        const apiSpy = sinon.spy(element.$.restAPI, 'getReviewedFiles');
+        const apiSpy = sinon.spy(element.restApiService, 'getReviewedFiles');
         element.editMode = true;
         return element._getReviewedFiles().then(files => {
           assert.equal(files.length, 0);
@@ -1888,6 +1728,7 @@
       const commentStubRes1 = [
         {
           patch_set: 2,
+          path: '/p',
           id: '503008e2_0ab203ee',
           line: 20,
           updated: '2018-02-08 18:49:18.000000000',
@@ -1898,6 +1739,7 @@
       const commentStubRes2 = [
         {
           patch_set: 2,
+          path: '/p',
           id: 'ecf0b9fa_fe1a5f62',
           line: 20,
           updated: '2018-02-08 18:49:18.000000000',
@@ -1906,6 +1748,7 @@
         },
         {
           patch_set: 2,
+          path: '/p',
           id: '503008e2_0ab203ee',
           line: 10,
           in_reply_to: 'ecf0b9fa_fe1a5f62',
@@ -1915,6 +1758,7 @@
         },
         {
           patch_set: 2,
+          path: '/p',
           id: '503008e2_0ab203ef',
           line: 20,
           in_reply_to: '503008e2_0ab203ee',
diff --git a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.ts b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.ts
index 1957f5c..b50bff4 100644
--- a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.ts
@@ -17,20 +17,13 @@
 import '@polymer/iron-input/iron-input';
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-included-in-dialog_html';
 import {customElement, property} from '@polymer/decorators';
 import {IncludedInInfo, NumericChangeId} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-
-export interface GrIncludedInDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 interface DisplayGroup {
   title: string;
@@ -63,18 +56,22 @@
   @property({type: String})
   _filterText = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
     if (!this.changeNum) {
       return Promise.reject(new Error('missing required property changeNum'));
     }
     this._filterText = '';
-    return this.$.restAPI.getChangeIncludedIn(this.changeNum).then(configs => {
-      if (!configs) {
-        return;
-      }
-      this._includedIn = configs;
-      this._loaded = true;
-    });
+    return this.restApiService
+      .getChangeIncludedIn(this.changeNum)
+      .then(configs => {
+        if (!configs) {
+          return;
+        }
+        this._includedIn = configs;
+        this._loaded = true;
+      });
   }
 
   _resetData() {
diff --git a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog_html.ts
index 8e90f3b..2029209 100644
--- a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog_html.ts
@@ -100,5 +100,4 @@
       </ul>
     </div>
   </template>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
index d528192..719734a 100644
--- a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
+++ b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-label-score-row/gr-label-score-row';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
index 8b0cf4b..bc61dad 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
@@ -21,7 +21,6 @@
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-date-formatter/gr-date-formatter';
 import '../../shared/gr-formatted-text/gr-formatted-text';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import '../../../styles/gr-voting-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -40,10 +39,18 @@
   VotingRangeInfo,
   NumericChangeId,
   ChangeMessageId,
+  PatchSetNum,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {CommentThread} from '../../../utils/comment-util';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {appContext} from '../../../services/app-context';
+import {pluralize} from '../../../utils/string-util';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
+import {
+  computeAllPatchSets,
+  computeLatestPatchNum,
+  computePredecessor,
+} from '../../../utils/patch-set-util';
 
 const PATCH_SET_PREFIX_PATTERN = /^(?:Uploaded\s*)?(?:P|p)atch (?:S|s)et \d+:\s*(.*)/;
 const LABEL_TITLE_SCORE_PATTERN = /^(-?)([A-Za-z0-9-]+?)([+-]\d+)?[.]?$/;
@@ -58,12 +65,6 @@
   id: ChangeMessageId;
 }
 
-export interface GrMessage {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 interface ChangeMessage extends ChangeMessageInfo {
   // TODO(TS): maybe should be an enum instead
   type: string;
@@ -192,6 +193,8 @@
   })
   _commentCountText = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   created() {
     super.created();
     this.addEventListener('click', e => this._handleClick(e));
@@ -199,13 +202,13 @@
 
   attached() {
     super.attached();
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this.config = config;
     });
-    this.$.restAPI.getLoggedIn().then(loggedIn => {
+    this.restApiService.getLoggedIn().then(loggedIn => {
       this._loggedIn = loggedIn;
     });
-    this.$.restAPI.getIsAdmin().then(isAdmin => {
+    this.restApiService.getIsAdmin().then(isAdmin => {
       this._isAdmin = !!isAdmin;
     });
   }
@@ -220,31 +223,15 @@
   }
 
   _computeCommentCountText(threadsLength?: number) {
-    if (threadsLength === 0) {
+    if (!threadsLength) {
       return undefined;
-    } else if (threadsLength === 1) {
-      return '1 comment';
-    } else {
-      return `${threadsLength} comments`;
     }
-  }
 
-  _onThreadListModified() {
-    // TODO(taoalpha): this won't propagate the changes to the files
-    // should consider replacing this with either top level events
-    // or gerrit level events
-
-    // emit the event so change-view can also get updated with latest changes
-    this.dispatchEvent(
-      new CustomEvent('comment-refresh', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    return pluralize(threadsLength, 'comment');
   }
 
   _computeMessageContentExpanded(content?: string, tag?: ReviewInputTag) {
-    return this._computeMessageContent(content, tag, true);
+    return this._computeMessageContent(true, content, tag);
   }
 
   _patchsetCommentSummary(commentThreads: CommentThread[] = []) {
@@ -276,18 +263,45 @@
     tag?: ReviewInputTag,
     commentThreads?: CommentThread[]
   ) {
-    const summary = this._computeMessageContent(content, tag, false);
+    const summary = this._computeMessageContent(false, content, tag);
     if (summary || !commentThreads) return summary;
     return this._patchsetCommentSummary(commentThreads);
   }
 
+  _isNewPatchsetTag(tag?: ReviewInputTag) {
+    return tag?.endsWith(':newPatchSet') || tag?.endsWith(':newWipPatchSet');
+  }
+
+  _handleViewPatchsetDiff(e: Event) {
+    if (!this.message || !this.change) return;
+    const match = this.message.message.match(/Uploaded patch set (\d+)./);
+    let patchNum: PatchSetNum;
+    // Message is of the form "Commit Message was updated" or "Patchset X
+    // was rebased"
+    if (!match || match.length < 1) {
+      patchNum = computeLatestPatchNum(computeAllPatchSets(this.change))!;
+    } else {
+      if (isNaN(Number(match[1])))
+        throw new Error('invalid patchnum in message');
+      patchNum = Number(match[1]) as PatchSetNum;
+    }
+    GerritNav.navigateToChange(
+      this.change,
+      patchNum,
+      computePredecessor(patchNum)
+    );
+    // stop propagation to stop message expansion
+    e.stopPropagation();
+  }
+
   _computeMessageContent(
-    content = '',
-    tag: ReviewInputTag = '' as ReviewInputTag,
-    isExpanded: boolean
+    isExpanded: boolean,
+    content?: string,
+    tag?: ReviewInputTag
   ) {
-    const isNewPatchSet =
-      tag.endsWith(':newPatchSet') || tag.endsWith(':newWipPatchSet');
+    if (!content) return '';
+    const isNewPatchSet = this._isNewPatchsetTag(tag);
+
     const lines = content.split('\n');
     const filteredLines = lines.filter(line => {
       if (!isExpanded && line.startsWith('>')) {
@@ -472,7 +486,7 @@
     e.preventDefault();
     if (!this.message || !this.message.id || !this.changeNum) return;
     this._isDeletingChangeMsg = true;
-    this.$.restAPI
+    this.restApiService
       .deleteChangeCommitMessage(this.changeNum, this.message.id)
       .then(() => {
         this._isDeletingChangeMsg = false;
@@ -488,7 +502,7 @@
 
   @observe('projectName')
   _projectNameChanged(name: string) {
-    this.$.restAPI.getProjectConfig(name as RepoName).then(config => {
+    this.restApiService.getProjectConfig(name as RepoName).then(config => {
       this._projectConfig = config;
     });
   }
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message_html.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message_html.ts
index ae4adf7..57beacf 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message_html.ts
@@ -111,13 +111,16 @@
       right: var(--spacing-l);
       top: var(--spacing-m);
     }
-    .dateContainer .patchset {
+    .dateContainer gr-button {
       margin-right: var(--spacing-m);
       color: var(--deemphasized-text-color);
     }
     .dateContainer .patchset:before {
       content: 'Patchset ';
     }
+    .dateContainer .patchsetDiffButton {
+      margin-right: var(--spacing-m);
+    }
     span.date {
       color: var(--deemphasized-text-color);
     }
@@ -253,7 +256,6 @@
               change-num="[[changeNum]]"
               logged-in="[[_loggedIn]]"
               hide-toggle-buttons
-              on-thread-list-modified="_onThreadListModified"
             >
             </gr-thread-list>
           </template>
@@ -276,6 +278,11 @@
         </div>
       </template>
       <span class="dateContainer">
+        <template is="dom-if" if="[[_isNewPatchsetTag(message.tag)]]">
+          <gr-button on-click="_handleViewPatchsetDiff" link>
+            View Diff
+          </gr-button>
+        </template>
         <template is="dom-if" if="[[message._revision_number]]">
           <span class="patchset">[[message._revision_number]]</span>
         </template>
@@ -306,5 +313,4 @@
       </span>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
index a705d45..facde01 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
@@ -17,6 +17,8 @@
 
 import '../../../test/common-test-setup-karma.js';
 import './gr-message.js';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
+import {createChange, createRevisions} from '../../../test/test-data-generators.js';
 
 const basicFixture = fixtureFromElement('gr-message');
 
@@ -228,20 +230,59 @@
       assert.deepEqual(stub.lastCall.args[0].detail, {id: element.message.id});
     });
 
+    suite('uploaded patchset X message navigates to X - 1 vs  X', () => {
+      let navStub;
+      setup(() => {
+        element.change = {...createChange(), revisions: createRevisions(4)};
+        navStub = sinon.stub(GerritNav, 'navigateToChange');
+      });
+
+      test('Patchset 1 navigates to Base', () => {
+        element.message = {
+          message: 'Uploaded patch set 1.',
+        };
+        element._handleViewPatchsetDiff(new MouseEvent('click'));
+        assert.isTrue(navStub.calledWithExactly(element.change, 1,
+            'PARENT'));
+      });
+
+      test('Patchset X navigates to X vs X - 1', () => {
+        element.message = {
+          message: 'Uploaded patch set 2.',
+        };
+        element._handleViewPatchsetDiff(new MouseEvent('click'));
+        assert.isTrue(navStub.calledWithExactly(element.change, 2, 1));
+
+        element.message = {
+          message: 'Uploaded patch set 200.',
+        };
+        element._handleViewPatchsetDiff(new MouseEvent('click'));
+        assert.isTrue(navStub.calledWithExactly(element.change, 200, 199));
+      });
+
+      test('Commit message updated', () => {
+        element.message = {
+          message: 'Commit message updated.',
+        };
+        element._handleViewPatchsetDiff(new MouseEvent('click'));
+        assert.isTrue(navStub.calledWithExactly(element.change, 4, 3));
+      });
+    });
+
     suite('compute messages', () => {
       test('empty', () => {
-        assert.equal(element._computeMessageContent('', '', true), '');
-        assert.equal(element._computeMessageContent('', '', false), '');
+        assert.equal(element._computeMessageContent(true, '', ''), '');
+        assert.equal(element._computeMessageContent(false, '', ''), '');
       });
 
       test('new patchset', () => {
         const original = 'Uploaded patch set 1.';
         const tag = 'autogenerated:gerrit:newPatchSet';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
         assert.equal(actual, original);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, original);
       });
 
@@ -249,11 +290,11 @@
         const original = 'Patch Set 27: Patch Set 26 was rebased';
         const tag = 'autogenerated:gerrit:newPatchSet';
         const expected = 'Patch Set 26 was rebased';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -261,11 +302,11 @@
         const original = 'Patch Set 1:\n\nThis change is ready for review.';
         const tag = undefined;
         const expected = 'This change is ready for review.';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -273,9 +314,9 @@
         const original = 'Patch Set 1: Code-Style+1';
         const tag = undefined;
         const expected = '';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -283,9 +324,9 @@
         const original = 'Patch Set 1:\n\n(3 comments)';
         const tag = undefined;
         const expected = '';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
     });
@@ -418,7 +459,6 @@
     test('single patchset comment posted', () => {
       const threads = [{
         comments: [{
-          __path: '/PATCHSET_LEVEL',
           change_message_id: '6a07f64a82f96e7337ca5f7f84cfc73abf8ac2a3',
           patch_set: 1,
           id: 'e365b138_bed65caa',
@@ -434,13 +474,12 @@
       }];
       assert.equal(element._computeMessageContentCollapsed(
           '', undefined, threads), 'testing the load');
-      assert.equal(element._computeMessageContent('', undefined, false), '');
+      assert.equal(element._computeMessageContent(false, '', undefined), '');
     });
 
     test('single patchset comment with reply', () => {
       const threads = [{
         comments: [{
-          __path: '/PATCHSET_LEVEL',
           patch_set: 1,
           id: 'e365b138_bed65caa',
           updated: '2020-05-15 13:35:56.000000000',
@@ -449,7 +488,6 @@
           path: '/PATCHSET_LEVEL',
           collapsed: false,
         }, {
-          __path: '/PATCHSET_LEVEL',
           change_message_id: '6a07f64a82f96e7337ca5f7f84cfc73abf8ac2a3',
           patch_set: 1,
           id: 'd6efcc85_4cbbb6f4',
@@ -467,7 +505,7 @@
       }];
       assert.equal(element._computeMessageContentCollapsed(
           '', undefined, threads), 'n');
-      assert.equal(element._computeMessageContent('', undefined, false), '');
+      assert.equal(element._computeMessageContent(false, '', undefined), '');
     });
   });
 
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_html.ts b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_html.ts
index d3a72072..e1ef3f8 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_html.ts
@@ -24,7 +24,6 @@
     }
     .header {
       align-items: center;
-      border-top: 1px solid var(--border-color);
       border-bottom: 1px solid var(--border-color);
       display: flex;
       justify-content: space-between;
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
index f8a4af2..e6c9f42 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
@@ -26,11 +25,10 @@
 import {htmlTemplate} from './gr-related-changes-list_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {ChangeStatus} from '../../../constants/constants';
-import {patchNumEquals} from '../../../utils/patch-set-util';
+
 import {changeIsOpen} from '../../../utils/change-util';
 import {getPluginEndpoints} from '../../shared/gr-js-api-interface/gr-plugin-endpoints';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   ChangeId,
   ChangeInfo,
@@ -43,12 +41,8 @@
   SubmittedTogetherInfo,
 } from '../../../types/common';
 import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
-
-export interface GrRelatedChangesList {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
+import {pluralize} from '../../../utils/string-util';
 
 function getEmptySubmitTogetherInfo(): SubmittedTogetherInfo {
   return {changes: [], non_visible_changes: 0};
@@ -117,6 +111,8 @@
   @property({type: Array})
   _sameTopic?: ChangeInfo[] = [];
 
+  private readonly restApiService = appContext.restApiService;
+
   clear() {
     this.loading = true;
     this.hidden = true;
@@ -135,7 +131,7 @@
     const change = this.change;
     this.loading = true;
     const promises: Array<Promise<void>> = [
-      this.$.restAPI
+      this.restApiService
         .getRelatedChanges(change._number, this.patchNum)
         .then(response => {
           if (!response) {
@@ -148,13 +144,13 @@
             response.changes
           );
         }),
-      this.$.restAPI
+      this.restApiService
         .getChangesSubmittedTogether(change._number)
         .then(response => {
           this._submittedTogether = response;
           this._fireReloadEvent();
         }),
-      this.$.restAPI
+      this.restApiService
         .getChangeCherryPicks(change.project, change.change_id, change._number)
         .then(response => {
           this._cherryPicks = response || [];
@@ -165,12 +161,14 @@
     // Get conflicts if change is open and is mergeable.
     if (changeIsOpen(change) && this.mergeable) {
       promises.push(
-        this.$.restAPI.getChangeConflicts(change._number).then(response => {
-          // Because the server doesn't always return a response and the
-          // template expects an array, always return an array.
-          this._conflicts = response ? response : [];
-          this._fireReloadEvent();
-        })
+        this.restApiService
+          .getChangeConflicts(change._number)
+          .then(response => {
+            // Because the server doesn't always return a response and the
+            // template expects an array, always return an array.
+            this._conflicts = response ? response : [];
+            this._fireReloadEvent();
+          })
       );
     }
 
@@ -181,7 +179,7 @@
             throw new Error('_getServerConfig returned undefined ');
           }
           if (!config.change.submit_whole_topic) {
-            return this.$.restAPI
+            return this.restApiService
               .getChangesWithSameTopic(change.topic, change._number)
               .then(response => {
                 this._sameTopic = response;
@@ -222,7 +220,7 @@
   }
 
   _getServerConfig() {
-    return this.$.restAPI.getConfig();
+    return this.restApiService.getConfig();
   }
 
   _computeChangeURL(
@@ -412,7 +410,7 @@
       return [];
     }
     for (const rev in change.revisions) {
-      if (patchNumEquals(change.revisions[rev]._number, patchNum)) {
+      if (change.revisions[rev]._number === patchNum) {
         changeRevision = rev;
       }
     }
@@ -453,8 +451,7 @@
   }
 
   _computeNonVisibleChangesNote(n: number) {
-    const noun = n === 1 ? 'change' : 'changes';
-    return `(+ ${n} non-visible ${noun})`;
+    return `(+ ${pluralize(n, 'non-visible change')})`;
   }
 }
 
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
index d4cd0f6..0f42028 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
@@ -214,5 +214,4 @@
     </gr-endpoint-decorator>
   </div>
   <div hidden$="[[!loading]]">Loading...</div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.js b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.js
index 3983c5a..e71df971 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.js
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.js
@@ -237,13 +237,13 @@
     };
     element.mergeable = true;
     element.addEventListener('new-section-loaded', loadedStub);
-    sinon.stub(element.$.restAPI, 'getRelatedChanges')
+    sinon.stub(element.restApiService, 'getRelatedChanges')
         .returns(Promise.resolve({changes: []}));
-    sinon.stub(element.$.restAPI, 'getChangesSubmittedTogether')
+    sinon.stub(element.restApiService, 'getChangesSubmittedTogether')
         .returns(Promise.resolve());
-    sinon.stub(element.$.restAPI, 'getChangeCherryPicks')
+    sinon.stub(element.restApiService, 'getChangeCherryPicks')
         .returns(Promise.resolve());
-    sinon.stub(element.$.restAPI, 'getChangeConflicts')
+    sinon.stub(element.restApiService, 'getChangeConflicts')
         .returns(Promise.resolve());
 
     return element.reload().then(() => {
@@ -257,13 +257,13 @@
     setup(() => {
       element = basicFixture.instantiate();
 
-      sinon.stub(element.$.restAPI, 'getRelatedChanges')
+      sinon.stub(element.restApiService, 'getRelatedChanges')
           .returns(Promise.resolve({changes: []}));
-      sinon.stub(element.$.restAPI, 'getChangesSubmittedTogether')
+      sinon.stub(element.restApiService, 'getChangesSubmittedTogether')
           .returns(Promise.resolve());
-      sinon.stub(element.$.restAPI, 'getChangeCherryPicks')
+      sinon.stub(element.restApiService, 'getChangeCherryPicks')
           .returns(Promise.resolve());
-      sinon.stub(element.$.restAPI, 'getChangeConflicts')
+      sinon.stub(element.restApiService, 'getChangeConflicts')
           .returns(Promise.resolve());
     });
 
@@ -286,13 +286,13 @@
     setup(() => {
       element = basicFixture.instantiate();
 
-      sinon.stub(element.$.restAPI, 'getRelatedChanges')
+      sinon.stub(element.restApiService, 'getRelatedChanges')
           .returns(Promise.resolve({changes: []}));
-      sinon.stub(element.$.restAPI, 'getChangesSubmittedTogether')
+      sinon.stub(element.restApiService, 'getChangesSubmittedTogether')
           .returns(Promise.resolve());
-      sinon.stub(element.$.restAPI, 'getChangeCherryPicks')
+      sinon.stub(element.restApiService, 'getChangeCherryPicks')
           .returns(Promise.resolve());
-      conflictsStub = sinon.stub(element.$.restAPI, 'getChangeConflicts')
+      conflictsStub = sinon.stub(element.restApiService, 'getChangeConflicts')
           .returns(Promise.resolve());
     });
 
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
index 7b34263..b92f179 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
@@ -22,7 +22,6 @@
 import '../../shared/gr-formatted-text/gr-formatted-text';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-storage/gr-storage';
 import '../../shared/gr-account-list/gr-account-list';
 import '../gr-label-scores/gr-label-scores';
@@ -43,7 +42,6 @@
   ReviewerState,
   SpecialFilePath,
 } from '../../../constants/constants';
-import {KnownExperimentId} from '../../../services/flags/flags';
 import {fetchChangeUpdates} from '../../../utils/patch-set-util';
 import {KeyboardShortcutMixin} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 import {accountKey, removeServiceUsers} from '../../../utils/account-util';
@@ -51,10 +49,7 @@
 import {IronA11yAnnouncer} from '@polymer/iron-a11y-announcer/iron-a11y-announcer';
 import {TargetElement} from '../../plugins/gr-plugin-types';
 import {customElement, observe, property} from '@polymer/decorators';
-import {
-  ErrorCallback,
-  RestApiService,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {FixIronA11yAnnouncer} from '../../../types/types';
 import {
   AccountAddition,
@@ -110,6 +105,8 @@
 import {isAttentionSetEnabled} from '../../../utils/attention-set-util';
 import {CODE_REVIEW, getMaxAccounts} from '../../../utils/label-util';
 import {isUnresolved} from '../../../utils/comment-util';
+import {pluralize} from '../../../utils/string-util';
+import {fireAlert, fireEvent, fireServerError} from '../../../utils/event-util';
 
 const STORAGE_DEBOUNCE_INTERVAL_MS = 400;
 
@@ -140,6 +137,7 @@
   SAVE: 'Save but do not send notification or change review state',
   START_REVIEW: 'Mark as ready for review and send reply',
   SEND: 'Send reply',
+  DISABLED_COMMENT_EDITING: 'Save draft comments to enable send',
 };
 
 const EMPTY_REPLY_MESSAGE = 'Cannot send an empty reply.';
@@ -157,7 +155,6 @@
 
 export interface GrReplyDialog {
   $: {
-    restAPI: RestApiService & Element;
     jsAPI: JsApiService & Element;
     reviewers: GrAccountList;
     ccs: GrAccountList;
@@ -373,6 +370,8 @@
   @property({type: Array, computed: '_computeAllReviewers(_reviewers.*)'})
   _allReviewers: (AccountInfo | GroupInfo)[] = [];
 
+  private readonly restApiService = appContext.restApiService;
+
   get keyBindings() {
     return {
       esc: '_handleEscKey',
@@ -380,8 +379,6 @@
     };
   }
 
-  _isPatchsetCommentsExperimentEnabled = false;
-
   constructor() {
     super();
     this.filterReviewerSuggestion = this._filterReviewerSuggestionGenerator(
@@ -421,16 +418,13 @@
   /** @override */
   ready() {
     super.ready();
-    this._isPatchsetCommentsExperimentEnabled = this.flagsService.isEnabled(
-      KnownExperimentId.PATCHSET_COMMENTS
-    );
     this.$.jsAPI.addElement(TargetElement.REPLY_DIALOG, this);
   }
 
   open(focusTarget?: FocusTarget) {
     if (!this.change) throw new Error('missing required change property');
     this.knownLatestState = LatestPatchState.CHECKING;
-    fetchChangeUpdates(this.change, this.$.restAPI).then(result => {
+    fetchChangeUpdates(this.change, this.restApiService).then(result => {
       this.knownLatestState = result.isLatest
         ? LatestPatchState.LATEST
         : LatestPatchState.NOT_LATEST;
@@ -445,15 +439,10 @@
       // Otherwise, check for an unsaved draft in localstorage.
       this.draft = this._loadStoredDraft();
     }
-    if (this.$.restAPI.hasPendingDiffDrafts()) {
+    if (this.restApiService.hasPendingDiffDrafts()) {
       this._savingComments = true;
-      this.$.restAPI.awaitPendingDiffDrafts().then(() => {
-        this.dispatchEvent(
-          new CustomEvent('comment-refresh', {
-            composed: true,
-            bubbles: true,
-          })
-        );
+      this.restApiService.awaitPendingDiffDrafts().then(() => {
+        fireEvent(this, 'comment-refresh');
         this._savingComments = false;
       });
     }
@@ -548,13 +537,7 @@
             const moveTo = isReviewer ? 'reviewer' : 'CC';
             const id = account.name || account.email || key;
             const message = `${id} moved from ${moveFrom} to ${moveTo}.`;
-            this.dispatchEvent(
-              new CustomEvent('show-alert', {
-                detail: {message},
-                composed: true,
-                bubbles: true,
-              })
-            );
+            fireAlert(this, message);
           }
         }
       }
@@ -568,7 +551,7 @@
     for (const splice of indexSplices) {
       for (const account of splice.removed) {
         if (!this._reviewersPendingRemove[type]) {
-          console.error('Invalid type ' + type + ' for reviewer.');
+          this.reporting.error(new Error(`Invalid type ${type} for reviewer.`));
           return;
         }
         this._reviewersPendingRemove[type].push(account);
@@ -616,7 +599,7 @@
       return;
     }
 
-    return this.$.restAPI
+    return this.restApiService
       .removeChangeReviewer(this.change._number, accountKey(account))
       .then((response?: Response) => {
         if (!response?.ok || !this.change) return;
@@ -686,17 +669,13 @@
     }
 
     if (this.draft) {
-      if (this._isPatchsetCommentsExperimentEnabled) {
-        const comment: CommentInput = {
-          message: this.draft,
-          unresolved: !this._isResolvedPatchsetLevelComment,
-        };
-        reviewInput.comments = {
-          [SpecialFilePath.PATCHSET_LEVEL_COMMENTS]: [comment],
-        };
-      } else {
-        reviewInput.message = this.draft;
-      }
+      const comment: CommentInput = {
+        message: this.draft,
+        unresolved: !this._isResolvedPatchsetLevelComment,
+      };
+      reviewInput.comments = {
+        [SpecialFilePath.PATCHSET_LEVEL_COMMENTS]: [comment],
+      };
     }
 
     const accountAdditions = new Map<AccountId | EmailAddress, boolean>();
@@ -729,13 +708,7 @@
           return new Map<AccountId | EmailAddress, boolean>();
         }
         if (!response.ok) {
-          this.dispatchEvent(
-            new CustomEvent('server-error', {
-              detail: {response},
-              composed: true,
-              bubbles: true,
-            })
-          );
+          fireServerError(response);
           return new Map<AccountId | EmailAddress, boolean>();
         }
 
@@ -798,8 +771,9 @@
     return account._account_id === change.owner._account_id;
   }
 
-  _handle400Error(response?: Response | null) {
-    if (!response) throw new Error('Reponse is empty.');
+  _handle400Error(r?: Response | null) {
+    if (!r) throw new Error('Reponse is empty.');
+    let response: Response = r;
     // A call to _saveReview could fail with a server error if erroneous
     // reviewers were requested. This is signalled with a 400 Bad Request
     // status. The default gr-rest-api-interface error handling would
@@ -816,12 +790,12 @@
     // Using response.clone() here, because getResponseObject() and
     // potentially the generic error handler will want to call text() on the
     // response object, which can only be done once per object.
-    const jsonPromise = this.$.restAPI.getResponseObject(response.clone());
+    const jsonPromise = this.restApiService.getResponseObject(response.clone());
     return jsonPromise.then((parsed: ParsedJSON) => {
       const result = parsed as ReviewResult;
       // Only perform custom error handling for 400s and a parseable
       // ReviewResult response.
-      if (response && response.status === 400 && result && result.reviewers) {
+      if (response.status === 400 && result && result.reviewers) {
         const errors: string[] = [];
         const addReviewers = Object.values(result.reviewers);
         addReviewers.forEach(r => errors.push(r.error ?? 'no explanation'));
@@ -831,13 +805,7 @@
           text: () => Promise.resolve(errors.join(', ')),
         };
       }
-      this.dispatchEvent(
-        new CustomEvent('server-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireServerError(response);
     });
   }
 
@@ -847,13 +815,7 @@
 
   _computeDraftsTitle(draftCommentThreads?: CommentThread[]) {
     const total = draftCommentThreads ? draftCommentThreads.length : 0;
-    if (total === 0) {
-      return '';
-    }
-    if (total === 1) {
-      return '1 Draft';
-    }
-    return `${total} Drafts`;
+    return pluralize(total, 'Draft');
   }
 
   _computeMessagePlaceholder(canBeStarted: boolean) {
@@ -912,9 +874,7 @@
   _onAttentionExpandedChange() {
     // If the attention-detail section is expanded without dispatching this
     // event, then the dialog may expand beyond the screen's bottom border.
-    this.dispatchEvent(
-      new CustomEvent('iron-resize', {composed: true, bubbles: true})
-    );
+    fireEvent(this, 'iron-resize');
   }
 
   _showAttentionSummary(config?: ServerInfo, attentionExpanded?: boolean) {
@@ -1127,8 +1087,11 @@
     if (containsAll(currentAttentionSet, newAttentionSet)) {
       return 'No additions to the attention set.';
     }
-    console.error(
-      '_computeDoNotUpdateMessage() should not be called when users were added to the attention set.'
+    this.reporting.error(
+      new Error(
+        '_computeDoNotUpdateMessage()' +
+          'should not be called when users were added to the attention set.'
+      )
     );
     return '';
   }
@@ -1229,7 +1192,7 @@
   }
 
   _getAccount() {
-    return this.$.restAPI.getAccount();
+    return this.restApiService.getAccount();
   }
 
   _cancelTapHandler(e: Event) {
@@ -1275,13 +1238,7 @@
       return;
     }
     if (this._sendDisabled) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          bubbles: true,
-          composed: true,
-          detail: {message: EMPTY_REPLY_MESSAGE},
-        })
-      );
+      fireAlert(this, EMPTY_REPLY_MESSAGE);
       return;
     }
     return this.send(this._includeComments, this.canBeStarted)
@@ -1302,7 +1259,7 @@
   _saveReview(review: ReviewInput, errFn?: ErrorCallback) {
     if (!this.change) throw new Error('missing required change property');
     if (!this.patchNum) throw new Error('missing required patchNum property');
-    return this.$.restAPI.saveChangeReview(
+    return this.restApiService.saveChangeReview(
       this.change._number,
       this.patchNum,
       review,
@@ -1331,7 +1288,9 @@
       this._focusOn(FocusTarget.REVIEWERS);
       return;
     }
-    console.error('_confirmPendingReviewer called without pending confirm');
+    this.reporting.error(
+      new Error('_confirmPendingReviewer called without pending confirm')
+    );
   }
 
   _cancelPendingReviewer() {
@@ -1386,12 +1345,7 @@
   }
 
   _handleHeightChanged() {
-    this.dispatchEvent(
-      new CustomEvent('autogrow', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'autogrow');
   }
 
   _handleLabelsChanged() {
@@ -1420,7 +1374,10 @@
       : ButtonLabels.SEND;
   }
 
-  _computeSendButtonTooltip(canBeStarted: boolean) {
+  _computeSendButtonTooltip(canBeStarted?: boolean, commentEditing?: boolean) {
+    if (commentEditing) {
+      return ButtonTooltips.DISABLED_COMMENT_EDITING;
+    }
     return canBeStarted ? ButtonTooltips.START_REVIEW : ButtonTooltips.SEND;
   }
 
@@ -1478,7 +1435,7 @@
 
   _getReviewerSuggestionsProvider(change: ChangeInfo) {
     const provider = GrReviewerSuggestionsProvider.create(
-      this.$.restAPI,
+      this.restApiService,
       change._number,
       SUGGESTIONS_PROVIDERS_USERS_TYPES.REVIEWER
     );
@@ -1488,7 +1445,7 @@
 
   _getCcSuggestionsProvider(change: ChangeInfo) {
     const provider = GrReviewerSuggestionsProvider.create(
-      this.$.restAPI,
+      this.restApiService,
       change._number,
       SUGGESTIONS_PROVIDERS_USERS_TYPES.CC
     );
@@ -1496,20 +1453,6 @@
     return provider;
   }
 
-  _onThreadListModified() {
-    // TODO(taoalpha): this won't propogate the changes to the files
-    // should consider replacing this with either top level events
-    // or gerrit level events
-
-    // emit the event so change-view can also get updated with latest changes
-    this.dispatchEvent(
-      new CustomEvent('comment-refresh', {
-        composed: true,
-        bubbles: true,
-      })
-    );
-  }
-
   reportAttentionSetChanges(
     modified: boolean,
     addedSet?: AttentionSetInput[],
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_html.ts
index c56a5c9..15e461a 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_html.ts
@@ -303,16 +303,14 @@
       </gr-endpoint-decorator>
     </section>
     <section class="previewContainer">
-      <template is="dom-if" if="[[_isPatchsetCommentsExperimentEnabled]]">
-        <label>
-          <input
-            id="resolvedPatchsetLevelCommentCheckbox"
-            type="checkbox"
-            checked="{{_isResolvedPatchsetLevelComment::change}}"
-          />
-          Resolved
-        </label>
-      </template>
+      <label>
+        <input
+          id="resolvedPatchsetLevelCommentCheckbox"
+          type="checkbox"
+          checked="{{_isResolvedPatchsetLevelComment::change}}"
+        />
+        Resolved
+      </label>
       <label class="preview-formatting">
         <input type="checkbox" checked="{{_previewFormatting::change}}" />
         Preview formatting
@@ -357,7 +355,6 @@
         change-num="[[change._number]]"
         logged-in="true"
         hide-toggle-buttons=""
-        on-thread-list-modified="_onThreadListModified"
       >
       </gr-thread-list>
       <span
@@ -608,7 +605,7 @@
             disabled="[[_sendDisabled]]"
             class="action send"
             has-tooltip=""
-            title$="[[_computeSendButtonTooltip(canBeStarted)]]"
+            title$="[[_computeSendButtonTooltip(canBeStarted, _commentEditing)]]"
             on-click="_sendTapHandler"
             >[[_sendButtonLabel]]</gr-button
           >
@@ -617,6 +614,5 @@
     </div>
   </div>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
index b612a57..09f8636 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
@@ -21,6 +21,7 @@
 import {mockPromise} from '../../../test/test-utils.js';
 import {SpecialFilePath} from '../../../constants/constants.js';
 import {appContext} from '../../../services/app-context.js';
+import {addListenerForTest} from '../../../test/test-utils.js';
 
 const basicFixture = fixtureFromElement('gr-reply-dialog');
 
@@ -131,7 +132,7 @@
           try {
             const result = jsonResponseProducer(review) || {};
             const resultStr =
-            element.$.restAPI.JSON_PREFIX + JSON.stringify(result);
+            element.restApiService.JSON_PREFIX + JSON.stringify(result);
             resolve({
               ok: true,
               text() {
@@ -778,23 +779,23 @@
     assert.isTrue(eraseDraftCommentStub.calledWith(location));
   });
 
-  test('400 converts to human-readable server-error', async () => {
+  test('400 converts to human-readable server-error', done => {
     sinon.stub(window, 'fetch').callsFake(() => {
       const text = '....{"reviewers":{"id1":{"error":"human readable"}}}';
       return Promise.resolve(cloneableResponse(400, text));
     });
 
-    let resolver;
-    const promise = new Promise(r => resolver = r);
-    element.addEventListener('server-error', resolver);
+    const listener = event => {
+      if (event.target !== document) return;
+      event.detail.response.text().then(body => {
+        if (body === 'human readable') {
+          done();
+        }
+      });
+    };
+    addListenerForTest(document, 'server-error', listener);
 
-    await flush();
-    element.send();
-
-    const event = await promise;
-    assert.equal(event.target, element);
-    const text = await event.detail.response.text();
-    assert.equal(text, 'human readable');
+    flush(() => { element.send(); });
   });
 
   test('non-json 400 is treated as a normal server-error', done => {
@@ -803,15 +804,15 @@
       return Promise.resolve(cloneableResponse(400, text));
     });
 
-    element.addEventListener('server-error', event => {
-      if (event.target !== element) {
-        return;
-      }
+    const listener = event => {
+      if (event.target !== document) return;
       event.detail.response.text().then(body => {
-        assert.equal(body, 'Comment validation error!');
-        done();
+        if (body === 'Comment validation error!') {
+          done();
+        }
       });
-    });
+    };
+    addListenerForTest(document, 'server-error', listener);
 
     // Async tick is needed because iron-selector content is distributed and
     // distributed content requires an observer to be set up.
@@ -977,7 +978,7 @@
   });
 
   test('_removeAccount', done => {
-    sinon.stub(element.$.restAPI, 'removeChangeReviewer')
+    sinon.stub(element.restApiService, 'removeChangeReviewer')
         .returns(Promise.resolve({ok: true}));
     const arr = [makeAccount(), makeAccount()];
     element.change.reviewers = {
@@ -1255,12 +1256,13 @@
         },
       },
     });
-    element.addEventListener('server-error', e => {
+    const listener = e => {
       e.detail.response.text().then(text => {
         assert.equal(text, [error1, error2, error3].join(', '));
         done();
       });
-    });
+    };
+    addListenerForTest(document, 'server-error', listener);
     element._handle400Error(cloneableResponse(400, text));
   });
 
@@ -1278,36 +1280,6 @@
     });
   });
 
-  suite('post review API', () => {
-    let startReviewStub;
-
-    setup(() => {
-      startReviewStub = sinon.stub(
-          element.$.restAPI,
-          'startReview')
-          .callsFake(() => Promise.resolve());
-    });
-
-    test('ready property in review input on start review', () => {
-      stubSaveReview(review => {
-        assert.isTrue(review.ready);
-        return {ready: true};
-      });
-      return element.send(true, true).then(() => {
-        assert.isFalse(startReviewStub.called);
-      });
-    });
-
-    test('no ready property in review input on save review', () => {
-      stubSaveReview(review => {
-        assert.isUndefined(review.ready);
-      });
-      return element.send(true, false).then(() => {
-        assert.isFalse(startReviewStub.called);
-      });
-    });
-  });
-
   suite('start review and save buttons', () => {
     let sendStub;
 
@@ -1371,8 +1343,9 @@
         const refreshHandler = sinon.stub();
 
         element.addEventListener('comment-refresh', refreshHandler);
-        sinon.stub(element.$.restAPI, 'hasPendingDiffDrafts').returns(true);
-        element.$.restAPI._pendingRequests.sendDiffDraft = [promise];
+        sinon.stub(element.restApiService, 'hasPendingDiffDrafts').returns(
+            true);
+        element.restApiService._pendingRequests.sendDiffDraft = [promise];
         element.open();
 
         assert.isFalse(refreshHandler.called);
@@ -1380,14 +1353,15 @@
 
         promise.resolve();
 
-        return element.$.restAPI.awaitPendingDiffDrafts().then(() => {
+        return element.restApiService.awaitPendingDiffDrafts().then(() => {
           assert.isTrue(refreshHandler.called);
           assert.isFalse(element._savingComments);
         });
       });
 
       test('no', () => {
-        sinon.stub(element.$.restAPI, 'hasPendingDiffDrafts').returns(false);
+        sinon.stub(element.restApiService, 'hasPendingDiffDrafts').returns(
+            false);
         element.open();
         assert.notOk(element._savingComments);
       });
diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.ts b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.ts
index 9c3fa42..254ecca 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.ts
@@ -16,7 +16,6 @@
  */
 import '../../shared/gr-account-chip/gr-account-chip';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -39,16 +38,11 @@
 } from '../../../types/common';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {GrAccountChip} from '../../shared/gr-account-chip/gr-account-chip';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {isRemovableReviewer} from '../../../utils/change-util';
 import {ReviewerState} from '../../../constants/constants';
-
-export interface GrReviewerList {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
+import {KnownExperimentId} from '../../../services/flags/flags';
 
 @customElement('gr-reviewer-list')
 export class GrReviewerList extends GestureEventListeners(
@@ -94,6 +88,21 @@
   @property({type: Object})
   _xhrPromise?: Promise<Response | undefined>;
 
+  @property({type: Boolean})
+  _isNewChangeSummaryUiEnabled = false;
+
+  private readonly restApiService = appContext.restApiService;
+
+  private readonly flagsService = appContext.flagsService;
+
+  /** @override */
+  ready() {
+    super.ready();
+    this._isNewChangeSummaryUiEnabled = this.flagsService.isEnabled(
+      KnownExperimentId.NEW_CHANGE_SUMMARY_UI
+    );
+  }
+
   @computed('ccsOnly')
   get _addLabel() {
     return this.ccsOnly ? 'Add CC' : 'Add reviewer';
@@ -323,6 +332,6 @@
 
   _removeReviewer(id: AccountId | EmailAddress): Promise<Response | undefined> {
     if (!this.change) return Promise.resolve(undefined);
-    return this.$.restAPI.removeChangeReviewer(this.change._number, id);
+    return this.restApiService.removeChangeReviewer(this.change._number, id);
   }
 }
diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_html.ts b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_html.ts
index 616a7db..ccdcf8d 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_html.ts
@@ -28,6 +28,16 @@
     .container {
       display: block;
     }
+    .addReviewer iron-icon {
+      color: inherit;
+      --iron-icon-height: 18px;
+      --iron-icon-width: 18px;
+    }
+    gr-button.addReviewer.new-change-summary-true {
+      --padding: 1px 4px;
+      vertical-align: top;
+      top: 1px;
+    }
     gr-button {
       --gr-button: {
         padding: 0px 0px;
@@ -51,6 +61,16 @@
         >
         </gr-account-chip>
       </template>
+      <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
+        <gr-button
+          link=""
+          id="addReviewer"
+          class="addReviewer new-change-summary-true"
+          on-click="_handleAddTap"
+          title="[[_addLabel]]"
+          ><iron-icon icon="gr-icons:edit"></iron-icon
+        ></gr-button>
+      </template>
     </div>
     <gr-button
       class="hiddenReviewers"
@@ -59,15 +79,16 @@
       on-click="_handleViewAll"
       >and [[_hiddenReviewerCount]] more</gr-button
     >
-    <div class="controlsContainer" hidden$="[[!mutable]]">
-      <gr-button
-        link=""
-        id="addReviewer"
-        class="addReviewer"
-        on-click="_handleAddTap"
-        >[[_addLabel]]</gr-button
-      >
-    </div>
+    <template is="dom-if" if="[[!_isNewChangeSummaryUiEnabled]]">
+      <div class="controlsContainer" hidden$="[[!mutable]]">
+        <gr-button
+          link=""
+          id="addReviewer"
+          class="addReviewer"
+          on-click="_handleAddTap"
+          >[[_addLabel]]</gr-button
+        >
+      </div>
+    </template>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.js b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.js
index d29abfc..89332c2 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.js
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.js
@@ -36,6 +36,7 @@
   });
 
   test('controls hidden on immutable element', () => {
+    flush();
     element.mutable = false;
     assert.isTrue(element.shadowRoot
         .querySelector('.controlsContainer').hasAttribute('hidden'));
@@ -48,6 +49,7 @@
     element.addEventListener('show-reply-dialog', () => {
       done();
     });
+    flush();
     MockInteractions.tap(element.shadowRoot
         .querySelector('.addReviewer'));
   });
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
index 6a32834..4976503 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
@@ -32,6 +32,8 @@
 } from '@polymer/polymer/interfaces';
 import {ChangeInfo} from '../../../types/common';
 import {CommentThread, isDraft, UIRobot} from '../../../utils/comment-util';
+import {pluralize} from '../../../utils/string-util';
+import {fireThreadListModifiedEvent} from '../../../utils/event-util';
 
 interface CommentThreadWithInfo {
   thread: CommentThread;
@@ -116,10 +118,7 @@
     unresolvedOnly: boolean
   ) {
     if (unresolvedOnly && threads.length && !displayedThreads.length) {
-      return (
-        `Show ${threads.length} resolved comment` +
-        (threads.length > 1 ? 's' : '')
-      );
+      return `Show ${pluralize(threads.length, 'resolved comment')}`;
     }
     return '';
   }
@@ -161,7 +160,9 @@
     if (c1.thread.patchNum !== c2.thread.patchNum) {
       if (!c1.thread.patchNum) return 1;
       if (!c2.thread.patchNum) return -1;
-      // TODO(TS): Explicit comparison for 'edit' and 'PARENT' missing?
+      // Threads left on Base when comparing Base vs X have patchNum = X
+      // and CommentSide = PARENT
+      // Threads left on 'edit' have patchNum set as latestPatchNum
       return c1.thread.patchNum > c2.thread.patchNum ? -1 : 1;
     }
 
@@ -399,7 +400,7 @@
       hasRobotComment,
       hasHumanReplyToRobotComment,
       unresolved: !!lastComment && !!lastComment.unresolved,
-      isEditing: !!lastComment && !!lastComment.__editing,
+      isEditing: isDraft(lastComment) && !!lastComment.__editing,
       hasDraft: !!lastComment && isDraft(lastComment),
       updated,
     };
@@ -421,11 +422,7 @@
   }
 
   _handleCommentsChanged(e: CustomEvent) {
-    this.dispatchEvent(
-      new CustomEvent('thread-list-modified', {
-        detail: {rootId: e.detail.rootId, path: e.detail.path},
-      })
-    );
+    fireThreadListModifiedEvent(this, e.detail.rootId, e.detail.path);
   }
 
   _isOnParent(side?: CommentSide) {
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
index e55f98a..2c21b4a 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
@@ -127,9 +127,10 @@
       </template>
       <gr-comment-thread
         show-file-path=""
+        show-ported-comment="[[thread.ported]]"
         change-num="[[changeNum]]"
         comments="[[thread.comments]]"
-        comment-side="[[thread.commentSide]]"
+        diff-side="[[thread.diffSide]]"
         show-file-name="[[_isFirstThreadWithFileName(_displayedThreads, thread, unresolvedOnly, _draftsOnly, onlyShowRobotCommentsWithHumanReply)]]"
         project-name="[[change.project]]"
         is-on-parent="[[_isOnParent(thread.commentSide)]]"
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_test.js b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_test.js
index efc072f..622e1a2 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_test.js
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_test.js
@@ -43,7 +43,7 @@
       {
         comments: [
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -79,7 +79,7 @@
       {
         comments: [
           {
-            __path: 'test.txt',
+            path: 'test.txt',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -102,7 +102,7 @@
       {
         comments: [
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -123,7 +123,7 @@
       {
         comments: [
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -201,7 +201,7 @@
       {
         comments: [
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -225,7 +225,7 @@
       {
         comments: [
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -240,7 +240,7 @@
             robot_id: 'rc2',
           },
           {
-            __path: '/COMMIT_MSG',
+            path: '/COMMIT_MSG',
             author: {
               _account_id: 1000000,
               name: 'user',
@@ -568,6 +568,7 @@
     modifiedThreads[5].comments.push({
       ...modifiedThreads[5].comments[0],
       __editing: true,
+      __draft: true,
     });
     element.threads = modifiedThreads;
     MockInteractions.tap(element.shadowRoot.querySelector('#draftToggle'));
diff --git a/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog.ts b/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog.ts
index cab17dd..d52da80 100644
--- a/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 import '../../shared/gr-dialog/gr-dialog';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-shell-command/gr-shell-command';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -24,7 +23,7 @@
 import {htmlTemplate} from './gr-upload-help-dialog_html';
 import {customElement, property} from '@polymer/decorators';
 import {RevisionInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 const COMMIT_COMMAND = 'git add . && git commit --amend --no-edit';
 const PUSH_COMMAND_PREFIX = 'git push origin HEAD:refs/for/';
@@ -32,12 +31,6 @@
 // Command names correspond to download plugin definitions.
 const PREFERRED_FETCH_COMMAND_ORDER = ['checkout', 'cherry pick', 'pull'];
 
-export interface GrUploadHelpDialog {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-upload-help-dialog')
 export class GrUploadHelpDialog extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -73,13 +66,17 @@
   @property({type: String, computed: '_computePushCommand(targetBranch)'})
   _pushCommand?: string;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
-    this.$.restAPI
+    this.restApiService
       .getLoggedIn()
       .then(loggedIn =>
-        loggedIn ? this.$.restAPI.getPreferences() : Promise.resolve(undefined)
+        loggedIn
+          ? this.restApiService.getPreferences()
+          : Promise.resolve(undefined)
       )
       .then(prefs => {
         if (prefs) {
diff --git a/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog_html.ts
index 1ee3a3a..d44cbb0 100644
--- a/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-upload-help-dialog/gr-upload-help-dialog_html.ts
@@ -66,5 +66,4 @@
       </ol>
     </div>
   </gr-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-tab.ts b/polygerrit-ui/app/elements/checks/gr-checks-tab.ts
new file mode 100644
index 0000000..b94430d
--- /dev/null
+++ b/polygerrit-ui/app/elements/checks/gr-checks-tab.ts
@@ -0,0 +1,77 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {html} from 'lit-html';
+import {css, customElement} from 'lit-element';
+import {GrLitElement} from '../lit/gr-lit-element';
+import {
+  CheckResult,
+  CheckRun,
+} from '../plugins/gr-checks-api/gr-checks-api-types';
+import {allResults$, allRuns$} from '../../services/checks/checks-model';
+
+function renderRun(run: CheckRun) {
+  return html`<div>
+    <span>${run.checkName}</span>, <span>${run.status}</span>
+  </div>`;
+}
+
+function renderResult(result: CheckResult) {
+  return html`<div>
+    <span>${result.summary}</span>
+  </div>`;
+}
+
+/**
+ * The "Checks" tab on the Gerrit change page. Gets its data from plugins that
+ * have registered with the Checks Plugin API.
+ */
+@customElement('gr-checks-tab')
+export class GrChecksTab extends GrLitElement {
+  runs: CheckRun[] = [];
+
+  results: CheckResult[] = [];
+
+  constructor() {
+    super();
+    this.subscribe('runs', allRuns$);
+    this.subscribe('results', allResults$);
+  }
+
+  static get styles() {
+    return css`
+      :host {
+        display: block;
+        padding: var(--spacing-m);
+      }
+    `;
+  }
+
+  render() {
+    return html`
+      <div><h2>Runs</h2></div>
+      ${this.runs.map(renderRun)}
+      <div><h2>Results</h2></div>
+      ${this.results.map(renderResult)}
+    `;
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'gr-checks-tab': GrChecksTab;
+  }
+}
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-tab_test.ts b/polygerrit-ui/app/elements/checks/gr-checks-tab_test.ts
new file mode 100644
index 0000000..85183ed
--- /dev/null
+++ b/polygerrit-ui/app/elements/checks/gr-checks-tab_test.ts
@@ -0,0 +1,26 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../test/common-test-setup-karma';
+import {GrChecksTab} from './gr-checks-tab';
+
+suite('gr-checks-tab test', () => {
+  test('is defined', () => {
+    const el = document.createElement('gr-checks-tab');
+    assert.instanceOf(el, GrChecksTab);
+  });
+});
diff --git a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
index ef0ced8..0361b9a 100644
--- a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
+++ b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
@@ -16,7 +16,6 @@
  */
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-dropdown/gr-dropdown';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import '../../shared/gr-avatar/gr-avatar';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -26,7 +25,8 @@
 import {getUserName} from '../../../utils/display-name-util';
 import {customElement, property} from '@polymer/decorators';
 import {AccountInfo, ServerInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
 const INTERPOLATE_URL_PATTERN = /\${([\w]+)}/g;
 
@@ -36,12 +36,6 @@
   }
 }
 
-export interface GrAccountDropdown {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-account-dropdown')
 export class GrAccountDropdown extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -71,12 +65,14 @@
   @property({type: String})
   _switchAccountUrl = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this._handleLocationChange();
     this.listen(window, 'location-change', '_handleLocationChange');
-    this.$.restAPI.getConfig().then(cfg => {
+    this.restApiService.getConfig().then(cfg => {
       this.config = cfg;
 
       if (cfg && cfg.auth && cfg.auth.switch_account_url) {
@@ -120,12 +116,7 @@
   }
 
   _handleShortcutsTap() {
-    this.dispatchEvent(
-      new CustomEvent('show-keyboard-shortcuts', {
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireEvent(this, 'show-keyboard-shortcuts');
   }
 
   _handleLocationChange() {
diff --git a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown_html.ts b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown_html.ts
index b67e1e8..0fa2f1e 100644
--- a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown_html.ts
@@ -49,5 +49,4 @@
       aria-label="Account avatar"
     ></gr-avatar>
   </gr-dropdown>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
index 7a56d1c..e868f03 100644
--- a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
+++ b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
@@ -19,7 +19,6 @@
 import '../gr-error-dialog/gr-error-dialog';
 import '../../shared/gr-alert/gr-alert';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -35,10 +34,10 @@
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GrErrorDialog} from '../gr-error-dialog/gr-error-dialog';
 import {GrAlert} from '../../shared/gr-alert/gr-alert';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-import {FetchRequest} from '../../shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper';
 import {ErrorType, FixIronA11yAnnouncer} from '../../../types/types';
 import {AccountId} from '../../../types/common';
+import {EventType} from '../../../utils/event-util';
+import {NetworkErrorEvent, ServerErrorEvent} from '../../../types/events';
 
 const HIDE_ALERT_TIMEOUT_MS = 5000;
 const CHECK_SIGN_IN_INTERVAL_MS = 60 * 1000;
@@ -71,7 +70,6 @@
     noInteractionOverlay: GrOverlay;
     errorDialog: GrErrorDialog;
     errorOverlay: GrOverlay;
-    restAPI: RestApiService & Element;
   };
 }
 @customElement('gr-error-manager')
@@ -115,11 +113,11 @@
 
   _authErrorHandlerDeregistrationHook?: Function;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
-
     this._authService = appContext.authService;
-
     this.reporting = appContext.reportingService;
     this.eventEmitter = appContext.eventEmitter;
   }
@@ -127,9 +125,9 @@
   /** @override */
   attached() {
     super.attached();
-    this.listen(document, 'server-error', '_handleServerError');
-    this.listen(document, 'network-error', '_handleNetworkError');
-    this.listen(document, 'show-alert', '_handleShowAlert');
+    this.listen(document, EventType.SERVER_ERROR, '_handleServerError');
+    this.listen(document, EventType.NETWORK_ERROR, '_handleNetworkError');
+    this.listen(document, EventType.SHOW_ALERT, '_handleShowAlert');
     this.listen(document, 'hide-alert', '_hideAlert');
     this.listen(document, 'show-error', '_handleShowErrorDialog');
     this.listen(document, 'visibilitychange', '_handleVisibilityChange');
@@ -149,9 +147,9 @@
   detached() {
     super.detached();
     this._clearHideAlertHandle();
-    this.unlisten(document, 'server-error', '_handleServerError');
-    this.unlisten(document, 'network-error', '_handleNetworkError');
-    this.unlisten(document, 'show-alert', '_handleShowAlert');
+    this.unlisten(document, EventType.SERVER_ERROR, '_handleServerError');
+    this.unlisten(document, EventType.NETWORK_ERROR, '_handleNetworkError');
+    this.unlisten(document, EventType.SHOW_ALERT, '_handleShowAlert');
     this.unlisten(document, 'hide-alert', '_hideAlert');
     this.unlisten(document, 'show-error', '_handleShowErrorDialog');
     this.unlisten(document, 'visibilitychange', '_handleVisibilityChange');
@@ -179,9 +177,7 @@
     });
   }
 
-  _handleServerError(
-    e: CustomEvent<{response: Response; request: FetchRequest}>
-  ) {
+  _handleServerError(e: ServerErrorEvent) {
     const {request, response} = e.detail;
     response.text().then(errorText => {
       const url = request && (request.anonymizedUrl || request.url);
@@ -203,7 +199,7 @@
         // This indicates the auth token may no longer valid.
         // Re-check on auth
         this._authService.clearCache();
-        this.$.restAPI.getLoggedIn();
+        this.restApiService.getLoggedIn();
       } else if (!this._shouldSuppressError(errorText)) {
         const trace =
           response.headers && response.headers.get('X-Gerrit-Trace');
@@ -238,7 +234,7 @@
     url,
     trace,
   }: ErrorMsg) {
-    this.$.restAPI.getLoggedIn().then(isLoggedIn => {
+    this.restApiService.getLoggedIn().then(isLoggedIn => {
       const tip = isLoggedIn
         ? 'You might have not enough privileges.'
         : 'You might have not enough privileges. Sign in and try again.';
@@ -298,7 +294,7 @@
     );
   }
 
-  _handleNetworkError(e: CustomEvent) {
+  _handleNetworkError(e: NetworkErrorEvent) {
     this._showAlert('Server unavailable');
     console.error(e.detail.error.message);
   }
@@ -335,7 +331,7 @@
     const el = this._createToastAlert();
     el.show(text, actionText, actionCallback);
     this._alertElement = el;
-    this.fire('iron-announce', {text}, {bubbles: true});
+    this.fire('iron-announce', {text: `Alert: ${text}`}, {bubbles: true});
     this.reporting.reportInteraction('show-alert', {text});
   }
 
@@ -421,10 +417,10 @@
     this._lastCredentialCheck = Date.now();
 
     // force to refetch account info
-    this.$.restAPI.invalidateAccountsCache();
+    this.restApiService.invalidateAccountsCache();
     this._authService.clearCache();
 
-    this.$.restAPI.getLoggedIn().then(isLoggedIn => {
+    this.restApiService.getLoggedIn().then(isLoggedIn => {
       // do nothing if its refreshing
       if (!this._refreshingCredentials) return;
 
@@ -436,7 +432,7 @@
         this._requestCheckLoggedIn();
       } else {
         // check account
-        this.$.restAPI.getAccount().then(account => {
+        this.restApiService.getAccount().then(account => {
           if (this._refreshingCredentials) {
             // If the credentials were refreshed but the account is different
             // then reload the page completely.
diff --git a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_html.ts b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_html.ts
index 1cefb78..c67ed07 100644
--- a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_html.ts
@@ -34,5 +34,4 @@
     no-cancel-on-outside-click=""
   >
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_test.js b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_test.js
index f13276f..7fc35c6 100644
--- a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_test.js
+++ b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_test.js
@@ -67,7 +67,7 @@
               element, '_showAuthErrorAlert'
           );
           const responseText = Promise.resolve('Authentication required\n');
-          sinon.stub(element.$.restAPI, 'getLoggedIn')
+          sinon.stub(element.restApiService, 'getLoggedIn')
               .returns(Promise.resolve(true));
           element.dispatchEvent(
               new CustomEvent('server-error', {
@@ -83,9 +83,9 @@
 
     test('recheck auth for 403 with auth error if authed before', done => {
       // starts with authed state
-      element.$.restAPI.getLoggedIn();
+      element.restApiService.getLoggedIn();
       const responseText = Promise.resolve('Authentication required\n');
-      sinon.stub(element.$.restAPI, 'getLoggedIn')
+      sinon.stub(element.restApiService, 'getLoggedIn')
           .returns(Promise.resolve(true));
       element.dispatchEvent(
           new CustomEvent('server-error', {
@@ -94,7 +94,7 @@
             composed: true, bubbles: true,
           }));
       flush(() => {
-        assert.isTrue(element.$.restAPI.getLoggedIn.calledOnce);
+        assert.isTrue(element.restApiService.getLoggedIn.calledOnce);
         done();
       });
     });
@@ -241,8 +241,9 @@
 
     test('show auth refresh toast', async () => {
       // starts with authed state
-      element.$.restAPI.getLoggedIn();
-      const refreshStub = sinon.stub(element.$.restAPI, 'getAccount').callsFake(
+      element.restApiService.getLoggedIn();
+      const refreshStub = sinon.stub(element.restApiService,
+          'getAccount').callsFake(
           () => Promise.resolve({}));
       const windowOpen = sinon.stub(window, 'open');
       const responseText = Promise.resolve('Authentication required\n');
@@ -313,7 +314,7 @@
 
     test('auth toast should dismiss existing toast', async () => {
       // starts with authed state
-      element.$.restAPI.getLoggedIn();
+      element.restApiService.getLoggedIn();
       const responseText = Promise.resolve('Authentication required\n');
 
       // fake an alert
@@ -353,7 +354,7 @@
 
     test('regular toast should dismiss regular toast', () => {
       // starts with authed state
-      element.$.restAPI.getLoggedIn();
+      element.restApiService.getLoggedIn();
 
       // fake an alert
       element.dispatchEvent(
@@ -379,7 +380,7 @@
 
     test('regular toast should not dismiss auth toast', done => {
       // starts with authed state
-      element.$.restAPI.getLoggedIn();
+      element.restApiService.getLoggedIn();
       const responseText = Promise.resolve('Authentication required\n');
 
       // fake auth
@@ -456,7 +457,7 @@
 
     test('refreshes with same credentials', done => {
       const accountPromise = Promise.resolve({_account_id: 1234});
-      sinon.stub(element.$.restAPI, 'getAccount')
+      sinon.stub(element.restApiService, 'getAccount')
           .returns(accountPromise);
       const requestCheckStub = sinon.stub(element, '_requestCheckLoggedIn');
       const handleRefreshStub = sinon.stub(element,
@@ -513,7 +514,7 @@
 
     test('reloads when refreshed credentials differ', done => {
       const accountPromise = Promise.resolve({_account_id: 1234});
-      sinon.stub(element.$.restAPI, 'getAccount')
+      sinon.stub(element.restApiService, 'getAccount')
           .returns(accountPromise);
       const requestCheckStub = sinon.stub(
           element,
diff --git a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.css.ts b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.css.ts
new file mode 100644
index 0000000..ccba289
--- /dev/null
+++ b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.css.ts
@@ -0,0 +1,30 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {css} from 'lit-element';
+
+export const cssTemplate = css`
+  .key {
+    background-color: var(--chip-background-color);
+    color: var(--primary-text-color);
+    border: 1px solid var(--border-color);
+    border-radius: var(--border-radius);
+    display: inline-block;
+    font-weight: var(--font-weight-bold);
+    padding: var(--spacing-xxs) var(--spacing-m);
+    text-align: center;
+  }
+`;
diff --git a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.ts b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.ts
index 796a167..091684f 100644
--- a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.ts
+++ b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display.ts
@@ -14,12 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../../styles/shared-styles';
-import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
-import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
-import {PolymerElement} from '@polymer/polymer/polymer-element';
-import {htmlTemplate} from './gr-key-binding-display_html';
-import {customElement, property} from '@polymer/decorators';
+import {html} from 'lit-html';
+import {GrLitElement} from '../../lit/gr-lit-element';
+import {customElement, property} from 'lit-element';
+import {cssTemplate} from './gr-key-binding-display.css';
+import {sharedStyles} from '../../../styles/shared-styles';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -28,21 +27,30 @@
 }
 
 @customElement('gr-key-binding-display')
-export class GrKeyBindingDisplay extends GestureEventListeners(
-  LegacyElementMixin(PolymerElement)
-) {
-  static get template() {
-    return htmlTemplate;
+export class GrKeyBindingDisplay extends GrLitElement {
+  static get styles() {
+    return [sharedStyles, cssTemplate];
+  }
+
+  render() {
+    const items = this.binding.map((binding, index) => [
+      index > 0 ? html` or ` : html``,
+      this._computeModifiers(binding).map(
+        modifier => html`<span class="key modifier">${modifier}</span> `
+      ),
+      html`<span class="key">${this._computeKey(binding)}</span>`,
+    ]);
+    return html`${items}`;
   }
 
   @property({type: Array})
   binding: string[][] = [];
 
-  _computeModifiers(binding: string[][]) {
+  _computeModifiers(binding: string[]) {
     return binding.slice(0, binding.length - 1);
   }
 
-  _computeKey(binding: string[][]) {
+  _computeKey(binding: string[]) {
     return binding[binding.length - 1];
   }
 }
diff --git a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_html.ts b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_html.ts
deleted file mode 100644
index 0a75104..0000000
--- a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_html.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-/**
- * @license
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import {html} from '@polymer/polymer/lib/utils/html-tag';
-
-export const htmlTemplate = html`
-  <style include="shared-styles">
-    .key {
-      background-color: var(--chip-background-color);
-      border: 1px solid var(--border-color);
-      border-radius: var(--border-radius);
-      display: inline-block;
-      font-weight: var(--font-weight-bold);
-      padding: var(--spacing-xxs) var(--spacing-m);
-      text-align: center;
-    }
-  </style>
-  <template is="dom-repeat" items="[[binding]]">
-    <template is="dom-if" if="[[index]]">
-      or
-    </template>
-    <template is="dom-repeat" items="[[_computeModifiers(item)]]" as="modifier">
-      <span class="key modifier">[[modifier]]</span>
-    </template>
-    <span class="key">[[_computeKey(item)]]</span>
-  </template>
-`;
diff --git a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.js b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.ts
similarity index 86%
rename from polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.js
rename to polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.ts
index 0c25e6e..875cde8 100644
--- a/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.js
+++ b/polygerrit-ui/app/elements/core/gr-key-binding-display/gr-key-binding-display_test.ts
@@ -17,11 +17,12 @@
 
 import '../../../test/common-test-setup-karma.js';
 import './gr-key-binding-display.js';
+import {GrKeyBindingDisplay} from './gr-key-binding-display.js';
 
 const basicFixture = fixtureFromElement('gr-key-binding-display');
 
 suite('gr-key-binding-display tests', () => {
-  let element;
+  let element: GrKeyBindingDisplay;
 
   setup(() => {
     element = basicFixture.instantiate();
@@ -45,10 +46,10 @@
 
     test('key with modifiers', () => {
       assert.deepEqual(element._computeModifiers(['Ctrl', 'x']), ['Ctrl']);
-      assert.deepEqual(
-          element._computeModifiers(['Shift', 'Meta', 'x']),
-          ['Shift', 'Meta']);
+      assert.deepEqual(element._computeModifiers(['Shift', 'Meta', 'x']), [
+        'Shift',
+        'Meta',
+      ]);
     });
   });
 });
-
diff --git a/polygerrit-ui/app/elements/core/gr-keyboard-shortcuts-dialog/gr-keyboard-shortcuts-dialog_html.ts b/polygerrit-ui/app/elements/core/gr-keyboard-shortcuts-dialog/gr-keyboard-shortcuts-dialog_html.ts
index 1860f38..3576dfe 100644
--- a/polygerrit-ui/app/elements/core/gr-keyboard-shortcuts-dialog/gr-keyboard-shortcuts-dialog_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-keyboard-shortcuts-dialog/gr-keyboard-shortcuts-dialog_html.ts
@@ -30,21 +30,39 @@
       display: flex;
       padding: 0 var(--spacing-xxl) var(--spacing-xxl);
     }
+    .column {
+      flex: 50%;
+    }
     header {
       align-items: center;
       border-bottom: 1px solid var(--border-color);
       display: flex;
       justify-content: space-between;
     }
-    table:last-of-type {
-      margin-left: var(--spacing-xxl);
+    table caption {
+      font-weight: var(--font-weight-bold);
+      padding-top: var(--spacing-l);
+      text-align: left;
+    }
+    tr {
+      height: 32px;
     }
     td {
       padding: var(--spacing-xs) 0;
     }
-    td:first-child {
+    td:first-child,
+    th:first-child {
       padding-right: var(--spacing-m);
       text-align: right;
+      width: 160px;
+      color: var(--deemphasized-text-color);
+    }
+    td:second-child {
+      min-width: 200px;
+    }
+    th {
+      color: var(--deemphasized-text-color);
+      text-align: left;
     }
     .header {
       font-weight: var(--font-weight-bold);
@@ -59,33 +77,19 @@
     <gr-button link="" on-click="_handleCloseTap">Close</gr-button>
   </header>
   <main>
-    <table>
-      <tbody>
-        <template is="dom-repeat" items="[[_left]]">
-          <tr>
-            <td></td>
-            <td class="header">[[item.section]]</td>
-          </tr>
-          <template is="dom-repeat" items="[[item.shortcuts]]" as="shortcut">
+    <div class="column">
+      <template is="dom-repeat" items="[[_left]]">
+        <table>
+          <caption>
+            [[item.section]]
+          </caption>
+          <thead>
             <tr>
-              <td>
-                <gr-key-binding-display binding="[[shortcut.binding]]">
-                </gr-key-binding-display>
-              </td>
-              <td>[[shortcut.text]]</td>
+              <th>Key</th>
+              <th>Action</th>
             </tr>
-          </template>
-        </template>
-      </tbody>
-    </table>
-    <template is="dom-if" if="[[_right]]">
-      <table>
-        <tbody>
-          <template is="dom-repeat" items="[[_right]]">
-            <tr>
-              <td></td>
-              <td class="header">[[item.section]]</td>
-            </tr>
+          </thead>
+          <tbody>
             <template is="dom-repeat" items="[[item.shortcuts]]" as="shortcut">
               <tr>
                 <td>
@@ -95,10 +99,36 @@
                 <td>[[shortcut.text]]</td>
               </tr>
             </template>
-          </template>
-        </tbody>
-      </table>
-    </template>
+          </tbody>
+        </table>
+      </template>
+    </div>
+    <div class="column">
+      <template is="dom-repeat" items="[[_right]]">
+        <table>
+          <caption>
+            [[item.section]]
+          </caption>
+          <thead>
+            <tr>
+              <th>Key</th>
+              <th>Action</th>
+            </tr>
+          </thead>
+          <tbody>
+            <template is="dom-repeat" items="[[item.shortcuts]]" as="shortcut">
+              <tr>
+                <td>
+                  <gr-key-binding-display binding="[[shortcut.binding]]">
+                  </gr-key-binding-display>
+                </td>
+                <td>[[shortcut.text]]</td>
+              </tr>
+            </template>
+          </tbody>
+        </table>
+      </template>
+    </div>
   </main>
   <footer></footer>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
index caa0521..2482497 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
@@ -18,7 +18,6 @@
 import '../../shared/gr-dropdown/gr-dropdown';
 import '../../shared/gr-icons/gr-icons';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-account-dropdown/gr-account-dropdown';
 import '../gr-smart-search/gr-smart-search';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -29,7 +28,6 @@
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {getAdminLinks, NavLink} from '../../../utils/admin-nav-util';
 import {customElement, property, observe} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AccountDetailInfo,
   RequireProperties,
@@ -40,6 +38,7 @@
 import {JsApiService} from '../../shared/gr-js-api-interface/gr-js-api-types';
 import {AuthType} from '../../../constants/constants';
 import {DropdownLink} from '../../shared/gr-dropdown/gr-dropdown';
+import {appContext} from '../../../services/app-context';
 
 type MainHeaderLink = RequireProperties<DropdownLink, 'url' | 'name'>;
 
@@ -105,7 +104,6 @@
 
 export interface GrMainHeader {
   $: {
-    restAPI: RestApiService & Element;
     jsAPI: JsApiService & Element;
   };
 }
@@ -161,6 +159,8 @@
   @property({type: Boolean})
   mobileSearchHidden = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   ready() {
     super.ready();
@@ -274,8 +274,8 @@
     this.loading = true;
 
     return Promise.all([
-      this.$.restAPI.getAccount(),
-      this.$.restAPI.getTopMenus(),
+      this.restApiService.getAccount(),
+      this.restApiService.getTopMenus(),
       getPluginLoader().awaitPluginsLoaded(),
     ]).then(result => {
       const account = result[0];
@@ -287,7 +287,7 @@
       return getAdminLinks(
         account,
         () =>
-          this.$.restAPI.getAccountCapabilities().then(capabilities => {
+          this.restApiService.getAccountCapabilities().then(capabilities => {
             if (!capabilities) {
               throw new Error('getAccountCapabilities returns undefined');
             }
@@ -301,14 +301,14 @@
   }
 
   _loadConfig() {
-    this.$.restAPI
+    this.restApiService
       .getConfig()
       .then(config => {
         if (!config) {
           throw new Error('getConfig returned undefined');
         }
         this._retrieveRegisterURL(config);
-        return getDocsBaseUrl(config, this.$.restAPI);
+        return getDocsBaseUrl(config, this.restApiService);
       })
       .then(docBaseUrl => {
         this._docBaseUrl = docBaseUrl;
@@ -321,7 +321,7 @@
       return;
     }
 
-    this.$.restAPI.getPreferences().then(prefs => {
+    this.restApiService.getPreferences().then(prefs => {
       this._userLinks =
         prefs && prefs.my ? prefs.my.map(this._createHeaderLink) : [];
     });
@@ -348,6 +348,7 @@
     // If not, it sets target='_blank' on the menu item. The server
     // makes assumptions that work for the GWT UI, but not PolyGerrit,
     // so we'll just disable it altogether for now.
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const {target, ...headerLink} = {...linkObj};
 
     // Normalize all urls to PolyGerrit style.
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_html.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_html.ts
index 5778fb8..0cdd0f2 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_html.ts
@@ -239,5 +239,4 @@
     </div>
   </nav>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
index 8470611..83bf3ca 100644
--- a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
+++ b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
@@ -16,23 +16,24 @@
  */
 import {
   BranchName,
+  ChangeConfigInfo,
   ChangeInfo,
+  CommentLinks,
+  CommitId,
+  DashboardId,
+  EditPatchSetNum,
+  GroupId,
+  Hashtag,
+  NumericChangeId,
+  ParentPatchSetNum,
   PatchSetNum,
   RepoName,
-  TopicName,
-  GroupId,
-  DashboardId,
-  NumericChangeId,
-  EditPatchSetNum,
-  ChangeConfigInfo,
-  CommitId,
-  Hashtag,
-  UrlEncodedCommentId,
-  CommentLinks,
-  ParentPatchSetNum,
   ServerInfo,
+  TopicName,
+  UrlEncodedCommentId,
 } from '../../../types/common';
 import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
+import {GerritView} from '../../../services/router/router-model';
 
 // Navigation parameters object format:
 //
@@ -396,22 +397,6 @@
   url?: string;
 }
 
-export enum GerritView {
-  ADMIN = 'admin',
-  AGREEMENTS = 'agreements',
-  CHANGE = 'change',
-  DASHBOARD = 'dashboard',
-  DIFF = 'diff',
-  DOCUMENTATION_SEARCH = 'documentation-search',
-  EDIT = 'edit',
-  GROUP = 'group',
-  PLUGIN_SCREEN = 'plugin-screen',
-  REPO = 'repo',
-  ROOT = 'root',
-  SEARCH = 'search',
-  SETTINGS = 'settings',
-}
-
 export enum GroupDetailView {
   MEMBERS = 'members',
   LOG = 'log',
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
index 21bf900..2f3d03c 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -27,6 +26,7 @@
 import {encodeURL, getBaseUrl} from '../../../utils/url-util';
 import {
   DashboardSection,
+  GeneratedWebLink,
   GenerateUrlChangeViewParameters,
   GenerateUrlDashboardViewParameters,
   GenerateUrlDiffViewParameters,
@@ -39,19 +39,14 @@
   GenerateWebLinksFileParameters,
   GenerateWebLinksParameters,
   GenerateWebLinksPatchsetParameters,
-  GerritView,
+  GerritNav,
+  GroupDetailView,
   isGenerateUrlDiffViewParameters,
   RepoDetailView,
   WeblinkType,
-  GroupDetailView,
-  GerritNav,
-  GeneratedWebLink,
 } from '../gr-navigation/gr-navigation';
 import {appContext} from '../../../services/app-context';
-import {
-  patchNumEquals,
-  convertToPatchSetNum,
-} from '../../../utils/patch-set-util';
+import {convertToPatchSetNum} from '../../../utils/patch-set-util';
 import {customElement, property} from '@polymer/decorators';
 import {assertNever} from '../../../utils/common-util';
 import {
@@ -63,13 +58,13 @@
   ServerInfo,
   UrlEncodedCommentId,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AppElement,
-  AppElementParams,
   AppElementAgreementParam,
+  AppElementParams,
 } from '../../gr-app-types';
 import {LocationChangeEventDetail} from '../../../types/events';
+import {GerritView, updateState} from '../../../services/router/router-model';
 
 const RoutePattern = {
   ROOT: '/',
@@ -267,12 +262,6 @@
   });
 })();
 
-export interface GrRouter {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 export interface PageContextWithQueryMap extends PageContext {
   queryMap: Map<string, string> | URLSearchParams;
 }
@@ -314,8 +303,15 @@
 
   private readonly reporting = appContext.reportingService;
 
+  private readonly restApiService = appContext.restApiService;
+
+  private readonly changeService = appContext.changeService;
+
   constructor() {
     super();
+    // TODO: This is just an artificical dependdency such that the service is
+    // instantiated and its observables subscribed. Remove this later.
+    this.changeService.dontDoAnything();
   }
 
   start() {
@@ -326,6 +322,11 @@
   }
 
   _setParams(params: AppElementParams | GenerateUrlParameters) {
+    updateState(
+      params.view,
+      'changeNum' in params ? params.changeNum : undefined,
+      'patchNum' in params ? params.patchNum ?? undefined : undefined
+    );
     this._appElement().params = params;
   }
 
@@ -390,9 +391,8 @@
       case WeblinkType.PATCHSET:
         return this._getPatchSetWeblink(params);
       default:
-        console.warn(`Unsupported weblink ${(params as any).type}!`);
-        // TODO(TS): use assertNever(params.type)
-        return [];
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        assertNever(params, `Unsupported weblink ${(params as any).type}!`);
     }
   }
 
@@ -658,7 +658,7 @@
       return Promise.resolve();
     }
 
-    return this.$.restAPI
+    return this.restApiService
       .getFromProjectLookup(params.changeNum)
       .then(project => {
         // Show a 404 and terminate if the lookup request failed. Attempting
@@ -690,10 +690,7 @@
 
     // Diffing a patch against itself is invalid, so if the base and revision
     // patches are equal clear the base.
-    if (
-      params.patchNum &&
-      patchNumEquals(params.basePatchNum, params.patchNum)
-    ) {
+    if (params.patchNum && params.basePatchNum === params.patchNum) {
       needsRedirect = true;
       params.basePatchNum = null;
     } else if (!hasPatchNum) {
@@ -745,7 +742,7 @@
    * (if it resolves).
    */
   _redirectIfNotLoggedIn(data: PageContext) {
-    return this.$.restAPI.getLoggedIn().then(loggedIn => {
+    return this.restApiService.getLoggedIn().then(loggedIn => {
       if (loggedIn) {
         return Promise.resolve();
       } else {
@@ -757,7 +754,7 @@
 
   /**  Page.js middleware that warms the REST API's logged-in cache line. */
   _loadUserMiddleware(_: PageContext, next: PageNextCallback) {
-    this.$.restAPI.getLoggedIn().then(() => {
+    this.restApiService.getLoggedIn().then(() => {
       next();
     });
   }
@@ -796,7 +793,9 @@
     authRedirect?: boolean
   ) {
     if (!this[handlerName]) {
-      console.error('Attempted to map route to unknown method: ', handlerName);
+      this.reporting.error(
+        new Error(`Attempted to map route to unknown method: ${handlerName}`)
+      );
       return;
     }
     page(
@@ -1125,7 +1124,7 @@
       this._redirect(newUrl);
       return null;
     }
-    return this.$.restAPI.getLoggedIn().then(loggedIn => {
+    return this.restApiService.getLoggedIn().then(loggedIn => {
       if (loggedIn) {
         this._redirect('/dashboard/self');
       } else {
@@ -1183,7 +1182,7 @@
     // User dashboard. We require viewing user to be logged in, else we
     // redirect to login for self dashboard or simple owner search for
     // other user dashboard.
-    return this.$.restAPI.getLoggedIn().then(loggedIn => {
+    return this.restApiService.getLoggedIn().then(loggedIn => {
       if (!loggedIn) {
         if (data.params[0].toLowerCase() === 'self') {
           this._redirectToLogin(data.canonicalPath);
@@ -1540,8 +1539,7 @@
     // Parameter order is based on the regex group number matched.
     const params: GenerateUrlChangeViewParameters = {
       project: ctx.params[0] as RepoName,
-      // TODO(TS): remove as unknown
-      changeNum: (ctx.params[1] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[1]) as NumericChangeId,
       basePatchNum: convertToPatchSetNum(ctx.params[4]),
       patchNum: convertToPatchSetNum(ctx.params[6]),
       view: GerritView.CHANGE,
@@ -1555,7 +1553,7 @@
   _handleCommentRoute(ctx: PageContextWithQueryMap) {
     const params: GenerateUrlDiffViewParameters = {
       project: ctx.params[0] as RepoName,
-      changeNum: (ctx.params[1] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[1]) as NumericChangeId,
       commentId: ctx.params[2] as UrlEncodedCommentId,
       view: GerritView.DIFF,
       commentLink: true,
@@ -1568,7 +1566,7 @@
     // Parameter order is based on the regex group number matched.
     const params: GenerateUrlDiffViewParameters = {
       project: ctx.params[0] as RepoName,
-      changeNum: (ctx.params[1] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[1]) as NumericChangeId,
       basePatchNum: convertToPatchSetNum(ctx.params[4]),
       patchNum: convertToPatchSetNum(ctx.params[6]),
       path: ctx.params[8],
@@ -1586,7 +1584,7 @@
   _handleChangeLegacyRoute(ctx: PageContextWithQueryMap) {
     // Parameter order is based on the regex group number matched.
     const params: GenerateUrlLegacyChangeViewParameters = {
-      changeNum: (ctx.params[0] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[0]) as NumericChangeId,
       basePatchNum: convertToPatchSetNum(ctx.params[3]),
       patchNum: convertToPatchSetNum(ctx.params[5]),
       view: GerritView.CHANGE,
@@ -1603,8 +1601,7 @@
   _handleDiffLegacyRoute(ctx: PageContextWithQueryMap) {
     // Parameter order is based on the regex group number matched.
     const params: GenerateUrlLegacyDiffViewParameters = {
-      // TODO(TS): remove "as unknown"
-      changeNum: (ctx.params[0] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[0]) as NumericChangeId,
       basePatchNum: convertToPatchSetNum(ctx.params[2]),
       patchNum: convertToPatchSetNum(ctx.params[4]),
       path: ctx.params[5],
@@ -1625,7 +1622,7 @@
     const project = ctx.params[0] as RepoName;
     this._redirectOrNavigate({
       project,
-      changeNum: (ctx.params[1] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[1]) as NumericChangeId,
       // for edit view params, patchNum cannot be undefined
       patchNum: convertToPatchSetNum(ctx.params[2])!,
       path: ctx.params[3],
@@ -1640,8 +1637,7 @@
     const project = ctx.params[0] as RepoName;
     this._redirectOrNavigate({
       project,
-      // TODO(TS): remove "as unknown"
-      changeNum: (ctx.params[1] as unknown) as NumericChangeId,
+      changeNum: Number(ctx.params[1]) as NumericChangeId,
       patchNum: convertToPatchSetNum(ctx.params[3]),
       view: GerritView.CHANGE,
       edit: true,
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router_html.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router_html.ts
index 91d8b41..1489006 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router_html.ts
@@ -16,6 +16,4 @@
  */
 import {html} from '@polymer/polymer/lib/utils/html-tag';
 
-export const htmlTemplate = html`
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
-`;
+export const htmlTemplate = html``;
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.js b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.js
index 927434b..ff8f8df 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.js
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.js
@@ -229,7 +229,7 @@
   });
 
   test('_redirectIfNotLoggedIn while logged in', () => {
-    sinon.stub(element.$.restAPI, 'getLoggedIn')
+    sinon.stub(element.restApiService, 'getLoggedIn')
         .returns(Promise.resolve(true));
     const data = {canonicalPath: ''};
     const redirectStub = sinon.stub(element, '_redirectToLogin');
@@ -239,7 +239,7 @@
   });
 
   test('_redirectIfNotLoggedIn while logged out', () => {
-    sinon.stub(element.$.restAPI, 'getLoggedIn')
+    sinon.stub(element.restApiService, 'getLoggedIn')
         .returns(Promise.resolve(false));
     const redirectStub = sinon.stub(element, '_redirectToLogin');
     const data = {canonicalPath: ''};
@@ -524,7 +524,7 @@
 
     setup(() => {
       projectLookupStub = sinon
-          .stub(element.$.restAPI, 'getFromProjectLookup');
+          .stub(element.restApiService, 'getFromProjectLookup');
       generateUrlStub = sinon.stub(element, '_generateUrl');
     });
 
@@ -794,7 +794,7 @@
       });
 
       test('redirects to dashboard if logged in', () => {
-        sinon.stub(element.$.restAPI, 'getLoggedIn')
+        sinon.stub(element.restApiService, 'getLoggedIn')
             .returns(Promise.resolve(true));
         const data = {
           canonicalPath: '/', path: '/', querystring: '', hash: '',
@@ -807,7 +807,7 @@
       });
 
       test('redirects to open changes if not logged in', () => {
-        sinon.stub(element.$.restAPI, 'getLoggedIn')
+        sinon.stub(element.restApiService, 'getLoggedIn')
             .returns(Promise.resolve(false));
         const data = {
           canonicalPath: '/', path: '/', querystring: '', hash: '',
@@ -905,7 +905,7 @@
       });
 
       test('own dashboard but signed out redirects to login', () => {
-        sinon.stub(element.$.restAPI, 'getLoggedIn')
+        sinon.stub(element.restApiService, 'getLoggedIn')
             .returns(Promise.resolve(false));
         const data = {canonicalPath: '/dashboard/', params: {0: 'seLF'}};
         return element._handleDashboardRoute(data, '').then(() => {
@@ -916,7 +916,7 @@
       });
 
       test('non-self dashboard but signed out does not redirect', () => {
-        sinon.stub(element.$.restAPI, 'getLoggedIn')
+        sinon.stub(element.restApiService, 'getLoggedIn')
             .returns(Promise.resolve(false));
         const data = {canonicalPath: '/dashboard/', params: {0: 'foo'}};
         return element._handleDashboardRoute(data, '').then(() => {
@@ -928,7 +928,7 @@
       });
 
       test('dashboard while signed in sets params', () => {
-        sinon.stub(element.$.restAPI, 'getLoggedIn')
+        sinon.stub(element.restApiService, 'getLoggedIn')
             .returns(Promise.resolve(true));
         const data = {canonicalPath: '/dashboard/', params: {0: 'foo'}};
         return element._handleDashboardRoute(data, '').then(() => {
@@ -1444,7 +1444,7 @@
         setup(() => {
           normalizeRangeStub = sinon.stub(element,
               '_normalizePatchRangeParams');
-          sinon.stub(element.$.restAPI, 'setInProjectLookup');
+          sinon.stub(element.restApiService, 'setInProjectLookup');
         });
 
         test('needs redirect', () => {
@@ -1498,7 +1498,7 @@
         setup(() => {
           normalizeRangeStub = sinon.stub(element,
               '_normalizePatchRangeParams');
-          sinon.stub(element.$.restAPI, 'setInProjectLookup');
+          sinon.stub(element.restApiService, 'setInProjectLookup');
         });
 
         test('needs redirect', () => {
@@ -1540,7 +1540,7 @@
           ]);
           assertDataToParams({params: groups.slice(1)}, '_handleCommentRoute', {
             project: 'gerrit',
-            changeNum: '264833',
+            changeNum: 264833,
             commentId: '00049681_f34fd6a9',
             commentLink: true,
             view: GerritNav.View.DIFF,
@@ -1551,7 +1551,7 @@
       test('_handleDiffEditRoute', () => {
         const normalizeRangeSpy =
             sinon.spy(element, '_normalizePatchRangeParams');
-        sinon.stub(element.$.restAPI, 'setInProjectLookup');
+        sinon.stub(element.restApiService, 'setInProjectLookup');
         const ctx = {
           params: [
             'foo/bar', // 0 Project
@@ -1580,7 +1580,7 @@
       test('_handleDiffEditRoute with lineNum', () => {
         const normalizeRangeSpy =
             sinon.spy(element, '_normalizePatchRangeParams');
-        sinon.stub(element.$.restAPI, 'setInProjectLookup');
+        sinon.stub(element.restApiService, 'setInProjectLookup');
         const ctx = {
           params: [
             'foo/bar', // 0 Project
@@ -1610,7 +1610,7 @@
       test('_handleChangeEditRoute', () => {
         const normalizeRangeSpy =
             sinon.spy(element, '_normalizePatchRangeParams');
-        sinon.stub(element.$.restAPI, 'setInProjectLookup');
+        sinon.stub(element.restApiService, 'setInProjectLookup');
         const ctx = {
           params: [
             'foo/bar', // 0 Project
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
index d785a2f..43f8a2b 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 import '../../shared/gr-autocomplete/gr-autocomplete';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -28,7 +27,6 @@
 } from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 import {customElement, property} from '@polymer/decorators';
 import {ServerInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AutocompleteQuery,
   AutocompleteSuggestion,
@@ -37,6 +35,7 @@
 import {getDocsBaseUrl} from '../../../utils/url-util';
 import {CustomKeyboardEvent} from '../../../types/events';
 import {MergeabilityComputationBehavior} from '../../../constants/constants';
+import {appContext} from '../../../services/app-context';
 
 // Possible static search options for auto complete, without negations.
 const SEARCH_OPERATORS: ReadonlyArray<string> = [
@@ -136,7 +135,6 @@
 
 export interface GrSearchBar {
   $: {
-    restAPI: RestApiService & Element;
     searchInput: GrAutocomplete;
   };
 }
@@ -187,6 +185,8 @@
   @property({type: String})
   docBaseUrl: string | null = null;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this.query = (input: string) => this._getSearchSuggestions(input);
@@ -194,7 +194,7 @@
 
   attached() {
     super.attached();
-    this.$.restAPI.getConfig().then((serverConfig?: ServerInfo) => {
+    this.restApiService.getConfig().then((serverConfig?: ServerInfo) => {
       const mergeability =
         serverConfig &&
         serverConfig.change &&
@@ -209,7 +209,7 @@
         this._addOperator('is:mergeable');
       }
       if (serverConfig) {
-        getDocsBaseUrl(serverConfig, this.$.restAPI).then(baseUrl => {
+        getDocsBaseUrl(serverConfig, this.restApiService).then(baseUrl => {
           this.docBaseUrl = baseUrl;
         });
       }
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_html.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_html.ts
index 2fbdc7e..a0de7f2 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_html.ts
@@ -47,6 +47,7 @@
         href$="[[_computeHelpDocLink(docBaseUrl)]]"
         target="_blank"
         class="help"
+        tabindex="-1"
       >
         <iron-icon
           icon="gr-icons:help-outline"
@@ -55,5 +56,4 @@
       </a>
     </gr-autocomplete>
   </form>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search.ts b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search.ts
index a818c59..b698732 100644
--- a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search.ts
+++ b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-search-bar/gr-search-bar';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -23,24 +22,18 @@
 import {GerritNav} from '../gr-navigation/gr-navigation';
 import {getUserName} from '../../../utils/display-name-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {AccountInfo, ServerInfo} from '../../../types/common';
 import {
   SearchBarHandleSearchDetail,
   SuggestionProvider,
 } from '../gr-search-bar/gr-search-bar';
 import {AutocompleteSuggestion} from '../../shared/gr-autocomplete/gr-autocomplete';
+import {appContext} from '../../../services/app-context';
 
 const MAX_AUTOCOMPLETE_RESULTS = 10;
 const SELF_EXPRESSION = 'self';
 const ME_EXPRESSION = 'me';
 
-export interface GrSmartSearch {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-smart-search')
 export class GrSmartSearch extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -70,10 +63,12 @@
   @property({type: String})
   label = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
-    this.$.restAPI.getConfig().then(cfg => {
+    this.restApiService.getConfig().then(cfg => {
       this._config = cfg;
     });
   }
@@ -97,7 +92,7 @@
     predicate: string,
     expression: string
   ): Promise<AutocompleteSuggestion[]> {
-    return this.$.restAPI
+    return this.restApiService
       .getSuggestedProjects(expression, MAX_AUTOCOMPLETE_RESULTS)
       .then(projects => {
         if (!projects) {
@@ -125,7 +120,7 @@
     if (expression.length === 0) {
       return Promise.resolve([]);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getSuggestedGroups(expression, MAX_AUTOCOMPLETE_RESULTS)
       .then(groups => {
         if (!groups) {
@@ -153,7 +148,7 @@
     if (expression.length === 0) {
       return Promise.resolve([]);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getSuggestedAccounts(expression, MAX_AUTOCOMPLETE_RESULTS)
       .then(accounts => {
         if (!accounts) {
diff --git a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_html.ts b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_html.ts
index 7088937..c08df15 100644
--- a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_html.ts
+++ b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_html.ts
@@ -27,5 +27,4 @@
     group-suggestions="[[_groupSuggestions]]"
     account-suggestions="[[_accountSuggestions]]"
   ></gr-search-bar>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_test.js b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_test.js
index dc7bf0e..d7e6c27 100644
--- a/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_test.js
+++ b/polygerrit-ui/app/elements/core/gr-smart-search/gr-smart-search_test.js
@@ -28,7 +28,7 @@
   });
 
   test('Autocompletes accounts', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedAccounts').callsFake(() =>
+    sinon.stub(element.restApiService, 'getSuggestedAccounts').callsFake(() =>
       Promise.resolve([
         {
           name: 'fred',
@@ -42,7 +42,7 @@
   });
 
   test('Inserts self as option when valid', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedAccounts').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedAccounts').callsFake( () =>
       Promise.resolve([
         {
           name: 'fred',
@@ -62,7 +62,7 @@
   });
 
   test('Inserts me as option when valid', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedAccounts').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedAccounts').callsFake( () =>
       Promise.resolve([
         {
           name: 'fred',
@@ -82,7 +82,7 @@
   });
 
   test('Autocompletes groups', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedGroups').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedGroups').callsFake( () =>
       Promise.resolve({
         Polygerrit: 0,
         gerrit: 0,
@@ -95,7 +95,7 @@
   });
 
   test('Autocompletes projects', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedProjects').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedProjects').callsFake( () =>
       Promise.resolve({Polygerrit: 0}));
     return element._fetchProjects('project', 'pol').then(s => {
       assert.deepEqual(s[0], {text: 'project:Polygerrit'});
@@ -103,7 +103,7 @@
   });
 
   test('Autocomplete doesnt override exact matches to input', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedGroups').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedGroups').callsFake( () =>
       Promise.resolve({
         Polygerrit: 0,
         gerrit: 0,
@@ -118,7 +118,7 @@
   });
 
   test('Autocompletes accounts with no email', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedAccounts').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedAccounts').callsFake( () =>
       Promise.resolve([{name: 'fred'}]));
     return element._fetchAccounts('owner', 'fr').then(s => {
       assert.deepEqual(s[0], {text: 'owner:"fred"', label: 'fred'});
@@ -126,7 +126,7 @@
   });
 
   test('Autocompletes accounts with email', () => {
-    sinon.stub(element.$.restAPI, 'getSuggestedAccounts').callsFake( () =>
+    sinon.stub(element.restApiService, 'getSuggestedAccounts').callsFake( () =>
       Promise.resolve([{email: 'fred@goog.co'}]));
     return element._fetchAccounts('owner', 'fr').then(s => {
       assert.deepEqual(s[0], {text: 'owner:fred@goog.co', label: ''});
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
index 0e73516..43b0588 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
@@ -18,7 +18,6 @@
 import '../../../styles/shared-styles';
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-diff/gr-diff';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -29,22 +28,21 @@
 import {ParsedChangeInfo} from '../../shared/gr-rest-api-interface/gr-reviewer-updates-parser';
 import {
   NumericChangeId,
-  DiffInfo,
-  DiffPreferencesInfo,
   EditPatchSetNum,
   FixId,
   FixSuggestionInfo,
   PatchSetNum,
   RobotId,
 } from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {isRobot} from '../../../utils/comment-util';
 import {OpenFixPreviewEvent} from '../../../types/events';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
 export interface GrApplyFixDialog {
   $: {
-    restAPI: RestApiService & Element;
     applyFixOverlay: GrOverlay;
   };
 }
@@ -102,6 +100,8 @@
 
   private refitOverlay?: () => void;
 
+  private restApiService = appContext.restApiService;
+
   /**
    * Given robot comment CustomEvent object, fetch diffs associated
    * with first robot comment suggested fix and open dialog.
@@ -130,12 +130,7 @@
     );
     return Promise.all(promises).then(() => {
       // ensures gr-overlay repositions overlay in center
-      this.$.applyFixOverlay.dispatchEvent(
-        new CustomEvent('iron-resize', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this.$.applyFixOverlay, 'iron-resize');
     });
   }
 
@@ -143,12 +138,7 @@
     super.attached();
     this.refitOverlay = () => {
       // re-center the dialog as content changed
-      this.$.applyFixOverlay.dispatchEvent(
-        new CustomEvent('iron-resize', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this.$.applyFixOverlay, 'iron-resize');
     };
     this.addEventListener('diff-context-expanded', this.refitOverlay);
   }
@@ -171,7 +161,7 @@
         new Error('Both _patchNum and changeNum must be set')
       );
     }
-    return this.$.restAPI
+    return this.restApiService
       .getRobotCommentFixPreview(this.changeNum, this._patchNum, fixId)
       .then(res => {
         if (res) {
@@ -243,12 +233,7 @@
     this._currentPreviews = [];
     this._isApplyFixLoading = false;
 
-    this.dispatchEvent(
-      new CustomEvent('close-fix-preview', {
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireEvent(this, 'close-fix-preview');
     this.$.applyFixOverlay.close();
   }
 
@@ -291,7 +276,7 @@
       return Promise.reject(new Error('Not all required properties are set.'));
     }
     this._isApplyFixLoading = true;
-    return this.$.restAPI
+    return this.restApiService
       .applyFixSuggestion(changeNum, patchNum, this._currentFix.fix_id)
       .then(res => {
         if (res && res.ok) {
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_html.ts b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_html.ts
index 057fd01..52fa9841 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_html.ts
@@ -95,5 +95,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_test.js b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_test.js
index cb73885..869b518 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog_test.js
@@ -56,7 +56,7 @@
 
   suite('dialog open', () => {
     setup(() => {
-      sinon.stub(element.$.restAPI, 'getRobotCommentFixPreview')
+      sinon.stub(element.restApiService, 'getRobotCommentFixPreview')
           .returns(Promise.resolve({
             f1: {
               meta_a: {},
@@ -147,7 +147,7 @@
   });
 
   test('next button state updated when suggestions changed', done => {
-    sinon.stub(element.$.restAPI, 'getRobotCommentFixPreview')
+    sinon.stub(element.restApiService, 'getRobotCommentFixPreview')
         .returns(Promise.resolve({}));
     sinon.stub(element.$.applyFixOverlay, 'open').returns(Promise.resolve());
 
@@ -186,13 +186,13 @@
 
   test('apply fix button should call apply ' +
   'and navigate to change view', () => {
-    sinon.stub(element.$.restAPI, 'applyFixSuggestion')
+    sinon.stub(element.restApiService, 'applyFixSuggestion')
         .returns(Promise.resolve({ok: true}));
     sinon.stub(GerritNav, 'navigateToChange');
     element._currentFix = {fix_id: '123'};
 
     return element._handleApplyFix().then(() => {
-      assert.isTrue(element.$.restAPI.applyFixSuggestion
+      assert.isTrue(element.restApiService.applyFixSuggestion
           .calledWithExactly('1', 2, '123'));
       assert.isTrue(GerritNav.navigateToChange.calledWithExactly({
         _number: '1',
@@ -211,13 +211,13 @@
   });
 
   test('should not navigate to change view if incorect reponse', done => {
-    sinon.stub(element.$.restAPI, 'applyFixSuggestion')
+    sinon.stub(element.restApiService, 'applyFixSuggestion')
         .returns(Promise.resolve({}));
     sinon.stub(GerritNav, 'navigateToChange');
     element._currentFix = {fix_id: '123'};
 
     element._handleApplyFix().then(() => {
-      assert.isTrue(element.$.restAPI.applyFixSuggestion
+      assert.isTrue(element.restApiService.applyFixSuggestion
           .calledWithExactly('1', 2, '123'));
       assert.isTrue(GerritNav.navigateToChange.notCalled);
 
@@ -227,7 +227,7 @@
   });
 
   test('select fix forward and back of multiple suggested fixes', done => {
-    sinon.stub(element.$.restAPI, 'getRobotCommentFixPreview')
+    sinon.stub(element.restApiService, 'getRobotCommentFixPreview')
         .returns(Promise.resolve({
           f1: {
             meta_a: {},
@@ -272,7 +272,7 @@
         });
   });
 
-  test('server-error should throw for failed apply call', done => {
+  test('server-error should throw for failed apply call', async () => {
     sinon.stub(window, 'fetch').callsFake((url => {
       if (url.endsWith('/apply')) {
         return Promise.reject(new Error('backend error'));
@@ -287,12 +287,13 @@
     document.addEventListener('network-error', errorStub);
     sinon.stub(GerritNav, 'navigateToChange');
     element._currentFix = {fix_id: '123'};
-    element._handleApplyFix();
-    flush(() => {
-      assert.isFalse(GerritNav.navigateToChange.called);
-      assert.isTrue(errorStub.called);
-      done();
+    let expectedError;
+    await element._handleApplyFix().catch(e => {
+      expectedError = e;
     });
+    assert.isOk(expectedError);
+    assert.isFalse(GerritNav.navigateToChange.called);
+    assert.isTrue(errorStub.called);
   });
 });
 
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
index 2f6a1b4..5210616 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
@@ -14,61 +14,51 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-comment-api_html';
-import {
-  getParentIndex,
-  isMergeParent,
-  patchNumEquals,
-} from '../../../utils/patch-set-util';
+import {CURRENT} from '../../../utils/patch-set-util';
 import {customElement, property} from '@polymer/decorators';
 import {
   CommentBasics,
-  ConfigInfo,
-  ParentPatchSetNum,
   PatchRange,
   PatchSetNum,
   PathToRobotCommentsInfoMap,
   RobotCommentInfo,
   UrlEncodedCommentId,
   NumericChangeId,
+  PathToCommentsInfoMap,
+  FileInfo,
+  ParentPatchSetNum,
 } from '../../../types/common';
 import {hasOwnProperty} from '../../../utils/common-util';
-import {CommentSide} from '../../../constants/constants';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   Comment,
   CommentMap,
   CommentThread,
   DraftInfo,
   isUnresolved,
-  sortComments,
   UIComment,
   UIDraft,
   UIHuman,
   UIRobot,
+  createCommentThreads,
+  isInPatchRange,
+  isDraftThread,
+  isInBaseOfPatchRange,
+  isInRevisionOfPatchRange,
 } from '../../../utils/comment-util';
 import {PatchSetFile, PatchNumOnly, isPatchSetFile} from '../../../types/types';
+import {appContext} from '../../../services/app-context';
+import {CommentSide, Side} from '../../../constants/constants';
+import {KnownExperimentId} from '../../../services/flags/flags';
+import {pluralize} from '../../../utils/string-util';
 
 export type CommentIdToCommentThreadMap = {
   [urlEncodedCommentId: string]: CommentThread;
 };
 
-export interface TwoSidesComments {
-  // TODO(TS): remove meta - it is not used anywhere
-  meta: {
-    changeNum: NumericChangeId;
-    path: string;
-    patchRange: PatchRange;
-    projectConfig?: ConfigInfo;
-  };
-  left: UIComment[];
-  right: UIComment[];
-}
-
 export class ChangeComments {
   private readonly _comments: {[path: string]: UIHuman[]};
 
@@ -76,7 +66,9 @@
 
   private readonly _drafts: {[path: string]: UIDraft[]};
 
-  private readonly _changeNum: NumericChangeId;
+  private readonly _portedComments: PathToCommentsInfoMap;
+
+  private readonly _portedDrafts: PathToCommentsInfoMap;
 
   /**
    * Construct a change comments object, which can be data-bound to child
@@ -86,13 +78,14 @@
     comments: {[path: string]: UIHuman[]} | undefined,
     robotComments: {[path: string]: UIRobot[]} | undefined,
     drafts: {[path: string]: UIDraft[]} | undefined,
-    changeNum: NumericChangeId
+    portedComments: PathToCommentsInfoMap | undefined,
+    portedDrafts: PathToCommentsInfoMap | undefined
   ) {
     this._comments = this._addPath(comments);
     this._robotComments = this._addPath(robotComments);
     this._drafts = this._addPath(drafts);
-    // TODO(TS): remove changeNum param - it is not used anywhere
-    this._changeNum = changeNum;
+    this._portedComments = portedComments || {};
+    this._portedDrafts = portedDrafts || {};
   }
 
   /**
@@ -117,18 +110,10 @@
     return updatedComments;
   }
 
-  get comments() {
-    return this._comments;
-  }
-
   get drafts() {
     return this._drafts;
   }
 
-  get robotComments() {
-    return this._robotComments;
-  }
-
   findCommentById(commentId?: UrlEncodedCommentId): UIComment | undefined {
     if (!commentId) return undefined;
     const findComment = (comments: {[path: string]: UIComment[]}) => {
@@ -158,9 +143,9 @@
    */
   getPaths(patchRange?: PatchRange): CommentMap {
     const responses: {[path: string]: UIComment[]}[] = [
-      this.comments,
+      this._comments,
       this.drafts,
-      this.robotComments,
+      this._robotComments,
     ];
     const commentMap: CommentMap = {};
     for (const response of responses) {
@@ -172,7 +157,7 @@
             if (!patchRange) {
               return true;
             }
-            return this._isInPatchRange(c, patchRange);
+            return isInPatchRange(c, patchRange);
           })
         ) {
           commentMap[path] = true;
@@ -251,9 +236,7 @@
       allComments = allComments.concat(drafts);
     }
     if (patchNum) {
-      allComments = allComments.filter(c =>
-        patchNumEquals(c.patch_set, patchNum)
-      );
+      allComments = allComments.filter(c => c.patch_set === patchNum);
     }
     return allComments.map(c => {
       return {...c};
@@ -281,6 +264,16 @@
     return allComments;
   }
 
+  cloneWithUpdatedDrafts(drafts: {[path: string]: UIDraft[]} | undefined) {
+    return new ChangeComments(
+      this._comments,
+      this._robotComments,
+      drafts,
+      this._portedComments,
+      this._portedDrafts
+    );
+  }
+
   /**
    * Get the drafts for a path and optional patch num.
    *
@@ -290,7 +283,7 @@
   getAllDraftsForPath(path: string, patchNum?: PatchSetNum): Comment[] {
     let comments = this._drafts[path] || [];
     if (patchNum) {
-      comments = comments.filter(c => patchNumEquals(c.patch_set, patchNum));
+      comments = comments.filter(c => c.patch_set === patchNum);
     }
     return comments.map(c => {
       return {...c, __draft: true};
@@ -322,52 +315,131 @@
    * @param projectConfig Optional project config object to
    * include in the meta sub-object.
    */
-  getCommentsBySideForPath(
-    path: string,
-    patchRange: PatchRange,
-    projectConfig?: ConfigInfo
-  ): TwoSidesComments {
+  getCommentsForPath(path: string, patchRange: PatchRange): Comment[] {
     let comments: Comment[] = [];
     let drafts: DraftInfo[] = [];
     let robotComments: RobotCommentInfo[] = [];
-    if (this.comments && this.comments[path]) {
-      comments = this.comments[path];
+    if (this._comments && this._comments[path]) {
+      comments = this._comments[path];
     }
     if (this.drafts && this.drafts[path]) {
       drafts = this.drafts[path];
     }
-    if (this.robotComments && this.robotComments[path]) {
-      robotComments = this.robotComments[path];
+    if (this._robotComments && this._robotComments[path]) {
+      robotComments = this._robotComments[path];
     }
 
     drafts.forEach(d => {
       d.__draft = true;
     });
 
-    const all: Comment[] = comments
+    return comments
       .concat(drafts)
       .concat(robotComments)
+      .filter(c => isInPatchRange(c, patchRange))
       .map(c => {
         return {...c};
       });
+  }
 
-    const baseComments = all.filter(c =>
-      this._isInBaseOfPatchRange(c, patchRange)
-    );
-    const revisionComments = all.filter(c =>
-      this._isInRevisionOfPatchRange(c, patchRange)
-    );
+  /**
+   * Get the ported threads for given patch range.
+   * Ported threads are comment threads that were posted on an older patchset
+   * and are displayed on a later patchset.
+   * It is simply the original thread displayed on a newer patchset.
+   *
+   * Threads are ported over to all subsequent patchsets. So, a thread created
+   * on patchset 5 say will be ported over to patchsets 6,7,8 and beyond.
+   *
+   * Ported threads add a boolean property ported true to the thread object
+   * to indicate to the user that this is a ported thread.
+   *
+   * Any interactions with ported threads are reflected on the original threads.
+   * Replying to a ported thread ported from Patchset 6 shown on Patchset 10
+   * say creates a draft reply associated with Patchset 6, since the user is
+   * interacting with the original thread.
+   *
+   * Only threads with unresolved comments or drafts are ported over.
+   * If the thread is associated with either the left patchset or the right
+   * patchset, then we filter that ported thread from the return value
+   * as it will be rendered by default.
+   *
+   * If there is no appropriate range for the ported comments, then the backend
+   * does not return the range of the ported thread and it becomes a file level
+   * thread.
+   *
+   * If a comment was created with Side=PARENT, then we only show this ported
+   * comment if Base is part of the patch range, always on the left side of
+   * the diff.
+   *
+   * @return only the ported threads for the specified file and patch range
+   */
+  _getPortedCommentThreads(
+    file: PatchSetFile,
+    patchRange: PatchRange
+  ): CommentThread[] {
+    const portedComments = this._portedComments[file.path] || [];
+    portedComments.push(...(this._portedDrafts[file.path] || []));
+    if (file.basePath) {
+      portedComments.push(...(this._portedComments[file.basePath] || []));
+      portedComments.push(...(this._portedDrafts[file.basePath] || []));
+    }
+    if (!portedComments.length) return [];
 
-    return {
-      meta: {
-        changeNum: this._changeNum,
-        path,
-        patchRange,
-        projectConfig,
-      },
-      left: baseComments,
-      right: revisionComments,
-    };
+    // when forming threads in diff view, we filter for current patchrange but
+    // ported comments will involve comments that may not belong to the
+    // current patchrange, so we need to form threads for them using all
+    // comments
+    const allComments: UIComment[] = this.getAllCommentsForFile(file, true);
+
+    return createCommentThreads(allComments).filter(thread => {
+      // Robot comments and drafts are not ported over. A human reply to
+      // the robot comment will be ported over, thefore it's possible to
+      // have the root comment of the thread not be ported, hence loop over
+      // entire thread
+      const portedComment = portedComments.find(portedComment =>
+        thread.comments.some(c => portedComment.id === c.id)
+      );
+      if (!portedComment) return false;
+
+      if (
+        isInBaseOfPatchRange(thread.comments[0], patchRange) ||
+        isInRevisionOfPatchRange(thread.comments[0], patchRange)
+      ) {
+        // no need to port this thread as it will be rendered by default
+        return false;
+      }
+
+      thread.diffSide = Side.RIGHT;
+      if (thread.commentSide === CommentSide.PARENT) {
+        // TODO(dhruvsri): Add handling for merge parents
+        if (
+          patchRange.basePatchNum !== ParentPatchSetNum ||
+          !!thread.mergeParentNum
+        )
+          return false;
+        thread.diffSide = Side.LEFT;
+      }
+
+      if (!isUnresolved(thread) && !isDraftThread(thread)) return false;
+
+      thread.range = portedComment.range;
+      thread.line = portedComment.line;
+      thread.ported = true;
+      return true;
+    });
+  }
+
+  getThreadsBySideForFile(
+    file: PatchSetFile,
+    patchRange: PatchRange
+  ): CommentThread[] {
+    const threads = createCommentThreads(
+      this.getCommentsForFile(file, patchRange),
+      patchRange
+    );
+    threads.push(...this._getPortedCommentThreads(file, patchRange));
+    return threads;
   }
 
   /**
@@ -382,56 +454,19 @@
    * @param projectConfig Optional project config object to
    * include in the meta sub-object.
    */
-  getCommentsBySideForFile(
-    file: PatchSetFile,
-    patchRange: PatchRange,
-    projectConfig?: ConfigInfo
-  ): TwoSidesComments {
-    const comments = this.getCommentsBySideForPath(
-      file.path,
-      patchRange,
-      projectConfig
-    );
+  getCommentsForFile(file: PatchSetFile, patchRange: PatchRange): Comment[] {
+    const comments = this.getCommentsForPath(file.path, patchRange);
     if (file.basePath) {
-      const commentsForBasePath = this.getCommentsBySideForPath(
-        file.basePath,
-        patchRange,
-        projectConfig
-      );
-      // merge in the left and right
-      comments.left = comments.left.concat(commentsForBasePath.left);
-      comments.right = comments.right.concat(commentsForBasePath.right);
+      comments.push(...this.getCommentsForPath(file.basePath, patchRange));
     }
     return comments;
   }
 
-  /**
-   * @param comments Object keyed by file, with a value of an array
-   * of comments left on that file.
-   * @return A flattened list of all comments, where each comment
-   * also includes the file that it was left on, which was the key of the
-   * originall object.
-   */
-  _commentObjToArrayWithFile<T>(comments: {
-    [path: string]: T[];
-  }): Array<T & {__path: string}> {
-    let commentArr: Array<T & {__path: string}> = [];
-    for (const file of Object.keys(comments)) {
-      const commentsForFile: Array<T & {__path: string}> = [];
-      for (const comment of comments[file]) {
-        commentsForFile.push({...comment, __path: file});
-      }
-      commentArr = commentArr.concat(commentsForFile);
-    }
-    return commentArr;
-  }
-
   _commentObjToArray<T>(comments: {[path: string]: T[]}): T[] {
-    let commentArr: T[] = [];
-    for (const file of Object.keys(comments)) {
-      commentArr = commentArr.concat(comments[file]);
-    }
-    return commentArr;
+    return Object.keys(comments).reduce((commentArr: T[], file) => {
+      comments[file].forEach(c => commentArr.push({...c}));
+      return commentArr;
+    }, []);
   }
 
   /**
@@ -447,7 +482,7 @@
       );
     }
 
-    return this.getCommentThreads(comments).length;
+    return createCommentThreads(comments).length;
   }
 
   /**
@@ -463,6 +498,45 @@
   }
 
   /**
+   * @param includeUnmodified Included unmodified status of the file in the
+   * comment string or not. For files we opt of chip instead of a string.
+   * @param filterPatchset Only count threads which belong to this patchset
+   */
+  computeCommentsString(
+    patchRange?: PatchRange,
+    path?: string,
+    changeFileInfo?: FileInfo,
+    includeUnmodified?: boolean
+  ) {
+    if (!path) return '';
+    if (!patchRange) return '';
+
+    const threads = this.getThreadsBySideForFile({path}, patchRange);
+    const commentThreadCount = threads.filter(thread => !isDraftThread(thread))
+      .length;
+    const unresolvedCount = threads.reduce((cnt, thread) => {
+      if (isUnresolved(thread)) cnt += 1;
+      return cnt;
+    }, 0);
+
+    const commentThreadString = pluralize(commentThreadCount, 'comment');
+    const unresolvedString =
+      unresolvedCount === 0 ? '' : `${unresolvedCount} unresolved`;
+
+    const unmodifiedString =
+      includeUnmodified && changeFileInfo?.status === 'U' ? 'no changes' : '';
+
+    return (
+      commentThreadString +
+      // Add a space if both comments and unresolved
+      (commentThreadString && unresolvedString ? ' ' : '') +
+      // Add parentheses around unresolved if it exists.
+      (unresolvedString ? `(${unresolvedString})` : '') +
+      (unmodifiedString ? `(${unmodifiedString})` : '')
+    );
+  }
+
+  /**
    * Computes a number of unresolved comment threads in a given file and path.
    */
   computeUnresolvedNum(file: PatchSetFile | PatchNumOnly) {
@@ -479,108 +553,14 @@
     }
 
     comments = comments.concat(drafts);
-    const threads = this.getCommentThreads(sortComments(comments));
+    const threads = createCommentThreads(comments);
     const unresolvedThreads = threads.filter(isUnresolved);
     return unresolvedThreads.length;
   }
 
   getAllThreadsForChange() {
-    const comments = this._commentObjToArrayWithFile(this.getAllComments(true));
-    const sortedComments = sortComments(comments);
-    return this.getCommentThreads(sortedComments);
-  }
-
-  /**
-   * Computes all of the comments in thread format.
-   *
-   * @param comments sorted by updated timestamp.
-   */
-  getCommentThreads(comments: UIComment[]) {
-    const threads: CommentThread[] = [];
-    const idThreadMap: CommentIdToCommentThreadMap = {};
-    for (const comment of comments) {
-      if (!comment.id) continue;
-      // If the comment is in reply to another comment, find that comment's
-      // thread and append to it.
-      if (comment.in_reply_to) {
-        const thread = idThreadMap[comment.in_reply_to];
-        if (thread) {
-          thread.comments.push(comment);
-          idThreadMap[comment.id] = thread;
-          continue;
-        }
-      }
-
-      // Otherwise, this comment starts its own thread.
-      if (!comment.__path && !comment.path) {
-        throw new Error('Comment missing required "path".');
-      }
-      const newThread: CommentThread = {
-        comments: [comment],
-        patchNum: comment.patch_set,
-        path: comment.__path || comment.path!,
-        line: comment.line,
-        rootId: comment.id,
-      };
-      if (comment.side) {
-        newThread.commentSide = comment.side;
-      }
-      threads.push(newThread);
-      idThreadMap[comment.id] = newThread;
-    }
-    return threads;
-  }
-
-  /**
-   * Whether the given comment should be included in the base side of the
-   * given patch range.
-   */
-  _isInBaseOfPatchRange(comment: CommentBasics, range: PatchRange) {
-    // If the base of the patch range is a parent of a merge, and the comment
-    // appears on a specific parent then only show the comment if the parent
-    // index of the comment matches that of the range.
-    if (comment.parent && comment.side === CommentSide.PARENT) {
-      return (
-        isMergeParent(range.basePatchNum) &&
-        comment.parent === getParentIndex(range.basePatchNum)
-      );
-    }
-
-    // If the base of the range is the parent of the patch:
-    if (
-      range.basePatchNum === ParentPatchSetNum &&
-      comment.side === CommentSide.PARENT &&
-      patchNumEquals(comment.patch_set, range.patchNum)
-    ) {
-      return true;
-    }
-    // If the base of the range is not the parent of the patch:
-    return (
-      range.basePatchNum !== ParentPatchSetNum &&
-      comment.side !== CommentSide.PARENT &&
-      patchNumEquals(comment.patch_set, range.basePatchNum)
-    );
-  }
-
-  /**
-   * Whether the given comment should be included in the revision side of the
-   * given patch range.
-   */
-  _isInRevisionOfPatchRange(comment: CommentBasics, range: PatchRange) {
-    return (
-      comment.side !== CommentSide.PARENT &&
-      patchNumEquals(comment.patch_set, range.patchNum)
-    );
-  }
-
-  /**
-   * Whether the given comment should be included in the given patch range.
-   */
-  _isInPatchRange(comment: CommentBasics, range: PatchRange): boolean {
-    return (
-      this._isInBaseOfPatchRange(comment, range) ||
-      this._isInRevisionOfPatchRange(comment, range)
-    );
+    const comments = this._commentObjToArray(this.getAllComments(true));
+    return createCommentThreads(comments);
   }
 }
 
@@ -588,12 +568,6 @@
 export const _testOnly_findCommentById =
   ChangeComments.prototype.findCommentById;
 
-export interface GrCommentApi {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-comment-api')
 export class GrCommentApi extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -605,14 +579,21 @@
   @property({type: Object})
   _changeComments?: ChangeComments;
 
+  private readonly restApiService = appContext.restApiService;
+
+  private readonly flagsService = appContext.flagsService;
+
+  private _isPortingCommentsExperimentEnabled = false;
+
   /** @override */
   created() {
     super.created();
-    this.addEventListener('reload-drafts', changeNum =>
-      // TODO(TS): This is a wrong code, however keep it as is for now
-      // If changeNum param in ChangeComments is removed, this also must be
-      // removed
-      this.reloadDrafts((changeNum as unknown) as NumericChangeId)
+  }
+
+  constructor() {
+    super();
+    this._isPortingCommentsExperimentEnabled = this.flagsService.isEnabled(
+      KnownExperimentId.PORTING_COMMENTS
     );
   }
 
@@ -621,24 +602,33 @@
    * number. The returned promise resolves when the comments have loaded, but
    * does not yield the comment data.
    */
-  loadAll(changeNum: NumericChangeId) {
-    const promises = [];
-    promises.push(this.$.restAPI.getDiffComments(changeNum));
-    promises.push(this.$.restAPI.getDiffRobotComments(changeNum));
-    promises.push(this.$.restAPI.getDiffDrafts(changeNum));
+  loadAll(changeNum: NumericChangeId, patchNum?: PatchSetNum) {
+    const revision = patchNum || CURRENT;
+    const commentsPromise = [
+      this.restApiService.getDiffComments(changeNum),
+      this.restApiService.getDiffRobotComments(changeNum),
+      this.restApiService.getDiffDrafts(changeNum),
+      this._isPortingCommentsExperimentEnabled
+        ? this.restApiService.getPortedComments(changeNum, revision)
+        : Promise.resolve({}),
+      this._isPortingCommentsExperimentEnabled
+        ? this.restApiService.getPortedDrafts(changeNum, revision)
+        : Promise.resolve({}),
+    ];
 
-    return Promise.all(promises).then(([comments, robotComments, drafts]) => {
-      this._changeComments = new ChangeComments(
-        comments,
-        // TODO(TS): Promise.all somehow resolve all types to
-        // PathToCommentsInfoMap given its PathToRobotCommentsInfoMap
-        // returned from the second promise
-        robotComments as PathToRobotCommentsInfoMap,
-        drafts,
-        changeNum
-      );
-      return this._changeComments;
-    });
+    return Promise.all(commentsPromise).then(
+      ([comments, robotComments, drafts, portedComments, portedDrafts]) => {
+        this._changeComments = new ChangeComments(
+          comments,
+          // TS 4.0.5 fails without 'as'
+          robotComments as PathToRobotCommentsInfoMap | undefined,
+          drafts,
+          portedComments,
+          portedDrafts
+        );
+        return this._changeComments;
+      }
+    );
   }
 
   /**
@@ -650,13 +640,9 @@
     if (!this._changeComments) {
       return this.loadAll(changeNum);
     }
-    const oldChangeComments = this._changeComments;
-    return this.$.restAPI.getDiffDrafts(changeNum).then(drafts => {
-      this._changeComments = new ChangeComments(
-        oldChangeComments.comments,
-        (oldChangeComments.robotComments as unknown) as PathToRobotCommentsInfoMap,
-        drafts,
-        changeNum
+    return this.restApiService.getDiffDrafts(changeNum).then(drafts => {
+      this._changeComments = this._changeComments!.cloneWithUpdatedDrafts(
+        drafts
       );
       return this._changeComments;
     });
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_html.ts b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_html.ts
index 91d8b41..1489006 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_html.ts
@@ -16,6 +16,4 @@
  */
 import {html} from '@polymer/polymer/lib/utils/html-tag';
 
-export const htmlTemplate = html`
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
-`;
+export const htmlTemplate = html``;
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_test.js b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_test.js
index be6f646..e107c16 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api_test.js
@@ -18,6 +18,9 @@
 import '../../../test/common-test-setup-karma.js';
 import './gr-comment-api.js';
 import {ChangeComments} from './gr-comment-api.js';
+import {isInRevisionOfPatchRange, isInBaseOfPatchRange, isDraftThread, isUnresolved, createCommentThreads} from '../../../utils/comment-util.js';
+import {createDraft, createComment, createChangeComments, createCommentThread} from '../../../test/test-data-generators.js';
+import {CommentSide, Side} from '../../../constants/constants.js';
 
 const basicFixture = fixtureFromElement('gr-comment-api');
 
@@ -33,23 +36,24 @@
   test('loads logged-out', () => {
     const changeNum = 1234;
 
-    sinon.stub(element.$.restAPI, 'getLoggedIn')
+    sinon.stub(element.restApiService, 'getLoggedIn')
         .returns(Promise.resolve(false));
-    sinon.stub(element.$.restAPI, 'getDiffComments')
+    sinon.stub(element.restApiService, 'getDiffComments')
         .returns(Promise.resolve({
           'foo.c': [{id: '123', message: 'foo bar', in_reply_to: '321'}],
         }));
-    sinon.stub(element.$.restAPI, 'getDiffRobotComments')
+    sinon.stub(element.restApiService, 'getDiffRobotComments')
         .returns(Promise.resolve({'foo.c': [{id: '321', message: 'done'}]}));
-    sinon.stub(element.$.restAPI, 'getDiffDrafts')
+    sinon.stub(element.restApiService, 'getDiffDrafts')
         .returns(Promise.resolve({}));
 
     return element.loadAll(changeNum).then(() => {
-      assert.isTrue(element.$.restAPI.getDiffComments.calledWithExactly(
+      assert.isTrue(element.restApiService.getDiffComments.calledWithExactly(
           changeNum));
-      assert.isTrue(element.$.restAPI.getDiffRobotComments.calledWithExactly(
-          changeNum));
-      assert.isTrue(element.$.restAPI.getDiffDrafts.calledWithExactly(
+      assert.isTrue(
+          element.restApiService.getDiffRobotComments.calledWithExactly(
+              changeNum));
+      assert.isTrue(element.restApiService.getDiffDrafts.calledWithExactly(
           changeNum));
       assert.isOk(element._changeComments._comments);
       assert.isOk(element._changeComments._robotComments);
@@ -60,23 +64,24 @@
   test('loads logged-in', () => {
     const changeNum = 1234;
 
-    sinon.stub(element.$.restAPI, 'getLoggedIn')
+    sinon.stub(element.restApiService, 'getLoggedIn')
         .returns(Promise.resolve(true));
-    sinon.stub(element.$.restAPI, 'getDiffComments')
+    sinon.stub(element.restApiService, 'getDiffComments')
         .returns(Promise.resolve({
           'foo.c': [{id: '123', message: 'foo bar', in_reply_to: '321'}],
         }));
-    sinon.stub(element.$.restAPI, 'getDiffRobotComments')
+    sinon.stub(element.restApiService, 'getDiffRobotComments')
         .returns(Promise.resolve({'foo.c': [{id: '321', message: 'done'}]}));
-    sinon.stub(element.$.restAPI, 'getDiffDrafts')
+    sinon.stub(element.restApiService, 'getDiffDrafts')
         .returns(Promise.resolve({'foo.c': [{id: '555', message: 'ack'}]}));
 
     return element.loadAll(changeNum).then(() => {
-      assert.isTrue(element.$.restAPI.getDiffComments.calledWithExactly(
+      assert.isTrue(element.restApiService.getDiffComments.calledWithExactly(
           changeNum));
-      assert.isTrue(element.$.restAPI.getDiffRobotComments.calledWithExactly(
-          changeNum));
-      assert.isTrue(element.$.restAPI.getDiffDrafts.calledWithExactly(
+      assert.isTrue(
+          element.restApiService.getDiffRobotComments.calledWithExactly(
+              changeNum));
+      assert.isTrue(element.restApiService.getDiffDrafts.calledWithExactly(
           changeNum));
       assert.isOk(element._changeComments._comments);
       assert.isOk(element._changeComments._robotComments);
@@ -89,11 +94,11 @@
     let robotCommentStub;
     let draftStub;
     setup(() => {
-      commentStub = sinon.stub(element.$.restAPI, 'getDiffComments')
+      commentStub = sinon.stub(element.restApiService, 'getDiffComments')
           .returns(Promise.resolve({}));
-      robotCommentStub = sinon.stub(element.$.restAPI,
+      robotCommentStub = sinon.stub(element.restApiService,
           'getDiffRobotComments').returns(Promise.resolve({}));
-      draftStub = sinon.stub(element.$.restAPI, 'getDiffDrafts')
+      draftStub = sinon.stub(element.restApiService, 'getDiffDrafts')
           .returns(Promise.resolve({}));
     });
 
@@ -143,180 +148,480 @@
       });
     });
 
+    suite('ported comments', () => {
+      let portedComments;
+      let changeComments;
+      const comment1 = {
+        ...createComment(),
+        unresolved: true,
+        id: '1',
+        line: 136,
+        patch_set: 2,
+        range: {
+          start_line: 1,
+          start_character: 1,
+          end_line: 1,
+          end_character: 1,
+        },
+      };
+
+      const comment2 = {
+        ...createComment(),
+        patch_set: 2,
+        id: '2',
+        line: 5,
+      };
+
+      const comment3 = {
+        ...createComment(),
+        side: CommentSide.PARENT,
+        line: 10,
+        unresolved: true,
+      };
+
+      const comment4 = {
+        ...comment3,
+        parent: -2,
+      };
+
+      const draft1 = {
+        ...createDraft(),
+        id: 'db977012_e1f13828',
+        line: 4,
+        patch_set: 2,
+      };
+      const draft2 = {
+        ...createDraft(),
+        id: '503008e2_0ab203ee',
+        line: 11,
+        unresolved: true,
+        // slightly larger timestamp so it's sorted higher
+        updated: '2018-02-13 22:49:48.018000001',
+        patch_set: 2,
+      };
+
+      setup(() => {
+        portedComments = {
+          'karma.conf.js': [{
+            ...comment1,
+            patch_set: 4,
+            range: {
+              start_line: 136,
+              start_character: 16,
+              end_line: 136,
+              end_character: 29,
+            },
+          }],
+        };
+
+        changeComments = new ChangeComments(
+            {/* comments */
+              'karma.conf.js': [
+                // resolved comment that will not be ported over
+                comment2,
+                // original comment that will be ported over to patchset 4
+                comment1,
+              ],
+            },
+            {}/* robot comments */,
+            {}/* drafts */,
+            portedComments,
+            {}/* ported drafts */
+        );
+      });
+
+      test('threads containing ported comment are returned', () => {
+        assert.equal(changeComments.getAllThreadsForChange().length,
+            2);
+
+        const portedThreads = changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 'PARENT'});
+
+        assert.equal(portedThreads.length, 1);
+        // check range of thread is from the ported comment and not the original
+        assert.deepEqual(portedThreads[0].range, {
+          start_line: 136,
+          start_character: 16,
+          end_line: 136,
+          end_character: 29,
+        });
+
+        // thread ported over if comparing patchset 1 vs patchset 4
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 1}
+        ).length, 1);
+
+        // verify ported thread is not returned if original thread will be
+        // shown
+        // original thread attached to right side
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 2, basePatchNum: 'PARENT'}
+        ).length, 0);
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 2, basePatchNum: 1}
+        ).length, 0);
+
+        // original thread attached to left side
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 3, basePatchNum: 2}
+        ).length, 0);
+      });
+
+      test('threads without any ported comment are filtered out', () => {
+        changeComments = new ChangeComments(
+            {/* comments */
+              // comment that is not ported over
+              'karma.conf.js': [comment2],
+            },
+            {}/* robot comments */,
+            {/* drafts */
+              'karma.conf.js': [draft2],
+            },
+            // comment1 that is ported over but does not have any thread
+            // that has a comment that matches it
+            portedComments,
+            {}/* ported drafts */
+        );
+
+        assert.equal(createCommentThreads(changeComments
+            .getAllCommentsForPath('karma.conf.js')).length, 1);
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 'PARENT'}
+        ).length, 0);
+      });
+
+      test('comments with side=PARENT are ported over', () => {
+        changeComments = new ChangeComments(
+            {/* comments */
+              // comment left on Base
+              'karma.conf.js': [comment3],
+            },
+            {}/* robot comments */,
+            {/* drafts */
+              'karma.conf.js': [draft2],
+            },
+            {/* ported comments */
+              'karma.conf.js': [{
+                ...comment3,
+                line: 31,
+                patch_set: 4,
+              }],
+            },
+            {}/* ported drafts */
+        );
+
+        const portedThreads = changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 'PARENT'});
+        assert.equal(portedThreads.length, 1);
+        assert.equal(portedThreads[0].line, 31);
+        assert.equal(portedThreads[0].diffSide, Side.LEFT);
+
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: -2}
+        ).length, 0);
+
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 2}
+        ).length, 0);
+      });
+
+      test('comments left on merge parent is not ported over', () => {
+        changeComments = new ChangeComments(
+            {/* comments */
+              // comment left on Base
+              'karma.conf.js': [comment4],
+            },
+            {}/* robot comments */,
+            {/* drafts */
+              'karma.conf.js': [draft2],
+            },
+            {/* ported comments */
+              'karma.conf.js': [{
+                ...comment4,
+                line: 31,
+                patch_set: 4,
+              }],
+            },
+            {}/* ported drafts */
+        );
+
+        const portedThreads = changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 'PARENT'});
+        assert.equal(portedThreads.length, 0);
+
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: -2}
+        ).length, 0);
+
+        assert.equal(changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 2}
+        ).length, 0);
+      });
+
+      test('ported comments contribute to comment count', () => {
+        assert.equal(changeComments.computeCommentsString(
+            {basePatchNum: 'PARENT', patchNum: 2}, 'karma.conf.js',
+            {__path: 'karma.conf.js'}), '2 comments (1 unresolved)');
+
+        // comment1 is ported over to patchset 4
+        assert.equal(changeComments.computeCommentsString(
+            {basePatchNum: 'PARENT', patchNum: 4}, 'karma.conf.js',
+            {__path: 'karma.conf.js'}), '1 comment (1 unresolved)');
+      });
+
+      test('drafts are ported over', () => {
+        changeComments = new ChangeComments(
+            {}/* comments */,
+            {}/* robotComments */,
+            {/* drafts */
+              // draft1: resolved draft that will be ported over to ps 4
+              // draft2: unresolved draft that will be ported over to ps 4
+              'karma.conf.js': [draft1, draft2],
+            },
+            {}/* ported comments */,
+            {/* ported drafts */
+              'karma.conf.js': [
+                {
+                  ...draft1,
+                  line: 5,
+                  patch_set: 4,
+                },
+                {
+                  ...draft2,
+                  line: 31,
+                  patch_set: 4,
+                },
+              ],
+            }
+        );
+
+        const portedThreads = changeComments._getPortedCommentThreads(
+            {path: 'karma.conf.js'}, {patchNum: 4, basePatchNum: 'PARENT'});
+
+        // resolved draft is ported over
+        assert.equal(portedThreads.length, 2);
+        assert.equal(portedThreads[0].line, 5);
+        assert.isTrue(isDraftThread(portedThreads[0]));
+        assert.isFalse(isUnresolved(portedThreads[0]));
+
+        // unresolved draft is ported over
+        assert.equal(portedThreads[1].line, 31);
+        assert.isTrue(isDraftThread(portedThreads[1]));
+        assert.isTrue(isUnresolved(portedThreads[1]));
+
+        assert.equal(createCommentThreads(
+            changeComments.getAllCommentsForPath('karma.conf.js'),
+            {patchNum: 4, basePatchNum: 'PARENT'}).length, 0);
+      });
+    });
+
     test('_isInBaseOfPatchRange', () => {
       const comment = {patch_set: 1};
       const patchRange = {basePatchNum: 1, patchNum: 2};
-      assert.isTrue(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isTrue(isInBaseOfPatchRange(comment,
           patchRange));
 
       patchRange.basePatchNum = PARENT;
-      assert.isFalse(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isFalse(isInBaseOfPatchRange(comment,
           patchRange));
 
       comment.side = PARENT;
-      assert.isFalse(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isFalse(isInBaseOfPatchRange(comment,
           patchRange));
 
       comment.patch_set = 2;
-      assert.isTrue(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isTrue(isInBaseOfPatchRange(comment,
           patchRange));
 
       patchRange.basePatchNum = -2;
       comment.side = PARENT;
       comment.parent = 1;
-      assert.isFalse(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isFalse(isInBaseOfPatchRange(comment,
           patchRange));
 
       comment.parent = 2;
-      assert.isTrue(element._changeComments._isInBaseOfPatchRange(comment,
+      assert.isTrue(isInBaseOfPatchRange(comment,
           patchRange));
     });
 
-    test('_isInRevisionOfPatchRange', () => {
+    test('isInRevisionOfPatchRange', () => {
       const comment = {patch_set: 123};
       const patchRange = {basePatchNum: 122, patchNum: 124};
-      assert.isFalse(element._changeComments._isInRevisionOfPatchRange(
+      assert.isFalse(isInRevisionOfPatchRange(
           comment, patchRange));
 
       patchRange.patchNum = 123;
-      assert.isTrue(element._changeComments._isInRevisionOfPatchRange(
+      assert.isTrue(isInRevisionOfPatchRange(
           comment, patchRange));
 
       comment.side = PARENT;
-      assert.isFalse(element._changeComments._isInRevisionOfPatchRange(
+      assert.isFalse(isInRevisionOfPatchRange(
           comment, patchRange));
     });
 
-    test('_isInPatchRange', () => {
-      const patchRange1 = {basePatchNum: 122, patchNum: 124};
-      const patchRange2 = {basePatchNum: 123, patchNum: 125};
-      const patchRange3 = {basePatchNum: 124, patchNum: 125};
-
-      const isInBasePatchStub = sinon.stub(element._changeComments,
-          '_isInBaseOfPatchRange');
-      const isInRevisionPatchStub = sinon.stub(element._changeComments,
-          '_isInRevisionOfPatchRange');
-
-      isInBasePatchStub.withArgs({}, patchRange1).returns(true);
-      isInBasePatchStub.withArgs({}, patchRange2).returns(false);
-      isInBasePatchStub.withArgs({}, patchRange3).returns(false);
-
-      isInRevisionPatchStub.withArgs({}, patchRange1).returns(false);
-      isInRevisionPatchStub.withArgs({}, patchRange2).returns(true);
-      isInRevisionPatchStub.withArgs({}, patchRange3).returns(false);
-
-      assert.isTrue(element._changeComments._isInPatchRange({}, patchRange1));
-      assert.isTrue(element._changeComments._isInPatchRange({}, patchRange2));
-      assert.isFalse(element._changeComments._isInPatchRange({},
-          patchRange3));
-    });
-
     suite('comment ranges and paths', () => {
+      const commentObjs = {};
       function makeTime(mins) {
         return `2013-02-26 15:0${mins}:43.986000000`;
       }
 
       setup(() => {
+        commentObjs['01'] = {
+          ...createComment(),
+          id: '01',
+          patch_set: 2,
+          side: PARENT,
+          line: 1,
+          updated: makeTime(1),
+          range: {
+            start_line: 1,
+            start_character: 2,
+            end_line: 2,
+            end_character: 2,
+          },
+        };
+
+        commentObjs['02'] = {
+          ...createComment(),
+          id: '02',
+          in_reply_to: '04',
+          patch_set: 2,
+          unresolved: true,
+          line: 1,
+          updated: makeTime(3),
+        };
+
+        commentObjs['03'] = {
+          ...createComment(),
+          id: '03',
+          patch_set: 2,
+          side: PARENT,
+          line: 2,
+          updated: makeTime(1),
+        };
+
+        commentObjs['04'] = {
+          ...createComment(),
+          id: '04',
+          patch_set: 2,
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['05'] = {
+          ...createComment(),
+          id: '05',
+          patch_set: 2,
+          line: 2,
+          updated: makeTime(1),
+        };
+
+        commentObjs['06'] = {
+          ...createComment(),
+          id: '06',
+          patch_set: 3,
+          line: 2,
+          updated: makeTime(1),
+        };
+
+        commentObjs['07'] = {
+          ...createComment(),
+          id: '07',
+          patch_set: 2,
+          side: PARENT,
+          unresolved: false,
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['08'] = {
+          ...createComment(),
+          id: '08',
+          patch_set: 2,
+          side: PARENT,
+          unresolved: true,
+          in_reply_to: '07',
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['09'] = {
+          ...createComment(),
+          id: '09',
+          patch_set: 3,
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['10'] = {
+          ...createComment(),
+          id: '10',
+          patch_set: 5,
+          side: PARENT,
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['11'] = {
+          ...createComment(),
+          id: '11',
+          patch_set: 5,
+          line: 1,
+          updated: makeTime(1),
+        };
+
+        commentObjs['12'] = {
+          ...createDraft(),
+          id: '12',
+          patch_set: 2,
+          side: PARENT,
+          line: 1,
+          updated: makeTime(3),
+        };
+
+        commentObjs['13'] = {
+          ...createDraft(),
+          id: '13',
+          in_reply_to: '04',
+          patch_set: 2,
+          line: 1,
+          // Draft gets lower timestamp than published comment, because we
+          // want to test that the draft still gets sorted to the end.
+          updated: makeTime(2),
+        };
+
+        commentObjs['14'] = {
+          ...createDraft(),
+          id: '14',
+          patch_set: 3,
+          line: 1,
+          path: 'file/two',
+          updated: makeTime(3),
+        };
+
         const drafts = {
           'file/one': [
-            {
-              id: '12',
-              patch_set: 2,
-              side: PARENT,
-              line: 1,
-              updated: makeTime(3),
-            },
-            {
-              id: '13',
-              in_reply_to: '04',
-              patch_set: 2,
-              line: 1,
-              // Draft gets lower timestamp than published comment, because we
-              // want to test that the draft still gets sorted to the end.
-              updated: makeTime(2),
-            },
+            commentObjs['12'],
+            commentObjs['13'],
           ],
           'file/two': [
-            {
-              id: '05',
-              patch_set: 3,
-              line: 1,
-              updated: makeTime(3),
-            },
+            commentObjs['14'],
           ],
         };
         const robotComments = {
           'file/one': [
-            {
-              id: '01',
-              patch_set: 2,
-              side: PARENT,
-              line: 1,
-              updated: makeTime(1),
-              range: {
-                start_line: 1,
-                start_character: 2,
-                end_line: 2,
-                end_character: 2,
-              },
-            }, {
-              id: '02',
-              in_reply_to: '04',
-              patch_set: 2,
-              unresolved: true,
-              line: 1,
-              updated: makeTime(3),
-            },
+            commentObjs['01'], commentObjs['02'],
           ],
         };
         const comments = {
-          'file/one': [
-            {
-              id: '03',
-              patch_set: 2,
-              side: PARENT,
-              line: 2,
-              updated: makeTime(1),
-            },
-            {id: '04', patch_set: 2, line: 1, updated: makeTime(1)},
-          ],
-          'file/two': [
-            {id: '05', patch_set: 2, line: 2, updated: makeTime(1)},
-            {id: '06', patch_set: 3, line: 2, updated: makeTime(1)},
-          ],
-          'file/three': [
-            {
-              id: '07',
-              patch_set: 2,
-              side: PARENT,
-              unresolved: false,
-              line: 1,
-              updated: makeTime(1),
-            },
-            {
-              id: '08',
-              patch_set: 2,
-              side: PARENT,
-              unresolved: true,
-              in_reply_to: '07',
-              line: 1,
-              updated: makeTime(1),
-            },
-            {id: '09', patch_set: 3, line: 1, updated: makeTime(1)},
-          ],
-          'file/four': [
-            {
-              id: '10',
-              patch_set: 5,
-              side: PARENT,
-              line: 1,
-              updated: makeTime(1),
-            },
-            {id: '11', patch_set: 5, line: 1, updated: makeTime(1)},
-          ],
+          'file/one': [commentObjs['03'], commentObjs['04']],
+          'file/two': [commentObjs['05'], commentObjs['06']],
+          'file/three': [commentObjs['07'], commentObjs['08'],
+            commentObjs['09']],
+          'file/four': [commentObjs['10'], commentObjs['11']],
         };
         element._changeComments =
-            new ChangeComments(comments, robotComments, drafts, 1234);
+            new ChangeComments(comments, robotComments, drafts, {}, {});
       });
 
       test('getPaths', () => {
@@ -346,33 +651,40 @@
         assert.property(paths, 'file/four');
       });
 
-      test('getCommentsBySideForPath', () => {
+      test('getCommentsForPath', () => {
         const patchRange = {basePatchNum: 1, patchNum: 3};
         let path = 'file/one';
-        let comments = element._changeComments.getCommentsBySideForPath(path,
+        let comments = element._changeComments.getCommentsForPath(path,
             patchRange);
-        assert.equal(comments.meta.changeNum, 1234);
-        assert.equal(comments.left.length, 0);
-        assert.equal(comments.right.length, 0);
+        assert.equal(comments.filter(c => isInBaseOfPatchRange(c, patchRange))
+            .length, 0);
+        assert.equal(comments.filter(c => isInRevisionOfPatchRange(c,
+            patchRange)).length, 0);
 
         path = 'file/two';
-        comments = element._changeComments.getCommentsBySideForPath(path,
+        comments = element._changeComments.getCommentsForPath(path,
             patchRange);
-        assert.equal(comments.left.length, 0);
-        assert.equal(comments.right.length, 2);
+        assert.equal(comments.filter(c => isInBaseOfPatchRange(c, patchRange))
+            .length, 0);
+        assert.equal(comments.filter(c => isInRevisionOfPatchRange(c,
+            patchRange)).length, 2);
 
         patchRange.basePatchNum = 2;
-        comments = element._changeComments.getCommentsBySideForPath(path,
+        comments = element._changeComments.getCommentsForPath(path,
             patchRange);
-        assert.equal(comments.left.length, 1);
-        assert.equal(comments.right.length, 2);
+        assert.equal(comments.filter(c => isInBaseOfPatchRange(c,
+            patchRange)).length, 1);
+        assert.equal(comments.filter(c => isInRevisionOfPatchRange(c,
+            patchRange)).length, 2);
 
         patchRange.basePatchNum = PARENT;
         path = 'file/three';
-        comments = element._changeComments.getCommentsBySideForPath(path,
+        comments = element._changeComments.getCommentsForPath(path,
             patchRange);
-        assert.equal(comments.left.length, 0);
-        assert.equal(comments.right.length, 1);
+        assert.equal(comments.filter(c => isInBaseOfPatchRange(c, patchRange))
+            .length, 0);
+        assert.equal(comments.filter(c => isInRevisionOfPatchRange(c,
+            patchRange)).length, 1);
       });
 
       test('getAllCommentsForPath', () => {
@@ -448,6 +760,78 @@
             element._changeComments.computeUnresolvedNum(1, 'path'), 0);
       });
 
+      test('computeCommentsString', () => {
+        const changeComments = createChangeComments();
+        const parentTo1 = {
+          basePatchNum: 'PARENT',
+          patchNum: 1,
+        };
+        const parentTo2 = {
+          basePatchNum: 'PARENT',
+          patchNum: 2,
+        };
+        const _1To2 = {
+          basePatchNum: 1,
+          patchNum: 2,
+        };
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo1, '/COMMIT_MSG',
+                {__path: '/COMMIT_MSG'}), '2 comments (1 unresolved)');
+        assert.equal(
+            changeComments.computeCommentsString(parentTo1, '/COMMIT_MSG',
+                {__path: '/COMMIT_MSG', status: 'U'}, true),
+            '2 comments (1 unresolved)(no changes)');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2, '/COMMIT_MSG',
+                {__path: '/COMMIT_MSG'}), '3 comments (1 unresolved)');
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo1, 'myfile.txt',
+                {__path: 'myfile.txt'}), '1 comment');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2, 'myfile.txt',
+                {__path: 'myfile.txt'}), '3 comments');
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo1,
+                'file_added_in_rev2.txt',
+                {__path: 'file_added_in_rev2.txt'}), '');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2,
+                'file_added_in_rev2.txt',
+                {__path: 'file_added_in_rev2.txt'}), '');
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo2, '/COMMIT_MSG',
+                {__path: '/COMMIT_MSG'}), '1 comment');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2, '/COMMIT_MSG',
+                {__path: '/COMMIT_MSG'}), '3 comments (1 unresolved)');
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo2, 'myfile.txt',
+                {__path: 'myfile.txt'}), '2 comments');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2, 'myfile.txt',
+                {__path: 'myfile.txt'}), '3 comments');
+
+        assert.equal(
+            changeComments.computeCommentsString(parentTo2,
+                'file_added_in_rev2.txt',
+                {__path: 'file_added_in_rev2.txt'}), '');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2,
+                'file_added_in_rev2.txt',
+                {__path: 'file_added_in_rev2.txt'}), '');
+        assert.equal(
+            changeComments.computeCommentsString(parentTo2, 'unresolved.file',
+                {__path: 'unresolved.file'}), '2 comments (1 unresolved)');
+        assert.equal(
+            changeComments.computeCommentsString(_1To2, 'unresolved.file',
+                {__path: 'unresolved.file'}), '2 comments (1 unresolved)');
+      });
+
       test('computeCommentThreadCount', () => {
         assert.equal(element._changeComments
             .computeCommentThreadCount({
@@ -521,220 +905,31 @@
       test('computeAllThreads', () => {
         const expectedThreads = [
           {
-            comments: [
-              {
-                id: '01',
-                patch_set: 2,
-                side: 'PARENT',
-                line: 1,
-                updated: '2013-02-26 15:01:43.986000000',
-                range: {
-                  start_line: 1,
-                  start_character: 2,
-                  end_line: 2,
-                  end_character: 2,
-                },
-                path: 'file/one',
-                __path: 'file/one',
-              },
-            ],
-            commentSide: 'PARENT',
-            patchNum: 2,
-            path: 'file/one',
-            line: 1,
-            rootId: '01',
+            ...createCommentThread([{...commentObjs['01'], path: 'file/one'}]),
           }, {
-            comments: [
-              {
-                id: '03',
-                patch_set: 2,
-                side: 'PARENT',
-                line: 2,
-                path: 'file/one',
-                __path: 'file/one',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            commentSide: 'PARENT',
-            patchNum: 2,
-            path: 'file/one',
-            line: 2,
-            rootId: '03',
+            ...createCommentThread([{...commentObjs['03'], path: 'file/one'}]),
           }, {
-            comments: [
-              {
-                id: '04',
-                patch_set: 2,
-                line: 1,
-                path: 'file/one',
-                __path: 'file/one',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-              {
-                id: '02',
-                in_reply_to: '04',
-                patch_set: 2,
-                unresolved: true,
-                line: 1,
-                path: 'file/one',
-                __path: 'file/one',
-                updated: '2013-02-26 15:03:43.986000000',
-              },
-              {
-                id: '13',
-                in_reply_to: '04',
-                patch_set: 2,
-                line: 1,
-                path: 'file/one',
-                __path: 'file/one',
-                __draft: true,
-                updated: '2013-02-26 15:02:43.986000000',
-              },
-            ],
-            patchNum: 2,
-            path: 'file/one',
-            line: 1,
-            rootId: '04',
+            ...createCommentThread([{...commentObjs['04'], path: 'file/one'},
+              {...commentObjs['02'], path: 'file/one'},
+              {...commentObjs['13'], path: 'file/one'}]),
           }, {
-            comments: [
-              {
-                id: '05',
-                patch_set: 2,
-                line: 2,
-                path: 'file/two',
-                __path: 'file/two',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            patchNum: 2,
-            path: 'file/two',
-            line: 2,
-            rootId: '05',
+            ...createCommentThread([{...commentObjs['05'], path: 'file/two'}]),
           }, {
-            comments: [
-              {
-                id: '06',
-                patch_set: 3,
-                line: 2,
-                path: 'file/two',
-                __path: 'file/two',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            patchNum: 3,
-            path: 'file/two',
-            line: 2,
-            rootId: '06',
+            ...createCommentThread([{...commentObjs['06'], path: 'file/two'}]),
           }, {
-            comments: [
-              {
-                id: '07',
-                patch_set: 2,
-                side: 'PARENT',
-                unresolved: false,
-                line: 1,
-                path: 'file/three',
-                __path: 'file/three',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-              {
-                id: '08',
-                in_reply_to: '07',
-                patch_set: 2,
-                side: 'PARENT',
-                unresolved: true,
-                line: 1,
-                path: 'file/three',
-                __path: 'file/three',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            commentSide: 'PARENT',
-            patchNum: 2,
-            path: 'file/three',
-            line: 1,
-            rootId: '07',
+            ...createCommentThread([{...commentObjs['07'], path: 'file/three'},
+              {...commentObjs['08'], path: 'file/three'}]),
           }, {
-            comments: [
-              {
-                id: '09',
-                patch_set: 3,
-                line: 1,
-                path: 'file/three',
-                __path: 'file/three',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            patchNum: 3,
-            path: 'file/three',
-            line: 1,
-            rootId: '09',
+            ...createCommentThread([{...commentObjs['09'], path: 'file/three'}]
+            ),
           }, {
-            comments: [
-              {
-                id: '10',
-                patch_set: 5,
-                side: 'PARENT',
-                line: 1,
-                path: 'file/four',
-                __path: 'file/four',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            commentSide: 'PARENT',
-            patchNum: 5,
-            path: 'file/four',
-            line: 1,
-            rootId: '10',
+            ...createCommentThread([{...commentObjs['10'], path: 'file/four'}]),
           }, {
-            comments: [
-              {
-                id: '11',
-                patch_set: 5,
-                line: 1,
-                path: 'file/four',
-                __path: 'file/four',
-                updated: '2013-02-26 15:01:43.986000000',
-              },
-            ],
-            rootId: '11',
-            patchNum: 5,
-            path: 'file/four',
-            line: 1,
+            ...createCommentThread([{...commentObjs['11'], path: 'file/four'}]),
           }, {
-            comments: [
-              {
-                id: '05',
-                patch_set: 3,
-                line: 1,
-                path: 'file/two',
-                __path: 'file/two',
-                __draft: true,
-                updated: '2013-02-26 15:03:43.986000000',
-              },
-            ],
-            rootId: '05',
-            patchNum: 3,
-            path: 'file/two',
-            line: 1,
+            ...createCommentThread([{...commentObjs['12'], path: 'file/one'}]),
           }, {
-            comments: [
-              {
-                id: '12',
-                patch_set: 2,
-                side: 'PARENT',
-                line: 1,
-                path: 'file/one',
-                __path: 'file/one',
-                __draft: true,
-                updated: '2013-02-26 15:03:43.986000000',
-              },
-            ],
-            rootId: '12',
-            commentSide: 'PARENT',
-            patchNum: 2,
-            path: 'file/one',
-            line: 1,
+            ...createCommentThread([{...commentObjs['14'], path: 'file/two'}]),
           },
         ];
         const threads = element._changeComments.getAllThreadsForChange();
@@ -743,48 +938,14 @@
 
       test('getCommentsForThreadGroup', () => {
         let expectedComments = [
-          {
-            __path: 'file/one',
-            path: 'file/one',
-            id: '04',
-            patch_set: 2,
-            line: 1,
-            updated: '2013-02-26 15:01:43.986000000',
-          },
-          {
-            __path: 'file/one',
-            path: 'file/one',
-            id: '02',
-            in_reply_to: '04',
-            patch_set: 2,
-            unresolved: true,
-            line: 1,
-            updated: '2013-02-26 15:03:43.986000000',
-          },
-          {
-            __path: 'file/one',
-            path: 'file/one',
-            __draft: true,
-            id: '13',
-            in_reply_to: '04',
-            patch_set: 2,
-            line: 1,
-            updated: '2013-02-26 15:02:43.986000000',
-          },
+          {...commentObjs['04'], path: 'file/one'},
+          {...commentObjs['02'], path: 'file/one'},
+          {...commentObjs['13'], path: 'file/one'},
         ];
         assert.deepEqual(element._changeComments.getCommentsForThread('04'),
             expectedComments);
 
-        expectedComments = [{
-          id: '12',
-          patch_set: 2,
-          side: 'PARENT',
-          line: 1,
-          path: 'file/one',
-          __path: 'file/one',
-          __draft: true,
-          updated: '2013-02-26 15:03:43.986000000',
-        }];
+        expectedComments = [{...commentObjs['12'], path: 'file/one'}];
 
         assert.deepEqual(element._changeComments.getCommentsForThread('12'),
             expectedComments);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.ts
index 7a26e77..763a524 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.ts
@@ -16,7 +16,7 @@
  */
 
 import {GrDiffBuilderUnified} from './gr-diff-builder-unified';
-import {DiffInfo, DiffPreferencesInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {GrDiffLine, GrDiffLineType} from '../gr-diff/gr-diff-line';
 
 export class GrDiffBuilderBinary extends GrDiffBuilderUnified {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-element.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-element.ts
index 6d81e9b..6e613d3 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-element.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-element.ts
@@ -31,12 +31,8 @@
 import {GrDiffBuilderBinary} from './gr-diff-builder-binary';
 import {CancelablePromise, util} from '../../../scripts/util';
 import {customElement, property, observe} from '@polymer/decorators';
-import {
-  BlameInfo,
-  DiffInfo,
-  DiffPreferencesInfo,
-  ImageInfo,
-} from '../../../types/common';
+import {BlameInfo, ImageInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {CoverageRange, DiffLayer} from '../../../types/types';
 import {
   GrDiffProcessor,
@@ -52,6 +48,7 @@
 import {GrDiffGroup} from '../gr-diff/gr-diff-group';
 import {PolymerSpliceChange} from '@polymer/polymer/interfaces';
 import {getLineNumber} from '../gr-diff/gr-diff-utils';
+import {fireAlert, fireEvent} from '../../../utils/event-util';
 
 const DiffViewMode = {
   SIDE_BY_SIDE: 'SIDE_BY_SIDE',
@@ -222,17 +219,13 @@
 
     const isBinary = !!(this.isImageDiff || this.diff.binary);
 
-    this.dispatchEvent(
-      new CustomEvent('render-start', {bubbles: true, composed: true})
-    );
+    fireEvent(this, 'render-start');
     this._cancelableRenderPromise = util.makeCancelable(
       this.$.processor.process(this.diff.content, isBinary).then(() => {
         if (this.isImageDiff) {
           (this._builder as GrDiffBuilderImage).renderDiff();
         }
-        this.dispatchEvent(
-          new CustomEvent('render-content', {bubbles: true, composed: true})
-        );
+        fireEvent(this, 'render-content');
       })
     );
     return (
@@ -309,7 +302,7 @@
     return this.getContentTdByLine(line, side, row);
   }
 
-  getLineElByNumber(lineNumber: string | number, side?: Side) {
+  getLineElByNumber(lineNumber: LineNumber, side?: Side) {
     const sideSelector = side ? '.' + side : '';
     return this.diffElement.querySelector(
       `.lineNum[data-value="${lineNumber}"]${sideSelector}`
@@ -339,16 +332,7 @@
       sectionEl.parentNode.removeChild(sectionEl);
     }
 
-    this.async(
-      () =>
-        this.dispatchEvent(
-          new CustomEvent('render-content', {
-            composed: true,
-            bubbles: true,
-          })
-        ),
-      1
-    );
+    this.async(() => fireEvent(this, 'render-content'), 1);
   }
 
   cancel() {
@@ -363,15 +347,7 @@
     const message =
       `The value of the '${pref}' user preference is ` +
       'invalid. Fix in diff preferences';
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {
-          message,
-        },
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireAlert(this, message);
     throw Error(`Invalid preference value: ${pref}`);
   }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.ts
index 15264ea..5b3f225 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.ts
@@ -16,7 +16,8 @@
  */
 
 import {GrDiffBuilderSideBySide} from './gr-diff-builder-side-by-side';
-import {DiffInfo, DiffPreferencesInfo, ImageInfo} from '../../../types/common';
+import {ImageInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {GrEndpointParam} from '../../plugins/gr-endpoint-param/gr-endpoint-param';
 
 // MIME types for images we allow showing. Do not include SVG, it can contain
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.ts
index 657dfa2..67f2dcb 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.ts
@@ -17,17 +17,17 @@
 
 import {GrDiffBuilder} from './gr-diff-builder';
 import {GrDiffGroup, GrDiffGroupType} from '../gr-diff/gr-diff-group';
-import {DiffInfo, DiffPreferencesInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {GrDiffLine, LineNumber} from '../gr-diff/gr-diff-line';
 import {DiffViewMode, Side} from '../../../constants/constants';
+import {DiffLayer} from '../../../types/types';
 
 export class GrDiffBuilderSideBySide extends GrDiffBuilder {
   constructor(
     diff: DiffInfo,
     prefs: DiffPreferencesInfo,
     outputEl: HTMLElement,
-    // TODO(TS): Replace any by a layer interface.
-    readonly layers: any[] = [],
+    readonly layers: DiffLayer[] = [],
     useNewContextControls = false
   ) {
     super(diff, prefs, outputEl, layers, useNewContextControls);
@@ -50,7 +50,7 @@
     if (group.dueToRebase) {
       sectionEl.classList.add('dueToRebase');
     }
-    if (group.dueToMove) {
+    if (group.moveDetails) {
       sectionEl.classList.add('dueToMove');
       sectionEl.appendChild(this._buildMoveControls(group));
     }
@@ -105,6 +105,7 @@
     row.classList.add('diff-row', 'side-by-side');
     row.setAttribute('left-type', leftLine.type);
     row.setAttribute('right-type', rightLine.type);
+    // TabIndex makes screen reader read a row when navigating with j/k
     row.tabIndex = -1;
 
     row.appendChild(this._createBlameCell(leftLine.beforeNumber));
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.ts
index 2028b0c..85af2ee 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.ts
@@ -17,16 +17,16 @@
 import {GrDiffLine, GrDiffLineType} from '../gr-diff/gr-diff-line';
 import {GrDiffBuilder} from './gr-diff-builder';
 import {GrDiffGroup, GrDiffGroupType} from '../gr-diff/gr-diff-group';
-import {DiffInfo, DiffPreferencesInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {DiffViewMode, Side} from '../../../constants/constants';
+import {DiffLayer} from '../../../types/types';
 
 export class GrDiffBuilderUnified extends GrDiffBuilder {
   constructor(
     diff: DiffInfo,
     prefs: DiffPreferencesInfo,
     outputEl: HTMLElement,
-    // TODO(TS): Replace any by a layer interface.
-    readonly layers: any[] = [],
+    readonly layers: DiffLayer[] = [],
     useNewContextControls = false
   ) {
     super(diff, prefs, outputEl, layers, useNewContextControls);
@@ -49,7 +49,7 @@
     if (group.dueToRebase) {
       sectionEl.classList.add('dueToRebase');
     }
-    if (group.dueToMove) {
+    if (group.moveDetails) {
       sectionEl.classList.add('dueToMove');
       sectionEl.appendChild(this._buildMoveControls(group));
     }
@@ -104,6 +104,7 @@
   _createRow(line: GrDiffLine) {
     const row = this._createElement('tr', line.type);
     row.classList.add('diff-row', 'unified');
+    // TabIndex makes screen reader read a row when navigating with j/k
     row.tabIndex = -1;
     row.appendChild(this._createBlameCell(line.beforeNumber));
     let lineNumberEl = this._createLineEl(
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified_test.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified_test.js
index 07c6410..c08764e 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified_test.js
@@ -105,7 +105,7 @@
       lines[0].text = 'def hello_world():';
       lines[1].text = '  print "Hello World"';
       const group = new GrDiffGroup(GrDiffGroupType.DELTA, lines);
-      group.dueToMove = true;
+      group.moveDetails = {changed: false};
 
       const sectionEl = diffBuilder.buildSectionElement(group);
 
@@ -116,7 +116,7 @@
       assert.equal(rowEls.length, 3);
       assert.isTrue(moveControlsRow.classList.contains('movedOut'));
       assert.equal(cells.length, 3);
-      assert.isTrue(cells[2].classList.contains('moveDescription'));
+      assert.isTrue(cells[2].classList.contains('moveLabel'));
       assert.equal(cells[2].textContent, 'Moved out');
     });
 
@@ -128,7 +128,7 @@
       lines[0].text = 'def hello_world():';
       lines[1].text = '  print "Hello World"';
       const group = new GrDiffGroup(GrDiffGroupType.DELTA, lines);
-      group.dueToMove = true;
+      group.moveDetails = {changed: false};
 
       const sectionEl = diffBuilder.buildSectionElement(group);
 
@@ -139,7 +139,7 @@
       assert.equal(rowEls.length, 3);
       assert.isTrue(moveControlsRow.classList.contains('movedIn'));
       assert.equal(cells.length, 3);
-      assert.isTrue(cells[2].classList.contains('moveDescription'));
+      assert.isTrue(cells[2].classList.contains('moveLabel'));
       assert.equal(cells[2].textContent, 'Moved in');
     });
   });
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
index a3778ef..9574c1d 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
@@ -23,9 +23,12 @@
   hideInContextControl,
   rangeBySide,
 } from '../gr-diff/gr-diff-group';
-import {BlameInfo, DiffInfo, DiffPreferencesInfo} from '../../../types/common';
+import {BlameInfo} from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {DiffViewMode, Side} from '../../../constants/constants';
 import {DiffLayer} from '../../../types/types';
+import {MovedChunkGoToLineDetail} from '../../../types/events';
+import {pluralize} from '../../../utils/string-util';
 
 /**
  * In JS, unicode code points above 0xFFFF occupy two elements of a string.
@@ -561,16 +564,17 @@
     let requiresLoad = false;
     if (type === GrDiffBuilder.ContextButtonType.ALL) {
       if (this.useNewContextControls) {
-        text = `+${numLines} common line`;
+        text = `+${pluralize(numLines, 'common line')}`;
+        button.setAttribute(
+          'aria-label',
+          `Show ${pluralize(numLines, 'common line')}`
+        );
       } else {
-        text = `Show ${numLines} common line`;
+        text = `Show ${pluralize(numLines, 'common line')}`;
         const icon = this._createElement('iron-icon', 'showContext');
         icon.setAttribute('icon', 'gr-icons:unfold-more');
         button.appendChild(icon);
       }
-      if (numLines > 1) {
-        text += 's';
-      }
       requiresLoad = contextGroups.find(c => !!c.skip) !== undefined;
       if (requiresLoad) {
         // Expanding content would require load of more data
@@ -582,6 +586,7 @@
       if (this.useNewContextControls) {
         text = `+${context}`;
         button.classList.add('aboveButton');
+        button.setAttribute('aria-label', `Show ${context} lines above`);
       } else {
         text = `+${context} above`;
       }
@@ -590,6 +595,7 @@
       if (this.useNewContextControls) {
         text = `+${context}`;
         button.classList.add('belowButton');
+        button.setAttribute('aria-label', `Show ${context} lines below`);
       } else {
         text = `+${context} below`;
       }
@@ -658,6 +664,9 @@
       button.classList.add(side);
       button.dataset['value'] = number.toString();
       button.textContent = number === 'FILE' ? 'File' : number.toString();
+      if (number === 'FILE') {
+        button.setAttribute('aria-label', 'Add file comment');
+      }
 
       // Add aria-labels for valid line numbers.
       // For unified diff, this method will be called with number set to 0 for
@@ -707,10 +716,19 @@
       }
 
       if (lineNumberEl) {
-        for (const layer of this.layers) {
-          if (typeof layer.annotate === 'function') {
-            layer.annotate(contentText, lineNumberEl, line);
+        const ANNOTATE_MAX_LINE_LENGTH = 1000;
+        // For performance reason, we skip annotating long lines.
+        if (line.text.length < ANNOTATE_MAX_LINE_LENGTH) {
+          for (const layer of this.layers) {
+            if (typeof layer.annotate === 'function') {
+              layer.annotate(contentText, lineNumberEl, line);
+            }
           }
+        } else {
+          const msg =
+            `A line is longer than ${ANNOTATE_MAX_LINE_LENGTH}.` +
+            ' Line annotation was skipped.';
+          console.warn(msg);
         }
       } else {
         console.error('The lineNumberEl is null, skipping layer annotations.');
@@ -891,6 +909,53 @@
     }
   }
 
+  _createMovedLineAnchor(line: number, side: Side) {
+    const anchor = this._createElementWithText('a', `${line}`);
+
+    // href is not actually used but important for Screen Readers
+    anchor.setAttribute('href', `#${line}`);
+    anchor.addEventListener('click', e => {
+      e.preventDefault();
+      anchor.dispatchEvent(
+        new CustomEvent<MovedChunkGoToLineDetail>('moved-link-clicked', {
+          detail: {
+            line,
+            side,
+          },
+          composed: true,
+          bubbles: true,
+        })
+      );
+    });
+    return anchor;
+  }
+
+  _createElementWithText(tagName: string, textContent: string) {
+    const element = this._createElement(tagName);
+    element.textContent = textContent;
+    return element;
+  }
+
+  _createMoveDescriptionDiv(movedIn: boolean, group: GrDiffGroup) {
+    const div = this._createElement('div');
+    if (group.moveDetails?.range) {
+      const {changed, range} = group.moveDetails;
+      const otherSide = movedIn ? Side.LEFT : Side.RIGHT;
+      const andChangedLabel = changed ? 'and changed ' : '';
+      const direction = movedIn ? 'from' : 'to';
+      const textLabel = `Moved ${andChangedLabel}${direction} lines `;
+      div.appendChild(this._createElementWithText('span', textLabel));
+      div.appendChild(this._createMovedLineAnchor(range.start, otherSide));
+      div.appendChild(this._createElementWithText('span', ' - '));
+      div.appendChild(this._createMovedLineAnchor(range.end, otherSide));
+    } else {
+      div.appendChild(
+        this._createElementWithText('span', movedIn ? 'Moved in' : 'Moved out')
+      );
+    }
+    return div;
+  }
+
   _buildMoveControls(group: GrDiffGroup) {
     const movedIn = group.adds.length > 0;
     const {
@@ -900,24 +965,27 @@
     } = this._getMoveControlsConfig();
 
     let controlsClass;
-    let descriptionText;
     let descriptionIndex;
+    const descriptionTextDiv = this._createMoveDescriptionDiv(movedIn, group);
     if (movedIn) {
       controlsClass = 'movedIn';
       descriptionIndex = movedInIndex;
-      descriptionText = 'Moved in';
     } else {
       controlsClass = 'movedOut';
       descriptionIndex = movedOutIndex;
-      descriptionText = 'Moved out';
     }
-    const controls = document.createElement('tr');
+
+    const controls = this._createElement('tr', `moveControls ${controlsClass}`);
     const cells = [...Array(numberOfCells).keys()].map(() =>
-      document.createElement('td')
+      this._createElement('td')
     );
-    controls.classList.add('moveControls', controlsClass);
-    cells[descriptionIndex].classList.add('moveDescription');
-    cells[descriptionIndex].textContent = descriptionText;
+    const moveDescriptionDiv = this._createElement('div', 'moveDescription');
+    const icon = this._createElement('iron-icon');
+    icon.setAttribute('icon', 'gr-icons:move-item');
+    moveDescriptionDiv.appendChild(icon);
+    moveDescriptionDiv.appendChild(descriptionTextDiv);
+    cells[descriptionIndex].appendChild(moveDescriptionDiv);
+    cells[descriptionIndex].classList.add('moveLabel');
     cells.forEach(c => {
       controls.appendChild(c);
     });
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
index e7fb30e..52ac7cc 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
@@ -20,6 +20,7 @@
   AbortStop,
   CursorMoveResult,
   GrCursorManager,
+  Stop,
   isTargetable,
 } from '../../shared/gr-cursor-manager/gr-cursor-manager';
 import {afterNextRender} from '@polymer/polymer/lib/utils/render-status';
@@ -35,6 +36,7 @@
 import {PolymerDomWrapper} from '../../../types/types';
 import {GrDiffGroupType} from '../gr-diff/gr-diff-group';
 import {GrDiff} from '../gr-diff/gr-diff';
+import {fireAlert, fireEvent} from '../../../utils/event-util';
 
 const DiffViewMode = {
   SIDE_BY_SIDE: 'SIDE_BY_SIDE',
@@ -63,14 +65,6 @@
     return htmlTemplate;
   }
 
-  private _boundHandleWindowScroll: () => void;
-
-  private _boundHandleDiffRenderStart: () => void;
-
-  private _boundHandleDiffRenderContent: () => void;
-
-  private _boundHandleDiffLineSelected: (e: Event) => void;
-
   private _preventAutoScrollOnManualScroll = false;
 
   private lastDisplayedNavigateToNextFileToast: number | null = null;
@@ -109,15 +103,6 @@
   @property({type: Boolean})
   _listeningForScroll = false;
 
-  constructor() {
-    super();
-    this._boundHandleWindowScroll = () => this._handleWindowScroll();
-    this._boundHandleDiffRenderStart = () => this._handleDiffRenderStart();
-    this._boundHandleDiffRenderContent = () => this._handleDiffRenderContent();
-    this._boundHandleDiffLineSelected = (e: Event) =>
-      this._handleDiffLineSelected(e);
-  }
-
   /** @override */
   ready() {
     super.ready();
@@ -154,6 +139,16 @@
     window.removeEventListener('scroll', this._boundHandleWindowScroll);
   }
 
+  // Don't remove - used by clients embedding gr-diff outside of Gerrit.
+  isAtStart() {
+    return this.$.cursorManager.isAtStart();
+  }
+
+  // Don't remove - used by clients embedding gr-diff outside of Gerrit.
+  isAtEnd() {
+    return this.$.cursorManager.isAtEnd();
+  }
+
   moveLeft() {
     this.side = Side.LEFT;
     if (this._isTargetBlank()) {
@@ -170,21 +165,21 @@
 
   moveDown() {
     if (this._getViewMode() === DiffViewMode.SIDE_BY_SIDE) {
-      this.$.cursorManager.next({
+      return this.$.cursorManager.next({
         filter: (row: Element) => this._rowHasSide(row),
       });
     } else {
-      this.$.cursorManager.next();
+      return this.$.cursorManager.next();
     }
   }
 
   moveUp() {
     if (this._getViewMode() === DiffViewMode.SIDE_BY_SIDE) {
-      this.$.cursorManager.previous({
+      return this.$.cursorManager.previous({
         filter: (row: Element) => this._rowHasSide(row),
       });
     } else {
-      this.$.cursorManager.previous();
+      return this.$.cursorManager.previous();
     }
   }
 
@@ -198,7 +193,10 @@
     }
   }
 
-  moveToNextChunk(clipToTop?: boolean, navigateToNextFile?: boolean) {
+  moveToNextChunk(
+    clipToTop?: boolean,
+    navigateToNextFile?: boolean
+  ): CursorMoveResult {
     const result = this.$.cursorManager.next({
       filter: (row: HTMLElement) => this._isFirstRowOfChunk(row),
       getTargetHeight: target =>
@@ -213,7 +211,7 @@
     if (
       navigateToNextFile &&
       result === CursorMoveResult.CLIPPED &&
-      this.$.cursorManager.isAtEnd()
+      this.isAtEnd()
     ) {
       if (
         this.lastDisplayedNavigateToNextFileToast &&
@@ -222,47 +220,39 @@
       ) {
         // reset for next file
         this.lastDisplayedNavigateToNextFileToast = null;
-        this.dispatchEvent(
-          new CustomEvent('navigate-to-next-unreviewed-file', {
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireEvent(this, 'navigate-to-next-unreviewed-file');
+      } else {
+        this.lastDisplayedNavigateToNextFileToast = Date.now();
+        fireAlert(this, 'Press n again to navigate to next unreviewed file');
       }
-      this.lastDisplayedNavigateToNextFileToast = Date.now();
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Press n again to navigate to next unreviewed file',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
     }
 
     this._fixSide();
+    return result;
   }
 
-  moveToPreviousChunk() {
-    this.$.cursorManager.previous({
+  moveToPreviousChunk(): CursorMoveResult {
+    const result = this.$.cursorManager.previous({
       filter: (row: HTMLElement) => this._isFirstRowOfChunk(row),
     });
     this._fixSide();
+    return result;
   }
 
-  moveToNextCommentThread() {
-    this.$.cursorManager.next({
+  moveToNextCommentThread(): CursorMoveResult {
+    const result = this.$.cursorManager.next({
       filter: (row: HTMLElement) => this._rowHasThread(row),
     });
     this._fixSide();
+    return result;
   }
 
-  moveToPreviousCommentThread() {
-    this.$.cursorManager.previous({
+  moveToPreviousCommentThread(): CursorMoveResult {
+    const result = this.$.cursorManager.previous({
       filter: (row: HTMLElement) => this._rowHasThread(row),
     });
     this._fixSide();
+    return result;
   }
 
   moveToLineNumber(number: number, side: Side, path?: string) {
@@ -339,13 +329,13 @@
     this._scrollMode = ScrollMode.KEEP_VISIBLE;
   }
 
-  _handleWindowScroll() {
+  private _boundHandleWindowScroll = () => {
     if (this._preventAutoScrollOnManualScroll) {
       this._scrollMode = ScrollMode.NEVER;
       this._focusOnMove = false;
       this._preventAutoScrollOnManualScroll = false;
     }
-  }
+  };
 
   reInitAndUpdateStops() {
     this.reInit();
@@ -357,25 +347,29 @@
     this.reInitCursor();
   }
 
-  _handleDiffRenderStart() {
-    this._preventAutoScrollOnManualScroll = true;
-  }
+  private boundHandleDiffLoadingChanged = () => {
+    this._updateStops();
+  };
 
-  _handleDiffRenderContent() {
+  private _boundHandleDiffRenderStart = () => {
+    this._preventAutoScrollOnManualScroll = true;
+  };
+
+  private _boundHandleDiffRenderContent = () => {
     this._updateStops();
     // When done rendering, turn focus on move and automatic scrolling back on
     this._focusOnMove = true;
     this._preventAutoScrollOnManualScroll = false;
-  }
+  };
 
-  _handleDiffLineSelected(event: Event) {
+  private _boundHandleDiffLineSelected = (event: Event) => {
     const customEvent = event as CustomEvent;
     this.moveToLineNumber(
       customEvent.detail.number,
       customEvent.detail.side,
       customEvent.detail.path
     );
-  }
+  };
 
   createCommentInPlace() {
     const diffWithRangeSelected = this.diffs.find(diff =>
@@ -398,7 +392,6 @@
    * {leftSide: true, number: 321} for line 321 of the base patch.
    * Returns null if an address is not available.
    *
-   * @return
    */
   getAddress() {
     if (!this.diffRow) {
@@ -525,7 +518,7 @@
 
   _updateStops() {
     this.$.cursorManager.stops = this.diffs.reduce(
-      (stops: HTMLElement[], diff) => stops.concat(diff.getCursorStops()),
+      (stops: Stop[], diff) => stops.concat(diff.getCursorStops()),
       []
     );
   }
@@ -555,6 +548,10 @@
       // might be the same.
       for (i = 0; i < splice?.removed.length; i++) {
         splice.removed[i].removeEventListener(
+          'loading-changed',
+          this.boundHandleDiffLoadingChanged
+        );
+        splice.removed[i].removeEventListener(
           'render-start',
           this._boundHandleDiffRenderStart
         );
@@ -570,6 +567,10 @@
 
       for (i = splice.index; i < splice.index + splice.addedCount; i++) {
         this.diffs[i].addEventListener(
+          'loading-changed',
+          this.boundHandleDiffLoadingChanged
+        );
+        this.diffs[i].addEventListener(
           'render-start',
           this._boundHandleDiffRenderStart
         );
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
index 8e95f3d..1e1d17e 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
@@ -19,13 +19,14 @@
 import '../gr-diff/gr-diff.js';
 import './gr-diff-cursor.js';
 import '../../shared/gr-rest-api-interface/gr-rest-api-interface.js';
-import {getMockDiffResponse} from '../../../test/mocks/diff-response.js';
 import {html} from '@polymer/polymer/lib/utils/html-tag.js';
+import {listenOnce} from '../../../test/test-utils.js';
+import {getMockDiffResponse} from '../../../test/mocks/diff-response.js';
+import {appContext} from '../../../services/app-context.js';
 
 const basicFixture = fixtureFromTemplate(html`
   <gr-diff></gr-diff>
   <gr-diff-cursor></gr-diff-cursor>
-  <gr-rest-api-interface></gr-rest-api-interface>
 `);
 
 const emptyFixture = fixtureFromElement('div');
@@ -39,7 +40,7 @@
     const fixtureElems = basicFixture.instantiate();
     diffElement = fixtureElems[0];
     cursorElement = fixtureElems[1];
-    const restAPI = fixtureElems[2];
+    const restAPI = appContext.restApiService;
 
     // Register the diff with the cursor.
     cursorElement.push('diffs', diffElement);
@@ -100,14 +101,14 @@
   test('cursor scroll behavior', () => {
     assert.equal(cursorElement._scrollMode, 'keep-visible');
 
-    cursorElement._handleDiffRenderStart();
+    diffElement.dispatchEvent(new Event('render-start'));
     assert.isTrue(cursorElement._focusOnMove);
 
-    cursorElement._handleWindowScroll();
+    window.dispatchEvent(new Event('scroll'));
     assert.equal(cursorElement._scrollMode, 'never');
     assert.isFalse(cursorElement._focusOnMove);
 
-    cursorElement._handleDiffRenderContent();
+    diffElement.dispatchEvent(new Event('render-content'));
     assert.isTrue(cursorElement._focusOnMove);
 
     cursorElement.reInitCursor();
@@ -117,7 +118,7 @@
   test('moves to selected line', () => {
     const moveToNumStub = sinon.stub(cursorElement, 'moveToLineNumber');
 
-    cursorElement._handleDiffLineSelected(
+    diffElement.dispatchEvent(
         new CustomEvent('line-selected', {
           detail: {number: '123', side: 'right', path: 'some/file'},
         }));
@@ -225,7 +226,7 @@
     assert.equal(cursorElement.side, 'left');
   });
 
-  suite('moved chunks (dueToMove=true)', () => {
+  suite('moved chunks without line range)', () => {
     setup(done => {
       const renderHandler = function() {
         diffElement.removeEventListener('render', renderHandler);
@@ -245,7 +246,7 @@
             'Sagittis tincidunt torquent, tempor nunc amet.',
             'At rhoncus id.',
           ],
-          due_to_move: true,
+          move_details: {changed: false},
         },
         {
           ab: [
@@ -258,7 +259,7 @@
             'Sagittis tincidunt torquent, tempor nunc amet.',
             'At rhoncus id.',
           ],
-          due_to_move: true,
+          move_details: {changed: false},
         },
         {
           ab: [
@@ -268,27 +269,91 @@
       ]};
     });
 
-    test('chunk skip functionality', () => {
-      const chunks = diffElement.root.querySelectorAll(
-          '.section.delta');
-      const indexOfChunk = function(chunk) {
-        return Array.prototype.indexOf.call(chunks, chunk);
+    test('renders moveControls with simple descriptions', () => {
+      const [movedIn, movedOut] = diffElement.root
+          .querySelectorAll('.dueToMove .moveControls');
+      assert.equal(movedIn.textContent, 'Moved in');
+      assert.equal(movedOut.textContent, 'Moved out');
+    });
+  });
+
+  suite('moved chunks (moveDetails)', () => {
+    setup(done => {
+      const renderHandler = function() {
+        diffElement.removeEventListener('render', renderHandler);
+        cursorElement.reInitCursor();
+        done();
       };
+      diffElement.addEventListener('render', renderHandler);
+      diffElement.diff = {...diff, content: [
+        {
+          ab: [
+            'Lorem ipsum dolor sit amet, suspendisse inceptos vehicula, ',
+          ],
+        },
+        {
+          b: [
+            'Nullam neque, ligula ac, id blandit.',
+            'Sagittis tincidunt torquent, tempor nunc amet.',
+            'At rhoncus id.',
+          ],
+          move_details: {changed: false, range: {start: 4, end: 6}},
+        },
+        {
+          ab: [
+            'Sem nascetur, erat ut, non in.',
+          ],
+        },
+        {
+          a: [
+            'Nullam neque, ligula ac, id blandit.',
+            'Sagittis tincidunt torquent, tempor nunc amet.',
+            'At rhoncus id.',
+          ],
+          move_details: {changed: false, range: {start: 2, end: 4}},
+        },
+        {
+          ab: [
+            'Arcu eget, rhoncus amet cursus, ipsum elementum.',
+          ],
+        },
+      ]};
+    });
 
-      // We should be initialized to the first chunk (b)
-      let currentIndex = indexOfChunk(cursorElement.diffRow.parentElement);
-      assert.equal(currentIndex, 0);
-      assert.equal(cursorElement.side, 'right');
+    test('renders moveControls with simple descriptions', () => {
+      const [movedIn, movedOut] = diffElement.root
+          .querySelectorAll('.dueToMove .moveControls');
+      assert.equal(movedIn.textContent, 'Moved from lines 4 - 6');
+      assert.equal(movedOut.textContent, 'Moved to lines 2 - 4');
+    });
 
-      // Move to the next chunk.
-      cursorElement.moveToNextChunk();
+    test('startLineAnchor of movedIn chunk fires events', done => {
+      const [movedIn] = diffElement.root
+          .querySelectorAll('.dueToMove .moveControls');
+      const [startLineAnchor] = movedIn.querySelectorAll('a');
 
-      // Since the next chunk only has content on the left side (a). we should have been
-      // automatically moved over.
-      const previousIndex = currentIndex;
-      currentIndex = indexOfChunk(cursorElement.diffRow.parentElement);
-      assert.equal(currentIndex, previousIndex + 1);
-      assert.equal(cursorElement.side, 'left');
+      const onMovedLinkClicked = e => {
+        assert.deepEqual(e.detail, {line: 4, side: 'left'});
+        done();
+      };
+      assert.equal(startLineAnchor.textContent, '4');
+      startLineAnchor
+          .addEventListener('moved-link-clicked', onMovedLinkClicked);
+      MockInteractions.click(startLineAnchor);
+    });
+
+    test('endLineAnchor of movedOut fires events', done => {
+      const [, movedOut] = diffElement.root
+          .querySelectorAll('.dueToMove .moveControls');
+      const [, endLineAnchor] = movedOut.querySelectorAll('a');
+
+      const onMovedLinkClicked = e => {
+        assert.deepEqual(e.detail, {line: 4, side: 'right'});
+        done();
+      };
+      assert.equal(endLineAnchor.textContent, '4');
+      endLineAnchor.addEventListener('moved-link-clicked', onMovedLinkClicked);
+      MockInteractions.click(endLineAnchor);
     });
   });
 
@@ -473,6 +538,12 @@
     });
   });
 
+  test('updates stops when loading changes', () => {
+    sinon.spy(cursorElement, '_updateStops');
+    diffElement.dispatchEvent(new Event('loading-changed'));
+    assert.isTrue(cursorElement._updateStops.called);
+  });
+
   suite('gr-diff-cursor event tests', () => {
     let someEmptyDiv;
 
@@ -490,5 +561,77 @@
       someEmptyDiv.appendChild(cursorElement);
     });
   });
+
+  suite('multi diff', () => {
+    const multiDiffFixture = fixtureFromTemplate(html`
+      <gr-diff></gr-diff>
+      <gr-diff></gr-diff>
+      <gr-diff></gr-diff>
+      <gr-diff-cursor></gr-diff-cursor>
+    `);
+
+    let diffElements;
+
+    setup(async () => {
+      const fixtureElems = multiDiffFixture.instantiate();
+      diffElements = fixtureElems.slice(0, 3);
+      cursorElement = fixtureElems[3];
+      const restAPI = appContext.restApiService;
+
+      // Register the diff with the cursor.
+      cursorElement.push('diffs', ...diffElements);
+
+      await restAPI.getDiffPreferences().then(prefs => {
+        for (const el of diffElements) {
+          el.prefs = prefs;
+        }
+      });
+    });
+
+    function getTargetDiffIndex() {
+      // Mocha has a bug where when `assert.equals` fails, it will try to
+      // JSON.stringify the operands, which fails when they are cyclic structures
+      // like GrDiffElement. The failure is difficult to attribute to a specific
+      // assertion because of the async nature assertion errors are handled and
+      // can cause the test simply timing out, causing a lot of debugging headache.
+      // Working with indices circumvents the problem.
+      return diffElements.indexOf(cursorElement.getTargetDiffElement());
+    }
+
+    test('do not skip loading diffs', async () => {
+      const diffRenderedPromises =
+          diffElements.map(diffEl => listenOnce(diffEl, 'render'));
+
+      diffElements[0].diff = getMockDiffResponse();
+      diffElements[2].diff = getMockDiffResponse();
+      await Promise.all([diffRenderedPromises[0], diffRenderedPromises[2]]);
+
+      const lastLine = diffElements[0].diff.meta_b.lines;
+
+      // Goto second last line of the first diff
+      cursorElement.moveToLineNumber(lastLine - 1, 'right');
+      assert.equal(
+          cursorElement.getTargetLineElement().textContent, lastLine - 1);
+
+      // Can move down until we reach the loading file
+      cursorElement.moveDown();
+      assert.equal(getTargetDiffIndex(), 0);
+      assert.equal(cursorElement.getTargetLineElement().textContent, lastLine);
+
+      // Cannot move down while still loading the diff we would switch to
+      cursorElement.moveDown();
+      assert.equal(getTargetDiffIndex(), 0);
+      assert.equal(cursorElement.getTargetLineElement().textContent, lastLine);
+
+      // Diff 1 finishing to load
+      diffElements[1].diff = getMockDiffResponse();
+      await diffRenderedPromises[1];
+
+      // Now we can go down
+      cursorElement.moveDown();
+      assert.equal(getTargetDiffIndex(), 1);
+      assert.equal(cursorElement.getTargetLineElement().textContent, 'File');
+    });
+  });
 });
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
index 3f43766..322d274 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
@@ -30,6 +30,7 @@
 import {GrSelectionActionBox} from '../gr-selection-action-box/gr-selection-action-box';
 import {GrDiffBuilderElement} from '../gr-diff-builder/gr-diff-builder-element';
 import {FILE} from '../gr-diff/gr-diff-line';
+import {getRange, getSide} from '../gr-diff/gr-diff-utils';
 
 interface SidedRange {
   side: Side;
@@ -199,13 +200,9 @@
   }
 
   _indexForThreadEl(threadEl: HTMLElement) {
-    const side = threadEl.getAttribute('comment-side') as Side;
-    const rangeString = threadEl.getAttribute('range');
-    if (!rangeString) return undefined;
-    const range = JSON.parse(rangeString) as CommentRange;
-
-    if (!range) return undefined;
-
+    const side = getSide(threadEl);
+    const range = getRange(threadEl);
+    if (!side || !range) return undefined;
     return this._indexOfCommentRange(side, range);
   }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.js b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.js
index 39d5c2a..11b1f38 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.js
@@ -151,7 +151,7 @@
     test('comment-thread-mouseenter from line comments is ignored', () => {
       const threadEl = document.createElement('div');
       threadEl.className = 'comment-thread';
-      threadEl.setAttribute('comment-side', 'right');
+      threadEl.setAttribute('diff-side', 'right');
       threadEl.setAttribute('line-num', 3);
       element.appendChild(threadEl);
       element.commentRanges = [{side: 'right'}];
@@ -165,7 +165,7 @@
     test('comment-thread-mouseenter from ranged comment causes set', () => {
       const threadEl = document.createElement('div');
       threadEl.className = 'comment-thread';
-      threadEl.setAttribute('comment-side', 'right');
+      threadEl.setAttribute('diff-side', 'right');
       threadEl.setAttribute('line-num', 3);
       threadEl.setAttribute('range', JSON.stringify({
         start_line: 3,
@@ -193,7 +193,7 @@
     test('comment-thread-mouseleave from line comments is ignored', () => {
       const threadEl = document.createElement('div');
       threadEl.className = 'comment-thread';
-      threadEl.setAttribute('comment-side', 'right');
+      threadEl.setAttribute('diff-side', 'right');
       threadEl.setAttribute('line-num', 3);
       element.appendChild(threadEl);
       element.commentRanges = [{side: 'right'}];
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
index c6f5d21..da50135 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-comment-thread/gr-comment-thread';
 import '../../shared/gr-js-api-interface/gr-js-api-interface';
 import '../gr-diff/gr-diff';
@@ -24,54 +23,57 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-diff-host_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
-import {rangesEqual} from '../gr-diff/gr-diff-utils';
+import {
+  getLine,
+  getRange,
+  getSide,
+  rangesEqual,
+} from '../gr-diff/gr-diff-utils';
 import {appContext} from '../../../services/app-context';
 import {
   getParentIndex,
   isMergeParent,
   isNumber,
 } from '../../../utils/patch-set-util';
-import {
-  Comment,
-  isDraft,
-  sortComments,
-  UIComment,
-} from '../../../utils/comment-util';
-import {TwoSidesComments} from '../gr-comment-api/gr-comment-api';
+import {CommentThread} from '../../../utils/comment-util';
 import {customElement, observe, property} from '@polymer/decorators';
 import {
   CommitRange,
   CoverageRange,
   DiffLayer,
   DiffLayerListener,
+  PatchSetFile,
 } from '../../../types/types';
 import {
   Base64ImageFile,
   BlameInfo,
   ChangeInfo,
   CommentRange,
-  DiffInfo,
-  DiffPreferencesInfo,
   NumericChangeId,
   PatchRange,
   PatchSetNum,
   RepoName,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {
+  DiffInfo,
+  DiffPreferencesInfo,
+  IgnoreWhitespaceType,
+} from '../../../types/diff';
 import {JsApiService} from '../../shared/gr-js-api-interface/gr-js-api-types';
 import {GrDiff, LineOfInterest} from '../gr-diff/gr-diff';
 import {GrSyntaxLayer} from '../gr-syntax-layer/gr-syntax-layer';
-import {
-  DiffViewMode,
-  IgnoreWhitespaceType,
-  Side,
-} from '../../../constants/constants';
+import {DiffViewMode, Side, CommentSide} from '../../../constants/constants';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {FilesWebLinks} from '../gr-patch-range-select/gr-patch-range-select';
-import {LineNumber} from '../gr-diff/gr-diff-line';
+import {LineNumber, FILE} from '../gr-diff/gr-diff-line';
 import {GrCommentThread} from '../../shared/gr-comment-thread/gr-comment-thread';
-import {PatchSetFile} from '../../../types/types';
 import {KnownExperimentId} from '../../../services/flags/flags';
+import {
+  firePageError,
+  fireAlert,
+  fireServerError,
+  fireEvent,
+} from '../../../utils/event-util';
 
 const MSG_EMPTY_BLAME = 'No blame information for this diff.';
 
@@ -109,23 +111,8 @@
   afterNumber?: LineNumber;
 }
 
-// TODO(TS): Consolidate this with the CommentThread interface of comment-api.
-// What is being used here is just a local object for collecting all the data
-// that is needed to create a GrCommentThread component, see
-// _createThreadElement().
-interface CommentThread {
-  comments: UIComment[];
-  // In the context of a diff each thread must have a side!
-  commentSide: Side;
-  patchNum?: PatchSetNum;
-  lineNum?: LineNumber;
-  isOnParent?: boolean;
-  range?: CommentRange;
-}
-
 export interface GrDiffHost {
   $: {
-    restAPI: RestApiService & Element;
     jsAPI: JsApiService & Element;
     syntaxLayer: GrSyntaxLayer & Element;
     diff: GrDiff;
@@ -211,8 +198,8 @@
   @property({type: Boolean})
   noRenderOnPrefsChange = false;
 
-  @property({type: Object, observer: '_commentsChanged'})
-  comments?: TwoSidesComments;
+  @property({type: Object, observer: '_threadsChanged'})
+  threads?: CommentThread[];
 
   @property({type: Boolean})
   lineWrapping = false;
@@ -276,6 +263,8 @@
 
   private readonly flags = appContext.flagsService;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   created() {
     super.created();
@@ -289,11 +278,12 @@
       'create-comment',
       e => this._handleCreateComment(e)
     );
-    this.addEventListener('comment-discard', e =>
-      this._handleCommentDiscard(e)
+    this.addEventListener('comment-discard', () =>
+      this._handleCommentSaveOrDiscard()
     );
-    this.addEventListener('comment-update', e => this._handleCommentUpdate(e));
-    this.addEventListener('comment-save', e => this._handleCommentSave(e));
+    this.addEventListener('comment-save', () =>
+      this._handleCommentSaveOrDiscard()
+    );
     this.addEventListener('render-start', () => this._handleRenderStart());
     this.addEventListener('render-content', () => this._handleRenderContent());
     this.addEventListener('normalize-range', event =>
@@ -329,7 +319,6 @@
   /**
    * @param shouldReportMetric indicate a new Diff Page. This is a
    * signal to report metrics event that started on location change.
-   * @return
    */
   async reload(shouldReportMetric?: boolean) {
     this.clear();
@@ -523,17 +512,11 @@
     if (!this.changeNum) throw new Error('Missing required "changeNum" prop.');
     if (!this.patchRange) throw new Error('Missing required "patchRange".');
     if (!this.path) throw new Error('Missing required "path" property.');
-    return this.$.restAPI
+    return this.restApiService
       .getBlame(this.changeNum, this.patchRange.patchNum, this.path, true)
       .then(blame => {
         if (!blame || !blame.length) {
-          this.dispatchEvent(
-            new CustomEvent('show-alert', {
-              detail: {message: MSG_EMPTY_BLAME},
-              composed: true,
-              bubbles: true,
-            })
-          );
+          fireAlert(this, MSG_EMPTY_BLAME);
           return Promise.reject(MSG_EMPTY_BLAME);
         }
 
@@ -563,7 +546,7 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _canReload() {
@@ -596,7 +579,7 @@
       if (!this.changeNum) throw new Error('Missing required "changeNum".');
       if (!this.patchRange) throw new Error('Missing required "patchRange".');
       if (!this.path) throw new Error('Missing required "path" property.');
-      this.$.restAPI
+      this.restApiService
         .getDiff(
           this.changeNum,
           this.patchRange.basePatchNum,
@@ -605,7 +588,7 @@
           this._getIgnoreWhitespace(),
           reject
         )
-        .then(resolve);
+        .then(diff => resolve(diff!)); // reject is called in case of error, so we can't get undefined here
     });
   }
 
@@ -613,13 +596,7 @@
     // Loading the diff may respond with 409 if the file is too large. In this
     // case, use a toast error..
     if (response.status === 409) {
-      this.dispatchEvent(
-        new CustomEvent('server-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireServerError(response);
       return;
     }
 
@@ -632,13 +609,7 @@
       return;
     }
 
-    this.dispatchEvent(
-      new CustomEvent('page-error', {
-        detail: {response},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    firePageError(this, response);
   }
 
   /**
@@ -705,60 +676,18 @@
     return isImageDiff(diff);
   }
 
-  _commentsChanged(newComments: TwoSidesComments) {
-    const allComments = [];
-    for (const side of [Side.LEFT, Side.RIGHT]) {
-      // This is needed by the threading.
-      for (const comment of newComments[side]) {
-        comment.__commentSide = side;
-      }
-      allComments.push(...newComments[side]);
-    }
+  _threadsChanged(threads: CommentThread[]) {
     // Currently, the only way this is ever changed here is when the initial
-    // comments are loaded, so it's okay performance wise to clear the threads
+    // threads are loaded, so it's okay performance wise to clear the threads
     // and recreate them. If this changes in future, we might want to reuse
     // some DOM nodes here.
     this._clearThreads();
-    const threads = this._createThreads(allComments);
     for (const thread of threads) {
       const threadEl = this._createThreadElement(thread);
       this._attachThreadElement(threadEl);
     }
   }
 
-  _createThreads(comments: UIComment[]): CommentThread[] {
-    const sortedComments = sortComments(comments);
-    const threads = [];
-    for (const comment of sortedComments) {
-      // If the comment is in reply to another comment, find that comment's
-      // thread and append to it.
-      if (comment.in_reply_to) {
-        const thread = threads.find(thread =>
-          thread.comments.some(c => c.id === comment.in_reply_to)
-        );
-        if (thread) {
-          thread.comments.push(comment);
-          continue;
-        }
-      }
-
-      // Otherwise, this comment starts its own thread.
-      if (!comment.__commentSide) throw new Error('Missing "__commentSide".');
-      const newThread: CommentThread = {
-        comments: [comment],
-        commentSide: comment.__commentSide,
-        patchNum: comment.patch_set,
-        lineNum: comment.line,
-        isOnParent: comment.side === 'PARENT',
-      };
-      if (comment.range) {
-        newThread.range = {...comment.range};
-      }
-      threads.push(newThread);
-    }
-    return threads;
-  }
-
   _computeIsBlameLoaded(blame: BlameInfo[] | null) {
     return !!blame;
   }
@@ -766,7 +695,7 @@
   _getImages(diff: DiffInfo) {
     if (!this.changeNum) throw new Error('Missing required "changeNum" prop.');
     if (!this.patchRange) throw new Error('Missing required "patchRange".');
-    return this.$.restAPI.getImagesForDiff(
+    return this.restApiService.getImagesForDiff(
       this.changeNum,
       diff,
       this.patchRange
@@ -774,13 +703,14 @@
   }
 
   _handleCreateComment(e: CustomEvent) {
-    const {lineNum, side, patchNum, isOnParent, range} = e.detail;
+    const {lineNum, side, patchNum, range, path, commentSide} = e.detail;
     const threadEl = this._getOrCreateThread(
       patchNum,
       lineNum,
       side,
-      range,
-      isOnParent
+      commentSide,
+      path,
+      range
     );
     threadEl.addOrEditDraft(lineNum, range);
 
@@ -794,19 +724,21 @@
   _getOrCreateThread(
     patchNum: PatchSetNum,
     lineNum: LineNumber | undefined,
-    commentSide: Side,
-    range?: CommentRange,
-    isOnParent?: boolean
+    diffSide: Side,
+    commentSide: CommentSide,
+    path: string,
+    range?: CommentRange
   ): GrCommentThread {
-    let threadEl = this._getThreadEl(lineNum, commentSide, range);
+    let threadEl = this._getThreadEl(lineNum, diffSide, range);
     if (!threadEl) {
       threadEl = this._createThreadElement({
         comments: [],
+        path,
+        diffSide,
         commentSide,
         patchNum,
-        lineNum,
+        line: lineNum,
         range,
-        isOnParent,
       });
       this._attachThreadElement(threadEl);
     }
@@ -827,18 +759,18 @@
   _createThreadElement(thread: CommentThread) {
     const threadEl = document.createElement('gr-comment-thread');
     threadEl.className = 'comment-thread';
-    threadEl.setAttribute('slot', `${thread.commentSide}-${thread.lineNum}`);
+    threadEl.setAttribute('slot', `${thread.diffSide}-${thread.line}`);
     threadEl.comments = thread.comments;
-    threadEl.commentSide = thread.commentSide;
-    threadEl.isOnParent = !!thread.isOnParent;
+    threadEl.diffSide = thread.diffSide;
+    threadEl.isOnParent = thread.commentSide === CommentSide.PARENT;
     threadEl.parentIndex = this._parentIndex;
     // Use path before renmaing when comment added on the left when comparing
     // two patch sets (not against base)
     if (
       this.file &&
       this.file.basePath &&
-      thread.commentSide === Side.LEFT &&
-      !thread.isOnParent
+      thread.diffSide === Side.LEFT &&
+      !threadEl.isOnParent
     ) {
       threadEl.path = this.file.basePath;
     } else {
@@ -847,8 +779,9 @@
     threadEl.changeNum = this.changeNum;
     threadEl.patchNum = thread.patchNum;
     threadEl.showPatchset = false;
+    threadEl.showPortedComment = !!thread.ported;
     // GrCommentThread does not understand 'FILE', but requires undefined.
-    threadEl.lineNum = thread.lineNum !== 'FILE' ? thread.lineNum : undefined;
+    threadEl.lineNum = thread.line !== 'FILE' ? thread.line : undefined;
     threadEl.projectName = this.projectName;
     threadEl.range = thread.range;
     const threadDiscardListener = (e: Event) => {
@@ -879,11 +812,7 @@
       throw new Error(`Unknown side: ${commentSide}`);
     }
     function matchesRange(threadEl: GrCommentThread) {
-      const rangeAtt = threadEl.getAttribute('range');
-      const threadRange = rangeAtt
-        ? (JSON.parse(rangeAtt) as CommentRange)
-        : undefined;
-      return rangesEqual(threadRange, range);
+      return rangesEqual(getRange(threadEl), range);
     }
 
     const filteredThreadEls = this._filterThreadElsForLocation(
@@ -901,35 +830,29 @@
   ) {
     function matchesLeftLine(threadEl: GrCommentThread) {
       return (
-        threadEl.getAttribute('comment-side') === Side.LEFT &&
-        threadEl.getAttribute('line-num') === String(lineInfo.beforeNumber)
+        getSide(threadEl) === Side.LEFT &&
+        getLine(threadEl) === lineInfo.beforeNumber
       );
     }
     function matchesRightLine(threadEl: GrCommentThread) {
       return (
-        threadEl.getAttribute('comment-side') === Side.RIGHT &&
-        threadEl.getAttribute('line-num') === String(lineInfo.afterNumber)
+        getSide(threadEl) === Side.RIGHT &&
+        getLine(threadEl) === lineInfo.afterNumber
       );
     }
     function matchesFileComment(threadEl: GrCommentThread) {
-      return (
-        threadEl.getAttribute('comment-side') === side &&
-        // line/range comments have 1-based line set, if line is falsy it's
-        // a file comment
-        !threadEl.getAttribute('line-num')
-      );
+      return getSide(threadEl) === side && getLine(threadEl) === FILE;
     }
 
     // Select the appropriate matchers for the desired side and line
-    // If side is BOTH, we want both the left and right matcher.
     const matchers: ((thread: GrCommentThread) => boolean)[] = [];
-    if (side !== Side.RIGHT) {
+    if (side === Side.LEFT) {
       matchers.push(matchesLeftLine);
     }
-    if (side !== Side.LEFT) {
+    if (side === Side.RIGHT) {
       matchers.push(matchesRightLine);
     }
-    if (lineInfo.afterNumber === 'FILE' || lineInfo.beforeNumber === 'FILE') {
+    if (lineInfo.afterNumber === FILE || lineInfo.beforeNumber === FILE) {
       matchers.push(matchesFileComment);
     }
     return threadEls.filter(threadEl =>
@@ -939,7 +862,7 @@
 
   _getIgnoreWhitespace(): IgnoreWhitespaceType {
     if (!this.prefs || !this.prefs.ignore_whitespace) {
-      return IgnoreWhitespaceType.IGNORE_NONE;
+      return 'IGNORE_NONE';
     }
     return this.prefs.ignore_whitespace;
   }
@@ -991,77 +914,8 @@
       : null;
   }
 
-  _handleCommentSave(e: CustomEvent) {
-    const comment = e.detail.comment;
-    const side = e.detail.comment.__commentSide;
-    const idx = this._findDraftIndex(comment, side);
-    this.set(['comments', side, idx], comment);
-    this._handleCommentSaveOrDiscard();
-  }
-
-  _handleCommentDiscard(e: CustomEvent) {
-    const comment = e.detail.comment;
-    this._removeComment(comment);
-    this._handleCommentSaveOrDiscard();
-  }
-
-  _handleCommentUpdate(e: CustomEvent) {
-    const comment = e.detail.comment;
-    const side = e.detail.comment.__commentSide;
-    let idx = this._findCommentIndex(comment, side);
-    if (idx === -1) {
-      idx = this._findDraftIndex(comment, side);
-    }
-    if (idx !== -1) {
-      // Update draft or comment.
-      this.set(['comments', side, idx], comment);
-    } else {
-      // Create new draft.
-      this.push(['comments', side], comment);
-    }
-  }
-
   _handleCommentSaveOrDiscard() {
-    this.dispatchEvent(
-      new CustomEvent('diff-comments-modified', {bubbles: true, composed: true})
-    );
-  }
-
-  _removeComment(comment: UIComment) {
-    const side = comment.__commentSide;
-    if (!side) throw new Error('Missing required "side" in comment.');
-    this._removeCommentFromSide(comment, side);
-  }
-
-  _removeCommentFromSide(comment: Comment, side: Side) {
-    let idx = this._findCommentIndex(comment, side);
-    if (idx === -1) {
-      idx = this._findDraftIndex(comment, side);
-    }
-    if (idx !== -1) {
-      this.splice('comments.' + side, idx, 1);
-    }
-  }
-
-  _findCommentIndex(comment: Comment, side: Side) {
-    if (!comment.id || !this.comments || !this.comments[side]) {
-      return -1;
-    }
-    return this.comments[side].findIndex(item => item.id === comment.id);
-  }
-
-  _findDraftIndex(comment: Comment, side: Side) {
-    if (
-      !isDraft(comment) ||
-      !comment.__draftID ||
-      !this.comments ||
-      !this.comments[side]
-    ) {
-      return -1;
-    }
-    return this.comments[side].findIndex(
-      item => isDraft(item) && item.__draftID === comment.__draftID
-    );
+    fireEvent(this, 'diff-comments-modified');
   }
 
   _isSyntaxHighlightingEnabled(
@@ -1071,18 +925,26 @@
     >,
     diff?: DiffInfo
   ) {
-    if (
-      !preferenceChangeRecord ||
-      !preferenceChangeRecord.base ||
-      !preferenceChangeRecord.base.syntax_highlighting ||
-      !diff
-    ) {
+    if (!preferenceChangeRecord?.base?.syntax_highlighting || !diff) {
       return false;
     }
-    return (
-      !this._anyLineTooLong(diff) &&
-      this.$.diff.getDiffLength(diff) <= SYNTAX_MAX_DIFF_LENGTH
-    );
+    if (this._anyLineTooLong(diff)) {
+      fireAlert(
+        this,
+        `A line is longer than ${SYNTAX_MAX_LINE_LENGTH}.` +
+          ' Syntax Highlighting was turned off.'
+      );
+      return false;
+    }
+    if (this.$.diff.getDiffLength(diff) > SYNTAX_MAX_DIFF_LENGTH) {
+      fireAlert(
+        this,
+        `A diff is longer than ${SYNTAX_MAX_DIFF_LENGTH}.` +
+          ' Syntax Highlighting was turned off.'
+      );
+      return false;
+    }
+    return true;
   }
 
   /**
@@ -1215,7 +1077,8 @@
 // TODO(TS): Be more specific than CustomEvent, which has detail:any.
 declare global {
   interface HTMLElementEventMap {
-    render: CustomEvent;
+    /* prettier-ignore */
+    'render': CustomEvent;
     'normalize-range': CustomEvent;
     'diff-context-expanded': CustomEvent;
     'create-comment': CustomEvent;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_html.ts b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_html.ts
index 9921dd6..48b82ec 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_html.ts
@@ -50,5 +50,4 @@
     diff="[[diff]]"
   ></gr-syntax-layer>
   <gr-js-api-interface id="jsAPI"></gr-js-api-interface>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
index 37b3a50..d09c811 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
@@ -20,9 +20,11 @@
 import {GrDiffBuilderImage} from '../gr-diff-builder/gr-diff-builder-image.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {dom} from '@polymer/polymer/lib/legacy/polymer.dom.js';
-import {sortComments} from '../../../utils/comment-util.js';
-import {Side} from '../../../constants/constants.js';
+import {sortComments, createCommentThreads} from '../../../utils/comment-util.js';
+import {Side, CommentSide} from '../../../constants/constants.js';
 import {createChange} from '../../../test/test-data-generators.js';
+import {FILE} from '../gr-diff/gr-diff-line.js';
+import {CoverageType} from '../../../types/types.js';
 
 const basicFixture = fixtureFromElement('gr-diff-host');
 
@@ -61,209 +63,21 @@
     });
   });
 
-  suite('handle comment-update', () => {
-    setup(() => {
-      sinon.stub(element, '_commentsChanged');
-      element.comments = {
-        meta: {
-          changeNum: '42',
-          patchRange: {
-            basePatchNum: 'PARENT',
-            patchNum: 3,
-          },
-          path: '/path/to/foo',
-          projectConfig: {foo: 'bar'},
-        },
-        left: [
-          {id: 'bc1', side: 'PARENT', __commentSide: 'left'},
-          {id: 'bc2', side: 'PARENT', __commentSide: 'left'},
-          {id: 'bd1', __draft: true, side: 'PARENT', __commentSide: 'left'},
-          {id: 'bd2', __draft: true, side: 'PARENT', __commentSide: 'left'},
-        ],
-        right: [
-          {id: 'c1', __commentSide: 'right'},
-          {id: 'c2', __commentSide: 'right'},
-          {id: 'd1', __draft: true, __commentSide: 'right'},
-          {id: 'd2', __draft: true, __commentSide: 'right'},
-        ],
-      };
-    });
-
-    test('creating a draft', () => {
-      const comment = {__draft: true, __draftID: 'tempID', side: 'PARENT',
-        __commentSide: 'left'};
-      element.dispatchEvent(
-          new CustomEvent('comment-update', {
-            detail: {comment},
-            composed: true, bubbles: true,
-          }));
-      assert.include(element.comments.left, comment);
-    });
-
-    test('discarding a draft', () => {
-      const draftID = 'tempID';
-      const id = 'savedID';
-      const comment = {
-        __draft: true,
-        __draftID: draftID,
-        side: 'PARENT',
-        __commentSide: 'left',
-      };
-      const diffCommentsModifiedStub = sinon.stub();
-      element.addEventListener('diff-comments-modified',
-          diffCommentsModifiedStub);
-      element.comments.left.push(comment);
-      comment.id = id;
-      element.dispatchEvent(
-          new CustomEvent('comment-discard', {
-            detail: {comment},
-            composed: true, bubbles: true,
-          }));
-      const drafts = element.comments.left
-          .filter(item => item.__draftID === draftID);
-      assert.equal(drafts.length, 0);
-      assert.isTrue(diffCommentsModifiedStub.called);
-    });
-
-    test('saving a draft', () => {
-      const draftID = 'tempID';
-      const id = 'savedID';
-      const comment = {
-        __draft: true,
-        __draftID: draftID,
-        side: 'PARENT',
-        __commentSide: 'left',
-      };
-      const diffCommentsModifiedStub = sinon.stub();
-      element.addEventListener('diff-comments-modified',
-          diffCommentsModifiedStub);
-      element.comments.left.push(comment);
-      comment.id = id;
-      element.dispatchEvent(
-          new CustomEvent('comment-save', {
-            detail: {comment},
-            composed: true, bubbles: true,
-          }));
-      const drafts = element.comments.left
-          .filter(item => item.__draftID === draftID);
-      assert.equal(drafts.length, 1);
-      assert.equal(drafts[0].id, id);
-      assert.isTrue(diffCommentsModifiedStub.called);
-    });
-  });
-
-  test('remove comment', () => {
-    sinon.stub(element, '_commentsChanged');
-    element.comments = {
-      meta: {
-        changeNum: '42',
-        patchRange: {
-          basePatchNum: 'PARENT',
-          patchNum: 3,
-        },
-        path: '/path/to/foo',
-        projectConfig: {foo: 'bar'},
-      },
-      left: [
-        {id: 'bc1', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bc2', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd1', __draft: true, side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd2', __draft: true, side: 'PARENT', __commentSide: 'left'},
-      ],
-      right: [
-        {id: 'c1', __commentSide: 'right'},
-        {id: 'c2', __commentSide: 'right'},
-        {id: 'd1', __draft: true, __commentSide: 'right'},
-        {id: 'd2', __draft: true, __commentSide: 'right'},
-      ],
-    };
-
-    // Using JSON.stringify because Safari 9.1 (11601.5.17.1) doesn’t seem
-    // to believe that one object deepEquals another even when they do :-/.
-    assert.equal(JSON.stringify(element.comments), JSON.stringify({
-      meta: {
-        changeNum: '42',
-        patchRange: {
-          basePatchNum: 'PARENT',
-          patchNum: 3,
-        },
-        path: '/path/to/foo',
-        projectConfig: {foo: 'bar'},
-      },
-      left: [
-        {id: 'bc1', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bc2', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd1', __draft: true, side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd2', __draft: true, side: 'PARENT', __commentSide: 'left'},
-      ],
-      right: [
-        {id: 'c1', __commentSide: 'right'},
-        {id: 'c2', __commentSide: 'right'},
-        {id: 'd1', __draft: true, __commentSide: 'right'},
-        {id: 'd2', __draft: true, __commentSide: 'right'},
-      ],
-    }));
-
-    element._removeComment({id: 'bc2', side: 'PARENT',
-      __commentSide: 'left'});
-    assert.deepEqual(element.comments, {
-      meta: {
-        changeNum: '42',
-        patchRange: {
-          basePatchNum: 'PARENT',
-          patchNum: 3,
-        },
-        path: '/path/to/foo',
-        projectConfig: {foo: 'bar'},
-      },
-      left: [
-        {id: 'bc1', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd1', __draft: true, side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd2', __draft: true, side: 'PARENT', __commentSide: 'left'},
-      ],
-      right: [
-        {id: 'c1', __commentSide: 'right'},
-        {id: 'c2', __commentSide: 'right'},
-        {id: 'd1', __draft: true, __commentSide: 'right'},
-        {id: 'd2', __draft: true, __commentSide: 'right'},
-      ],
-    });
-
-    element._removeComment({id: 'd2', __commentSide: 'right'});
-    assert.deepEqual(element.comments, {
-      meta: {
-        changeNum: '42',
-        patchRange: {
-          basePatchNum: 'PARENT',
-          patchNum: 3,
-        },
-        path: '/path/to/foo',
-        projectConfig: {foo: 'bar'},
-      },
-      left: [
-        {id: 'bc1', side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd1', __draft: true, side: 'PARENT', __commentSide: 'left'},
-        {id: 'bd2', __draft: true, side: 'PARENT', __commentSide: 'left'},
-      ],
-      right: [
-        {id: 'c1', __commentSide: 'right'},
-        {id: 'c2', __commentSide: 'right'},
-        {id: 'd1', __draft: true, __commentSide: 'right'},
-      ],
-    });
-  });
-
   test('thread-discard handling', () => {
-    const threads = element._createThreads([
+    const threads = createCommentThreads([
       {
         id: 4711,
-        __commentSide: 'left',
+        diffSide: Side.LEFT,
         updated: '2015-12-20 15:01:20.396000000',
+        patch_set: 1,
+        path: 'some/path',
       },
       {
         id: 42,
-        __commentSide: 'left',
+        diffSide: Side.LEFT,
         updated: '2017-12-20 15:01:20.396000000',
+        patch_set: 1,
+        path: 'some/path',
       },
     ]);
     element._parentIndex = 1;
@@ -320,11 +134,11 @@
           resolve => {
             notifySyntaxProcessed = resolve;
           }));
-      sinon.stub(element.$.restAPI, 'getDiff').returns(
+      sinon.stub(element.restApiService, 'getDiff').returns(
           Promise.resolve({content: []}));
       element.patchRange = {};
       element.change = createChange();
-      element.$.restAPI.getDiffPreferences().then(prefs => {
+      element.restApiService.getDiffPreferences().then(prefs => {
         element.prefs = prefs;
         return element.reload(true);
       });
@@ -341,7 +155,7 @@
     });
 
     test('ends total timer w/ no syntax layer processing', async () => {
-      sinon.stub(element.$.restAPI, 'getDiff').returns(
+      sinon.stub(element.restApiService, 'getDiff').returns(
           Promise.resolve({content: []}));
       element.patchRange = {};
       element.change = createChange();
@@ -363,12 +177,12 @@
           resolve => {
             notifySyntaxProcessed = resolve;
           }));
-      sinon.stub(element.$.restAPI, 'getDiff').returns(
+      sinon.stub(element.restApiService, 'getDiff').returns(
           Promise.resolve({content: []}));
       element.patchRange = {};
       element.change = createChange();
       let reloadComplete = false;
-      element.$.restAPI.getDiffPreferences()
+      element.restApiService.getDiffPreferences()
           .then(prefs => {
             element.prefs = prefs;
             return element.reload();
@@ -417,7 +231,7 @@
     test('reload() loads files weblinks', () => {
       const weblinksStub = sinon.stub(GerritNav, '_generateWeblinks')
           .returns({name: 'stubb', url: '#s'});
-      sinon.stub(element.$.restAPI, 'getDiff').returns(Promise.resolve({
+      sinon.stub(element.restApiService, 'getDiff').returns(Promise.resolve({
         content: [],
       }));
       element.projectName = 'test-project';
@@ -450,7 +264,7 @@
     });
 
     test('prefetch getDiff', done => {
-      const diffRestApiStub = sinon.stub(element.$.restAPI, 'getDiff')
+      const diffRestApiStub = sinon.stub(element.restApiService, 'getDiff')
           .returns(Promise.resolve({content: []}));
       element.changeNum = 123;
       element.patchRange = {basePatchNum: 1, patchNum: 2};
@@ -475,7 +289,7 @@
     test('reload resolves on error', () => {
       const onErrStub = sinon.stub(element, '_handleGetDiffError');
       const error = new Response(null, {ok: false, status: 500});
-      sinon.stub(element.$.restAPI, 'getDiff').callsFake(
+      sinon.stub(element.restApiService, 'getDiff').callsFake(
           (changeNum, basePatchNum, patchNum, path, whitespace, onErr) => {
             onErr(error);
           });
@@ -491,11 +305,15 @@
 
       setup(() => {
         serverErrorStub = sinon.stub();
-        element.addEventListener('server-error', serverErrorStub);
+        document.addEventListener('server-error', serverErrorStub);
         pageErrorStub = sinon.stub();
         element.addEventListener('page-error', pageErrorStub);
       });
 
+      teardown(() => {
+        document.removeEventListener('server-error', serverErrorStub);
+      });
+
       test('page error on HTTP-409', () => {
         element._handleGetDiffError({status: 409});
         assert.isTrue(serverErrorStub.calledOnce);
@@ -534,7 +352,7 @@
           'wsAAAAAAAAAAAAA/////w==',
           type: 'image/bmp',
         };
-        sinon.stub(element.$.restAPI,
+        sinon.stub(element.restApiService,
             'getB64FileContents')
             .callsFake(
                 (changeId, patchNum, path, opt_parentIndex) => Promise.resolve(
@@ -567,7 +385,7 @@
           content: [{skip: 66}],
           binary: true,
         };
-        sinon.stub(element.$.restAPI, 'getDiff')
+        sinon.stub(element.restApiService, 'getDiff')
             .returns(Promise.resolve(mockDiff));
 
         const rendered = () => {
@@ -625,7 +443,7 @@
 
         element.addEventListener('render', rendered);
 
-        element.$.restAPI.getDiffPreferences().then(prefs => {
+        element.restApiService.getDiffPreferences().then(prefs => {
           element.prefs = prefs;
           element.reload();
         });
@@ -648,7 +466,7 @@
           content: [{skip: 66}],
           binary: true,
         };
-        sinon.stub(element.$.restAPI, 'getDiff')
+        sinon.stub(element.restApiService, 'getDiff')
             .returns(Promise.resolve(mockDiff));
 
         const rendered = () => {
@@ -708,7 +526,7 @@
 
         element.addEventListener('render', rendered);
 
-        element.$.restAPI.getDiffPreferences().then(prefs => {
+        element.restApiService.getDiffPreferences().then(prefs => {
           element.prefs = prefs;
           element.reload();
         });
@@ -730,7 +548,7 @@
           content: [{skip: 66}],
           binary: true,
         };
-        sinon.stub(element.$.restAPI, 'getDiff')
+        sinon.stub(element.restApiService, 'getDiff')
             .returns(Promise.resolve(mockDiff));
 
         element.addEventListener('render', () => {
@@ -749,7 +567,7 @@
           done();
         });
 
-        element.$.restAPI.getDiffPreferences().then(prefs => {
+        element.restApiService.getDiffPreferences().then(prefs => {
           element.prefs = prefs;
           element.reload();
         });
@@ -771,7 +589,7 @@
           content: [{skip: 66}],
           binary: true,
         };
-        sinon.stub(element.$.restAPI, 'getDiff')
+        sinon.stub(element.restApiService, 'getDiff')
             .returns(Promise.resolve(mockDiff));
 
         element.addEventListener('render', () => {
@@ -790,7 +608,7 @@
           done();
         });
 
-        element.$.restAPI.getDiffPreferences().then(prefs => {
+        element.restApiService.getDiffPreferences().then(prefs => {
           element.prefs = prefs;
           element.reload();
         });
@@ -814,7 +632,7 @@
         };
         mockFile1.type = 'image/jpeg-evil';
 
-        sinon.stub(element.$.restAPI, 'getDiff')
+        sinon.stub(element.restApiService, 'getDiff')
             .returns(Promise.resolve(mockDiff));
 
         element.addEventListener('render', () => {
@@ -828,7 +646,7 @@
           done();
         });
 
-        element.$.restAPI.getDiffPreferences().then(prefs => {
+        element.restApiService.getDiffPreferences().then(prefs => {
           element.prefs = prefs;
           element.reload();
         });
@@ -889,7 +707,7 @@
       const mockBlame = [{id: 'commit id', ranges: [{start: 1, end: 2}]}];
       const showAlertStub = sinon.stub();
       element.addEventListener('show-alert', showAlertStub);
-      const getBlameStub = sinon.stub(element.$.restAPI, 'getBlame')
+      const getBlameStub = sinon.stub(element.restApiService, 'getBlame')
           .returns(Promise.resolve(mockBlame));
       element.changeNum = 42;
       element.patchRange = {patchNum: 5, basePatchNum: 4};
@@ -907,7 +725,7 @@
       const mockBlame = [];
       const showAlertStub = sinon.stub();
       element.addEventListener('show-alert', showAlertStub);
-      sinon.stub(element.$.restAPI, 'getBlame')
+      sinon.stub(element.restApiService, 'getBlame')
           .returns(Promise.resolve(mockBlame));
       element.changeNum = 42;
       element.patchRange = {patchNum: 5, basePatchNum: 4};
@@ -1128,7 +946,7 @@
       {
         id: 'new_draft',
         message: 'i do not like either of you',
-        __commentSide: 'left',
+        diffSide: Side.LEFT,
         __draft: true,
         updated: '2015-12-20 15:01:20.396000000',
       },
@@ -1137,12 +955,12 @@
         message: 'i like you, jack',
         updated: '2015-12-23 15:00:20.396000000',
         line: 1,
-        __commentSide: 'left',
+        diffSide: Side.LEFT,
       }, {
         id: 'jacks_reply',
         message: 'i like you, too',
         updated: '2015-12-24 15:01:20.396000000',
-        __commentSide: 'left',
+        diffSide: Side.LEFT,
         line: 1,
         in_reply_to: 'sallys_confession',
       },
@@ -1160,43 +978,47 @@
         message: 'i like you, jack',
         updated: '2015-12-23 15:00:20.396000000',
         line: 1,
-        __commentSide: 'left',
+        patch_set: 1,
+        path: 'some/path',
       }, {
         id: 'jacks_reply',
         message: 'i like you, too',
         updated: '2015-12-24 15:01:20.396000000',
-        __commentSide: 'left',
         line: 1,
         in_reply_to: 'sallys_confession',
+        patch_set: 1,
+        path: 'some/path',
       },
       {
         id: 'new_draft',
         message: 'i do not like either of you',
-        __commentSide: 'left',
         __draft: true,
         updated: '2015-12-20 15:01:20.396000000',
+        patch_set: 1,
+        path: 'some/path',
       },
     ];
 
-    const actualThreads = element._createThreads(comments);
+    const actualThreads = createCommentThreads(comments,
+        {basePatchNum: 1, patchNum: 4});
 
     assert.equal(actualThreads.length, 2);
 
-    assert.equal(actualThreads[0].commentSide, 'left');
+    assert.equal(actualThreads[0].diffSide, Side.LEFT);
     assert.equal(actualThreads[0].comments.length, 2);
     assert.deepEqual(actualThreads[0].comments[0], comments[0]);
     assert.deepEqual(actualThreads[0].comments[1], comments[1]);
-    assert.equal(actualThreads[0].patchNum, undefined);
-    assert.equal(actualThreads[0].lineNum, 1);
+    assert.equal(actualThreads[0].patchNum, 1);
+    assert.equal(actualThreads[0].line, 1);
 
-    assert.equal(actualThreads[1].commentSide, 'left');
+    assert.equal(actualThreads[1].diffSide, Side.LEFT);
     assert.equal(actualThreads[1].comments.length, 1);
     assert.deepEqual(actualThreads[1].comments[0], comments[2]);
-    assert.equal(actualThreads[1].patchNum, undefined);
-    assert.equal(actualThreads[1].lineNum, undefined);
+    assert.equal(actualThreads[1].patchNum, 1);
+    assert.equal(actualThreads[1].line, FILE);
   });
 
-  test('_createThreads inherits patchNum and range', () => {
+  test('_createThreads derives patchNum and range', () => {
     const comments = [{
       id: 'betsys_confession',
       message: 'i like you, jack',
@@ -1208,15 +1030,20 @@
         end_character: 2,
       },
       patch_set: 5,
-      __commentSide: 'left',
+      path: '/p',
       line: 1,
     }];
 
     const expectedThreads = [
       {
-        commentSide: 'left',
+        diffSide: Side.LEFT,
+        commentSide: CommentSide.REVISION,
+        path: '/p',
+        rootId: 'betsys_confession',
+        mergeParentNum: undefined,
         comments: [{
           id: 'betsys_confession',
+          path: '/p',
           message: 'i like you, jack',
           updated: '2015-12-24 15:00:10.396000000',
           range: {
@@ -1226,7 +1053,6 @@
             end_character: 2,
           },
           patch_set: 5,
-          __commentSide: 'left',
           line: 1,
         }],
         patchNum: 5,
@@ -1236,13 +1062,12 @@
           end_line: 1,
           end_character: 2,
         },
-        lineNum: 1,
-        isOnParent: false,
+        line: 1,
       },
     ];
 
     assert.deepEqual(
-        element._createThreads(comments),
+        createCommentThreads(comments, {basePatchNum: 5, patchNum: 10}),
         expectedThreads);
   });
 
@@ -1253,56 +1078,32 @@
             id: 'sallys_confession',
             message: 'i like you, jack',
             updated: '2015-12-23 15:00:20.396000000',
-            __commentSide: 'left',
+            diffSide: Side.LEFT,
+            path: '/p',
           }, {
             id: 'jacks_reply',
             message: 'i like you, too',
             updated: '2015-12-24 15:01:20.396000000',
-            __commentSide: 'left',
+            diffSide: Side.LEFT,
+            path: '/p',
           },
         ];
-        assert.equal(element._createThreads(comments).length, 2);
-      });
-
-  test('_createThreads derives isOnParent using  side from first comment',
-      () => {
-        const comments = [
-          {
-            id: 'sallys_confession',
-            message: 'i like you, jack',
-            updated: '2015-12-23 15:00:20.396000000',
-            __commentSide: 'left',
-          }, {
-            id: 'jacks_reply',
-            message: 'i like you, too',
-            updated: '2015-12-24 15:01:20.396000000',
-            __commentSide: 'left',
-            in_reply_to: 'sallys_confession',
-          },
-        ];
-
-        assert.equal(element._createThreads(comments)[0].isOnParent, false);
-
-        comments[0].side = 'REVISION';
-        assert.equal(element._createThreads(comments)[0].isOnParent, false);
-
-        comments[0].side = 'PARENT';
-        assert.equal(element._createThreads(comments)[0].isOnParent, true);
+        assert.equal(createCommentThreads(comments).length, 2);
       });
 
   test('_getOrCreateThread', () => {
-    const commentSide = 'left';
+    const diffSide = Side.LEFT;
+    const commentSide = CommentSide.PARENT;
 
     assert.isOk(element._getOrCreateThread('2', 3,
-        commentSide, undefined, false));
+        diffSide, commentSide, '/p'));
 
     let threads = dom(element.$.diff)
         .queryDistributedElements('gr-comment-thread');
 
     assert.equal(threads.length, 1);
-    assert.equal(threads[0].commentSide, commentSide);
+    assert.equal(threads[0].diffSide, diffSide);
     assert.equal(threads[0].range, undefined);
-    assert.equal(threads[0].isOnParent, false);
     assert.equal(threads[0].patchNum, 2);
 
     // Try to fetch a thread with a different range.
@@ -1314,63 +1115,62 @@
     };
 
     assert.isOk(element._getOrCreateThread(
-        '3', 1, commentSide, range, true));
+        '3', 1, diffSide, commentSide, '/p', range));
 
     threads = dom(element.$.diff)
         .queryDistributedElements('gr-comment-thread');
 
     assert.equal(threads.length, 2);
-    assert.equal(threads[1].commentSide, commentSide);
+    assert.equal(threads[1].diffSide, diffSide);
     assert.equal(threads[1].range, range);
-    assert.equal(threads[1].isOnParent, true);
     assert.equal(threads[1].patchNum, 3);
   });
 
-  test('thread should use old file path if first created' +
+  test('thread should use old file path if first created ' +
    'on patch set (left) before renaming', () => {
-    const commentSide = 'left';
+    const diffSide = Side.LEFT;
     element.file = {basePath: 'file_renamed.txt', path: element.path};
 
     assert.isOk(element._getOrCreateThread('2', 3,
-        commentSide, undefined, /* isOnParent= */ false));
+        diffSide, CommentSide.REVISION, '/p'));
 
     const threads = dom(element.$.diff)
         .queryDistributedElements('gr-comment-thread');
 
     assert.equal(threads.length, 1);
-    assert.equal(threads[0].commentSide, commentSide);
+    assert.equal(threads[0].diffSide, diffSide);
     assert.equal(threads[0].path, element.file.basePath);
   });
 
   test('thread should use new file path if first created' +
    'on patch set (right) after renaming', () => {
-    const commentSide = 'right';
+    const diffSide = Side.RIGHT;
     element.file = {basePath: 'file_renamed.txt', path: element.path};
 
     assert.isOk(element._getOrCreateThread('2', 3,
-        commentSide, undefined, /* isOnParent= */ false));
+        diffSide, CommentSide.REVISION, '/p'));
 
     const threads = dom(element.$.diff)
         .queryDistributedElements('gr-comment-thread');
 
     assert.equal(threads.length, 1);
-    assert.equal(threads[0].commentSide, commentSide);
+    assert.equal(threads[0].diffSide, diffSide);
     assert.equal(threads[0].path, element.file.path);
   });
 
   test('thread should use new file path if first created' +
    'on patch set (left) but is base', () => {
-    const commentSide = 'left';
+    const diffSide = Side.LEFT;
     element.file = {basePath: 'file_renamed.txt', path: element.path};
 
     assert.isOk(element._getOrCreateThread('2', 3,
-        commentSide, undefined, /* isOnParent= */ true));
+        diffSide, CommentSide.PARENT, '/p', undefined));
 
     const threads = dom(element.$.diff)
         .queryDistributedElements('gr-comment-thread');
 
     assert.equal(threads.length, 1);
-    assert.equal(threads[0].commentSide, commentSide);
+    assert.equal(threads[0].diffSide, diffSide);
     assert.equal(threads[0].path, element.file.path);
   });
 
@@ -1390,23 +1190,21 @@
 
     const l3 = document.createElement('div');
     l3.setAttribute('line-num', 3);
-    l3.setAttribute('comment-side', 'left');
+    l3.setAttribute('diff-side', Side.LEFT);
 
     const l5 = document.createElement('div');
     l5.setAttribute('line-num', 5);
-    l5.setAttribute('comment-side', 'left');
+    l5.setAttribute('diff-side', Side.LEFT);
 
     const r3 = document.createElement('div');
     r3.setAttribute('line-num', 3);
-    r3.setAttribute('comment-side', 'right');
+    r3.setAttribute('diff-side', Side.RIGHT);
 
     const r5 = document.createElement('div');
     r5.setAttribute('line-num', 5);
-    r5.setAttribute('comment-side', 'right');
+    r5.setAttribute('diff-side', Side.RIGHT);
 
     const threadEls = [l3, l5, r3, r5];
-    assert.deepEqual(element._filterThreadElsForLocation(threadEls, line),
-        [l3, r5]);
     assert.deepEqual(element._filterThreadElsForLocation(threadEls, line,
         Side.LEFT), [l3]);
     assert.deepEqual(element._filterThreadElsForLocation(threadEls, line,
@@ -1417,18 +1215,14 @@
     const line = {beforeNumber: 'FILE', afterNumber: 'FILE'};
 
     const l = document.createElement('div');
-    l.setAttribute('comment-side', 'left');
+    l.setAttribute('diff-side', Side.LEFT);
     l.setAttribute('line-num', 'FILE');
 
     const r = document.createElement('div');
-    r.setAttribute('comment-side', 'right');
+    r.setAttribute('diff-side', Side.RIGHT);
     r.setAttribute('line-num', 'FILE');
 
     const threadEls = [l, r];
-    assert.deepEqual(element._filterThreadElsForLocation(threadEls, line),
-        [l, r]);
-    assert.deepEqual(element._filterThreadElsForLocation(threadEls, line,
-        Side.BOTH), [l, r]);
     assert.deepEqual(element._filterThreadElsForLocation(threadEls, line,
         Side.LEFT), [l]);
     assert.deepEqual(element._filterThreadElsForLocation(threadEls, line,
@@ -1478,7 +1272,7 @@
     test('starts syntax layer processing on render event', async () => {
       sinon.stub(element.$.syntaxLayer, 'process')
           .returns(Promise.resolve());
-      sinon.stub(element.$.restAPI, 'getDiff').returns(
+      sinon.stub(element.restApiService, 'getDiff').returns(
           Promise.resolve({content: []}));
       element.reload();
       await flush();
@@ -1528,31 +1322,37 @@
 
   suite('coverage layer', () => {
     let notifyStub;
+    let coverageProviderStub;
+    const exampleRanges = [
+      {
+        type: CoverageType.COVERED,
+        side: Side.RIGHT,
+        code_range: {
+          start_line: 1,
+          end_line: 2,
+        },
+      },
+      {
+        type: CoverageType.NOT_COVERED,
+        side: Side.RIGHT,
+        code_range: {
+          start_line: 3,
+          end_line: 4,
+        },
+      },
+    ];
+
     setup(() => {
       notifyStub = sinon.stub();
+      coverageProviderStub = sinon.stub().returns(
+          Promise.resolve(exampleRanges));
+
       stub('gr-js-api-interface', {
         getCoverageAnnotationApis() {
           return Promise.resolve([{
             notify: notifyStub,
             getCoverageProvider() {
-              return () => Promise.resolve([
-                {
-                  type: 'COVERED',
-                  side: 'right',
-                  code_range: {
-                    start_line: 1,
-                    end_line: 2,
-                  },
-                },
-                {
-                  type: 'NOT_COVERED',
-                  side: 'right',
-                  code_range: {
-                    start_line: 3,
-                    end_line: 4,
-                  },
-                },
-              ]);
+              return coverageProviderStub;
             },
           }]);
         },
@@ -1588,9 +1388,38 @@
       element.reload();
       flush(() => {
         assert.equal(notifyStub.callCount, 2);
+        assert.isTrue(notifyStub.calledWithExactly(
+            'some/path', 1, 2, Side.RIGHT));
+        assert.isTrue(notifyStub.calledWithExactly(
+            'some/path', 3, 4, Side.RIGHT));
         done();
       });
     });
+
+    test('provider is called with appropriate params', done => {
+      element.patchRange.basePatchNum = 1;
+      element.patchRange.patchNum = 3;
+
+      element.reload();
+      flush(() => {
+        assert.isTrue(coverageProviderStub.calledWithExactly(
+            123, 'some/path', 1, 3, element.change));
+        done();
+      });
+    });
+
+    test('provider is called with appropriate params - special patchset values',
+        done => {
+          element.patchRange.basePatchNum = 'PARENT';
+          element.patchRange.patchNum = 'invalid';
+
+          element.reload();
+          flush(() => {
+            assert.isTrue(coverageProviderStub.calledWithExactly(
+                123, 'some/path', undefined, undefined, element.change));
+            done();
+          });
+        });
   });
 
   suite('trailing newlines', () => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
index e0333cc..cfe2cfe 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
@@ -18,9 +18,7 @@
 import '@polymer/iron-a11y-announcer/iron-a11y-announcer';
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {DiffViewMode} from '../../../constants/constants';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -28,12 +26,7 @@
 import {customElement, property} from '@polymer/decorators';
 import {IronA11yAnnouncer} from '@polymer/iron-a11y-announcer/iron-a11y-announcer';
 import {FixIronA11yAnnouncer} from '../../../types/types';
-
-export interface GrDiffModeSelector {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 @customElement('gr-diff-mode-selector')
 export class GrDiffModeSelector extends GestureEventListeners(
@@ -53,6 +46,8 @@
   @property({type: Boolean})
   saveOnChange = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   attached() {
     ((IronA11yAnnouncer as unknown) as FixIronA11yAnnouncer).requestAvailability();
   }
@@ -62,7 +57,7 @@
    */
   setMode(newMode: DiffViewMode) {
     if (this.saveOnChange && this.mode && this.mode !== newMode) {
-      this.$.restAPI.savePreferences({diff_view: newMode});
+      this.restApiService.savePreferences({diff_view: newMode});
     }
     this.mode = newMode;
     let annoucement;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
index a5bf269..9943b58 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
@@ -52,5 +52,4 @@
   >
     <iron-icon icon="gr-icons:unified"></iron-icon>
   </gr-button>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.js b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.js
index 07a1d16..049f01d 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.js
@@ -40,7 +40,7 @@
   });
 
   test('setMode', () => {
-    const saveStub = sinon.stub(element.$.restAPI, 'savePreferences');
+    const saveStub = sinon.stub(element.restApiService, 'savePreferences');
 
     // Setting the mode initially does not save prefs.
     element.saveOnChange = true;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-preferences-dialog/gr-diff-preferences-dialog.ts b/polygerrit-ui/app/elements/diff/gr-diff-preferences-dialog/gr-diff-preferences-dialog.ts
index c66af58..8829afc 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-preferences-dialog/gr-diff-preferences-dialog.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-preferences-dialog/gr-diff-preferences-dialog.ts
@@ -26,7 +26,7 @@
 import {GrDiffPreferences} from '../../shared/gr-diff-preferences/gr-diff-preferences';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
-import {DiffPreferencesInfo} from '../../../types/common';
+import {DiffPreferencesInfo} from '../../../types/diff';
 
 export interface GrDiffPreferencesDialog {
   $: {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.ts b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.ts
index ab7ab8a..5a432dd 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor.ts
@@ -30,7 +30,7 @@
 } from '../gr-diff/gr-diff-group';
 import {CancelablePromise, util} from '../../../scripts/util';
 import {customElement, property} from '@polymer/decorators';
-import {DiffContent} from '../../../types/common';
+import {DiffContent} from '../../../types/diff';
 import {Side} from '../../../constants/constants';
 
 const WHOLE_FILE = -1;
@@ -366,7 +366,7 @@
     const group = new GrDiffGroup(type, lines);
     group.keyLocation = !!chunk.keyLocation;
     group.dueToRebase = !!chunk.due_to_rebase;
-    group.dueToMove = !!chunk.due_to_move;
+    group.moveDetails = chunk.move_details;
     group.skip = chunk.skip;
     group.ignoredWhitespaceOnly = !!chunk.common;
     if (chunk.skip) {
@@ -679,15 +679,18 @@
    */
   _breakdownChunk(chunk: DiffContent): DiffContent[] {
     let key: 'a' | 'b' | 'ab' | null = null;
-    if (chunk.a && !chunk.b) {
+    const {a, b, ab, move_details} = chunk;
+    if (a?.length && !b?.length) {
       key = 'a';
-    } else if (chunk.b && !chunk.a) {
+    } else if (b?.length && !a?.length) {
       key = 'b';
-    } else if (chunk.ab) {
+    } else if (ab?.length) {
       key = 'ab';
     }
 
-    if (!key) {
+    // Move chunks should not be divided because of move label
+    // positioned in the top of the chunk
+    if (!key || move_details) {
       return [chunk];
     }
 
@@ -697,8 +700,8 @@
       if (chunk.due_to_rebase) {
         subChunk.due_to_rebase = true;
       }
-      if (chunk.due_to_move) {
-        subChunk.due_to_move = true;
+      if (chunk.move_details) {
+        subChunk.move_details = chunk.move_details;
       }
       return subChunk;
     });
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.js b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.js
index ce7a3c4..0c3c9bf 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-processor/gr-diff-processor_test.js
@@ -590,6 +590,43 @@
       assert.deepEqual(result[1].ab, content[0].ab.slice(120));
     });
 
+    test('breaks down added chunks', () => {
+      const size = 120 * 2 + 5;
+      const content = _.times(size, () => `${Math.random()}`);
+      element.context = 5;
+      const splitContent = element._splitLargeChunks([{a: [], b: content}])
+          .map(r => r.b);
+      assert.equal(splitContent.length, 3);
+      assert.deepEqual(splitContent[0], content.slice(0, 5));
+      assert.deepEqual(splitContent[1], content.slice(5, 125));
+      assert.deepEqual(splitContent[2], content.slice(125));
+    });
+
+    test('breaks down removed chunks', () => {
+      const size = 120 * 2 + 5;
+      const content = _.times(size, () => `${Math.random()}`);
+      element.context = 5;
+      const splitContent = element._splitLargeChunks([{a: content, b: []}])
+          .map(r => r.a);
+      assert.equal(splitContent.length, 3);
+      assert.deepEqual(splitContent[0], content.slice(0, 5));
+      assert.deepEqual(splitContent[1], content.slice(5, 125));
+      assert.deepEqual(splitContent[2], content.slice(125));
+    });
+
+    test('does not break down moved chunks', () => {
+      const size = 120 * 2 + 5;
+      const content = _.times(size, () => `${Math.random()}`);
+      element.context = 5;
+      const splitContent = element._splitLargeChunks([{
+        a: content,
+        b: [],
+        move_details: {changed: false},
+      }]).map(r => r.a);
+      assert.equal(splitContent.length, 1);
+      assert.deepEqual(splitContent[0], content);
+    });
+
     test('does not break-down common chunks w/ context', () => {
       const content = [{
         ab: _.times(75, () => `${Math.random()}`),
@@ -1019,16 +1056,6 @@
             }
           });
 
-      test('_breakdownChunk keeps due_to_move for broken down additions',
-          () => {
-            sinon.spy(element, '_breakdown');
-            const chunk = {b: ['blah', 'blah', 'blah'], due_to_move: true};
-            const result = element._breakdownChunk(chunk);
-            for (const subResult of result) {
-              assert.isTrue(subResult.due_to_move);
-            }
-          });
-
       test('_breakdown common case', () => {
         const array = 'Lorem ipsum dolor sit amet, suspendisse inceptos'
             .split(' ');
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-selection/gr-diff-selection.ts b/polygerrit-ui/app/elements/diff/gr-diff-selection/gr-diff-selection.ts
index b75ba8f..08c8226 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-selection/gr-diff-selection.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-selection/gr-diff-selection.ts
@@ -27,9 +27,10 @@
 } from '../gr-diff-highlight/gr-range-normalizer';
 import {descendedFromClass, querySelectorAll} from '../../../utils/dom-util';
 import {customElement, property, observe} from '@polymer/decorators';
-import {DiffInfo} from '../../../types/common';
+import {DiffInfo} from '../../../types/diff';
 import {Side} from '../../../constants/constants';
 import {GrDiffBuilderElement} from '../gr-diff-builder/gr-diff-builder-element';
+import {getSide, isThreadEl} from '../gr-diff/gr-diff-utils';
 
 /**
  * Possible CSS classes indicating the state of selection. Dynamically added/
@@ -96,10 +97,10 @@
   }
 
   _handleDownOnRangeComment(node: Element) {
-    if (node?.nodeName?.toLowerCase() === 'gr-comment-thread') {
+    if (isThreadEl(node)) {
       this._setClasses([
         SelectionClass.COMMENT,
-        node.getAttribute('comment-side') === Side.LEFT
+        getSide(node) === Side.LEFT
           ? SelectionClass.LEFT
           : SelectionClass.RIGHT,
       ]);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
index fc46123..84b227b 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
@@ -21,7 +21,6 @@
 import '../../shared/gr-dropdown/gr-dropdown';
 import '../../shared/gr-dropdown-list/gr-dropdown-list';
 import '../../shared/gr-icons/gr-icons';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import '../../shared/revision-info/revision-info';
 import '../gr-comment-api/gr-comment-api';
@@ -40,13 +39,11 @@
   KeyboardShortcutMixin,
   Shortcut,
 } from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
-import {GrCountStringFormatter} from '../../shared/gr-count-string-formatter/gr-count-string-formatter';
-import {GerritNav, GerritView} from '../../core/gr-navigation/gr-navigation';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {appContext} from '../../../services/app-context';
 import {
   computeAllPatchSets,
   computeLatestPatchNum,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {
@@ -58,25 +55,18 @@
 } from '../../../utils/path-list-util';
 import {changeBaseURL, changeIsOpen} from '../../../utils/change-util';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrDiffHost} from '../gr-diff-host/gr-diff-host';
 import {
   DropdownItem,
   GrDropdownList,
 } from '../../shared/gr-dropdown-list/gr-dropdown-list';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
-import {
-  ChangeComments,
-  GrCommentApi,
-  TwoSidesComments,
-} from '../gr-comment-api/gr-comment-api';
+import {ChangeComments, GrCommentApi} from '../gr-comment-api/gr-comment-api';
 import {GrDiffModeSelector} from '../gr-diff-mode-selector/gr-diff-mode-selector';
 import {
   ChangeInfo,
   CommitId,
   ConfigInfo,
-  DiffInfo,
-  DiffPreferencesInfo,
   EditInfo,
   EditPatchSetNum,
   ElementPropertyDeepChange,
@@ -89,6 +79,7 @@
   RepoName,
   RevisionInfo,
 } from '../../../types/common';
+import {DiffInfo, DiffPreferencesInfo} from '../../../types/diff';
 import {ChangeViewState, CommitRange, FileRange} from '../../../types/types';
 import {FilesWebLinks} from '../gr-patch-range-select/gr-patch-range-select';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
@@ -98,10 +89,15 @@
 import {GrApplyFixDialog} from '../gr-apply-fix-dialog/gr-apply-fix-dialog';
 import {LineOfInterest} from '../gr-diff/gr-diff';
 import {RevisionInfo as RevisionInfoObj} from '../../shared/revision-info/revision-info';
-import {CommentMap} from '../../../utils/comment-util';
+import {
+  CommentMap,
+  isInBaseOfPatchRange,
+  getPatchRangeForCommentUrl,
+} from '../../../utils/comment-util';
 import {AppElementParams} from '../../gr-app-types';
 import {CustomKeyboardEvent, OpenFixPreviewEvent} from '../../../types/events';
-
+import {fireAlert, fireTitleChange} from '../../../utils/event-util';
+import {GerritView} from '../../../services/router/router-model';
 const ERR_REVIEW_STATUS = 'Couldn’t change file review status.';
 const MSG_LOADING_BLAME = 'Loading blame...';
 const MSG_LOADED_BLAME = 'Blame loaded';
@@ -118,7 +114,6 @@
 
 export interface GrDiffView {
   $: {
-    restAPI: RestApiService & Element;
     commentAPI: GrCommentApi;
     cursor: GrDiffCursor;
     diffHost: GrDiffHost;
@@ -188,9 +183,7 @@
 
   @property({
     type: Array,
-    computed:
-      '_formatFilesForDropdown(_files, ' +
-      '_patchRange.patchNum, _changeComments)',
+    computed: '_formatFilesForDropdown(_files, _patchRange, _changeComments)',
   })
   _formattedFiles?: DropdownItem[];
 
@@ -239,9 +232,6 @@
   @property({type: Object})
   _commentMap?: CommentMap;
 
-  @property({type: Object})
-  _commentsForDiff?: TwoSidesComments;
-
   @property({
     type: Object,
     computed: '_computeCommentSkips(_commentMap, _fileList, _path)',
@@ -324,6 +314,8 @@
 
   flagsService = appContext.flagsService;
 
+  private readonly restApiService = appContext.restApiService;
+
   _throttledToggleFileReviewed?: EventListener;
 
   _onRenderHandler?: EventListener;
@@ -359,19 +351,19 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   @observe('_change.project')
   _getProjectConfig(project?: RepoName) {
     if (!project) return;
-    return this.$.restAPI.getProjectConfig(project).then(config => {
+    return this.restApiService.getProjectConfig(project).then(config => {
       this._projectConfig = config;
     });
   }
 
   _getChangeDetail(changeNum: NumericChangeId) {
-    return this.$.restAPI.getDiffChangeDetail(changeNum).then(change => {
+    return this.restApiService.getDiffChangeDetail(changeNum).then(change => {
       if (!change) throw new Error('Missing "change" in API response.');
       this._change = change;
       return change;
@@ -380,7 +372,7 @@
 
   _getChangeEdit() {
     if (!this._changeNum) throw new Error('Missing this._changeNum');
-    return this.$.restAPI.getChangeEdit(this._changeNum);
+    return this.restApiService.getChangeEdit(this._changeNum);
   }
 
   _getSortedFileList(files?: Files) {
@@ -418,7 +410,7 @@
     }
 
     const patchRange = patchRangeRecord.base;
-    return this.$.restAPI
+    return this.restApiService
       .getChangeFiles(changeNum, patchRange)
       .then(changeFiles => {
         if (!changeFiles) return;
@@ -433,13 +425,13 @@
   }
 
   _getDiffPreferences() {
-    return this.$.restAPI.getDiffPreferences().then(prefs => {
+    return this.restApiService.getDiffPreferences().then(prefs => {
       this._prefs = prefs;
     });
   }
 
   _getPreferences() {
-    return this.$.restAPI.getPreferences();
+    return this.restApiService.getPreferences();
   }
 
   _getWindowWidth() {
@@ -457,13 +449,7 @@
     this.$.reviewed.checked = reviewed;
     if (!this._patchRange?.patchNum) return;
     this._saveReviewedState(reviewed).catch(err => {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: ERR_REVIEW_STATUS},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, ERR_REVIEW_STATUS);
       throw err;
     });
   }
@@ -472,7 +458,7 @@
     if (!this._changeNum) return Promise.resolve(undefined);
     if (!this._patchRange?.patchNum) return Promise.resolve(undefined);
     if (!this._path) return Promise.resolve(undefined);
-    return this.$.restAPI.saveFileReviewed(
+    return this.restApiService.saveFileReviewed(
       this._changeNum,
       this._patchRange?.patchNum,
       this._path,
@@ -605,6 +591,7 @@
     if (this.modifierPressed(e)) return;
 
     e.preventDefault();
+    this.classList.remove('hideComments');
     this.$.cursor.createCommentInPlace();
   }
 
@@ -853,10 +840,12 @@
     patchNum?: PatchSetNum
   ): Promise<Set<string>> {
     if (!changeNum || !patchNum) return Promise.resolve(new Set<string>());
-    return this.$.restAPI.getReviewedFiles(changeNum, patchNum).then(files => {
-      this._reviewedFiles = new Set(files);
-      return this._reviewedFiles;
-    });
+    return this.restApiService
+      .getReviewedFiles(changeNum, patchNum)
+      .then(files => {
+        this._reviewedFiles = new Set(files);
+        return this._reviewedFiles;
+      });
   }
 
   _getReviewedStatus(
@@ -880,51 +869,36 @@
 
   _displayDiffBaseAgainstLeftToast() {
     if (!this._patchRange) return;
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {
-          // \u2190 = ←
-          message:
-            `Patchset ${this._patchRange.basePatchNum} vs ` +
-            `${this._patchRange.patchNum} selected. Press v + \u2190 to view ` +
-            `Base vs ${this._patchRange.basePatchNum}`,
-        },
-        composed: true,
-        bubbles: true,
-      })
+    fireAlert(
+      this,
+      `Patchset ${this._patchRange.basePatchNum} vs ` +
+        `${this._patchRange.patchNum} selected. Press v + \u2190 to view ` +
+        `Base vs ${this._patchRange.basePatchNum}`
     );
   }
 
   _displayDiffAgainstLatestToast(latestPatchNum?: PatchSetNum) {
     if (!this._patchRange) return;
-    const leftPatchset = patchNumEquals(
-      this._patchRange.basePatchNum,
-      ParentPatchSetNum
-    )
-      ? 'Base'
-      : `Patchset ${this._patchRange.basePatchNum}`;
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {
-          // \u2191 = ↑
-          message: `${leftPatchset} vs
+    const leftPatchset =
+      this._patchRange.basePatchNum === ParentPatchSetNum
+        ? 'Base'
+        : `Patchset ${this._patchRange.basePatchNum}`;
+    fireAlert(
+      this,
+      `${leftPatchset} vs
             ${this._patchRange.patchNum} selected\n. Press v + \u2191 to view
-            ${leftPatchset} vs Patchset ${latestPatchNum}`,
-        },
-        composed: true,
-        bubbles: true,
-      })
+            ${leftPatchset} vs Patchset ${latestPatchNum}`
     );
   }
 
   _displayToasts() {
     if (!this._patchRange) return;
-    if (!patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum !== ParentPatchSetNum) {
       this._displayDiffBaseAgainstLeftToast();
       return;
     }
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (!patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum !== latestPatchNum) {
       this._displayDiffAgainstLatestToast(latestPatchNum);
       return;
     }
@@ -939,23 +913,40 @@
       if (!hasOwnProperty(this._change.revisions, commitSha)) continue;
       const revision = this._change.revisions[commitSha];
       const patchNum = revision._number;
-      if (patchNumEquals(patchNum, this._patchRange.patchNum)) {
+      if (patchNum === this._patchRange.patchNum) {
         commit = commitSha as CommitId;
         const commitObj = revision.commit;
         const parents = commitObj?.parents || [];
         if (
-          patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum) &&
+          this._patchRange.basePatchNum === ParentPatchSetNum &&
           parents.length
         ) {
           baseCommit = parents[parents.length - 1].commit;
         }
-      } else if (patchNumEquals(patchNum, this._patchRange.basePatchNum)) {
+      } else if (patchNum === this._patchRange.basePatchNum) {
         baseCommit = commitSha as CommitId;
       }
     }
     this._commitRange = commit && baseCommit ? {commit, baseCommit} : undefined;
   }
 
+  _updateUrlToDiffUrl(lineNum?: number, leftSide?: boolean) {
+    if (!this._change) return;
+    if (!this._patchRange) return;
+    if (!this._changeNum) return;
+    if (!this._path) return;
+    const url = GerritNav.getUrlForDiffById(
+      this._changeNum,
+      this._change.project,
+      this._path,
+      this._patchRange.patchNum,
+      this._patchRange.basePatchNum,
+      lineNum,
+      leftSide
+    );
+    history.replaceState(null, '', url);
+  }
+
   _initPatchRange() {
     let leftSide = false;
     if (!this._change) return;
@@ -965,37 +956,17 @@
         this.params.commentId
       );
       if (!comment) {
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {
-              message: 'comment not found',
-            },
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireAlert(this, 'comment not found');
         GerritNav.navigateToChange(this._change);
         return;
       }
       this._path = comment.path;
+
       const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-      if (!comment.patch_set) throw new Error('Missing comment.patch_set');
       if (!latestPatchNum) throw new Error('Missing _allPatchSets');
-      if (patchNumEquals(latestPatchNum, comment.patch_set)) {
-        this._patchRange = {
-          patchNum: latestPatchNum,
-          basePatchNum: ParentPatchSetNum,
-        };
-        leftSide = comment.__commentSide === 'left';
-      } else {
-        this._patchRange = {
-          patchNum: latestPatchNum,
-          basePatchNum: comment.patch_set,
-        };
-        // comment is now on the left side since we are showing
-        // comment.patch_set vs latest
-        leftSide = true;
-      }
+      this._patchRange = getPatchRangeForCommentUrl(comment, latestPatchNum);
+      leftSide = isInBaseOfPatchRange(comment, this._patchRange);
+
       this._focusLineNum = comment.line;
     } else {
       if (this.params.path) {
@@ -1014,13 +985,13 @@
     }
     if (!this._patchRange) throw new Error('Failed to initialize patchRange.');
     this._initLineOfInterestAndCursor(leftSide);
-    this._commentMap = this._getPaths(this._patchRange);
 
-    this._commentsForDiff = this._getCommentsForPath(
-      this._path,
-      this._patchRange,
-      this._projectConfig
-    );
+    if (this.params?.commentId) {
+      // url is of type /comment/{commentId} which isn't meaningful
+      this._updateUrlToDiffUrl(this._focusLineNum, leftSide);
+    }
+
+    this._commentMap = this._getPaths(this._patchRange);
   }
 
   _isFileUnchanged(diff: DiffInfo) {
@@ -1045,7 +1016,7 @@
     this._focusLineNum = undefined;
 
     if (value.changeNum && value.project) {
-      this.$.restAPI.setInProjectLookup(value.changeNum, value.project);
+      this.restApiService.setInProjectLookup(value.changeNum, value.project);
     }
 
     this._changeNum = value.changeNum;
@@ -1071,7 +1042,7 @@
     );
 
     promises.push(this._getChangeDetail(this._changeNum));
-    promises.push(this._loadComments());
+    promises.push(this._loadComments(value.patchNum));
 
     promises.push(this._getChangeEdit());
 
@@ -1083,7 +1054,18 @@
         this._loading = false;
         this._initPatchRange();
         this._initCommitRange();
-        this.$.diffHost.comments = this._commentsForDiff;
+
+        if (!this._path) throw new Error('path must be defined');
+        if (!this._changeComments)
+          throw new Error('change comments must be defined');
+        if (!this._patchRange) throw new Error('patch range must be defined');
+
+        // TODO(dhruvsri): check if basePath should be set here
+        this.$.diffHost.threads = this._changeComments.getThreadsBySideForFile(
+          {path: this._path},
+          this._patchRange
+        );
+
         const edit = r[4] as EditInfo | undefined;
         if (edit) {
           this.set(`_change.revisions.${edit.commit.commit}`, {
@@ -1113,17 +1095,12 @@
             return;
           }
 
-          this.dispatchEvent(
-            new CustomEvent('show-alert', {
-              detail: {
-                message: `File is unchanged between Patchset
+          fireAlert(
+            this,
+            `File is unchanged between Patchset
                   ${this._patchRange.basePatchNum} and
                   ${this._patchRange.patchNum}. Showing diff of Base vs
-                  ${this._patchRange.basePatchNum}`,
-              },
-              composed: true,
-              bubbles: true,
-            })
+                  ${this._patchRange.basePatchNum}`
           );
           GerritNav.navigateToDiff(
             this._change,
@@ -1146,7 +1123,7 @@
   _changeViewStateChanged(changeViewState: Partial<ChangeViewState>) {
     if (changeViewState.diffMode === null) {
       // If screen size is small, always default to unified view.
-      this.$.restAPI.getPreferences().then(prefs => {
+      this.restApiService.getPreferences().then(prefs => {
         if (prefs) {
           this.set('changeViewState.diffMode', prefs.default_diff_view);
         }
@@ -1221,13 +1198,7 @@
 
   _pathChanged(path: string) {
     if (path) {
-      this.dispatchEvent(
-        new CustomEvent('title-change', {
-          detail: {title: computeTruncatedPath(path)},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireTitleChange(this, computeTruncatedPath(path));
     }
 
     if (!this._fileList || this._fileList.length === 0) return;
@@ -1276,7 +1247,7 @@
     if (!patchRange) return {patchNum, basePatchNum};
     if (
       patchRange.basePatchNum !== ParentPatchSetNum ||
-      !patchNumEquals(patchRange.patchNum, latestPatchNum as PatchSetNum)
+      patchRange.patchNum !== latestPatchNum
     ) {
       patchNum = patchRange.patchNum;
       basePatchNum = patchRange.basePatchNum;
@@ -1321,11 +1292,11 @@
 
   _formatFilesForDropdown(
     files?: Files,
-    patchNum?: PatchSetNum,
+    patchRange?: PatchRange,
     changeComments?: ChangeComments
   ): DropdownItem[] {
     if (!files) return [];
-    if (!patchNum) return [];
+    if (!patchRange) return [];
     if (!changeComments) return [];
 
     const dropdownContent: DropdownItem[] = [];
@@ -1334,51 +1305,18 @@
         text: computeDisplayPath(path),
         mobileText: computeTruncatedPath(path),
         value: path,
-        bottomText: this._computeCommentString(
-          changeComments,
-          patchNum,
+        bottomText: changeComments.computeCommentsString(
+          patchRange,
           path,
-          files.changeFilesByPath[path]
+          files.changeFilesByPath[path],
+          /* includeUnmodified= */ true
         ),
+        file: {...files.changeFilesByPath[path], __path: path},
       });
     }
     return dropdownContent;
   }
 
-  _computeCommentString(
-    changeComments?: ChangeComments,
-    patchNum?: PatchSetNum,
-    path?: string,
-    changeFileInfo?: FileInfo
-  ) {
-    if (!changeComments) return '';
-    if (!path) return '';
-    if (!changeFileInfo) return '';
-
-    const unresolvedCount = changeComments.computeUnresolvedNum({
-      patchNum,
-      path,
-    });
-    const commentThreadCount = changeComments.computeCommentThreadCount({
-      patchNum,
-      path,
-    });
-    const commentThreadString = GrCountStringFormatter.computePluralString(
-      commentThreadCount,
-      'comment'
-    );
-    const unresolvedString = GrCountStringFormatter.computeString(
-      unresolvedCount,
-      'unresolved'
-    );
-
-    const unmodifiedString = changeFileInfo.status === 'U' ? 'no changes' : '';
-
-    return [unmodifiedString, commentThreadString, unresolvedString]
-      .filter(v => v && v.length > 0)
-      .join(', ');
-  }
-
   _computePrefsButtonHidden(
     prefs?: DiffPreferencesInfo,
     prefsDisabled?: boolean
@@ -1411,8 +1349,8 @@
 
     const {basePatchNum, patchNum} = e.detail;
     if (
-      patchNumEquals(basePatchNum, this._patchRange.basePatchNum) &&
-      patchNumEquals(patchNum, this._patchRange.patchNum)
+      basePatchNum === this._patchRange.basePatchNum &&
+      patchNum === this._patchRange.patchNum
     ) {
       return;
     }
@@ -1455,26 +1393,12 @@
     _: Event,
     detail: {side: Side | CommentSide; number: number}
   ) {
-    if (!this._change) return;
-    if (!this._path) return;
-    if (!this._changeNum) return;
-    if (!this._patchRange) return;
-
-    const number = detail.number;
     // for on-comment-anchor-tap side can be PARENT/REVISIONS
     // for on-line-selected side can be left/right
-    const leftSide =
-      detail.side === Side.LEFT || detail.side === CommentSide.PARENT;
-    const url = GerritNav.getUrlForDiffById(
-      this._changeNum,
-      this._change.project,
-      this._path,
-      this._patchRange.patchNum,
-      this._patchRange.basePatchNum,
-      number,
-      leftSide
+    this._updateUrlToDiffUrl(
+      detail.number,
+      detail.side === Side.LEFT || detail.side === CommentSide.PARENT
     );
-    history.replaceState(null, '', url);
   }
 
   _computeDownloadDropdownLinks(
@@ -1571,11 +1495,13 @@
     return url;
   }
 
-  _loadComments() {
+  _loadComments(patchSet?: PatchSetNum) {
     if (!this._changeNum) throw new Error('Missing this._changeNum');
-    return this.$.commentAPI.loadAll(this._changeNum).then(comments => {
-      this._changeComments = comments;
-    });
+    return this.$.commentAPI
+      .loadAll(this._changeNum, patchSet)
+      .then(comments => {
+        this._changeComments = comments;
+      });
   }
 
   @observe('_files.changeFilesByPath', '_path', '_patchRange', '_projectConfig')
@@ -1593,13 +1519,10 @@
 
     const file = files[path];
     if (file && file.old_path) {
-      this._commentsForDiff = this._changeComments.getCommentsBySideForFile(
+      this.$.diffHost.threads = this._changeComments.getThreadsBySideForFile(
         {path, basePath: file.old_path},
-        patchRange,
-        projectConfig
+        patchRange
       );
-
-      this.$.diffHost.comments = this._commentsForDiff;
     }
   }
 
@@ -1608,26 +1531,10 @@
     return this._changeComments.getPaths(patchRange);
   }
 
-  _getCommentsForPath(
-    path?: string,
-    patchRange?: PatchRange,
-    projectConfig?: ConfigInfo
-  ) {
-    if (!path) return undefined;
-    if (!patchRange) return undefined;
-    if (!this._changeComments) return undefined;
-
-    return this._changeComments.getCommentsBySideForPath(
-      path,
-      patchRange,
-      projectConfig
-    );
-  }
-
   _getDiffDrafts() {
     if (!this._changeNum) throw new Error('Missing this._changeNum');
 
-    return this.$.restAPI.getDiffDrafts(this._changeNum);
+    return this.restApiService.getDiffDrafts(this._changeNum);
   }
 
   _computeCommentSkips(
@@ -1672,7 +1579,7 @@
     patchRangeRecord: PolymerDeepPropertyChange<PatchRange, PatchRange>
   ) {
     const patchRange = patchRangeRecord.base || {};
-    return patchNumEquals(patchRange.patchNum, EditPatchSetNum);
+    return patchRange.patchNum === EditPatchSetNum;
   }
 
   _computeBlameToggleLabel(loaded?: boolean, loading?: boolean) {
@@ -1681,24 +1588,12 @@
 
   _loadBlame() {
     this._isBlameLoading = true;
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {message: MSG_LOADING_BLAME},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireAlert(this, MSG_LOADING_BLAME);
     this.$.diffHost
       .loadBlame()
       .then(() => {
         this._isBlameLoading = false;
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message: MSG_LOADED_BLAME},
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireAlert(this, MSG_LOADED_BLAME);
       })
       .catch(() => {
         this._isBlameLoading = false;
@@ -1743,16 +1638,8 @@
     if (!this._path) return;
     if (!this._patchRange) return;
 
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Base is already selected.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
+      fireAlert(this, 'Base is already selected.');
       return;
     }
     GerritNav.navigateToDiff(
@@ -1768,16 +1655,8 @@
     if (!this._path) return;
     if (!this._patchRange) return;
 
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Left is already base.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
+      fireAlert(this, 'Left is already base.');
       return;
     }
     GerritNav.navigateToDiff(
@@ -1798,16 +1677,8 @@
     if (!this._patchRange) return;
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Latest is already selected.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.patchNum === latestPatchNum) {
+      fireAlert(this, 'Latest is already selected.');
       return;
     }
 
@@ -1826,16 +1697,8 @@
     if (!this._patchRange) return;
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Right is already latest.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+    if (this._patchRange.patchNum === latestPatchNum) {
+      fireAlert(this, 'Right is already latest.');
       return;
     }
     GerritNav.navigateToDiff(
@@ -1854,18 +1717,10 @@
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (
-      patchNumEquals(this._patchRange.patchNum, latestPatchNum) &&
-      patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)
+      this._patchRange.patchNum === latestPatchNum &&
+      this._patchRange.basePatchNum === ParentPatchSetNum
     ) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'Already diffing base against latest.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'Already diffing base against latest.');
       return;
     }
     GerritNav.navigateToDiff(this._change, this._path, latestPatchNum);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
index be2dce5..9ffb7df 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
@@ -425,7 +425,6 @@
     on-reload-diff-preference="_handleReloadingDiffPreference"
   >
   </gr-diff-preferences-dialog>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
   <gr-diff-cursor
     id="cursor"
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
index 9a08723..72e1a8f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
@@ -23,11 +23,11 @@
 import {SPECIAL_PATCH_SET_NUM} from '../../../utils/patch-set-util.js';
 import {Shortcut} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.js';
 import {_testOnly_findCommentById} from '../gr-comment-api/gr-comment-api.js';
-import {appContext} from '../../../services/app-context.js';
-import {GerritView} from '../../core/gr-navigation/gr-navigation.js';
+import {GerritView} from '../../../services/router/router-model.js';
 import {
   createChange,
   createRevisions,
+  createComment,
 } from '../../../test/test-data-generators.js';
 
 const basicFixture = fixtureFromElement('gr-diff-view');
@@ -90,7 +90,6 @@
 
     setup(async () => {
       clock = sinon.useFakeTimers();
-      sinon.stub(appContext.flagsService, 'isEnabled').returns(true);
       stub('gr-rest-api-interface', {
         getConfig() {
           return Promise.resolve({change: {}});
@@ -119,6 +118,9 @@
         getDiffDrafts() {
           return Promise.resolve({});
         },
+        getPortedComments() {
+          return Promise.resolve({});
+        },
         getReviewedFiles() {
           return Promise.resolve([]);
         },
@@ -135,24 +137,26 @@
       sinon.stub(element.$.commentAPI, 'loadAll').returns(Promise.resolve({
         _comments: {'/COMMIT_MSG': [
           {
+            ...createComment(),
             id: 'c1',
             line: 10,
             patch_set: 2,
-            __commentSide: 'left',
             path: '/COMMIT_MSG',
           }, {
+            ...createComment(),
             id: 'c3',
             line: 10,
             patch_set: 'PARENT',
-            __commentSide: 'left',
             path: '/COMMIT_MSG',
           },
         ]},
         computeCommentThreadCount: () => {},
+        computeCommentsString: () => '',
         computeUnresolvedNum: () => {},
         getPaths: () => {},
-        getCommentsBySideForPath: () => {},
+        getThreadsBySideForFile: () => [],
         findCommentById: _testOnly_findCommentById,
+
       }));
       await element._loadComments();
       await flush();
@@ -176,43 +180,51 @@
         basePatchNum: 1,
         path: '/COMMIT_MSG',
       };
+      element._path = '/COMMIT_MSG';
+      element._patchRange = {};
       return element._paramsChanged.returnValues[0].then(() => {
         assert.isTrue(element.reporting.diffViewDisplayed.calledOnce);
       });
     });
 
-    test('comment route', () => {
-      const initLineOfInterestAndCursorStub =
+    suite('comment route', () => {
+      let initLineOfInterestAndCursorStub; let getUrlStub; let replaceStateStub;
+      setup(() => {
+        initLineOfInterestAndCursorStub =
         sinon.stub(element, '_initLineOfInterestAndCursor');
-      sinon.stub(element, '_getFiles');
-      sinon.stub(element.reporting, 'diffViewDisplayed');
-      sinon.stub(element.$.diffHost, 'reload').returns(Promise.resolve());
-      sinon.spy(element, '_paramsChanged');
-      sinon.stub(element, '_getChangeDetail').returns(Promise.resolve({
-        ...createChange(),
-        revisions: createRevisions(11),
-      }));
-      element.params = {
-        view: GerritNav.View.DIFF,
-        changeNum: '42',
-        commentLink: true,
-        commentId: 'c1',
-      };
-      sinon.stub(element.$.diffHost, '_commentsChanged');
-      sinon.stub(element, '_getCommentsForPath').returns({
-        left: [{id: 'c1', __commentSide: 'left', line: 10}],
-        right: [{id: 'c2', __commentSide: 'right', line: 11}],
+        getUrlStub = sinon.stub(GerritNav, 'getUrlForDiffById');
+        replaceStateStub = sinon.stub(history, 'replaceState');
+        sinon.stub(element, '_getFiles');
+        sinon.stub(element.reporting, 'diffViewDisplayed');
+        sinon.stub(element.$.diffHost, 'reload').returns(Promise.resolve());
+        sinon.spy(element, '_paramsChanged');
+        sinon.stub(element, '_getChangeDetail').returns(Promise.resolve({
+          ...createChange(),
+          revisions: createRevisions(11),
+        }));
       });
-      element._change = {
-        ...createChange(),
-        revisions: createRevisions(11),
-      };
-      return element._paramsChanged.returnValues[0].then(() => {
-        assert.isTrue(initLineOfInterestAndCursorStub.
-            calledWithExactly(true));
-        assert.equal(element._focusLineNum, 10);
-        assert.equal(element._patchRange.patchNum, 11);
-        assert.equal(element._patchRange.basePatchNum, 2);
+
+      test('comment url resolves to comment.patch_set vs latest', () => {
+        element.params = {
+          view: GerritNav.View.DIFF,
+          changeNum: '42',
+          commentLink: true,
+          commentId: 'c1',
+        };
+        element._change = {
+          ...createChange(),
+          revisions: createRevisions(11),
+        };
+        return element._paramsChanged.returnValues[0].then(() => {
+          assert.isTrue(initLineOfInterestAndCursorStub.
+              calledWithExactly(true));
+          assert.equal(element._focusLineNum, 10);
+          assert.equal(element._patchRange.patchNum, 11);
+          assert.equal(element._patchRange.basePatchNum, 2);
+          assert.isTrue(replaceStateStub.called);
+          assert.isTrue(getUrlStub.calledWithExactly('42', 'test-project',
+              '/COMMIT_MSG', 11, 2, 10, true));
+        });
       });
     });
 
@@ -232,6 +244,8 @@
         basePatchNum: 1,
         path: '/COMMIT_MSG',
       };
+      element._path = '/COMMIT_MSG';
+      element._patchRange = {};
       return element._paramsChanged.returnValues[0].then(() => {
         assert.isTrue(element._isBlameLoaded);
         assert.isTrue(element._loadBlame.calledOnce);
@@ -257,7 +271,6 @@
             commentLink: true,
             commentId: 'c1',
           };
-          sinon.stub(element.$.diffHost, '_commentsChanged');
           element._change = {
             ...createChange(),
             revisions: createRevisions(11),
@@ -287,7 +300,6 @@
             commentLink: true,
             commentId: 'c3',
           };
-          sinon.stub(element.$.diffHost, '_commentsChanged');
           element._change = {
             ...createChange(),
             revisions: createRevisions(11),
@@ -333,8 +345,8 @@
       sinon.stub(element, '_loadBlame');
       sinon.stub(element.$.diffHost, 'reload').returns(Promise.resolve());
       sinon.spy(element, '_paramsChanged');
-      element.$.restAPI.getDiffChangeDetail.restore();
-      sinon.stub(element.$.restAPI, 'getDiffChangeDetail')
+      element.restApiService.getDiffChangeDetail.restore();
+      sinon.stub(element.restApiService, 'getDiffChangeDetail')
           .returns(
               Promise.resolve({
                 ...createChange(),
@@ -900,44 +912,6 @@
       assert.isTrue(overlayOpenStub.called);
     });
 
-    test('_computeCommentString', done => {
-      const path = '/test';
-      element.$.commentAPI.loadAll().then(comments => {
-        const commentThreadCountStub =
-            sinon.stub(comments, 'computeCommentThreadCount');
-        const unresolvedCountStub =
-            sinon.stub(comments, 'computeUnresolvedNum');
-        commentThreadCountStub.withArgs({patchNum: 1, path}).returns(0);
-        commentThreadCountStub.withArgs({patchNum: 2, path}).returns(1);
-        commentThreadCountStub.withArgs({patchNum: 3, path}).returns(2);
-        commentThreadCountStub.withArgs({patchNum: 4, path}).returns(0);
-        unresolvedCountStub.withArgs({patchNum: 1, path}).returns(1);
-        unresolvedCountStub.withArgs({patchNum: 2, path}).returns(0);
-        unresolvedCountStub.withArgs({patchNum: 3, path}).returns(2);
-        unresolvedCountStub.withArgs({patchNum: 4, path}).returns(0);
-
-        assert.equal(element._computeCommentString(comments, 1, path, {}),
-            '1 unresolved');
-        assert.equal(
-            element._computeCommentString(comments, 2, path, {status: 'M'}),
-            '1 comment');
-        assert.equal(
-            element._computeCommentString(comments, 2, path, {status: 'U'}),
-            'no changes, 1 comment');
-        assert.equal(
-            element._computeCommentString(comments, 3, path, {status: 'A'}),
-            '2 comments, 2 unresolved');
-        assert.equal(
-            element._computeCommentString(
-                comments, 4, path, {status: 'M'}
-            ), '');
-        assert.equal(
-            element._computeCommentString(comments, 4, path, {status: 'U'}),
-            'no changes');
-        done();
-      });
-    });
-
     suite('url params', () => {
       setup(() => {
         sinon.stub(element, '_getFiles');
@@ -957,9 +931,6 @@
           basePatchNum: PARENT,
           patchNum: 10,
         };
-        // computeCommentThreadCount is an empty function hence stubbing
-        // function that depends on it's return value
-        sinon.stub(element, '_computeCommentString').returns('');
         element._change = {_number: 42};
         element._files = getFilesFromFileList(
             ['chell.go', 'glados.txt', 'wheatley.md',
@@ -971,28 +942,43 @@
             mobileText: 'chell.go',
             value: 'chell.go',
             bottomText: '',
+            file: {
+              __path: 'chell.go',
+            },
           }, {
             text: 'glados.txt',
             mobileText: 'glados.txt',
             value: 'glados.txt',
             bottomText: '',
+            file: {
+              __path: 'glados.txt',
+            },
           }, {
             text: 'wheatley.md',
             mobileText: 'wheatley.md',
             value: 'wheatley.md',
             bottomText: '',
+            file: {
+              __path: 'wheatley.md',
+            },
           },
           {
             text: 'Commit message',
             mobileText: 'Commit message',
             value: '/COMMIT_MSG',
             bottomText: '',
+            file: {
+              __path: '/COMMIT_MSG',
+            },
           },
           {
             text: 'Merge list',
             mobileText: 'Merge list',
             value: '/MERGE_LIST',
             bottomText: '',
+            file: {
+              __path: '/MERGE_LIST',
+            },
           },
         ];
 
@@ -1232,7 +1218,7 @@
       const prefsPromise = new Promise(resolve => {
         resolvePrefs = resolve;
       });
-      sinon.stub(element.$.restAPI, 'getPreferences')
+      sinon.stub(element.restApiService, 'getPreferences')
           .callsFake(() => prefsPromise);
 
       // Attach a new gr-diff-view so we can intercept the preferences fetch.
@@ -1449,7 +1435,6 @@
         await flush();
       });
       test('empty', () => {
-        sinon.stub(element, '_getCommentsForPath');
         sinon.stub(element, '_getPaths').returns(new Map());
         element._initPatchRange();
         assert.equal(Object.keys(element._commentMap).length, 0);
@@ -1461,7 +1446,6 @@
           'path/to/file/one.cpp': [{patch_set: 3, message: 'lorem'}],
           'path-to/file/two.py': [{patch_set: 5, message: 'ipsum'}],
         });
-        sinon.stub(element, '_getCommentsForPath').returns({meta: {}});
         element._changeNum = '42';
         element._patchRange = {
           basePatchNum: 3,
@@ -1623,9 +1607,9 @@
 
     test('_getReviewedStatus', () => {
       const promises = [];
-      element.$.restAPI.getReviewedFiles.restore();
+      element.restApiService.getReviewedFiles.restore();
 
-      sinon.stub(element.$.restAPI, 'getReviewedFiles')
+      sinon.stub(element.restApiService, 'getReviewedFiles')
           .returns(Promise.resolve(['path']));
 
       promises.push(element._getReviewedStatus(true, null, null, 'path')
@@ -1690,7 +1674,7 @@
 
     test('_paramsChanged sets in projectLookup', () => {
       sinon.stub(element, '_initLineOfInterestAndCursor');
-      const setStub = sinon.stub(element.$.restAPI, 'setInProjectLookup');
+      const setStub = sinon.stub(element.restApiService, 'setInProjectLookup');
       element._paramsChanged({
         view: GerritNav.View.DIFF,
         changeNum: 101,
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group.ts
index 588b9d1..11d3ce3 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group.ts
@@ -83,8 +83,9 @@
 
   const numHidden = hiddenEnd - hiddenStart;
 
-  // Only collapse if there is more than 1 line to be hidden.
-  if (numHidden > 1) {
+  // Showing a context control row for less than 4 lines does not make much,
+  // because then that row would consume as much space as the collapsed code.
+  if (numHidden > 3) {
     if (hiddenStart) {
       [before, hidden] = _splitCommonGroups(hidden, hiddenStart);
     }
@@ -237,8 +238,6 @@
 
   dueToRebase = false;
 
-  dueToMove = false;
-
   /**
    * True means all changes in this line are whitespace changes that should
    * not be highlighted as changed as per the user settings.
@@ -269,6 +268,14 @@
     right: {start: null, end: null},
   };
 
+  moveDetails?: {
+    changed: boolean;
+    range?: {
+      start: number;
+      end: number;
+    };
+  };
+
   /**
    * Creates a new group with the same properties but different lines.
    *
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group_test.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group_test.js
index 3423834..8182941 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-group_test.js
@@ -122,17 +122,19 @@
           new GrDiffLine(GrDiffLineType.ADD, 0, 11),
           new GrDiffLine(GrDiffLineType.REMOVE, 10),
           new GrDiffLine(GrDiffLineType.ADD, 0, 12),
+          new GrDiffLine(GrDiffLineType.REMOVE, 11),
+          new GrDiffLine(GrDiffLineType.ADD, 0, 13),
         ]),
         new GrDiffGroup(GrDiffGroupType.BOTH, [
-          new GrDiffLine(GrDiffLineType.BOTH, 11, 13),
           new GrDiffLine(GrDiffLineType.BOTH, 12, 14),
           new GrDiffLine(GrDiffLineType.BOTH, 13, 15),
+          new GrDiffLine(GrDiffLineType.BOTH, 14, 16),
         ]),
       ];
     });
 
     test('hides hidden groups in context control', () => {
-      const collapsedGroups = hideInContextControl(groups, 3, 6);
+      const collapsedGroups = hideInContextControl(groups, 3, 7);
       assert.equal(collapsedGroups.length, 3);
 
       assert.equal(collapsedGroups[0], groups[0]);
@@ -145,7 +147,7 @@
     });
 
     test('splits partially hidden groups', () => {
-      const collapsedGroups = hideInContextControl(groups, 4, 7);
+      const collapsedGroups = hideInContextControl(groups, 4, 8);
       assert.equal(collapsedGroups.length, 4);
       assert.equal(collapsedGroups[0], groups[0]);
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
index 8984dc8..038153a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
@@ -17,6 +17,7 @@
 
 import {CommentRange} from '../../../types/common';
 import {FILE, LineNumber} from './gr-diff-line';
+import {Side} from '../../../constants/constants';
 
 /**
  * Compare two ranges. Either argument may be falsy, but will only return
@@ -46,3 +47,50 @@
   const lineNumber = Number(lineNumberStr);
   return Number.isInteger(lineNumber) ? lineNumber : null;
 }
+
+export function getLine(threadEl: HTMLElement): LineNumber {
+  const lineAtt = threadEl.getAttribute('line-num');
+  if (!lineAtt || lineAtt === 'FILE') return FILE;
+  const line = Number(lineAtt);
+  if (isNaN(line)) throw new Error(`cannot parse line number: ${lineAtt}`);
+  if (line < 1) throw new Error(`line number smaller than 1: ${line}`);
+  return line;
+}
+
+export function getSide(threadEl: HTMLElement): Side | undefined {
+  // TODO(dhruvsri): Remove check for comment-side once all users of gr-diff
+  // start setting diff-side
+  const sideAtt =
+    threadEl.getAttribute('diff-side') || threadEl.getAttribute('comment-side');
+  if (!sideAtt) {
+    console.warn('comment thread without side');
+    return undefined;
+  }
+  if (sideAtt !== Side.LEFT && sideAtt !== Side.RIGHT)
+    throw Error(`unexpected value for side: ${sideAtt}`);
+  return sideAtt as Side;
+}
+
+export function getRange(threadEl: HTMLElement): CommentRange | undefined {
+  const rangeAtt = threadEl.getAttribute('range');
+  if (!rangeAtt) return undefined;
+  const range = JSON.parse(rangeAtt) as CommentRange;
+  if (!range.start_line) throw new Error(`invalid range: ${rangeAtt}`);
+  return range;
+}
+
+// TODO: This type should be exposed to gr-diff clients in a separate type file.
+// For Gerrit these are instances of GrCommentThread, but other gr-diff users
+// have different HTML elements in use for comment threads.
+// TODO: Also document the required HTML attritbutes that thread elements must
+// have, e.g. 'diff-side', 'range', 'line-num', 'data-value'.
+export interface GrDiffThreadElement extends HTMLElement {
+  rootId: string;
+}
+
+export function isThreadEl(node: Node): node is GrDiffThreadElement {
+  return (
+    node.nodeType === Node.ELEMENT_NODE &&
+    (node as Element).classList.contains('comment-thread')
+  );
+}
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
index 0091a0b..5942687 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
@@ -16,6 +16,7 @@
  */
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
+import '../../shared/gr-icons/gr-icons';
 import '../gr-diff-builder/gr-diff-builder-element';
 import '../gr-diff-highlight/gr-diff-highlight';
 import '../gr-diff-selection/gr-diff-selection';
@@ -26,22 +27,32 @@
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {htmlTemplate} from './gr-diff_html';
-import {FILE, LineNumber} from './gr-diff-line';
-import {getLineNumber, rangesEqual} from './gr-diff-utils';
+import {LineNumber} from './gr-diff-line';
+import {
+  getLine,
+  getLineNumber,
+  getRange,
+  getSide,
+  GrDiffThreadElement,
+  isThreadEl,
+  rangesEqual,
+} from './gr-diff-utils';
 import {getHiddenScroll} from '../../../scripts/hiddenscroll';
-import {isMergeParent, patchNumEquals} from '../../../utils/patch-set-util';
+import {isMergeParent} from '../../../utils/patch-set-util';
 import {customElement, observe, property} from '@polymer/decorators';
 import {
   BlameInfo,
   CommentRange,
-  DiffInfo,
-  DiffPreferencesInfo,
-  DiffPreferencesInfoKey,
   EditPatchSetNum,
   ImageInfo,
   ParentPatchSetNum,
   PatchRange,
 } from '../../../types/common';
+import {
+  DiffInfo,
+  DiffPreferencesInfo,
+  DiffPreferencesInfoKey,
+} from '../../../types/diff';
 import {GrDiffHighlight} from '../gr-diff-highlight/gr-diff-highlight';
 import {GrDiffBuilderElement} from '../gr-diff-builder/gr-diff-builder-element';
 import {
@@ -50,10 +61,13 @@
   PolymerDomWrapper,
 } from '../../../types/types';
 import {CommentRangeLayer} from '../gr-ranged-comment-layer/gr-ranged-comment-layer';
-import {DiffViewMode, Side} from '../../../constants/constants';
+import {CommentSide, DiffViewMode, Side} from '../../../constants/constants';
 import {KeyLocations} from '../gr-diff-processor/gr-diff-processor';
 import {FlattenedNodesObserver} from '@polymer/polymer/lib/utils/flattened-nodes-observer';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
+import {AbortStop} from '../../shared/gr-cursor-manager/gr-cursor-manager';
+import {fireAlert, fireEvent} from '../../../utils/event-util';
+import {MovedChunkGoToLineEvent} from '../../../types/events';
 // TODO(davido): See: https://github.com/GoogleChromeLabs/shadow-selection-polyfill/issues/9
 // @ts-ignore
 import * as shadow from 'shadow-selection-polyfill/shadow.js';
@@ -65,27 +79,6 @@
 const FULL_CONTEXT = -1;
 const LIMITED_CONTEXT = 10;
 
-function getSide(threadEl: GrCommentThread): Side {
-  const sideAtt = threadEl.getAttribute('comment-side');
-  if (!sideAtt) throw Error('comment thread without side');
-  if (sideAtt !== 'left' && sideAtt !== 'right')
-    throw Error(`unexpected value for side: ${sideAtt}`);
-  return sideAtt as Side;
-}
-
-function isThreadEl(node: Node): node is GrCommentThread {
-  return (
-    node.nodeType === Node.ELEMENT_NODE &&
-    (node as Element).classList.contains('comment-thread')
-  );
-}
-
-// TODO(TS): Replace by proper GrCommentThread once converted.
-type GrCommentThread = PolymerElement & {
-  rootId: string;
-  range: CommentRange;
-};
-
 const COMMIT_MSG_PATH = '/COMMIT_MSG';
 /**
  * 72 is the unofficial length standard for git commit messages.
@@ -194,9 +187,18 @@
   @property({type: Object})
   lineOfInterest?: LineOfInterest;
 
-  /** True when diff is changed, until the content is done rendering. */
-  @property({type: Boolean})
-  _loading = false;
+  /**
+   * True when diff is changed, until the content is done rendering.
+   *
+   * This is readOnly, meaning one can listen for the loading-changed event, but
+   * not write to it from the outside. Code in this class should use the
+   * "private" _setLoading method.
+   */
+  @property({type: Boolean, notify: true, readOnly: true})
+  loading!: boolean;
+
+  // Polymer generated when setting readOnly above.
+  _setLoading!: (loading: boolean) => void;
 
   @property({type: Boolean})
   loggedIn = false;
@@ -278,10 +280,12 @@
   /** @override */
   created() {
     super.created();
+    this._setLoading(true);
     this.addEventListener('create-range-comment', (e: Event) =>
       this._handleCreateRangeComment(e as CustomEvent)
     );
     this.addEventListener('render-content', () => this._handleRenderContent());
+    this.addEventListener('moved-link-clicked', e => this._movedLinkClicked(e));
   }
 
   /** @override */
@@ -376,17 +380,16 @@
   // TODO(brohlfs): Rewrite gr-diff to be agnostic of GrCommentThread, because
   // other users of gr-diff may use different comment widgets.
   _updateRanges(
-    addedThreadEls: GrCommentThread[],
-    removedThreadEls: GrCommentThread[]
+    addedThreadEls: GrDiffThreadElement[],
+    removedThreadEls: GrDiffThreadElement[]
   ) {
     function commentRangeFromThreadEl(
-      threadEl: GrCommentThread
+      threadEl: GrDiffThreadElement
     ): CommentRangeLayer | undefined {
       const side = getSide(threadEl);
-
-      const rangeAtt = threadEl.getAttribute('range');
-      if (!rangeAtt) return undefined;
-      const range = JSON.parse(rangeAtt) as CommentRange;
+      if (!side) return undefined;
+      const range = getRange(threadEl);
+      if (!range) return undefined;
 
       return {side, range, hovering: false, rootId: threadEl.rootId};
     }
@@ -416,7 +419,6 @@
    * The key locations based on the comments and line of interests,
    * where lines should not be collapsed.
    *
-   * @return
    */
   _computeKeyLocations() {
     const keyLocations: KeyLocations = {left: {}, right: {}};
@@ -430,12 +432,13 @@
 
     for (const threadEl of threadEls) {
       const side = getSide(threadEl);
-      const lineNum = Number(threadEl.getAttribute('line-num')) || FILE;
-      const commentRange = threadEl.range || {};
+      if (!side) continue;
+      const lineNum = getLine(threadEl);
+      const commentRange = getRange(threadEl);
       keyLocations[side][lineNum] = true;
       // Add start_line as well if exists,
       // the being and end of the range should not be collapsed.
-      if (commentRange.start_line) {
+      if (commentRange?.start_line) {
         keyLocations[side][commentRange.start_line] = true;
       }
     }
@@ -443,23 +446,13 @@
   }
 
   // Dispatch events that are handled by the gr-diff-highlight.
-  _redispatchHoverEvents(addedThreadEls: GrCommentThread[]) {
+  _redispatchHoverEvents(addedThreadEls: HTMLElement[]) {
     for (const threadEl of addedThreadEls) {
       threadEl.addEventListener('mouseenter', () => {
-        threadEl.dispatchEvent(
-          new CustomEvent('comment-thread-mouseenter', {
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireEvent(threadEl, 'comment-thread-mouseenter');
       });
       threadEl.addEventListener('mouseleave', () => {
-        threadEl.dispatchEvent(
-          new CustomEvent('comment-thread-mouseleave', {
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireEvent(threadEl, 'comment-thread-mouseleave');
       });
     }
   }
@@ -470,14 +463,17 @@
     this.cancelDebouncer(RENDER_DIFF_TABLE_DEBOUNCE_NAME);
   }
 
-  getCursorStops(): HTMLElement[] {
+  getCursorStops(): Array<HTMLElement | AbortStop> {
     if (this.hidden && this.noAutoRender) return [];
-    if (!this.root) return [];
+
+    if (this.loading) {
+      return [new AbortStop()];
+    }
 
     return Array.from(
-      this.root.querySelectorAll<HTMLElement>(
+      this.root?.querySelectorAll<HTMLElement>(
         ':not(.contextControl) > .diff-row'
-      )
+      ) || []
     ).filter(tr => tr.querySelector('button'));
   }
 
@@ -545,11 +541,17 @@
   }
 
   _selectLine(el: Element) {
+    const lineNumber = Number(el.getAttribute('data-value'));
+    const side = el.classList.contains('left') ? Side.LEFT : Side.RIGHT;
+    this._dispatchSelectedLine(lineNumber, side);
+  }
+
+  _dispatchSelectedLine(number: LineNumber, side: Side) {
     this.dispatchEvent(
       new CustomEvent('line-selected', {
         detail: {
-          side: el.classList.contains('left') ? Side.LEFT : Side.RIGHT,
-          number: el.getAttribute('data-value'),
+          number,
+          side,
           path: this.path,
         },
         composed: true,
@@ -558,6 +560,10 @@
     );
   }
 
+  _movedLinkClicked(e: MovedChunkGoToLineEvent) {
+    this._dispatchSelectedLine(e.detail.line, e.detail.side);
+  }
+
   addDraftAtLine(el: Element) {
     this._selectLine(el);
     if (!this._isValidElForComment(el)) {
@@ -566,22 +572,11 @@
 
     const lineNum = getLineNumber(el);
     if (lineNum === null) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: 'Invalid line number'},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'Invalid line number');
       return;
     }
 
-    // TODO(TS): existing logic always pass undefined lineNum
-    // for file level comment, the drafts API will reject the
-    // request if file level draft contains the `line: 'FILE'` field
-    // probably should do this inside of the _createComment, this
-    // is just to keep existing behavior.
-    this._createComment(el, lineNum === FILE ? undefined : lineNum);
+    this._createComment(el, lineNum);
   }
 
   createRangeComment() {
@@ -610,53 +605,28 @@
 
   _isValidElForComment(el: Element) {
     if (!this.loggedIn) {
-      this.dispatchEvent(
-        new CustomEvent('show-auth-required', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this, 'show-auth-required');
       return false;
     }
     if (!this.patchRange) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: 'Cannot create comment. Patch range undefined.'},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'Cannot create comment. Patch range undefined.');
       return false;
     }
     const patchNum = el.classList.contains(Side.LEFT)
       ? this.patchRange.basePatchNum
       : this.patchRange.patchNum;
 
-    const isEdit = patchNumEquals(patchNum, EditPatchSetNum);
+    const isEdit = patchNum === EditPatchSetNum;
     const isEditBase =
-      patchNumEquals(patchNum, ParentPatchSetNum) &&
-      patchNumEquals(this.patchRange.patchNum, EditPatchSetNum);
+      patchNum === ParentPatchSetNum &&
+      this.patchRange.patchNum === EditPatchSetNum;
 
     if (isEdit) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {message: 'You cannot comment on an edit.'},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'You cannot comment on an edit.');
       return false;
     }
     if (isEditBase) {
-      this.dispatchEvent(
-        new CustomEvent('show-alert', {
-          detail: {
-            message: 'You cannot comment on the base patchset of an edit.',
-          },
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireAlert(this, 'You cannot comment on the base patchset of an edit.');
       return false;
     }
     return true;
@@ -679,6 +649,7 @@
       lineEl,
       contentEl
     );
+    const commentSide = isOnParent ? CommentSide.PARENT : CommentSide.REVISION;
     this.dispatchEvent(
       new CustomEvent('create-comment', {
         bubbles: true,
@@ -686,9 +657,11 @@
         detail: {
           lineNum,
           side,
+          commentSide,
           patchNum: patchForNewThreads,
-          isOnParent,
           range,
+          path: this.path,
+          isOnParent,
         },
       })
     );
@@ -840,7 +813,7 @@
   }
 
   _diffChanged(newValue?: DiffInfo) {
-    this._loading = true;
+    this._setLoading(true);
     this._cleanup();
     if (newValue) {
       this._diffLength = this.getDiffLength(newValue);
@@ -866,9 +839,7 @@
 
   _renderDiffTable() {
     if (!this.prefs) {
-      this.dispatchEvent(
-        new CustomEvent('render', {bubbles: true, composed: true})
-      );
+      fireEvent(this, 'render');
       return;
     }
     if (
@@ -878,9 +849,7 @@
       this._safetyBypass === null
     ) {
       this._showWarning = true;
-      this.dispatchEvent(
-        new CustomEvent('render', {bubbles: true, composed: true})
-      );
+      fireEvent(this, 'render');
       return;
     }
 
@@ -900,7 +869,7 @@
   }
 
   _handleRenderContent() {
-    this._loading = false;
+    this._setLoading(false);
     this._unobserveIncrementalNodes();
     this._incrementalNodeObserver = (dom(
       this
@@ -913,10 +882,11 @@
       // for each line from the start.
       let lastEl;
       for (const threadEl of addedThreadEls) {
-        const lineNumString = threadEl.getAttribute('line-num') || 'FILE';
+        const lineNum = getLine(threadEl);
         const commentSide = getSide(threadEl);
+        if (!commentSide) continue;
         const lineEl = this.$.diffBuilder.getLineElByNumber(
-          lineNumString,
+          lineNum,
           commentSide
         );
         // When the line the comment refers to does not exist, log an error
@@ -926,7 +896,7 @@
           console.error(
             'thread attached to line ',
             commentSide,
-            lineNumString,
+            lineNum,
             ' which does not exist.'
           );
           continue;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
index 48a4596..557d1eb 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
@@ -27,7 +27,10 @@
     :host {
       font-family: var(--monospace-font-family, ''), 'Roboto Mono';
       font-size: var(--font-size, var(--font-size-code, 12px));
-      line-height: var(--line-height-code, 1.334);
+      /* usually 16px = 12px + 4px */
+      line-height: calc(
+        var(--font-size, var(--font-size-code, 12px)) + var(--spacing-s, 4px)
+      );
     }
 
     .thread-group {
@@ -142,7 +145,7 @@
       width: 100%;
     }
     .full-width .contentText {
-      white-space: pre-wrap;
+      white-space: break-spaces;
       word-wrap: break-word;
     }
     .lineNumButton,
@@ -208,17 +211,49 @@
 
     /* dueToMove */
     .dueToMove .content.add .contentText,
-    .dueToMove .moveControls.movedIn .moveDescription,
+    .dueToMove .moveControls.movedIn .moveLabel,
     .delta.total.dueToMove .content.add .contentText {
-      background-color: var(--light-moved-add-highlight-color);
+      background-color: var(--diff-moved-in-background);
     }
+
     .dueToMove .content.remove .contentText,
-    .dueToMove .moveControls.movedOut .moveDescription,
+    .dueToMove .moveControls.movedOut .moveLabel,
     .delta.total.dueToMove .content.remove .contentText {
-      background-color: var(--light-remove-add-highlight-color);
+      background-color: var(--diff-moved-out-background);
     }
-    .moveControls {
-      text-align: right;
+
+    .delta.dueToMove .movedIn .moveDescription {
+      color: var(--diff-moved-in-background);
+      background-color: var(--diff-moved-in-label-background);
+    }
+    .delta.dueToMove .movedOut .moveDescription {
+      color: var(--diff-moved-out-background);
+      background-color: var(--diff-moved-out-label-background);
+    }
+    .moveLabel {
+      display: flex;
+      justify-content: flex-end;
+      font-family: var(--header-font-family);
+    }
+    .delta.dueToMove .moveDescription {
+      border-radius: var(--spacing-l);
+      padding: var(--spacing-s) var(--spacing-m);
+      margin: var(--spacing-s);
+      font-weight: 500;
+      line-height: var(--spacing-xl);
+      vertical-align: middle;
+      display: flex;
+    }
+
+    .moveDescription iron-icon {
+      color: inherit;
+      margin-right: var(--spacing-s);
+      height: var(--spacing-xl);
+      width: var(--spacing-xl);
+    }
+
+    .moveDescription a {
+      color: inherit;
     }
 
     /* ignoredWhitespaceOnly */
@@ -280,8 +315,8 @@
       background-color: var(--view-background-color);
     }
     .contextBackground {
-      /* 
-       * One line of background behind the context expanders which they can 
+      /*
+       * One line of background behind the context expanders which they can
        * render on top of, plus some padding.
        */
       height: calc(var(--line-height-normal) + var(--spacing-s));
@@ -517,9 +552,9 @@
 
     /** Make comments selectable when selected */
     .selected-left.selected-comment
-      ::slotted(gr-comment-thread[comment-side='left']),
+      ::slotted(gr-comment-thread[diff-side='left']),
     .selected-right.selected-comment
-      ::slotted(gr-comment-thread[comment-side='right']) {
+      ::slotted(gr-comment-thread[diff-side='right']) {
       -webkit-user-select: text;
       -moz-user-select: text;
       -ms-user-select: text;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
index 36b3b8f..c5a8db4 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
@@ -585,7 +585,7 @@
     });
 
     suite('getCursorStops', () => {
-      const setupDiff = function() {
+      function setupDiff() {
         element.diff = getMockDiffResponse();
         element.prefs = {
           context: 10,
@@ -605,8 +605,9 @@
         };
 
         element._renderDiffTable();
+        element._setLoading(false);
         flush();
-      };
+      }
 
       test('getCursorStops returns [] when hidden and noAutoRender', () => {
         element.noAutoRender = true;
@@ -949,7 +950,7 @@
     test('line comments are key locations', () => {
       const threadEl = document.createElement('div');
       threadEl.className = 'comment-thread';
-      threadEl.setAttribute('comment-side', 'right');
+      threadEl.setAttribute('diff-side', 'right');
       threadEl.setAttribute('line-num', 3);
       element.appendChild(threadEl);
       flush();
@@ -965,7 +966,7 @@
     test('file comments are key locations', () => {
       const threadEl = document.createElement('div');
       threadEl.className = 'comment-thread';
-      threadEl.setAttribute('comment-side', 'left');
+      threadEl.setAttribute('diff-side', 'left');
       element.appendChild(threadEl);
       flush();
 
diff --git a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
index 2a9fe54..671bd41 100644
--- a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
+++ b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
@@ -22,7 +22,7 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-patch-range-select_html';
-import {GrCountStringFormatter} from '../../shared/gr-count-string-formatter/gr-count-string-formatter';
+import {pluralize} from '../../../utils/string-util';
 import {appContext} from '../../../services/app-context';
 import {
   computeLatestPatchNum,
@@ -30,7 +30,6 @@
   getParentIndex,
   getRevisionByPatchNum,
   isMergeParent,
-  patchNumEquals,
   sortRevisions,
   PatchSet,
 } from '../../../utils/patch-set-util';
@@ -346,7 +345,7 @@
     patchNum: PatchSetNum,
     sortedRevisions: RevisionInfo[]
   ): boolean {
-    if (patchNumEquals(basePatchNum, ParentPatchSetNum)) {
+    if (basePatchNum === ParentPatchSetNum) {
       return false;
     }
 
@@ -367,6 +366,7 @@
     );
   }
 
+  // TODO(dhruvsri): have ported comments contribute to this count
   _computePatchSetCommentsString(
     changeComments: ChangeComments,
     patchNum: PatchSetNum
@@ -378,16 +378,11 @@
     const commentThreadCount = changeComments.computeCommentThreadCount({
       patchNum,
     });
-    const commentThreadString = GrCountStringFormatter.computePluralString(
-      commentThreadCount,
-      'comment'
-    );
+    const commentThreadString = pluralize(commentThreadCount, 'comment');
 
     const unresolvedCount = changeComments.computeUnresolvedNum({patchNum});
-    const unresolvedString = GrCountStringFormatter.computeString(
-      unresolvedCount,
-      'unresolved'
-    );
+    const unresolvedString =
+      unresolvedCount === 0 ? '' : `${unresolvedCount} unresolved`;
 
     if (!commentThreadString.length && !unresolvedString.length) {
       return '';
@@ -445,7 +440,7 @@
       });
       detail.patchNum = patchSetValue;
     } else {
-      if (patchNumEquals(detail.basePatchNum, patchSetValue)) return;
+      if (detail.basePatchNum === patchSetValue) return;
       this.reporting.reportInteraction('left-patchset-changed', {
         previous: detail.basePatchNum,
         current: e.detail.value,
diff --git a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.ts b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.ts
index d702fb1..ee52ab6 100644
--- a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.ts
+++ b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.ts
@@ -22,6 +22,7 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-selection-action-box_html';
+import {fireEvent} from '../../../utils/event-util';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -50,7 +51,7 @@
    */
 
   @property({type: Object})
-  keyEventTarget: Record<string, any> = document.body;
+  keyEventTarget = document.body;
 
   @property({type: Boolean})
   positionBelow = false;
@@ -122,11 +123,6 @@
     } // 0 = main button
     e.preventDefault();
     e.stopPropagation();
-    this.dispatchEvent(
-      new CustomEvent('create-comment-requested', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'create-comment-requested');
   }
 }
diff --git a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
index 334c8f4..197a0c4 100644
--- a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
+++ b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
@@ -23,8 +23,8 @@
 import {FILE, GrDiffLine, GrDiffLineType} from '../gr-diff/gr-diff-line';
 import {CancelablePromise, util} from '../../../scripts/util';
 import {customElement, property} from '@polymer/decorators';
+import {DiffFileMetaInfo, DiffInfo} from '../../../types/diff';
 import {DiffLayer, DiffLayerListener, HighlightJS} from '../../../types/types';
-import {DiffFileMetaInfo, DiffInfo} from '../../../types/common';
 import {GrLibLoader} from '../../shared/gr-lib-loader/gr-lib-loader';
 import {Side} from '../../../constants/constants';
 
@@ -304,7 +304,7 @@
     this._processPromise = util.makeCancelable(
       this._loadHLJS().then(
         () =>
-          new Promise(resolve => {
+          new Promise<void>(resolve => {
             const nextStep = () => {
               this._processHandle = null;
               this._processNextLine(state, rangesCache);
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
index 5967b03..7df3d75 100644
--- a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
@@ -17,7 +17,6 @@
 import '../../../styles/gr-table-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-list-view/gr-list-view';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -28,14 +27,10 @@
 } from '../../../mixins/gr-list-view-mixin/gr-list-view-mixin';
 import {getBaseUrl} from '../../../utils/url-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {DocResult} from '../../../types/common';
+import {fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
-export interface GrDocumentationSearch {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-documentation-search')
 export class GrDocumentationSearch extends ListViewMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -59,12 +54,12 @@
   @property({type: String})
   _filter = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
-    this.dispatchEvent(
-      new CustomEvent('title-change', {detail: {title: 'Documentation Search'}})
-    );
+    fireTitleChange(this, 'Documentation Search');
   }
 
   _paramsChanged(params: ListViewParams) {
@@ -76,14 +71,16 @@
 
   _getDocumentationSearches(filter: string) {
     this._documentationSearches = [];
-    return this.$.restAPI.getDocumentationSearches(filter).then(searches => {
-      // Late response.
-      if (filter !== this._filter || !searches) {
-        return;
-      }
-      this._documentationSearches = searches;
-      this._loading = false;
-    });
+    return this.restApiService
+      .getDocumentationSearches(filter)
+      .then(searches => {
+        // Late response.
+        if (filter !== this._filter || !searches) {
+          return;
+        }
+        this._documentationSearches = searches;
+        this._loading = false;
+      });
   }
 
   _computeSearchUrl(url?: string) {
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_html.ts b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_html.ts
index 9f5aae3..dd1faeb 100644
--- a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_html.ts
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_html.ts
@@ -54,5 +54,4 @@
       </tbody>
     </table>
   </gr-list-view>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.js b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.js
index ce80f2f..79d40b5 100644
--- a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.js
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.js
@@ -72,14 +72,14 @@
 
     test('_paramsChanged', done => {
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'getDocumentationSearches')
           .callsFake(() => Promise.resolve(documentationSearches));
       const value = {
         filter: 'test',
       };
       element._paramsChanged(value).then(() => {
-        assert.isTrue(element.$.restAPI.getDocumentationSearches.lastCall
+        assert.isTrue(element.restApiService.getDocumentationSearches.lastCall
             .calledWithExactly('test'));
         done();
       });
diff --git a/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor_html.ts b/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor_html.ts
index ba8af3c..77b4bc6 100644
--- a/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor_html.ts
+++ b/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor_html.ts
@@ -23,7 +23,8 @@
       box-sizing: border-box;
       font-family: var(--monospace-font-family);
       font-size: var(--font-size-code);
-      line-height: var(--line-height-code);
+      /* usually 16px = 12px + 4px */
+      line-height: calc(var(--font-size-code) + var(--spacing-s));
       min-height: 60vh;
       resize: none;
       white-space: pre;
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
index cf011bb..b36edd4 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
@@ -20,7 +20,6 @@
 import '../../shared/gr-dialog/gr-dialog';
 import '../../shared/gr-dropdown/gr-dropdown';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -33,15 +32,14 @@
 import {ChangeInfo, PatchSetNum} from '../../../types/common';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GrDialog} from '../../shared/gr-dialog/gr-dialog';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AutocompleteQuery,
   AutocompleteSuggestion,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
+import {appContext} from '../../../services/app-context';
 
 export interface GrEditControls {
   $: {
-    restAPI: RestApiService & Element;
     overlay: GrOverlay;
     openDialog: GrDialog;
     deleteDialog: GrDialog;
@@ -79,6 +77,8 @@
   @property({type: Object})
   _query: AutocompleteQuery;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = (input: string) => this._queryFiles(input);
@@ -221,7 +221,7 @@
       this._closeDialog(this.$.openDialog, true);
       return;
     }
-    return this.$.restAPI
+    return this.restApiService
       .saveFileUploadChangeEdit(this.change._number, path, fileData)
       .then(res => {
         if (!res || !res.ok) {
@@ -236,7 +236,7 @@
     // Get the dialog before the api call as the event will change during bubbling
     // which will make Polymer.dom(e).path an empty array in polymer 2
     const dialog = this._getDialogFromEvent(e);
-    this.$.restAPI
+    this.restApiService
       .deleteFileInChangeEdit(this.change._number, this._path)
       .then(res => {
         if (!res || !res.ok) {
@@ -249,7 +249,7 @@
 
   _handleRestoreConfirm(e: Event) {
     const dialog = this._getDialogFromEvent(e);
-    this.$.restAPI
+    this.restApiService
       .restoreFileInChangeEdit(this.change._number, this._path)
       .then(res => {
         if (!res || !res.ok) {
@@ -262,7 +262,7 @@
 
   _handleRenameConfirm(e: Event) {
     const dialog = this._getDialogFromEvent(e);
-    return this.$.restAPI
+    return this.restApiService
       .renameFileInChangeEdit(this.change._number, this._path, this._newPath)
       .then(res => {
         if (!res || !res.ok) {
@@ -274,7 +274,7 @@
   }
 
   _queryFiles(input: string): Promise<AutocompleteSuggestion[]> {
-    return this.$.restAPI
+    return this.restApiService
       .queryChangeFiles(this.change._number, this.patchNum, input)
       .then(res => {
         if (!res) throw new Error('Failed to retrieve files. Reponse not set.');
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_html.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_html.ts
index b67f6cd..eac796e 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_html.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_html.ts
@@ -179,5 +179,4 @@
       </div>
     </gr-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
index 98d1545..e366233 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
@@ -19,7 +19,6 @@
 import './gr-edit-controls.js';
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
-import {createIronOverlayBackdropStyleEl} from '../../../test/test-utils.js';
 
 const basicFixture = fixtureFromElement('gr-edit-controls');
 
@@ -29,24 +28,18 @@
   let showDialogSpy;
   let closeDialogSpy;
   let queryStub;
-  let ironOverlayBackdropStyleEl;
 
   setup(() => {
-    ironOverlayBackdropStyleEl = createIronOverlayBackdropStyleEl();
     element = basicFixture.instantiate();
     element.change = {_number: '42'};
     showDialogSpy = sinon.spy(element, '_showDialog');
     closeDialogSpy = sinon.spy(element, '_closeDialog');
     sinon.stub(element, '_hideAllDialogs');
-    queryStub = sinon.stub(element.$.restAPI, 'queryChangeFiles')
+    queryStub = sinon.stub(element.restApiService, 'queryChangeFiles')
         .returns(Promise.resolve([]));
     flush();
   });
 
-  teardown(() => {
-    ironOverlayBackdropStyleEl.remove();
-  });
-
   test('all actions exist', () => {
     // We take 1 away from the total found, due to an extra button being
     // added for the file uploads (browse).
@@ -121,7 +114,7 @@
 
     setup(() => {
       navStub = sinon.stub(GerritNav, 'navigateToChange');
-      deleteStub = sinon.stub(element.$.restAPI, 'deleteFileInChangeEdit');
+      deleteStub = sinon.stub(element.restApiService, 'deleteFileInChangeEdit');
       deleteAutocomplete =
           element.$.deleteDialog.querySelector('gr-autocomplete');
     });
@@ -205,7 +198,7 @@
 
     setup(() => {
       navStub = sinon.stub(GerritNav, 'navigateToChange');
-      renameStub = sinon.stub(element.$.restAPI, 'renameFileInChangeEdit');
+      renameStub = sinon.stub(element.restApiService, 'renameFileInChangeEdit');
       renameAutocomplete =
           element.$.renameDialog.querySelector('gr-autocomplete');
     });
@@ -298,7 +291,8 @@
 
     setup(() => {
       navStub = sinon.stub(GerritNav, 'navigateToChange');
-      restoreStub = sinon.stub(element.$.restAPI, 'restoreFileInChangeEdit');
+      restoreStub = sinon.stub(element.restApiService,
+          'restoreFileInChangeEdit');
     });
 
     test('restore hidden by default', () => {
@@ -362,7 +356,7 @@
 
     setup(() => {
       navStub = sinon.stub(GerritNav, 'navigateToChange');
-      fileStub = sinon.stub(element.$.restAPI, 'saveFileUploadChangeEdit');
+      fileStub = sinon.stub(element.restApiService, 'saveFileUploadChangeEdit');
     });
 
     test('_handleUploadConfirm', () => {
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
index a0562de..197203f 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
@@ -18,7 +18,6 @@
 import '../../plugins/gr-endpoint-param/gr-endpoint-param';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-editable-label/gr-editable-label';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-storage/gr-storage';
 import '../gr-default-editor/gr-default-editor';
 import '../../../styles/shared-styles';
@@ -34,10 +33,7 @@
 import {SPECIAL_PATCH_SET_NUM} from '../../../utils/patch-set-util';
 import {computeTruncatedPath} from '../../../utils/path-list-util';
 import {customElement, property} from '@polymer/decorators';
-import {
-  RestApiService,
-  ErrorCallback,
-} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {ErrorCallback} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   ChangeInfo,
   PatchSetNum,
@@ -47,6 +43,8 @@
 } from '../../../types/common';
 import {GrStorage} from '../../shared/gr-storage/gr-storage';
 import {HttpMethod, NotifyType} from '../../../constants/constants';
+import {fireAlert, fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 const RESTORED_MESSAGE = 'Content restored from a previous edit.';
 const SAVING_MESSAGE = 'Saving changes...';
@@ -59,7 +57,6 @@
 
 export interface GrEditorView {
   $: {
-    restAPI: RestApiService & Element;
     storage: GrStorage;
   };
 }
@@ -125,6 +122,10 @@
   @property({type: Number})
   _lineNum?: number;
 
+  private readonly restApiService = appContext.restApiService;
+
+  reporting = appContext.reportingService;
+
   get keyBindings() {
     return {
       'ctrl+s meta+s': '_handleSaveShortcut',
@@ -152,11 +153,11 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _getEditPrefs() {
-    return this.$.restAPI.getEditPreferences();
+    return this.restApiService.getEditPreferences();
   }
 
   _paramsChanged(value: GenerateUrlEditViewParameters) {
@@ -176,13 +177,7 @@
     // has been queued, the event can bubble up to the handler in gr-app.
     this.async(() => {
       const title = `Editing ${computeTruncatedPath(value.path)}`;
-      this.dispatchEvent(
-        new CustomEvent('title-change', {
-          detail: {title},
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireTitleChange(this, title);
     });
 
     const promises = [];
@@ -195,7 +190,7 @@
   }
 
   _getChangeDetail(changeNum: NumericChangeId) {
-    return this.$.restAPI.getDiffChangeDetail(changeNum).then(change => {
+    return this.restApiService.getDiffChangeDetail(changeNum).then(change => {
       this._change = change;
     });
   }
@@ -209,7 +204,7 @@
     if (path === this._path) {
       return Promise.resolve();
     }
-    return this.$.restAPI
+    return this.restApiService
       .renameFileInChangeEdit(this._changeNum, this._path, path)
       .then(res => {
         if (!res || !res.ok) {
@@ -246,7 +241,7 @@
       this.storageKey
     );
 
-    return this.$.restAPI
+    return this.restApiService
       .getFileContent(changeNum, path, patchNum)
       .then(res => {
         const content = (res && (res as Base64FileContent).content) || '';
@@ -255,13 +250,7 @@
           storedContent.message &&
           storedContent.message !== content
         ) {
-          this.dispatchEvent(
-            new CustomEvent('show-alert', {
-              detail: {message: RESTORED_MESSAGE},
-              bubbles: true,
-              composed: true,
-            })
-          );
+          fireAlert(this, RESTORED_MESSAGE);
 
           this._newContent = storedContent.message;
         } else {
@@ -289,7 +278,7 @@
     this.$.storage.eraseEditableContentItem(this.storageKey);
     if (!this._newContent)
       return Promise.reject(new Error('new content undefined'));
-    return this.$.restAPI
+    return this.restApiService
       .saveChangeEdit(this._changeNum, this._path, this._newContent)
       .then(res => {
         this._saving = false;
@@ -305,13 +294,7 @@
   }
 
   _showAlert(message: string) {
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {message},
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireAlert(this, message);
   }
 
   _computeSaveDisabled(
@@ -348,12 +331,12 @@
     this._saveEdit().then(() => {
       const handleError: ErrorCallback = response => {
         this._showAlert(PUBLISH_FAILED_MSG);
-        console.error(response);
+        this.reporting.error(new Error(response?.statusText));
       };
 
       this._showAlert(PUBLISHING_EDIT_MSG);
 
-      this.$.restAPI
+      this.restApiService
         .executeChangeAction(
           changeNum,
           HttpMethod.POST,
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_html.ts b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_html.ts
index 1e05232..0b03856 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_html.ts
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_html.ts
@@ -133,6 +133,5 @@
       ></gr-default-editor>
     </gr-endpoint-decorator>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
 `;
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_test.js b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_test.js
index b04277e..419e63e 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_test.js
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view_test.js
@@ -43,9 +43,10 @@
     });
 
     element = basicFixture.instantiate();
-    savePathStub = sinon.stub(element.$.restAPI, 'renameFileInChangeEdit');
-    saveFileStub = sinon.stub(element.$.restAPI, 'saveChangeEdit');
-    changeDetailStub = sinon.stub(element.$.restAPI, 'getDiffChangeDetail');
+    savePathStub = sinon.stub(element.restApiService, 'renameFileInChangeEdit');
+    saveFileStub = sinon.stub(element.restApiService, 'saveChangeEdit');
+    changeDetailStub = sinon.stub(element.restApiService,
+        'getDiffChangeDetail');
     navigateStub = sinon.stub(element, '_viewEditInChangeView');
   });
 
@@ -199,7 +200,7 @@
       const saveSpy = sinon.spy(element, '_saveEdit');
       const alertStub = sinon.stub(element, '_showAlert');
       const changeActionsStub =
-        sinon.stub(element.$.restAPI, 'executeChangeAction');
+        sinon.stub(element.restApiService, 'executeChangeAction');
       saveFileStub.returns(Promise.resolve({ok: true}));
       element._newContent = newText;
       flush();
@@ -255,7 +256,7 @@
     });
 
     test('res.ok', () => {
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({
             ok: true,
             type: 'text/javascript',
@@ -271,7 +272,7 @@
     });
 
     test('!res.ok', () => {
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({}));
 
       // Ensure no data is set with a bad response.
@@ -283,7 +284,7 @@
     });
 
     test('content is undefined', () => {
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({
             ok: true,
             type: 'text/javascript',
@@ -297,7 +298,7 @@
     });
 
     test('content and type is undefined', () => {
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({
             ok: true,
           }));
@@ -382,7 +383,7 @@
     test('local edit exists', () => {
       sinon.stub(element.$.storage, 'getEditableContentItem')
           .returns({message: 'pending edit'});
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({
             ok: true,
             type: 'text/javascript',
@@ -405,7 +406,7 @@
     test('local edit exists, is same as remote edit', () => {
       sinon.stub(element.$.storage, 'getEditableContentItem')
           .returns({message: 'pending edit'});
-      sinon.stub(element.$.restAPI, 'getFileContent')
+      sinon.stub(element.restApiService, 'getFileContent')
           .returns(Promise.resolve({
             ok: true,
             type: 'text/javascript',
diff --git a/polygerrit-ui/app/elements/gr-app-element.ts b/polygerrit-ui/app/elements/gr-app-element.ts
index c2fb124..1d42bba 100644
--- a/polygerrit-ui/app/elements/gr-app-element.ts
+++ b/polygerrit-ui/app/elements/gr-app-element.ts
@@ -38,7 +38,6 @@
 import './settings/gr-registration-dialog/gr-registration-dialog';
 import './settings/gr-settings-view/gr-settings-view';
 import './shared/gr-lib-loader/gr-lib-loader';
-import './shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -49,11 +48,10 @@
   Shortcut,
   SPECIAL_SHORTCUT,
 } from '../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
-import {GerritNav, GerritView} from './core/gr-navigation/gr-navigation';
+import {GerritNav} from './core/gr-navigation/gr-navigation';
 import {appContext} from '../services/app-context';
 import {flush} from '@polymer/polymer/lib/utils/flush';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../services/services/gr-rest-api/gr-rest-api';
 import {GrRouter} from './core/gr-router/gr-router';
 import {
   AccountDetailInfo,
@@ -79,6 +77,8 @@
   TitleChangeEventDetail,
 } from '../types/events';
 import {ViewState} from '../types/types';
+import {EventType} from '../utils/event-util';
+import {GerritView} from '../services/router/router-model';
 
 interface ErrorInfo {
   text: string;
@@ -88,7 +88,6 @@
 
 export interface GrAppElement {
   $: {
-    restAPI: RestApiService & Element;
     router: GrRouter;
     errorManager: GrErrorManager;
     errorView: HTMLDivElement;
@@ -194,6 +193,8 @@
 
   private reporting = appContext.reportingService;
 
+  private restApiService = appContext.restApiService;
+
   keyboardShortcuts() {
     return {
       [Shortcut.OPEN_SHORTCUT_HELP_DIALOG]: '_showKeyboardShortcuts',
@@ -209,12 +210,16 @@
   created() {
     super.created();
     this._bindKeyboardShortcuts();
-    this.addEventListener('page-error', e => this._handlePageError(e));
-    this.addEventListener('title-change', e => this._handleTitleChange(e));
+    this.addEventListener(EventType.PAGE_ERROR, e => {
+      this._handlePageError(e);
+    });
+    this.addEventListener(EventType.TITLE_CHANGE, e => {
+      this._handleTitleChange(e);
+    });
     this.addEventListener('location-change', e =>
       this._handleLocationChange(e)
     );
-    this.addEventListener('rpc-log', e => this._handleRpcLog(e));
+    document.addEventListener('gr-rpc-log', e => this._handleRpcLog(e));
     this.addEventListener('shortcut-triggered', e =>
       this._handleShortcutTriggered(e)
     );
@@ -231,19 +236,19 @@
     this.reporting.appStarted();
     this.$.router.start();
 
-    this.$.restAPI.getAccount().then(account => {
+    this.restApiService.getAccount().then(account => {
       this._account = account;
       const role = account ? 'user' : 'guest';
       this.reporting.reportLifeCycle(`Started as ${role}`);
     });
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this._serverConfig = config;
 
       if (config && config.gerrit && config.gerrit.report_bug_url) {
         this._feedbackUrl = config.gerrit.report_bug_url;
       }
     });
-    this.$.restAPI.getVersion().then(version => {
+    this.restApiService.getVersion().then(version => {
       this._version = version;
       this._logWelcome();
     });
@@ -433,9 +438,9 @@
     if (!account) return;
 
     // Preferences are cached when a user is logged in; warm them.
-    this.$.restAPI.getPreferences();
-    this.$.restAPI.getDiffPreferences();
-    this.$.restAPI.getEditPreferences();
+    this.restApiService.getPreferences();
+    this.restApiService.getDiffPreferences();
+    this.restApiService.getEditPreferences();
     this.$.errorManager.knownAccountId =
       (this._account && this._account._account_id) || null;
   }
@@ -487,6 +492,9 @@
         registrationOverlay.refit();
       });
     }
+    // To fix bug announce read after each new view, we reset announce with
+    // empty space
+    this.fire('iron-announce', {text: ' '}, {bubbles: true});
   }
 
   _handleShortcutTriggered(event: ShortcutTriggeredEvent) {
@@ -499,11 +507,10 @@
     if (e.ctrlKey) key = 'ctrl+' + key;
     if (e.metaKey) key = 'meta+' + key;
     if (e.altKey) key = 'alt+' + key;
+    const path = event.composedPath();
     this.reporting.reportInteraction('shortcut-triggered', {
       key,
-      from:
-        (event.path && event.path[0] && (event.path[0] as Element).nodeName) ??
-        'unknown',
+      from: (path && path[0] && (path[0] as Element).nodeName) ?? 'unknown',
     });
   }
 
diff --git a/polygerrit-ui/app/elements/gr-app-element_html.ts b/polygerrit-ui/app/elements/gr-app-element_html.ts
index c1258fb..6116705 100644
--- a/polygerrit-ui/app/elements/gr-app-element_html.ts
+++ b/polygerrit-ui/app/elements/gr-app-element_html.ts
@@ -223,7 +223,6 @@
     id="errorManager"
     login-url="[[_loginUrl]]"
   ></gr-error-manager>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-router id="router"></gr-router>
   <gr-plugin-host id="plugins" config="[[_serverConfig]]"> </gr-plugin-host>
   <gr-lib-loader id="libLoader"></gr-lib-loader>
diff --git a/polygerrit-ui/app/elements/gr-app-global-var-init.ts b/polygerrit-ui/app/elements/gr-app-global-var-init.ts
index fac5f45..7a27b03 100644
--- a/polygerrit-ui/app/elements/gr-app-global-var-init.ts
+++ b/polygerrit-ui/app/elements/gr-app-global-var-init.ts
@@ -22,61 +22,13 @@
  * expose these variables until plugins switch to direct import from polygerrit.
  */
 
-import {
-  getAccountDisplayName,
-  getDisplayName,
-  getGroupDisplayName,
-  getUserName,
-} from '../utils/display-name-util';
 import {GrAnnotation} from './diff/gr-diff-highlight/gr-annotation';
-import {GrAttributeHelper} from './plugins/gr-attribute-helper/gr-attribute-helper';
 import {GrDiffLine, GrDiffLineType} from './diff/gr-diff/gr-diff-line';
 import {GrDiffGroup, GrDiffGroupType} from './diff/gr-diff/gr-diff-group';
-import {GrDiffBuilder} from './diff/gr-diff-builder/gr-diff-builder';
-import {GrDiffBuilderSideBySide} from './diff/gr-diff-builder/gr-diff-builder-side-by-side';
-import {GrDiffBuilderImage} from './diff/gr-diff-builder/gr-diff-builder-image';
-import {GrDiffBuilderUnified} from './diff/gr-diff-builder/gr-diff-builder-unified';
-import {GrDiffBuilderBinary} from './diff/gr-diff-builder/gr-diff-builder-binary';
-import {GrChangeActionsInterface} from './shared/gr-js-api-interface/gr-change-actions-js-api';
-import {GrChangeReplyInterface} from './shared/gr-js-api-interface/gr-change-reply-js-api';
-import {GrEditConstants} from './edit/gr-edit-constants';
-import {
-  GrDomHooksManager,
-  GrDomHook,
-} from './plugins/gr-dom-hooks/gr-dom-hooks';
-import {GrEtagDecorator} from './shared/gr-rest-api-interface/gr-etag-decorator';
-import {GrThemeApi} from './plugins/gr-theme-api/gr-theme-api';
-import {
-  SiteBasedCache,
-  FetchPromisesCache,
-  GrRestApiHelper,
-} from './shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper';
-import {GrLinkTextParser} from './shared/gr-linked-text/link-text-parser';
-import {
-  getPluginEndpoints,
-  GrPluginEndpoints,
-} from './shared/gr-js-api-interface/gr-plugin-endpoints';
-import {GrReviewerUpdatesParser} from './shared/gr-rest-api-interface/gr-reviewer-updates-parser';
-import {GrPopupInterface} from './plugins/gr-popup-interface/gr-popup-interface';
-import {GrCountStringFormatter} from './shared/gr-count-string-formatter/gr-count-string-formatter';
-import {
-  GrReviewerSuggestionsProvider,
-  SUGGESTIONS_PROVIDERS_USERS_TYPES,
-} from '../scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider';
+import {getPluginEndpoints} from './shared/gr-js-api-interface/gr-plugin-endpoints';
 import {util} from '../scripts/util';
 import {page} from '../utils/page-wrapper-utils';
 import {appContext} from '../services/app-context';
-import {GrAdminApi} from './plugins/gr-admin-api/gr-admin-api';
-import {GrAnnotationActionsContext} from './shared/gr-js-api-interface/gr-annotation-actions-context';
-import {GrAnnotationActionsInterface} from './shared/gr-js-api-interface/gr-annotation-actions-js-api';
-import {GrChangeMetadataApi} from './plugins/gr-change-metadata-api/gr-change-metadata-api';
-import {GrEmailSuggestionsProvider} from '../scripts/gr-email-suggestions-provider/gr-email-suggestions-provider';
-import {GrGroupSuggestionsProvider} from '../scripts/gr-group-suggestions-provider/gr-group-suggestions-provider';
-import {GrEventHelper} from './plugins/gr-event-helper/gr-event-helper';
-import {GrPluginRestApi} from './shared/gr-js-api-interface/gr-plugin-rest-api';
-import {GrRepoApi} from './plugins/gr-repo-api/gr-repo-api';
-import {GrSettingsApi} from './plugins/gr-settings-api/gr-settings-api';
-import {GrStylesApi} from './plugins/gr-styles-api/gr-styles-api';
 import {
   getPluginLoader,
   PluginLoader,
@@ -92,60 +44,18 @@
 import {getBaseUrl} from '../utils/url-util';
 import {GerritNav} from './core/gr-navigation/gr-navigation';
 import {getRootElement} from '../scripts/rootElement';
-import {rangesEqual} from './diff/gr-diff/gr-diff-utils';
 import {RevisionInfo} from './shared/revision-info/revision-info';
-import {CoverageType} from '../types/types';
-import {_setHiddenScroll, getHiddenScroll} from '../scripts/hiddenscroll';
 
 export function initGlobalVariables() {
-  window.GrDisplayNameUtils = {
-    getUserName,
-    getDisplayName,
-    getAccountDisplayName,
-    getGroupDisplayName,
-  };
   window.GrAnnotation = GrAnnotation;
-  window.GrAttributeHelper = GrAttributeHelper;
   window.GrDiffLine = GrDiffLine;
   window.GrDiffLineType = GrDiffLineType;
   window.GrDiffGroup = GrDiffGroup;
   window.GrDiffGroupType = GrDiffGroupType;
-  window.GrDiffBuilder = GrDiffBuilder;
-  window.GrDiffBuilderSideBySide = GrDiffBuilderSideBySide;
-  window.GrDiffBuilderImage = GrDiffBuilderImage;
-  window.GrDiffBuilderUnified = GrDiffBuilderUnified;
-  window.GrDiffBuilderBinary = GrDiffBuilderBinary;
-  window.GrChangeActionsInterface = GrChangeActionsInterface;
-  window.GrChangeReplyInterface = GrChangeReplyInterface;
-  window.GrEditConstants = GrEditConstants;
-  window.GrDomHooksManager = GrDomHooksManager;
-  window.GrDomHook = GrDomHook;
-  window.GrEtagDecorator = GrEtagDecorator;
-  window.GrThemeApi = GrThemeApi;
-  window.SiteBasedCache = SiteBasedCache;
-  window.FetchPromisesCache = FetchPromisesCache;
-  window.GrRestApiHelper = GrRestApiHelper;
-  window.GrLinkTextParser = GrLinkTextParser;
-  window.GrPluginEndpoints = GrPluginEndpoints;
-  window.GrReviewerUpdatesParser = GrReviewerUpdatesParser;
-  window.GrPopupInterface = GrPopupInterface;
-  window.GrCountStringFormatter = GrCountStringFormatter;
-  window.GrReviewerSuggestionsProvider = GrReviewerSuggestionsProvider;
   window.util = util;
   window.page = page;
   window.Auth = appContext.authService;
   window.EventEmitter = appContext.eventEmitter;
-  window.GrAdminApi = GrAdminApi;
-  window.GrAnnotationActionsContext = GrAnnotationActionsContext;
-  window.GrAnnotationActionsInterface = GrAnnotationActionsInterface;
-  window.GrChangeMetadataApi = GrChangeMetadataApi;
-  window.GrEmailSuggestionsProvider = GrEmailSuggestionsProvider;
-  window.GrGroupSuggestionsProvider = GrGroupSuggestionsProvider;
-  window.GrEventHelper = GrEventHelper;
-  window.GrPluginRestApi = GrPluginRestApi;
-  window.GrRepoApi = GrRepoApi;
-  window.GrSettingsApi = GrSettingsApi;
-  window.GrStylesApi = GrStylesApi;
   window.PluginLoader = PluginLoader;
   window.GrPluginActionContext = GrPluginActionContext;
 
@@ -167,14 +77,5 @@
   // TODO: should define as a getter
   window.Gerrit._endpoints = getPluginEndpoints();
 
-  // TODO(TS): seems not used, probably just remove
-  window.Gerrit.slotToContent = (slot: any) => slot;
-  window.Gerrit.rangesEqual = rangesEqual;
-  window.Gerrit.SUGGESTIONS_PROVIDERS_USERS_TYPES = SUGGESTIONS_PROVIDERS_USERS_TYPES;
   window.Gerrit.RevisionInfo = RevisionInfo;
-  window.Gerrit.CoverageType = CoverageType;
-  Object.defineProperty(window.Gerrit, 'hiddenscroll', {
-    get: getHiddenScroll,
-    set: _setHiddenScroll,
-  });
 }
diff --git a/polygerrit-ui/app/elements/gr-app-init.ts b/polygerrit-ui/app/elements/gr-app-init.ts
index 6d79ce1..ab38326 100644
--- a/polygerrit-ui/app/elements/gr-app-init.ts
+++ b/polygerrit-ui/app/elements/gr-app-init.ts
@@ -22,17 +22,6 @@
 } from '../services/gr-reporting/gr-reporting_impl';
 import {appContext} from '../services/app-context';
 
-interface UninitializedPolymer {
-  lazyRegister: boolean;
-}
-
-if (!window.Polymer) {
-  // Without as... it violates internal google rules.
-  ((window.Polymer as unknown) as UninitializedPolymer) = {
-    lazyRegister: true,
-  };
-}
-
 initAppContext();
 initVisibilityReporter(appContext);
 initPerformanceReporter(appContext);
diff --git a/polygerrit-ui/app/elements/gr-app-types.ts b/polygerrit-ui/app/elements/gr-app-types.ts
index b05117f..4809562 100644
--- a/polygerrit-ui/app/elements/gr-app-types.ts
+++ b/polygerrit-ui/app/elements/gr-app-types.ts
@@ -16,7 +16,6 @@
  */
 import {
   GenerateUrlParameters,
-  GerritView,
   GroupDetailView,
   RepoDetailView,
 } from './core/gr-navigation/gr-navigation';
@@ -28,6 +27,7 @@
   RepoName,
   UrlEncodedCommentId,
 } from '../types/common';
+import {GerritView} from '../services/router/router-model';
 
 export interface AppElement extends HTMLElement {
   params: AppElementParams | GenerateUrlParameters;
diff --git a/polygerrit-ui/app/elements/gr-app_test.js b/polygerrit-ui/app/elements/gr-app_test.js
index 4c5e965..013d9387 100644
--- a/polygerrit-ui/app/elements/gr-app_test.js
+++ b/polygerrit-ui/app/elements/gr-app_test.js
@@ -70,7 +70,7 @@
   });
 
   test('passes config to gr-plugin-host', () => {
-    const config = appElement().$.restAPI.getConfig;
+    const config = appElement().restApiService.getConfig;
     return config.lastCall.returnValue.then(config => {
       assert.deepEqual(appElement().$.plugins.config, config);
     });
diff --git a/polygerrit-ui/app/elements/lit/gr-lit-element.ts b/polygerrit-ui/app/elements/lit/gr-lit-element.ts
new file mode 100644
index 0000000..9ebadd5
--- /dev/null
+++ b/polygerrit-ui/app/elements/lit/gr-lit-element.ts
@@ -0,0 +1,52 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {LitElement} from 'lit-element';
+import {Observable, Subject} from 'rxjs';
+import {takeUntil} from 'rxjs/operators';
+
+/**
+ * Base class for Gerrit's lit-elements.
+ *
+ * Adds basic functionality that we want to have available in all Gerrit's
+ * components.
+ */
+export abstract class GrLitElement extends LitElement {
+  disconnected$ = new Subject();
+
+  /**
+   * Hooks up an element property with an observable. Apart from subscribing it
+   * makes sure that you are unsubscribed when the component is disconnected.
+   * And it requests a template check when a new value comes in.
+   *
+   * Should be called from connectedCallback() such that you will be
+   * re-subscribed when the component is re-connected.
+   *
+   * TODO: Maybe distinctUntilChanged should be applied to obs$?
+   */
+  subscribe<Key extends keyof this>(prop: Key, obs$: Observable<this[Key]>) {
+    obs$.pipe(takeUntil(this.disconnected$)).subscribe(value => {
+      const oldValue = this[prop];
+      this[prop] = value;
+      this.requestUpdate(prop, oldValue);
+    });
+  }
+
+  disconnectedCallback() {
+    this.disconnected$.next();
+    super.disconnectedCallback();
+  }
+}
diff --git a/polygerrit-ui/app/elements/lit/gr-lit-element_test.ts b/polygerrit-ui/app/elements/lit/gr-lit-element_test.ts
new file mode 100644
index 0000000..9b7b0e2
--- /dev/null
+++ b/polygerrit-ui/app/elements/lit/gr-lit-element_test.ts
@@ -0,0 +1,40 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../test/common-test-setup-karma';
+import {html, customElement} from 'lit-element';
+import {GrLitElement} from './gr-lit-element';
+
+@customElement('test-gr-lit-element')
+export class TestGrLitElement extends GrLitElement {
+  render() {
+    return html`<span>test</span>`;
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'test-gr-lit-element': GrLitElement;
+  }
+}
+
+suite('gr-lit-element test', () => {
+  test('is defined', () => {
+    const el = document.createElement('test-gr-lit-element');
+    assert.instanceOf(el, TestGrLitElement);
+  });
+});
diff --git a/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper.ts b/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper.ts
index 6fc7a17..0641b49 100644
--- a/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper.ts
@@ -16,9 +16,11 @@
  */
 
 export class GrAttributeHelper {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   private readonly _promises = new Map<string, Promise<any>>();
 
-  // TOOD(TS): Change any to something more like HTMLElement.
+  // TODO(TS): Change any to something more like HTMLElement.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   constructor(public element: any) {}
 
   _getChangedEventName(name: string): string {
@@ -32,6 +34,7 @@
     return this.element[name] !== undefined;
   }
 
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   _reportValue(callback: (value: any) => void, value: any) {
     try {
       callback(value);
@@ -46,6 +49,7 @@
    * @param name Property name.
    * @return Unbind function.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   bind(name: string, callback: (value: any) => void) {
     const attributeChangedEventName = this._getChangedEventName(name);
     const changedHandler = (e: CustomEvent) =>
@@ -71,6 +75,7 @@
       return Promise.resolve(this.element[name]);
     }
     if (!this._promises.has(name)) {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
       let resolve: (value: any) => void;
       const promise = new Promise(r => (resolve = r));
       const unbind = this.bind(name, value => {
@@ -85,6 +90,7 @@
   /**
    * Sets value and dispatches event to force notify.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   set(name: string, value: any) {
     this.element[name] = value;
     this.element.dispatchEvent(
diff --git a/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api-types.ts b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api-types.ts
new file mode 100644
index 0000000..7343c3c
--- /dev/null
+++ b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api-types.ts
@@ -0,0 +1,374 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Settings
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+// The entire API is currently in DRAFT state.
+// Changes to all type and interfaces are expected.
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+export interface GrChecksApiInterface {
+  /**
+   * Must only be called once. You cannot register twice. You cannot unregister.
+   */
+  register(provider: ChecksProvider, config?: ChecksApiConfig): void;
+
+  /**
+   * Forces Gerrit to call fetch() on the registered provider. Can be called
+   * when the provider has gotten an update and does not want wait for the next
+   * polling interval to pass.
+   */
+  announceUpdate(): void;
+}
+
+export interface ChecksApiConfig {
+  /**
+   * How often should the provider be called for new CheckData while the user
+   * navigates change related pages and the browser tab remains visible?
+   * Set to 0 to disable polling. Default is 60 seconds.
+   */
+  fetchPollingIntervalSeconds: number;
+}
+
+export interface ChecksProvider {
+  /**
+   * Gerrit calls this method when ...
+   * - ... the change or diff page is loaded.
+   * - ... the user switches back to a Gerrit tab with a change or diff page.
+   * - ... while the tab is visible in a regular polling interval, see
+   *       ChecksApiConfig.
+   */
+  fetch(change: number, patchset: number): Promise<FetchResponse>;
+}
+
+export interface FetchResponse {
+  responseCode: ResponseCode;
+
+  /** Only relevant when the responseCode is ERROR. */
+  errorMessage?: string;
+
+  /**
+   * Only relevant when the responseCode is NOT_LOGGED_IN.
+   * Gerrit displays a "Login" button and calls this callback when the user
+   * clicks on the button.
+   */
+  loginCallback?: () => void;
+
+  /**
+   * Top-level actions that are not associated with a specific run or result.
+   * Will be shown as buttons in the header of the Checks tab.
+   */
+  actions?: Action[];
+  runs?: CheckRun[];
+}
+
+export enum ResponseCode {
+  OK,
+  ERROR,
+  NOT_LOGGED_IN,
+}
+
+/**
+ * A CheckRun models an entity that has start/end timestamps and can be in
+ * either of the states RUNNABLE, RUNNING, COMPLETED. By itself it cannot model
+ * an error, neither can it be failed or successful by itself. A run can be
+ * associated with 0 to n results (see below). So until runs are completed the
+ * runs are more interesting for the user: What is going on at the moment? When
+ * runs are completed the users' interest shifts to results: What do I have to
+ * fix? The only actions that can be associated with runs are RUN and CANCEL.
+ */
+export interface CheckRun {
+  /**
+   * Gerrit requests check runs and results from the plugin by change number and
+   * patchset number. So these two properties can as well be left empty when
+   * returning results to the Gerrit UI and are thus optional.
+   */
+  change?: number;
+  /**
+   * Typically only runs for the latest patchset are requested and presented.
+   * Older runs and their results are only available on request, e.g. by
+   * switching to another patchset in a dropdown
+   *
+   * TBD: Check data providers may decide that runs and results are applicable
+   * to a newer patchset, even if they were produced for an older, e.g. because
+   * only the commit message was changed. Maybe that warrants the addition of
+   * another optional field, e.g. `original_patchset`.
+   */
+  patchset?: number;
+  /**
+   * The UI will focus on just the latest attempt per run. Former attempts are
+   * accessible, but initially collapsed/hidden. Lower number means older
+   * attempt. Every run has its own attempt numbering, so attempt 3 of run A is
+   * not directly related to attempt 3 of run B.
+   *
+   * RUNNABLE runs must use `undefined` as attempt.
+   * COMPLETED and RUNNING runs must use an attempt number >=0.
+   *
+   * TBD: Optionally providing aggregate information about former attempts will
+   * probably be a useful feature, but we are deferring the exact data modeling
+   * of that to later.
+   */
+  attempt?: number;
+
+  /**
+   * An optional opaque identifier not used by Gerrit directly, but might be
+   * used by plugin extensions and callbacks.
+   */
+  externalId?: string;
+
+  // The following 3 properties are independent of this run *instance*. They
+  // just describe what the check is about and will be identical for other
+  // attempts or patchsets or changes.
+
+  /**
+   * The unique name of the check. There can’t be two runs with the same
+   * change/patchset/attempt/checkName combination.
+   * Multiple attempts of the same run must have the same checkName.
+   * It should be expected that this string is cut off at ~30 chars in the UI.
+   * The full name will then be shown in a tooltip.
+   */
+  checkName: string;
+  /**
+   * Optional description of the check. Only shown as a tooltip or in a
+   * hovercard.
+   */
+  checkDescription?: string;
+  /**
+   * Optional http link to an external page with more detailed information about
+   * this run. Must begin with 'http'.
+   */
+  checkLink?: string;
+
+  /**
+   * RUNNABLE:  Not run (yet). Mostly useful for runs that the user can trigger
+   *            (see actions). Cannot contain results.
+   * RUNNING:   Subsumes "scheduled".
+   * COMPLETED: The attempt of the run has finished. Does not indicate at all
+   *            whether the run was successful or not. Outcomes can and should
+   *            be modeled using the CheckResult entity.
+   */
+  status: RunStatus;
+  /**
+   * Optional short description of the run status. This is a plain string
+   * without styling or formatting options. It will only be shown as a tooltip
+   * or in a hovercard.
+   *
+   * Examples:
+   * "40 tests running, 30 completed: 0 failing so far",
+   * "Scheduled 5 minutes ago, not running yet".
+   */
+  statusDescription?: string;
+  /**
+   * Optional http link to an external page with more detailed information about
+   * the run status. Must begin with 'http'.
+   */
+  statusLink?: string;
+
+  /**
+   * Optional reference to a Gerrit label (e.g. "Verified") that this result
+   * influences. Allows the user to understand and navigate the relationship
+   * between check runs/results and submit requirements,
+   * see also https://gerrit-review.googlesource.com/c/homepage/+/279176.
+   */
+  labelName?: string;
+
+  /**
+   * Optional callbacks to the plugin. Must be implemented individually by
+   * each plugin. The most important actions (which get special UI treatment)
+   * are:
+   * "Run" for RUNNABLE and COMPLETED runs.
+   * "Cancel" for RUNNING runs.
+   */
+  actions: Action[];
+
+  scheduledTimestamp?: Date;
+  startedTimestamp?: Date;
+  finishedTimestamp?: Date;
+
+  /**
+   * List of results produced by this run.
+   * RUNNABLE runs must not have results.
+   * RUNNING runs can contain (intermediate) results.
+   * Nesting the results in runs enforces that:
+   * - A run can have 0-n results.
+   * - A result is associated with exactly one run.
+   */
+  results: CheckResult[];
+}
+
+export interface Action {
+  name: string;
+  tooltip?: string;
+  /**
+   * Primary actions will get a more prominent treatment in the UI. For example
+   * primary actions might be rendered as buttons versus just menu entries in
+   * an overflow menu.
+   */
+  primary: boolean;
+  callback: ActionCallback;
+}
+
+export type ActionCallback = (
+  change: number,
+  patchset: number,
+  attempt: number,
+  externalId: string,
+  /** Identical to 'checkName' property of CheckRun. */
+  checkName: string,
+  /** Identical to 'name' property of Action entity. */
+  actionName: string
+) => Promise<ActionResult>;
+
+export interface ActionResult {
+  /** An empty errorMessage means success. */
+  errorMessage?: string;
+}
+
+export enum RunStatus {
+  RUNNABLE,
+  RUNNING,
+  COMPLETED,
+}
+
+export interface CheckResult {
+  /**
+   * An optional opaque identifier not used by Gerrit directly, but might be
+   * used by plugin extensions and callbacks.
+   */
+  externalId?: string;
+
+  /**
+   * INFO:    The user will typically not bother to look into this category,
+   *          only for looking up something that they are searching for. Can be
+   *          used for reporting secondary metrics and analysis, or a wider
+   *          range of artifacts produced by the checks system.
+   * WARNING: A warning is something that should be read before submitting the
+   *          change. The user should not ignore it, but it is also not blocking
+   *          submit. It has a similar level of importance as an unresolved
+   *          comment.
+   * ERROR:   An error indicates that the change must not or cannot be submitted
+   *          without fixing the problem. Errors will be visualized very
+   *          prominently to the user.
+   *
+   * The ‘tags’ field below can be used for further categorization, e.g. for
+   * distinguishing FAILED vs TIMED_OUT.
+   */
+  category: Category;
+
+  /**
+   * Short description of the check result.
+   *
+   * It should be expected that this string might be cut off at ~80 chars in the
+   * UI. The full description will then be shown in a tooltip.
+   * This is a plain string without styling or formatting options.
+   *
+   * Examples:
+   * MessageConverterTest failed with: 'kermit' expected, but got 'ernie'.
+   * Binary size of javascript bundle has increased by 27%.
+   */
+  summary: string;
+
+  /**
+   * Exhaustive optional message describing the check result.
+   * Will be initially collapsed. Might potentially be very long, e.g. a log of
+   * MB size. The UI is not limiting this. Data providing plugins are
+   * responsible for not killing the browser. :-)
+   *
+   * For now this is just a plain unformatted string. The only formatting
+   * applied is the one that Gerrit also applies to human comments. TBD: Both
+   * human comments and check result messages should get richer formatting
+   * options.
+   */
+  message?: string;
+
+  /**
+   * Tags allow a plugins to further categorize a result, e.g. making a list
+   * of results filterable by the end-user.
+   * The name is free-form, but there is a predefined set of TagColors to
+   * choose from with a recommendation of color for common tags, see below.
+   *
+   * Examples:
+   * PASS, FAIL, SCHEDULED, OBSOLETE, SKIPPED, TIMED_OUT, INFRA_ERROR, FLAKY
+   * WIN, MAC, LINUX
+   * BUILD, TEST, LINT
+   * INTEGRATION, E2E, SCREENSHOT
+   */
+  tags: Tag[];
+
+  /**
+   * Links provide an opportunity for the end-user to easily access details and
+   * artifacts. Links are displayed by an icon+tooltip only. They don’t have a
+   * name, making them clearly distinguishable from tags and actions.
+   *
+   * There is a fixed set of LinkIcons to choose from, see below.
+   *
+   * Examples:
+   * Link to test log.
+   * Link to result artifacts such as images and screenshots.
+   * Link to downloadable artifacts such as ZIP or APK files.
+   */
+  links: Link[];
+
+  /**
+   * Callbacks to the plugin. Must be implemented individually by each
+   * plugin. Actions are rendered as buttons. If there are more than two actions
+   * per result, then further actions are put into an overflow menu. Sort order
+   * is defined by the data provider.
+   *
+   * Examples:
+   * Acknowledge/Dismiss, Delete, Report a bug, Report as not useful,
+   * Make blocking, Downgrade severity.
+   */
+  actions: Action[];
+}
+
+export enum Category {
+  INFO,
+  WARNING,
+  ERROR,
+}
+
+export interface Tag {
+  name: string;
+  tooltip?: string;
+  color?: TagColor;
+}
+
+// TBD: Add more ...
+// TBD: Clarify standard colors for common tags.
+export enum TagColor {
+  GRAY,
+  GREEN,
+}
+
+export interface Link {
+  /** Must begin with 'http'. */
+  url: string;
+  tooltip?: string;
+  /**
+   * Primary links will get a more prominent treatment in the UI, e.g. being
+   * always visible in the results table or also showing up in the change page
+   * summary of checks.
+   */
+  primary: boolean;
+  icon: LinkIcon;
+}
+
+// TBD: Add more ...
+export enum LinkIcon {
+  EXTERNAL,
+  DOWNLOAD,
+}
diff --git a/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api.ts b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api.ts
new file mode 100644
index 0000000..beff673
--- /dev/null
+++ b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api.ts
@@ -0,0 +1,62 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Settings
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {PluginApi} from '../gr-plugin-types';
+import {
+  ChecksApiConfig,
+  ChecksProvider,
+  GrChecksApiInterface,
+} from './gr-checks-api-types';
+import {appContext} from '../../../services/app-context';
+
+const DEFAULT_CONFIG: ChecksApiConfig = {
+  fetchPollingIntervalSeconds: 60,
+};
+
+enum State {
+  NOT_REGISTERED,
+  REGISTERED,
+}
+
+/**
+ * Plugin API for checks.
+ *
+ * This object is created/returned to plugins that want to provide check data.
+ * Plugins normally just call register() once at startup and then wait for
+ * fetch() being called on the provider interface.
+ */
+export class GrChecksApi implements GrChecksApiInterface {
+  private state = State.NOT_REGISTERED;
+
+  private readonly checksService = appContext.checksService;
+
+  constructor(readonly plugin: PluginApi) {}
+
+  announceUpdate() {
+    this.checksService.announceUpdate(this.plugin.getPluginName());
+  }
+
+  register(provider: ChecksProvider, config?: ChecksApiConfig): void {
+    if (this.state === State.REGISTERED)
+      throw new Error('Only one provider can be registered per plugin.');
+    this.state = State.REGISTERED;
+    this.checksService.register(
+      this.plugin.getPluginName(),
+      provider,
+      config ?? DEFAULT_CONFIG
+    );
+  }
+}
diff --git a/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api_test.ts b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api_test.ts
new file mode 100644
index 0000000..45cbb47
--- /dev/null
+++ b/polygerrit-ui/app/elements/plugins/gr-checks-api/gr-checks-api_test.ts
@@ -0,0 +1,50 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../../test/common-test-setup-karma.js';
+import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';
+import {_testOnly_initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit.js';
+import {GrChecksApi} from './gr-checks-api';
+import {PluginApi} from '../gr-plugin-types';
+
+const gerritPluginApi = _testOnly_initGerritPluginApi();
+
+suite('gr-settings-api tests', () => {
+  let checksApi: GrChecksApi | undefined;
+
+  setup(() => {
+    let pluginApi: PluginApi | undefined = undefined;
+    gerritPluginApi.install(
+      p => {
+        pluginApi = p;
+      },
+      '0.1',
+      'http://test.com/plugins/testplugin/static/test.js'
+    );
+    getPluginLoader().loadPlugins([]);
+    assert.isOk(pluginApi);
+    checksApi = pluginApi!.checks();
+  });
+
+  teardown(() => {
+    checksApi = undefined;
+  });
+
+  test('exists', () => {
+    assert.isOk(checksApi);
+  });
+});
diff --git a/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.ts b/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.ts
index 3a83729..716cd67 100644
--- a/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-endpoint-decorator/gr-endpoint-decorator.ts
@@ -30,7 +30,7 @@
 const INIT_PROPERTIES_TIMEOUT_MS = 10000;
 
 @customElement('gr-endpoint-decorator')
-class GrEndpointDecorator extends GestureEventListeners(
+export class GrEndpointDecorator extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
 ) {
   static get template() {
@@ -125,12 +125,13 @@
           )
         );
     });
-    // TODO(TS): Should be a number, but TS thinks that is must be some weird
-    // NodeJS.Timeout object.
-    let timeoutId: any;
+    let timeoutId: number;
     const timeout = new Promise(
       () =>
-        (timeoutId = setTimeout(() => {
+        // specify window here so that TS pulls the correct setTimeout method
+        // if window is not specified, then the function is pulled from node
+        // and the return type is NodeJS.Timeout object
+        (timeoutId = window.setTimeout(() => {
           console.warn(
             'Timeout waiting for endpoint properties initialization: ' +
               `plugin ${plugin.getPluginName()}, endpoint ${this.name}`
diff --git a/polygerrit-ui/app/elements/plugins/gr-event-helper/gr-event-helper.ts b/polygerrit-ui/app/elements/plugins/gr-event-helper/gr-event-helper.ts
index 02fcdec..5a4d2ae 100644
--- a/polygerrit-ui/app/elements/plugins/gr-event-helper/gr-event-helper.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-event-helper/gr-event-helper.ts
@@ -72,8 +72,9 @@
     const capture = options?.capture;
     const event = options?.event || 'click';
     const handler = (e: Event) => {
-      if (!e.path) return;
-      if (e.path.indexOf(this.element) !== -1) {
+      const path = e.composedPath();
+      if (!path) return;
+      if (path.indexOf(this.element) !== -1) {
         let mayContinue = true;
         try {
           mayContinue = callback(e);
diff --git a/polygerrit-ui/app/elements/plugins/gr-plugin-types.ts b/polygerrit-ui/app/elements/plugins/gr-plugin-types.ts
index 410da215..2cd0f78 100644
--- a/polygerrit-ui/app/elements/plugins/gr-plugin-types.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-plugin-types.ts
@@ -19,6 +19,7 @@
 import {GrEventHelper} from './gr-event-helper/gr-event-helper';
 import {GrPopupInterface} from './gr-popup-interface/gr-popup-interface';
 import {ConfigInfo} from '../../types/common';
+import {GrChecksApi} from './gr-checks-api/gr-checks-api';
 
 interface GerritElementExtensions {
   content?: HTMLElement & {hidden?: boolean};
@@ -69,6 +70,7 @@
 
 export interface PanelInfo {
   body: Element;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   p: {[key: string]: any};
   onUnload: () => void;
 }
@@ -89,8 +91,10 @@
   popup(moduleName?: string): Promise<GrPopupInterface | null>;
   hook(endpointName: string, opt_options?: RegisterOptions): HookApi;
   getPluginName(): string;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   on(eventName: string, target: any): void;
   attributeHelper(element: Element): GrAttributeHelper;
+  checks(): GrChecksApi;
   restApi(): GrPluginRestApi;
   eventHelper(element: Node): GrEventHelper;
   registerDynamicCustomComponent(
diff --git a/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface_test.js b/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface_test.js
index be8836b..8a7788f 100644
--- a/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface_test.js
+++ b/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface_test.js
@@ -21,7 +21,6 @@
 import {_testOnly_initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit.js';
 import {html} from '@polymer/polymer/lib/utils/html-tag.js';
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
-import {createIronOverlayBackdropStyleEl} from '../../../test/test-utils.js';
 
 class GrUserTestPopupElement extends PolymerElement {
   static get is() { return 'gr-user-test-popup'; }
@@ -40,10 +39,8 @@
   let container;
   let instance;
   let plugin;
-  let ironOverlayBackdropStyleEl;
 
   setup(() => {
-    ironOverlayBackdropStyleEl = createIronOverlayBackdropStyleEl();
     pluginApi.install(p => { plugin = p; }, '0.1',
         'http://test.com/plugins/testplugin/static/test.js');
     container = containerFixture.instantiate();
@@ -54,10 +51,6 @@
     });
   });
 
-  teardown(() => {
-    ironOverlayBackdropStyleEl.remove();
-  });
-
   suite('manual', () => {
     setup(() => {
       instance = new GrPopupInterface(plugin);
diff --git a/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-plugin-repo-command.ts b/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-plugin-repo-command.ts
index b3a40c5..a9aba13 100644
--- a/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-plugin-repo-command.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-plugin-repo-command.ts
@@ -17,6 +17,7 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-plugin-repo-command_html';
 import {customElement, property} from '@polymer/decorators';
+import {fireEvent} from '../../../utils/event-util';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -33,8 +34,6 @@
   }
 
   _handleClick() {
-    this.dispatchEvent(
-      new CustomEvent('command-tap', {composed: true, bubbles: true})
-    );
+    fireEvent(this, 'command-tap');
   }
 }
diff --git a/polygerrit-ui/app/elements/plugins/gr-styles-api/gr-styles-api.ts b/polygerrit-ui/app/elements/plugins/gr-styles-api/gr-styles-api.ts
index 419c8db..5c57208 100644
--- a/polygerrit-ui/app/elements/plugins/gr-styles-api/gr-styles-api.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-styles-api/gr-styles-api.ts
@@ -22,13 +22,6 @@
  * 2. we have css variables which are more recommended way to custom styling
  */
 
-/**
- * // import { useShadow } from '@polymer/polymer/lib/utils/settings';
- * TODO(TS): polymer/lib/utils/settings.d.ts is not exporting useShadow
- * while the js is, to avoid the error, re-define it here
- */
-const useShadow = !window.ShadyDOM || !window.ShadyDOM.inUse;
-
 let styleObjectCount = 0;
 
 interface PgElement extends Element {
@@ -50,10 +43,9 @@
    * if it hasn't been added yet. A root node is an document or is the
    * associated shadowRoot. This class can be added to any element with the same
    * root node.
-   *
    */
   getClassName(element: Element) {
-    let rootNodeEl = useShadow ? element.getRootNode() : document.body;
+    let rootNodeEl = element.getRootNode();
     if (rootNodeEl === document) {
       rootNodeEl = document.head;
     }
diff --git a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.ts b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.ts
index 9c781c8..5786576 100644
--- a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.ts
+++ b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-input/iron-input';
 import '../../shared/gr-avatar/gr-avatar';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -26,14 +25,10 @@
 import {htmlTemplate} from './gr-account-info_html';
 import {customElement, property, observe} from '@polymer/decorators';
 import {AccountInfo, ServerInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {EditableAccountField} from '../../../constants/constants';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
-export interface GrAccountInfo {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-account-info')
 export class GrAccountInfo extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -101,19 +96,21 @@
   @property({type: String})
   _avatarChangeUrl = '';
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
     const promises = [];
 
     this._loading = true;
 
     promises.push(
-      this.$.restAPI.getConfig().then(config => {
+      this.restApiService.getConfig().then(config => {
         this._serverConfig = config;
       })
     );
 
     promises.push(
-      this.$.restAPI.getAccount().then(account => {
+      this.restApiService.getAccount().then(account => {
         if (!account) return;
         this._hasNameChange = false;
         this._hasUsernameChange = false;
@@ -128,7 +125,7 @@
     );
 
     promises.push(
-      this.$.restAPI.getAvatarChangeUrl().then(url => {
+      this.restApiService.getAvatarChangeUrl().then(url => {
         this._avatarChangeUrl = url || '';
       })
     );
@@ -155,12 +152,7 @@
         this._hasDisplayNameChange = false;
         this._hasStatusChange = false;
         this._saving = false;
-        this.dispatchEvent(
-          new CustomEvent('account-detail-update', {
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireEvent(this, 'account-detail-update');
       });
   }
 
@@ -168,7 +160,7 @@
     // Note that we are intentionally not acting on this._account.name being the
     // empty string (which is falsy).
     return this._hasNameChange && this.nameMutable && this._account?.name
-      ? this.$.restAPI.setAccountName(this._account.name)
+      ? this.restApiService.setAccountName(this._account.name)
       : Promise.resolve();
   }
 
@@ -176,20 +168,20 @@
     // Note that we are intentionally not acting on this._username being the
     // empty string (which is falsy).
     return this._hasUsernameChange && this.usernameMutable && this._username
-      ? this.$.restAPI.setAccountUsername(this._username)
+      ? this.restApiService.setAccountUsername(this._username)
       : Promise.resolve();
   }
 
   _maybeSetDisplayName() {
     return this._hasDisplayNameChange &&
       this._account?.display_name !== undefined
-      ? this.$.restAPI.setAccountDisplayName(this._account.display_name)
+      ? this.restApiService.setAccountDisplayName(this._account.display_name)
       : Promise.resolve();
   }
 
   _maybeSetStatus() {
     return this._hasStatusChange && this._account?.status !== undefined
-      ? this.$.restAPI.setAccountStatus(this._account.status)
+      ? this.restApiService.setAccountStatus(this._account.status)
       : Promise.resolve();
   }
 
diff --git a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_html.ts b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_html.ts
index d69a279..f207876 100644
--- a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_html.ts
@@ -128,5 +128,4 @@
       </span>
     </section>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_test.js b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_test.js
index d359ad2..a92c023 100644
--- a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info_test.js
@@ -133,11 +133,12 @@
       element.set('_serverConfig',
           {auth: {editable_account_fields: ['FULL_NAME', 'USER_NAME']}});
 
-      nameStub = sinon.stub(element.$.restAPI, 'setAccountName').callsFake(
+      nameStub = sinon.stub(element.restApiService, 'setAccountName').callsFake(
           name => Promise.resolve());
-      usernameStub = sinon.stub(element.$.restAPI, 'setAccountUsername')
+      usernameStub = sinon.stub(element.restApiService, 'setAccountUsername')
           .callsFake(username => Promise.resolve());
-      statusStub = sinon.stub(element.$.restAPI, 'setAccountStatus').callsFake(
+      statusStub = sinon.stub(element.restApiService,
+          'setAccountStatus').callsFake(
           status => Promise.resolve());
     });
 
@@ -217,11 +218,12 @@
       element.set('_serverConfig',
           {auth: {editable_account_fields: ['FULL_NAME']}});
 
-      nameStub = sinon.stub(element.$.restAPI, 'setAccountName').callsFake(
+      nameStub = sinon.stub(element.restApiService, 'setAccountName').callsFake(
           name => Promise.resolve());
-      statusStub = sinon.stub(element.$.restAPI, 'setAccountStatus').callsFake(
+      statusStub = sinon.stub(element.restApiService,
+          'setAccountStatus').callsFake(
           status => Promise.resolve());
-      sinon.stub(element.$.restAPI, 'setAccountUsername').callsFake(
+      sinon.stub(element.restApiService, 'setAccountUsername').callsFake(
           username => Promise.resolve());
     });
 
@@ -261,7 +263,8 @@
       element.set('_serverConfig',
           {auth: {editable_account_fields: []}});
 
-      statusStub = sinon.stub(element.$.restAPI, 'setAccountStatus').callsFake(
+      statusStub = sinon.stub(element.restApiService,
+          'setAccountStatus').callsFake(
           status => Promise.resolve());
     });
 
diff --git a/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list.ts b/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list.ts
index 5523be1..da180c3 100644
--- a/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list.ts
+++ b/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list.ts
@@ -17,21 +17,15 @@
 
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-agreements-list_html';
 import {getBaseUrl} from '../../../utils/url-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {ContributorAgreementInfo} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
-export interface GrAgreementsList {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-agreements-list')
 export class GrAgreementsList extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -43,6 +37,8 @@
   @property({type: Array})
   _agreements?: ContributorAgreementInfo[];
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
@@ -50,7 +46,7 @@
   }
 
   loadData() {
-    return this.$.restAPI.getAccountAgreements().then(agreements => {
+    return this.restApiService.getAccountAgreements().then(agreements => {
       this._agreements = agreements;
     });
   }
diff --git a/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list_html.ts b/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list_html.ts
index 194ca2b..1afac0d 100644
--- a/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-agreements-list/gr-agreements-list_html.ts
@@ -52,5 +52,4 @@
     </table>
     <a href$="[[getUrl()]]">New Contributor Agreement</a>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.ts b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.ts
index c0d6126..df927d6 100644
--- a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.ts
@@ -16,7 +16,6 @@
  */
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import '../../../styles/gr-form-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
@@ -25,7 +24,9 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-change-table-editor_html';
 import {ChangeTableMixin} from '../../../mixins/gr-change-table-mixin/gr-change-table-mixin';
-import {customElement, property} from '@polymer/decorators';
+import {customElement, property, observe} from '@polymer/decorators';
+import {ServerInfo} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
 @customElement('gr-change-table-editor')
 class GrChangeTableEditor extends ChangeTableMixin(
@@ -41,6 +42,27 @@
   @property({type: Boolean, notify: true})
   showNumber?: boolean;
 
+  @property({type: Object})
+  serverConfig?: ServerInfo;
+
+  @property({type: Array})
+  defaultColumns?: string[];
+
+  flagsService = appContext.flagsService;
+
+  @observe('serverConfig')
+  _configChanged(config: ServerInfo) {
+    this.defaultColumns = this.getEnabledColumns(
+      this.columnNames,
+      config,
+      this.flagsService.enabledExperiments
+    );
+    if (!this.displayedColumns) return;
+    this.displayedColumns = this.displayedColumns.filter(column =>
+      this.isColumnEnabled(column, config, this.flagsService.enabledExperiments)
+    );
+  }
+
   /**
    * Get the list of enabled column names from whichever checkboxes are
    * checked (excluding the number checkbox).
diff --git a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_html.ts b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_html.ts
index 1233cf1..4c87d83 100644
--- a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_html.ts
@@ -61,7 +61,7 @@
             />
           </td>
         </tr>
-        <template is="dom-repeat" items="[[columnNames]]">
+        <template is="dom-repeat" items="[[defaultColumns]]">
           <tr>
             <td>[[item]]</td>
             <td
diff --git a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_test.js b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_test.js
index 42085ff..db5c035 100644
--- a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor_test.js
@@ -41,6 +41,9 @@
 
     element.set('displayedColumns', columns);
     element.showNumber = false;
+    element.serverConfig = {
+      change: {},
+    };
     flush();
   });
 
@@ -51,13 +54,25 @@
 
     // The `+ 1` is for the number column, which isn't included in the change
     // table behavior's list.
-    assert.equal(rows.length, element.columnNames.length + 1);
-    for (let i = 0; i < columns.length; i++) {
+    assert.equal(rows.length, element.defaultColumns.length + 1);
+    for (let i = 0; i < element.defaultColumns.length; i++) {
       tds = rows[i + 1].querySelectorAll('td');
-      assert.equal(tds[0].textContent, columns[i]);
+      assert.equal(tds[0].textContent, element.defaultColumns[i]);
     }
   });
 
+  test('disabled experiments are hidden', () => {
+    assert.isFalse(element.displayedColumns.includes('Assignee'));
+    element.set('displayedColumns', columns);
+    element.serverConfig = {
+      change: {
+        enable_assignee: true,
+      },
+    };
+    flush();
+    assert.isTrue(element.displayedColumns.includes('Assignee'));
+  });
+
   test('hide item', () => {
     const checkbox = element.shadowRoot
         .querySelector('table tr:nth-child(2) input');
@@ -80,6 +95,10 @@
       'Branch',
       'Updated',
     ]);
+    // trigger computation of enabled displayed columns
+    element.serverConfig = {
+      change: {},
+    };
     flush();
     const checkbox = element.shadowRoot
         .querySelector('table tr:nth-child(2) input');
@@ -97,12 +116,15 @@
   });
 
   test('_getDisplayedColumns', () => {
-    assert.deepEqual(element._getDisplayedColumns(), columns);
+    const enabledColumns = columns.filter(column => element.isColumnEnabled(
+        column, element.serverConfig, []
+    ));
+    assert.deepEqual(element._getDisplayedColumns(), enabledColumns);
     MockInteractions.tap(
         element.shadowRoot
-            .querySelector('.checkboxContainer input[name=Assignee]'));
+            .querySelector('.checkboxContainer input[name=Subject]'));
     assert.deepEqual(element._getDisplayedColumns(),
-        columns.filter(c => c !== 'Assignee'));
+        enabledColumns.filter(c => c !== 'Subject'));
   });
 
   test('_handleCheckboxContainerClick relays taps to checkboxes', () => {
@@ -140,12 +162,12 @@
 
   test('_handleTargetClick', () => {
     sinon.spy(element, '_handleTargetClick');
-    assert.include(element.displayedColumns, 'Assignee');
+    assert.include(element.displayedColumns, 'Subject');
     MockInteractions
         .tap(element.shadowRoot
-            .querySelector('.checkboxContainer input[name=Assignee]'));
+            .querySelector('.checkboxContainer input[name=Subject]'));
     assert.isTrue(element._handleTargetClick.calledOnce);
-    assert.notInclude(element.displayedColumns, 'Assignee');
+    assert.notInclude(element.displayedColumns, 'Subject');
   });
 });
 
diff --git a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
index 28cd672..68785e7 100644
--- a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
+++ b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
@@ -19,25 +19,19 @@
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-cla-view_html';
 import {getBaseUrl} from '../../../utils/url-util';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {customElement, property} from '@polymer/decorators';
 import {
   ServerInfo,
   GroupInfo,
   ContributorAgreementInfo,
 } from '../../../types/common';
-
-export interface GrClaView {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {fireAlert, fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -74,30 +68,26 @@
   @property({type: String})
   _agreementsUrl?: string;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     this.loadData();
 
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'New Contributor Agreement'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'New Contributor Agreement');
   }
 
   loadData() {
     const promises = [];
     promises.push(
-      this.$.restAPI.getConfig(true).then(config => {
+      this.restApiService.getConfig(true).then(config => {
         this._serverConfig = config;
       })
     );
 
     promises.push(
-      this.$.restAPI.getAccountGroups().then(groups => {
+      this.restApiService.getAccountGroups().then(groups => {
         if (!groups) return;
         this._groups = groups.sort((a, b) =>
           (a.name || '').localeCompare(b.name || '')
@@ -106,7 +96,7 @@
     );
 
     promises.push(
-      this.$.restAPI
+      this.restApiService
         .getAccountAgreements()
         .then((agreements: ContributorAgreementInfo[] | undefined) => {
           this._signedAgreements = agreements || [];
@@ -143,7 +133,7 @@
     this._createToast('Agreement saving...');
 
     const name = this._agreementName;
-    return this.$.restAPI.saveAccountAgreement({name}).then(res => {
+    return this.restApiService.saveAccountAgreement({name}).then(res => {
       let message = 'Agreement failed to be submitted, please try again';
       if (res.status === 200) {
         message = 'Agreement has been successfully submitted.';
@@ -156,13 +146,7 @@
   }
 
   _createToast(message: string) {
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {message},
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireAlert(this, message);
   }
 
   _computeShowAgreementsClass(showAgreements: boolean) {
diff --git a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
index c461718..91ca402 100644
--- a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
@@ -122,5 +122,4 @@
       </div>
     </div>
   </main>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.ts b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.ts
index d49cb5a..411d3aa 100644
--- a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.ts
+++ b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.ts
@@ -17,19 +17,17 @@
 import '@polymer/iron-input/iron-input';
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-edit-preferences_html';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {EditPreferencesInfo} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
 export interface GrEditPreferences {
   $: {
-    restAPI: RestApiService & Element;
     editSyntaxHighlighting: HTMLInputElement;
     showAutoCloseBrackets: HTMLInputElement;
     showIndentWithTabs: HTMLInputElement;
@@ -52,8 +50,10 @@
   @property({type: Object})
   editPrefs?: EditPreferencesInfo;
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getEditPreferences().then(prefs => {
+    return this.restApiService.getEditPreferences().then(prefs => {
       this.editPrefs = prefs;
     });
   }
@@ -101,7 +101,7 @@
   save() {
     if (!this.editPrefs)
       return Promise.reject(new Error('Missing edit preferences'));
-    return this.$.restAPI.saveEditPreferences(this.editPrefs).then(() => {
+    return this.restApiService.saveEditPreferences(this.editPrefs).then(() => {
       this.hasUnsavedChanges = false;
     });
   }
diff --git a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_html.ts b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_html.ts
index 47e4592..bcff4df 100644
--- a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_html.ts
@@ -160,5 +160,4 @@
       </span>
     </section>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_test.js b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_test.js
index b1b8b61..01c6861 100644
--- a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences_test.js
@@ -92,7 +92,7 @@
   });
 
   test('save changes', () => {
-    sinon.stub(element.$.restAPI, 'saveEditPreferences')
+    sinon.stub(element.restApiService, 'saveEditPreferences')
         .returns(Promise.resolve());
     const showTabsCheckbox = valueOf('Show tabs', 'editPreferences')
         .firstElementChild;
diff --git a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.ts b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.ts
index fd10a16..9960d83 100644
--- a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.ts
@@ -16,7 +16,6 @@
  */
 import '@polymer/iron-input/iron-input';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -24,14 +23,8 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-email-editor_html';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {EmailInfo} from '../../../types/common';
-
-export interface GrEmailEditor {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 @customElement('gr-email-editor')
 export class GrEmailEditor extends GestureEventListeners(
@@ -53,8 +46,10 @@
   @property({type: String})
   _newPreferred: string | null = null;
 
+  readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getAccountEmails().then(emails => {
+    return this.restApiService.getAccountEmails().then(emails => {
       this._emails = emails ?? [];
     });
   }
@@ -63,12 +58,12 @@
     const promises: Promise<unknown>[] = [];
 
     for (const emailObj of this._emailsToRemove) {
-      promises.push(this.$.restAPI.deleteAccountEmail(emailObj.email));
+      promises.push(this.restApiService.deleteAccountEmail(emailObj.email));
     }
 
     if (this._newPreferred) {
       promises.push(
-        this.$.restAPI.setPreferredAccountEmail(this._newPreferred)
+        this.restApiService.setPreferredAccountEmail(this._newPreferred)
       );
     }
 
diff --git a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_html.ts b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_html.ts
index 525fca6..0591e4b 100644
--- a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_html.ts
@@ -95,5 +95,4 @@
       </tbody>
     </table>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_test.ts b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_test.ts
index 18ff95c..143d49c 100644
--- a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_test.ts
+++ b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor_test.ts
@@ -114,9 +114,12 @@
   });
 
   test('save changes', done => {
-    const deleteEmailStub = sinon.stub(element.$.restAPI, 'deleteAccountEmail');
+    const deleteEmailStub = sinon.stub(
+      element.restApiService,
+      'deleteAccountEmail'
+    );
     const setPreferredStub = sinon.stub(
-      element.$.restAPI,
+      element.restApiService,
       'setPreferredAccountEmail'
     );
 
diff --git a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor.ts b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor.ts
index 21e414b..0fd0ad9 100644
--- a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor.ts
@@ -19,7 +19,6 @@
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-copy-clipboard/gr-copy-clipboard';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -31,11 +30,10 @@
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {IronAutogrowTextareaElement} from '@polymer/iron-autogrow-textarea/iron-autogrow-textarea';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 export interface GrGpgEditor {
   $: {
-    restAPI: RestApiService & Element;
     viewKeyOverlay: GrOverlay;
     addButton: GrButton;
     newKey: IronAutogrowTextareaElement;
@@ -70,9 +68,11 @@
   @property({type: Array})
   _keysToRemove: GpgKeyInfo[] = [];
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
     this._keys = [];
-    return this.$.restAPI.getAccountGPGKeys().then(keys => {
+    return this.restApiService.getAccountGPGKeys().then(keys => {
       if (!keys) {
         return;
       }
@@ -86,7 +86,7 @@
 
   save() {
     const promises = this._keysToRemove.map(key =>
-      this.$.restAPI.deleteAccountGPGKey(key.id!)
+      this.restApiService.deleteAccountGPGKey(key.id!)
     );
 
     return Promise.all(promises).then(() => {
@@ -117,7 +117,7 @@
   _handleAddKey() {
     this.$.addButton.disabled = true;
     this.$.newKey.disabled = true;
-    return this.$.restAPI
+    return this.restApiService
       .addAccountGPGKey({add: [this._newKey.trim()]})
       .then(() => {
         this.$.newKey.disabled = false;
diff --git a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_html.ts b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_html.ts
index 432bc4f..69ac702 100644
--- a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_html.ts
@@ -133,5 +133,4 @@
       >
     </fieldset>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.js b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.js
index 2792176..1a84aeb4 100644
--- a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.js
@@ -74,7 +74,7 @@
   test('remove key', done => {
     const lastKey = keys[Object.keys(keys)[1]];
 
-    const saveStub = sinon.stub(element.$.restAPI, 'deleteAccountGPGKey')
+    const saveStub = sinon.stub(element.restApiService, 'deleteAccountGPGKey')
         .callsFake(() => Promise.resolve());
 
     assert.equal(element._keysToRemove.length, 0);
@@ -130,7 +130,8 @@
       },
     };
 
-    const addStub = sinon.stub(element.$.restAPI, 'addAccountGPGKey').callsFake(
+    const addStub = sinon.stub(element.restApiService,
+        'addAccountGPGKey').callsFake(
         () => Promise.resolve(newKeyObject));
 
     element._newKey = newKeyString;
@@ -155,7 +156,8 @@
   test('add invalid key', done => {
     const newKeyString = 'not even close to valid';
 
-    const addStub = sinon.stub(element.$.restAPI, 'addAccountGPGKey').callsFake(
+    const addStub = sinon.stub(element.restApiService,
+        'addAccountGPGKey').callsFake(
         () => Promise.reject(new Error('error')));
 
     element._newKey = newKeyString;
diff --git a/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list.ts b/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list.ts
index d631c53..c69bebd 100644
--- a/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list.ts
+++ b/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list.ts
@@ -16,21 +16,14 @@
  */
 import '../../../styles/shared-styles';
 import '../../../styles/gr-form-styles';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-group-list_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {customElement, property} from '@polymer/decorators';
 import {GroupInfo, GroupId} from '../../../types/common';
-
-export interface GrGroupList {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -48,8 +41,10 @@
   @property({type: Array})
   _groups: GroupInfo[] = [];
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getAccountGroups().then(groups => {
+    return this.restApiService.getAccountGroups().then(groups => {
       if (!groups) return;
       this._groups = groups.sort((a, b) =>
         (a.name || '').localeCompare(b.name || '')
diff --git a/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list_html.ts b/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list_html.ts
index e52583d..0ae3490 100644
--- a/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-group-list/gr-group-list_html.ts
@@ -57,5 +57,4 @@
       </tbody>
     </table>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.ts b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.ts
index 02683e3..9bb4b00 100644
--- a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.ts
+++ b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.ts
@@ -18,7 +18,6 @@
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-copy-clipboard/gr-copy-clipboard';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -26,7 +25,7 @@
 import {htmlTemplate} from './gr-http-password_html';
 import {property, customElement} from '@polymer/decorators';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -36,7 +35,6 @@
 
 export interface GrHttpPassword {
   $: {
-    restAPI: RestApiService & Element;
     generatedPasswordOverlay: GrOverlay;
   };
 }
@@ -58,6 +56,8 @@
   @property({type: String})
   _passwordUrl: string | null = null;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
@@ -68,7 +68,7 @@
     const promises = [];
 
     promises.push(
-      this.$.restAPI.getAccount().then(account => {
+      this.restApiService.getAccount().then(account => {
         if (account) {
           this._username = account.username;
         }
@@ -76,7 +76,7 @@
     );
 
     promises.push(
-      this.$.restAPI.getConfig().then(info => {
+      this.restApiService.getConfig().then(info => {
         if (info) {
           this._passwordUrl = info.auth.http_password_url || null;
         } else {
@@ -91,7 +91,7 @@
   _handleGenerateTap() {
     this._generatedPassword = 'Generating...';
     this.$.generatedPasswordOverlay.open();
-    this.$.restAPI.generateAccountHttpPassword().then(newPassword => {
+    this.restApiService.generateAccountHttpPassword().then(newPassword => {
       this._generatedPassword = newPassword;
     });
   }
diff --git a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_html.ts b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_html.ts
index 41084b5..549fc93 100644
--- a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_html.ts
@@ -94,5 +94,4 @@
       >
     </div>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_test.js b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_test.js
index 920ad48..6f47952 100644
--- a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password_test.js
@@ -42,7 +42,7 @@
     const button = element.$.generateButton;
     const nextPassword = 'the new password';
     let generateResolve;
-    const generateStub = sinon.stub(element.$.restAPI,
+    const generateStub = sinon.stub(element.restApiService,
         'generateAccountHttpPassword')
         .callsFake(() => new Promise(resolve => {
           generateResolve = resolve;
diff --git a/polygerrit-ui/app/elements/settings/gr-identities/gr-identities.ts b/polygerrit-ui/app/elements/settings/gr-identities/gr-identities.ts
index 5f2b6a5..837332a 100644
--- a/polygerrit-ui/app/elements/settings/gr-identities/gr-identities.ts
+++ b/polygerrit-ui/app/elements/settings/gr-identities/gr-identities.ts
@@ -19,23 +19,21 @@
 import '../../admin/gr-confirm-delete-item-dialog/gr-confirm-delete-item-dialog';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-identities_html';
 import {getBaseUrl} from '../../../utils/url-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {AccountExternalIdInfo, ServerInfo} from '../../../types/common';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {PolymerDomRepeatEvent} from '../../../types/types';
+import {appContext} from '../../../services/app-context';
 
 const AUTH = ['OPENID', 'OAUTH'];
 
 export interface GrIdentities {
   $: {
-    restAPI: RestApiService & Element;
     overlay: GrOverlay;
   };
 }
@@ -63,8 +61,10 @@
   })
   _showLinkAnotherIdentity?: boolean;
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getExternalIds().then(id => {
+    return this.restApiService.getExternalIds().then(id => {
       this._identities = id ?? [];
     });
   }
@@ -79,9 +79,11 @@
 
   _handleDeleteItemConfirm() {
     this.$.overlay.close();
-    return this.$.restAPI.deleteAccountIdentity([this._idName!]).then(() => {
-      this.loadData();
-    });
+    return this.restApiService
+      .deleteAccountIdentity([this._idName!])
+      .then(() => {
+        this.loadData();
+      });
   }
 
   _handleConfirmDialogCancel() {
diff --git a/polygerrit-ui/app/elements/settings/gr-identities/gr-identities_html.ts b/polygerrit-ui/app/elements/settings/gr-identities/gr-identities_html.ts
index 1472103..34af7eb 100644
--- a/polygerrit-ui/app/elements/settings/gr-identities/gr-identities_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-identities/gr-identities_html.ts
@@ -103,5 +103,4 @@
       item-type="id"
     ></gr-confirm-delete-item-dialog>
   </gr-overlay>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.ts b/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.ts
index 0498b35..805c9ca 100644
--- a/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-input/iron-input';
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-date-formatter/gr-date-formatter';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import '../../../styles/gr-form-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
diff --git a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.ts b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.ts
index 0e73062..85e692d 100644
--- a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.ts
+++ b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-input/iron-input';
 import '../../../styles/gr-form-styles';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -25,12 +24,12 @@
 import {htmlTemplate} from './gr-registration-dialog_html';
 import {customElement, property, observe} from '@polymer/decorators';
 import {ServerInfo, AccountDetailInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {EditableAccountField} from '../../../constants/constants';
+import {appContext} from '../../../services/app-context';
+import {fireEvent} from '../../../utils/event-util';
 
 export interface GrRegistrationDialog {
   $: {
-    restAPI: RestApiService & Element;
     name: HTMLInputElement;
     username: HTMLInputElement;
     email: HTMLSelectElement;
@@ -83,6 +82,8 @@
   })
   _usernameMutable = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   ready() {
     super.ready();
@@ -107,11 +108,11 @@
   loadData() {
     this._loading = true;
 
-    const loadAccount = this.$.restAPI.getAccount().then(account => {
+    const loadAccount = this.restApiService.getAccount().then(account => {
       this._account = {...this._account, ...account};
     });
 
-    const loadConfig = this.$.restAPI.getConfig().then(config => {
+    const loadConfig = this.restApiService.getConfig().then(config => {
       this._serverConfig = config;
     });
 
@@ -123,22 +124,19 @@
   _save() {
     this._saving = true;
     const promises = [
-      this.$.restAPI.setAccountName(this.$.name.value),
-      this.$.restAPI.setPreferredAccountEmail(this.$.email.value || ''),
+      this.restApiService.setAccountName(this.$.name.value),
+      this.restApiService.setPreferredAccountEmail(this.$.email.value || ''),
     ];
 
     if (this._usernameMutable) {
-      promises.push(this.$.restAPI.setAccountUsername(this.$.username.value));
+      promises.push(
+        this.restApiService.setAccountUsername(this.$.username.value)
+      );
     }
 
     return Promise.all(promises).then(() => {
       this._saving = false;
-      this.dispatchEvent(
-        new CustomEvent('account-detail-update', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this, 'account-detail-update');
     });
   }
 
@@ -154,12 +152,7 @@
 
   close() {
     this._saving = true; // disable buttons indefinitely
-    this.dispatchEvent(
-      new CustomEvent('close', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'close');
   }
 
   _computeSaveDisabled(name?: string, email?: string, saving?: boolean) {
diff --git a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog_html.ts b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog_html.ts
index 11fbbc9..a1d6a5c 100644
--- a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog_html.ts
@@ -129,5 +129,4 @@
       >
     </footer>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
index 9f9840b..809139d 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
@@ -30,7 +30,6 @@
 import '../../shared/gr-date-formatter/gr-date-formatter';
 import '../../shared/gr-diff-preferences/gr-diff-preferences';
 import '../../shared/gr-page-nav/gr-page-nav';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../shared/gr-select/gr-select';
 import '../gr-account-info/gr-account-info';
 import '../gr-agreements-list/gr-agreements-list';
@@ -57,7 +56,6 @@
 import {GrIdentities} from '../gr-identities/gr-identities';
 import {GrEditPreferences} from '../gr-edit-preferences/gr-edit-preferences';
 import {GrDiffPreferences} from '../../shared/gr-diff-preferences/gr-diff-preferences';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   PreferencesInput,
   ServerInfo,
@@ -65,9 +63,11 @@
 } from '../../../types/common';
 import {GrSshEditor} from '../gr-ssh-editor/gr-ssh-editor';
 import {GrGpgEditor} from '../gr-gpg-editor/gr-gpg-editor';
-import {GerritView} from '../../core/gr-navigation/gr-navigation';
 import {GrEmailEditor} from '../gr-email-editor/gr-email-editor';
 import {CustomKeyboardEvent} from '../../../types/events';
+import {fireAlert, fireTitleChange} from '../../../utils/event-util';
+import {appContext} from '../../../services/app-context';
+import {GerritView} from '../../../services/router/router-model';
 
 const PREFS_SECTION_FIELDS: Array<keyof PreferencesInput> = [
   'changes_per_page',
@@ -101,7 +101,6 @@
 
 export interface GrSettingsView {
   $: {
-    restAPI: RestApiService & Element;
     accountInfo: GrAccountInfo;
     watchedProjectsEditor: GrWatchedProjectsEditor;
     groupList: GrGroupList;
@@ -148,9 +147,6 @@
   @property({type: Boolean})
   _accountInfoChanged?: boolean;
 
-  @property({type: Array})
-  _changeTableColumnsNotDisplayed?: string[];
-
   @property({type: Object})
   _localPrefs: PreferencesInput = {};
 
@@ -213,19 +209,15 @@
 
   public _testOnly_loadingPromise?: Promise<void>;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
     // Polymer 2: anchor tag won't work on shadow DOM
     // we need to manually calling scrollIntoView when hash changed
     this.listen(window, 'location-change', '_handleLocationChange');
-    this.dispatchEvent(
-      new CustomEvent('title-change', {
-        detail: {title: 'Settings'},
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireTitleChange(this, 'Settings');
 
     this._isDark = !!window.localStorage.getItem('dark-theme');
 
@@ -239,20 +231,23 @@
     ];
 
     promises.push(
-      this.$.restAPI.getPreferences().then(prefs => {
+      this.restApiService.getPreferences().then(prefs => {
         if (!prefs) {
           throw new Error('getPreferences returned undefined');
         }
         this.prefs = prefs;
         this._showNumber = !!prefs.legacycid_in_change_table;
         this._copyPrefs(CopyPrefsDirection.PrefsToLocalPrefs);
-        this._cloneMenu(prefs.my);
-        this._cloneChangeTableColumns(prefs.change_table);
+        this._localMenu = this._cloneMenu(prefs.my);
+        this._localChangeTableColumns =
+          prefs.change_table.length === 0
+            ? this.columnNames
+            : this.renameProjectToRepoColumn(prefs.change_table);
       })
     );
 
     promises.push(
-      this.$.restAPI.getConfig().then(config => {
+      this.restApiService.getConfig().then(config => {
         this._serverConfig = config;
         const configPromises: Array<Promise<void>> = [];
 
@@ -269,7 +264,7 @@
         }
 
         configPromises.push(
-          getDocsBaseUrl(config, this.$.restAPI).then(baseUrl => {
+          getDocsBaseUrl(config, this.restApiService).then(baseUrl => {
             this._docsBaseUrl = baseUrl;
           })
         );
@@ -284,18 +279,14 @@
       this.params.emailToken
     ) {
       promises.push(
-        this.$.restAPI.confirmEmail(this.params.emailToken).then(message => {
-          if (message) {
-            this.dispatchEvent(
-              new CustomEvent('show-alert', {
-                detail: {message},
-                composed: true,
-                bubbles: true,
-              })
-            );
-          }
-          this.$.emailEditor.loadData();
-        })
+        this.restApiService
+          .confirmEmail(this.params.emailToken)
+          .then(message => {
+            if (message) {
+              fireAlert(this, message);
+            }
+            this.$.emailEditor.loadData();
+          })
       );
     } else {
       promises.push(this.$.emailEditor.loadData());
@@ -350,29 +341,10 @@
   }
 
   _cloneMenu(prefs: TopMenuItemInfo[]) {
-    const menu = [];
-    for (const item of prefs) {
-      menu.push({
-        name: item.name,
-        url: item.url,
-        target: item.target,
-      });
-    }
-    this._localMenu = menu;
-  }
-
-  _cloneChangeTableColumns(changeTable: string[]) {
-    let columns = this.getVisibleColumns(changeTable);
-
-    if (columns.length === 0) {
-      columns = this.columnNames;
-      this._changeTableColumnsNotDisplayed = [];
-    } else {
-      this._changeTableColumnsNotDisplayed = this.getComplementColumns(
-        changeTable
-      );
-    }
-    this._localChangeTableColumns = columns;
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    return prefs.map(({id, ...item}) => {
+      return item;
+    });
   }
 
   @observe('_localChangeTableColumns', '_showNumber')
@@ -438,7 +410,7 @@
   _handleSavePreferences() {
     this._copyPrefs(CopyPrefsDirection.LocalPrefsToPrefs);
 
-    return this.$.restAPI.savePreferences(this.prefs).then(() => {
+    return this.restApiService.savePreferences(this.prefs).then(() => {
       this._prefsChanged = false;
     });
   }
@@ -446,8 +418,7 @@
   _handleSaveChangeTable() {
     this.set('prefs.change_table', this._localChangeTableColumns);
     this.set('prefs.legacycid_in_change_table', this._showNumber);
-    this._cloneChangeTableColumns(this._localChangeTableColumns);
-    return this.$.restAPI.savePreferences(this.prefs).then(() => {
+    return this.restApiService.savePreferences(this.prefs).then(() => {
       this._changeTableChanged = false;
     });
   }
@@ -462,16 +433,15 @@
 
   _handleSaveMenu() {
     this.set('prefs.my', this._localMenu);
-    this._cloneMenu(this._localMenu);
-    return this.$.restAPI.savePreferences(this.prefs).then(() => {
+    return this.restApiService.savePreferences(this.prefs).then(() => {
       this._menuChanged = false;
     });
   }
 
   _handleResetMenuButton() {
-    return this.$.restAPI.getDefaultPreferences().then(data => {
+    return this.restApiService.getDefaultPreferences().then(data => {
       if (data?.my) {
-        this._cloneMenu(data.my);
+        this._localMenu = this._cloneMenu(data.my);
       }
     });
   }
@@ -508,7 +478,7 @@
     if (!this._isNewEmailValid(this._newEmail)) return;
 
     this._addingEmail = true;
-    this.$.restAPI.addAccountEmail(this._newEmail).then(response => {
+    this.restApiService.addAccountEmail(this._newEmail).then(response => {
       this._addingEmail = false;
 
       // If it was unsuccessful.
@@ -542,15 +512,7 @@
       applyDarkTheme();
     }
     this._isDark = !!window.localStorage.getItem('dark-theme');
-    this.dispatchEvent(
-      new CustomEvent('show-alert', {
-        detail: {
-          message: `Theme changed to ${this._isDark ? 'dark' : 'light'}.`,
-        },
-        bubbles: true,
-        composed: true,
-      })
-    );
+    fireAlert(this, `Theme changed to ${this._isDark ? 'dark' : 'light'}.`);
   }
 
   _showHttpAuth(config?: ServerInfo) {
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_html.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_html.ts
index 78f84b1..ec8f6e7 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_html.ts
@@ -340,6 +340,7 @@
       <fieldset id="changeTableColumns">
         <gr-change-table-editor
           show-number="{{_showNumber}}"
+          server-config="[[_serverConfig]]"
           displayed-columns="{{_localChangeTableColumns}}"
         >
         </gr-change-table-editor>
@@ -552,5 +553,4 @@
       <gr-endpoint-decorator name="settings-screen"> </gr-endpoint-decorator>
     </main>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.js b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.js
index 0535e15..4c5a2a2 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.js
@@ -19,7 +19,7 @@
 import {getComputedStyleValue} from '../../../utils/dom-util.js';
 import './gr-settings-view.js';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom.js';
-import {GerritView} from '../../core/gr-navigation/gr-navigation.js';
+import {GerritView} from '../../../services/router/router-model.js';
 
 const basicFixture = fixtureFromElement('gr-settings-view');
 const blankFixture = fixtureFromElement('div');
@@ -51,7 +51,7 @@
   }
 
   function stubAddAccountEmail(statusCode) {
-    return sinon.stub(element.$.restAPI, 'addAccountEmail').callsFake(
+    return sinon.stub(element.restApiService, 'addAccountEmail').callsFake(
         () => Promise.resolve({status: statusCode}));
   }
 
@@ -351,9 +351,7 @@
     let newColumns = ['Owner', 'Project', 'Branch'];
     element._localChangeTableColumns = newColumns.slice(0);
     element._showNumber = false;
-    const cloneStub = sinon.stub(element, '_cloneChangeTableColumns');
     element._handleSaveChangeTable();
-    assert.isTrue(cloneStub.calledOnce);
     assert.deepEqual(element.prefs.change_table, newColumns);
     assert.isNotOk(element.prefs.legacycid_in_change_table);
 
@@ -361,7 +359,6 @@
     element._localChangeTableColumns = newColumns;
     element._showNumber = true;
     element._handleSaveChangeTable();
-    assert.isTrue(cloneStub.calledTwice);
     assert.deepEqual(element.prefs.change_table, newColumns);
     assert.isTrue(element.prefs.legacycid_in_change_table);
   });
@@ -481,7 +478,7 @@
     setup(() => {
       sinon.stub(element.$.emailEditor, 'loadData');
       sinon.stub(
-          element.$.restAPI,
+          element.restApiService,
           'confirmEmail')
           .callsFake(
               () => new Promise(
@@ -491,8 +488,8 @@
     });
 
     test('it is used to confirm email via rest API', () => {
-      assert.isTrue(element.$.restAPI.confirmEmail.calledOnce);
-      assert.isTrue(element.$.restAPI.confirmEmail.calledWith('foo'));
+      assert.isTrue(element.restApiService.confirmEmail.calledOnce);
+      assert.isTrue(element.restApiService.confirmEmail.calledWith('foo'));
     });
 
     test('emails are not loaded initially', () => {
diff --git a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor.ts b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor.ts
index 507caef..b30b2cb 100644
--- a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor.ts
@@ -19,7 +19,6 @@
 import '../../shared/gr-button/gr-button';
 import '../../shared/gr-copy-clipboard/gr-copy-clipboard';
 import '../../shared/gr-overlay/gr-overlay';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
@@ -31,11 +30,10 @@
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {IronAutogrowTextareaElement} from '@polymer/iron-autogrow-textarea/iron-autogrow-textarea';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 export interface GrSshEditor {
   $: {
-    restAPI: RestApiService & Element;
     addButton: GrButton;
     newKey: IronAutogrowTextareaElement;
     viewKeyOverlay: GrOverlay;
@@ -70,8 +68,10 @@
   @property({type: Array})
   _keysToRemove: SshKeyInfo[] = [];
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getAccountSSHKeys().then(keys => {
+    return this.restApiService.getAccountSSHKeys().then(keys => {
       if (!keys) return;
       this._keys = keys;
     });
@@ -79,7 +79,7 @@
 
   save() {
     const promises = this._keysToRemove.map(key =>
-      this.$.restAPI.deleteAccountSSHKey(`${key.seq}`)
+      this.restApiService.deleteAccountSSHKey(`${key.seq}`)
     );
     return Promise.all(promises).then(() => {
       this._keysToRemove = [];
@@ -113,7 +113,7 @@
   _handleAddKey() {
     this.$.addButton.disabled = true;
     this.$.newKey.disabled = true;
-    return this.$.restAPI
+    return this.restApiService
       .addAccountSSHKey(this._newKey.trim())
       .then(key => {
         this.$.newKey.disabled = false;
diff --git a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_html.ts b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_html.ts
index 96f770a..0bee1d3 100644
--- a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_html.ts
@@ -139,5 +139,4 @@
       >
     </fieldset>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.js b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.js
index 29ba692..73e707f 100644
--- a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.js
+++ b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.js
@@ -65,7 +65,7 @@
   test('remove key', done => {
     const lastKey = keys[1];
 
-    const saveStub = sinon.stub(element.$.restAPI, 'deleteAccountSSHKey')
+    const saveStub = sinon.stub(element.restApiService, 'deleteAccountSSHKey')
         .callsFake(() => Promise.resolve());
 
     assert.equal(element._keysToRemove.length, 0);
@@ -116,7 +116,8 @@
       valid: true,
     };
 
-    const addStub = sinon.stub(element.$.restAPI, 'addAccountSSHKey').callsFake(
+    const addStub = sinon.stub(element.restApiService,
+        'addAccountSSHKey').callsFake(
         () => Promise.resolve(newKeyObject));
 
     element._newKey = newKeyString;
@@ -141,7 +142,8 @@
   test('add invalid key', done => {
     const newKeyString = 'not even close to valid';
 
-    const addStub = sinon.stub(element.$.restAPI, 'addAccountSSHKey').callsFake(
+    const addStub = sinon.stub(element.restApiService,
+        'addAccountSSHKey').callsFake(
         () => Promise.reject(new Error('error')));
 
     element._newKey = newKeyString;
diff --git a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.ts b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.ts
index 15f9c6b..36444a3 100644
--- a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.ts
+++ b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-input/iron-input';
 import '../../shared/gr-autocomplete/gr-autocomplete';
 import '../../shared/gr-button/gr-button';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/gr-form-styles';
 import '../../../styles/shared-styles';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
@@ -31,9 +30,9 @@
   GrAutocomplete,
   AutocompleteSuggestion,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {hasOwnProperty} from '../../../utils/common-util';
 import {ProjectWatchInfo} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
 const NOTIFICATION_TYPES = [
   {name: 'Changes', key: 'notify_new_changes'},
@@ -45,7 +44,6 @@
 
 export interface GrWatchedProjectsEditor {
   $: {
-    restAPI: RestApiService & Element;
     newFilter: HTMLInputElement;
     newProject: GrAutocomplete;
   };
@@ -70,21 +68,23 @@
   @property({type: Object})
   _query?: AutocompleteQuery;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = input => this._getProjectSuggestions(input);
   }
 
   loadData() {
-    return this.$.restAPI.getWatchedProjects().then(projs => {
+    return this.restApiService.getWatchedProjects().then(projs => {
       this._projects = projs;
     });
   }
 
   save() {
-    let deletePromise;
+    let deletePromise: Promise<Response | undefined>;
     if (this._projectsToRemove.length) {
-      deletePromise = this.$.restAPI.deleteWatchedProjects(
+      deletePromise = this.restApiService.deleteWatchedProjects(
         this._projectsToRemove
       );
     } else {
@@ -94,7 +94,7 @@
     return deletePromise
       .then(() => {
         if (this._projects) {
-          return this.$.restAPI.saveWatchedProjects(this._projects);
+          return this.restApiService.saveWatchedProjects(this._projects);
         } else {
           return Promise.resolve(undefined);
         }
@@ -119,7 +119,7 @@
   }
 
   _getProjectSuggestions(input: string) {
-    return this.$.restAPI.getSuggestedProjects(input).then(response => {
+    return this.restApiService.getSuggestedProjects(input).then(response => {
       const projects: AutocompleteSuggestion[] = [];
       for (const key in response) {
         if (!hasOwnProperty(response, key)) {
diff --git a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_html.ts b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_html.ts
index e3a90a2..edc8fb2 100644
--- a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_html.ts
@@ -120,5 +120,4 @@
       </tfoot>
     </table>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
index 9623442..8ff7a3a 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
@@ -17,7 +17,6 @@
 import '../gr-account-link/gr-account-link';
 import '../gr-button/gr-button';
 import '../gr-icons/gr-icons';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -25,13 +24,8 @@
 import {htmlTemplate} from './gr-account-chip_html';
 import {customElement, property} from '@polymer/decorators';
 import {AccountInfo, ChangeInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
-export interface GrAccountChip {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-account-chip')
 export class GrAccountChip extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -94,6 +88,8 @@
   @property({type: Boolean})
   transparentBackground = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   ready() {
     super.ready();
@@ -118,7 +114,7 @@
   }
 
   _getHasAvatars() {
-    return this.$.restAPI
+    return this.restApiService
       .getConfig()
       .then(cfg =>
         Promise.resolve(!!(cfg && cfg.plugin && cfg.plugin.has_avatars))
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
index 991104f..3bb1458 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
@@ -109,5 +109,4 @@
       <iron-icon icon="gr-icons:close"></iron-icon>
     </gr-button>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.ts b/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.ts
index 925480f..2562a1a 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-entry/gr-account-entry.ts
@@ -16,7 +16,6 @@
  */
 import '../../../styles/shared-styles';
 import '../gr-autocomplete/gr-autocomplete';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
diff --git a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.ts b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.ts
index be23cb3..a6c4201 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.ts
@@ -18,7 +18,6 @@
 import '../../../styles/shared-styles';
 import '../gr-avatar/gr-avatar';
 import '../gr-hovercard-account/gr-hovercard-account';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -27,16 +26,11 @@
 import {getDisplayName} from '../../../utils/display-name-util';
 import {isServiceUser} from '../../../utils/account-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {ReportingService} from '../../../services/gr-reporting/gr-reporting';
 import {ChangeInfo, AccountInfo, ServerInfo} from '../../../types/common';
 import {hasOwnProperty} from '../../../utils/common-util';
+import {fireEvent} from '../../../utils/event-util';
 
-export interface GrAccountLabel {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-account-label')
 export class GrAccountLabel extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -106,6 +100,8 @@
 
   reporting: ReportingService;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this.reporting = appContext.reportingService;
@@ -114,10 +110,10 @@
   /** @override */
   ready() {
     super.ready();
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this._config = config;
     });
-    this.$.restAPI.getAccount().then(account => {
+    this.restApiService.getAccount().then(account => {
       this._selfAccount = account;
     });
     this.addEventListener('attention-set-updated', () => {
@@ -232,16 +228,14 @@
       'attention-icon-remove',
       this._reportingDetails()
     );
-    this.$.restAPI
+    this.restApiService
       .removeFromAttentionSet(
         this.change._number,
         this.account._account_id,
         reason
       )
       .then(() => {
-        this.dispatchEvent(
-          new CustomEvent('hide-alert', {bubbles: true, composed: true})
-        );
+        fireEvent(this, 'hide-alert');
       });
   }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_html.ts b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_html.ts
index 1d8b13e..b62df9e 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_html.ts
@@ -132,5 +132,4 @@
       </template>
     </span>
   </span>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_test.js b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_test.js
index 2e54db2..42b1dd7 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label_test.js
@@ -99,7 +99,8 @@
     });
 
     test('tap attention button', () => {
-      const apiStub = sinon.stub(element.$.restAPI, 'removeFromAttentionSet')
+      const apiStub = sinon.stub(element.restApiService,
+          'removeFromAttentionSet')
           .callsFake(() => Promise.resolve());
       const button = element.shadowRoot.querySelector('#attentionButton');
       assert.ok(button);
diff --git a/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.ts b/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.ts
index c5e71fc..5cc1240 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-list/gr-account-list.ts
@@ -38,6 +38,7 @@
 import {GrAccountChip} from '../gr-account-chip/gr-account-chip';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {PaperInputElementExt} from '../../../types/types';
+import {fireAlert} from '../../../utils/event-util';
 
 const VALID_EMAIL_ALERT = 'Please input a valid email.';
 
@@ -256,13 +257,7 @@
         // Repopulate the input with what the user tried to enter and have
         // a toast tell them why they can't enter it.
         this.$.entry.setText(item);
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message: VALID_EMAIL_ALERT},
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireAlert(this, VALID_EMAIL_ALERT);
         return false;
       } else {
         const account = {email: item, _pendingAdd: true};
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.ts b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.ts
index 451bdfa..aff6d50 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.ts
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete-dropdown/gr-autocomplete-dropdown.ts
@@ -26,11 +26,12 @@
 import {IronFitMixin} from '../../../mixins/iron-fit-mixin/iron-fit-mixin';
 import {customElement, property, observe} from '@polymer/decorators';
 import {IronFitBehavior} from '@polymer/iron-fit-behavior/iron-fit-behavior';
+import {GrCursorManager} from '../gr-cursor-manager/gr-cursor-manager';
+import {fireEvent} from '../../../utils/event-util';
 
-// TODO(TS): Update once GrCursorManager is upated
 export interface GrAutocompleteDropdown {
   $: {
-    cursor: any;
+    cursor: GrCursorManager;
     suggestions: Element;
   };
 }
@@ -115,7 +116,7 @@
   }
 
   getCurrentText() {
-    return this.getCursorTarget().dataset['value'];
+    return this.getCursorTarget()?.dataset['value'] || '';
   }
 
   _handleUp(e: Event) {
@@ -204,12 +205,7 @@
   }
 
   _fireClose() {
-    this.dispatchEvent(
-      new CustomEvent('dropdown-closed', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'dropdown-closed');
   }
 
   getCursorTarget() {
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.ts b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.ts
index 668ea1b..6151a1d9 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.ts
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.ts
@@ -30,6 +30,7 @@
 import {GrCursorManager} from '../gr-cursor-manager/gr-cursor-manager';
 import {PaperInputElementExt} from '../../../types/types';
 import {CustomKeyboardEvent} from '../../../types/events';
+import {fireEvent} from '../../../utils/event-util';
 
 const TOKENIZE_REGEX = /(?:[^\s"]+|"[^"]*")+/g;
 const DEBOUNCE_WAIT_MS = 200;
@@ -55,9 +56,7 @@
 export interface AutocompleteSuggestion {
   name?: string;
   label?: string;
-  // TODO(TS): this value can be string or arbitrary object (in gr-create-repo-dialog)
-  // probably should limit it to string only as it seems not used
-  value?: any;
+  value?: string;
   text?: string;
 }
 
@@ -406,12 +405,7 @@
     if (this._suggestions.length) {
       this.set('_suggestions', []);
     } else {
-      this.dispatchEvent(
-        new CustomEvent('cancel', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this, 'cancel');
     }
   }
 
@@ -450,7 +444,7 @@
   }
 
   _handleBodyClick(e: Event) {
-    const eventPath = e.path;
+    const eventPath = e.composedPath();
     if (!eventPath) return;
     for (let i = 0; i < eventPath.length; i++) {
       if (eventPath[i] === this) {
diff --git a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.ts b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.ts
index 45bac9f..38f5196 100644
--- a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.ts
+++ b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar.ts
@@ -16,7 +16,6 @@
  */
 import '../../../styles/shared-styles';
 import '../gr-js-api-interface/gr-js-api-interface';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -25,13 +24,8 @@
 import {getPluginLoader} from '../gr-js-api-interface/gr-plugin-loader';
 import {customElement, property} from '@polymer/decorators';
 import {AccountInfo} from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
-export interface GrAvatar {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-avatar')
 export class GrAvatar extends GestureEventListeners(
   LegacyElementMixin(PolymerElement)
@@ -49,6 +43,8 @@
   @property({type: Boolean})
   _hasAvatars = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
@@ -63,7 +59,7 @@
   }
 
   _getConfig() {
-    return this.$.restAPI.getConfig();
+    return this.restApiService.getConfig();
   }
 
   _accountChanged() {
diff --git a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
index 0d8e78f..d105c5d 100644
--- a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
@@ -25,5 +25,4 @@
       background-color: var(--avatar-background-color, #f1f2f3);
     }
   </style>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_test.js b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_test.js
index 261d59c..baec672 100644
--- a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_test.js
@@ -104,7 +104,7 @@
       getPluginLoader().loadPlugins([]);
 
       return Promise.all([
-        element.$.restAPI.getConfig(),
+        element.restApiService.getConfig(),
         getPluginLoader().awaitPluginsLoaded(),
       ]).then(() => {
         assert.isFalse(element.hasAttribute('hidden'));
@@ -134,7 +134,7 @@
       getPluginLoader().loadPlugins([]);
 
       return Promise.all([
-        element.$.restAPI.getConfig(),
+        element.restApiService.getConfig(),
         getPluginLoader().awaitPluginsLoaded(),
       ]).then(() => {
         assert.isTrue(element.hasAttribute('hidden'));
@@ -167,7 +167,7 @@
       getPluginLoader().loadPlugins([]);
 
       return Promise.all([
-        element.$.restAPI.getConfig(),
+        element.restApiService.getConfig(),
         getPluginLoader().awaitPluginsLoaded(),
       ]).then(() => {
         assert.isTrue(element.hasAttribute('hidden'));
diff --git a/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.ts b/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.ts
index 44ec4f5..d83ca49 100644
--- a/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.ts
+++ b/polygerrit-ui/app/elements/shared/gr-change-status/gr-change-status.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-tooltip-content/gr-tooltip-content';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
index 878c01c..dd48556 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 import '../../../styles/shared-styles';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-storage/gr-storage';
 import '../gr-comment/gr-comment';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
@@ -37,7 +36,6 @@
 import {CommentSide, Side, SpecialFilePath} from '../../../constants/constants';
 import {computeDisplayPath} from '../../../utils/path-list-util';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   CommentRange,
   ConfigInfo,
@@ -50,14 +48,17 @@
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {GrStorage, StorageLocation} from '../gr-storage/gr-storage';
 import {CustomKeyboardEvent} from '../../../types/events';
+import {LineNumber, FILE} from '../../diff/gr-diff/gr-diff-line';
+import {GrButton} from '../gr-button/gr-button';
 
 const UNRESOLVED_EXPAND_COUNT = 5;
 const NEWLINE_PATTERN = /\n/g;
 
 export interface GrCommentThread {
   $: {
-    restAPI: RestApiService & Element;
     storage: GrStorage;
+    replyBtn: GrButton;
+    quoteBtn: GrButton;
   };
 }
 
@@ -88,9 +89,9 @@
    * diff widget like gr-diff to show the thread in the right location:
    *
    * line-num:
-   *     1-based line number or undefined if it refers to the entire file.
+   *     1-based line number or 'FILE' if it refers to the entire file.
    *
-   * comment-side:
+   * diff-side:
    *     "left" or "right". These indicate which of the two diffed versions
    *     the comment relates to. In the case of unified diff, the left
    *     version is the one whose line number column is further to the left.
@@ -116,7 +117,7 @@
   keyEventTarget: HTMLElement = document.body;
 
   @property({type: String, reflectToAttribute: true})
-  commentSide?: Side;
+  diffSide?: Side;
 
   @property({type: String})
   patchNum?: PatchSetNum;
@@ -146,8 +147,8 @@
   @property({type: Boolean})
   showFilePath = false;
 
-  @property({type: Number, reflectToAttribute: true})
-  lineNum?: number;
+  @property({type: Object, reflectToAttribute: true})
+  lineNum?: LineNumber;
 
   @property({type: Boolean, notify: true, reflectToAttribute: true})
   unresolved?: boolean;
@@ -171,6 +172,9 @@
   showFileName = true;
 
   @property({type: Boolean})
+  showPortedComment = false;
+
+  @property({type: Boolean})
   showPatchset = true;
 
   get keyBindings() {
@@ -183,6 +187,8 @@
 
   flagsService = appContext.flagsService;
 
+  readonly restApiService = appContext.restApiService;
+
   /** @override */
   created() {
     super.created();
@@ -200,7 +206,7 @@
     this._setInitialExpandedState();
   }
 
-  addOrEditDraft(lineNum?: number, rangeParam?: CommentRange) {
+  addOrEditDraft(lineNum?: LineNumber, rangeParam?: CommentRange) {
     const lastComment = this.comments[this.comments.length - 1] || {};
     if (isDraft(lastComment)) {
       const commentEl = this._commentElWithDraftID(
@@ -223,7 +229,7 @@
     }
   }
 
-  addDraft(lineNum?: number, range?: CommentRange, unresolved?: boolean) {
+  addDraft(lineNum?: LineNumber, range?: CommentRange, unresolved?: boolean) {
     const draft = this._newDraft(lineNum, range);
     draft.__editing = true;
     draft.unresolved = unresolved === false ? unresolved : true;
@@ -239,20 +245,24 @@
     );
   }
 
-  _getDiffUrlForPath(path: string) {
-    if (!this.changeNum) throw new Error('changeNum is missing');
-    if (!this.projectName) throw new Error('projectName is missing');
+  _getDiffUrlForPath(
+    projectName?: RepoName,
+    changeNum?: NumericChangeId,
+    path?: string,
+    patchNum?: PatchSetNum
+  ) {
+    if (!changeNum || !projectName || !path) return undefined;
     if (isDraft(this.comments[0])) {
       return GerritNav.getUrlForDiffById(
-        this.changeNum,
-        this.projectName,
+        changeNum,
+        projectName,
         path,
-        this.patchNum
+        patchNum
       );
     }
     const id = this.comments[0].id;
     if (!id) throw new Error('A published comment is missing the id.');
-    return GerritNav.getUrlForComment(this.changeNum, this.projectName, id);
+    return GerritNav.getUrlForComment(changeNum, projectName, id);
   }
 
   _getDiffUrlForComment(
@@ -272,7 +282,7 @@
         path,
         patchNum,
         undefined,
-        this.lineNum
+        this.lineNum === FILE ? undefined : this.lineNum
       );
     }
     const id = this.comments[0].id;
@@ -284,6 +294,11 @@
     return path === SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
   }
 
+  _computeShowPortedComment(comment: UIComment) {
+    if (this._orderedComments.length === 0) return false;
+    return this.showPortedComment && comment.id === this._orderedComments[0].id;
+  }
+
   _computeDisplayPath(path: string) {
     const displayPath = computeDisplayPath(path);
     if (displayPath === SpecialFilePath.PATCHSET_LEVEL_COMMENTS) {
@@ -293,20 +308,20 @@
   }
 
   _computeDisplayLine() {
-    if (this.lineNum) return `#${this.lineNum}`;
-    // If range is set, then lineNum equals the end line of the range.
-    if (!this.lineNum && !this.range) {
+    if (this.lineNum === FILE) {
       if (this.path === SpecialFilePath.PATCHSET_LEVEL_COMMENTS) {
         return '';
       }
-      return 'FILE';
+      return FILE;
     }
+    if (this.lineNum) return `#${this.lineNum}`;
+    // If range is set, then lineNum equals the end line of the range.
     if (this.range) return `#${this.range.end_line}`;
     return '';
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   @observe('comments.*')
@@ -397,15 +412,6 @@
     if (!id) throw new Error('Cannot reply to comment without id.');
     const reply = this._newReply(id, content, unresolved);
 
-    // If there is currently a comment in an editing state, add an attribute
-    // so that the gr-comment knows not to populate the draft text.
-    for (let i = 0; i < this.comments.length; i++) {
-      if (this.comments[i].__editing) {
-        reply.__otherEditing = true;
-        break;
-      }
-    }
-
     if (isEditing) {
       reply.__editing = true;
     }
@@ -490,7 +496,7 @@
     return d;
   }
 
-  _newDraft(lineNum?: number, range?: CommentRange) {
+  _newDraft(lineNum?: LineNumber, range?: CommentRange) {
     const d: UIDraft = {
       __draft: true,
       __draftID: Math.random().toString(36),
@@ -504,8 +510,6 @@
       if (rootComment.patch_set !== undefined)
         d.patch_set = rootComment.patch_set;
       if (rootComment.side !== undefined) d.side = rootComment.side;
-      if (rootComment.__commentSide !== undefined)
-        d.__commentSide = rootComment.__commentSide;
       if (rootComment.line !== undefined) d.line = rootComment.line;
       if (rootComment.range !== undefined) d.range = rootComment.range;
       if (rootComment.parent !== undefined) d.parent = rootComment.parent;
@@ -514,9 +518,8 @@
       d.path = this.path;
       d.patch_set = this.patchNum;
       d.side = this._getSide(this.isOnParent);
-      d.__commentSide = this.commentSide;
 
-      if (lineNum) {
+      if (lineNum && lineNum !== FILE) {
         d.line = lineNum;
       }
       if (range) {
@@ -565,7 +568,7 @@
     // Check to see if there are any other open comments getting edited and
     // set the local storage value to its message value.
     for (const changeComment of this.comments) {
-      if (changeComment.__editing) {
+      if (isDraft(changeComment) && changeComment.__editing) {
         const commentLocation: StorageLocation = {
           changeNum: this.changeNum,
           patchNum: this.patchNum,
@@ -635,7 +638,7 @@
     if (!name) {
       return;
     }
-    this.$.restAPI.getProjectConfig(name).then(config => {
+    this.restApiService.getProjectConfig(name).then(config => {
       this._projectConfig = config;
     });
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
index 4c15383..dd9f9e8 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
@@ -83,7 +83,9 @@
           <span> [[_computeDisplayPath(path)]] </span>
         </template>
         <template is="dom-if" if="[[!_isPatchsetLevelComment(path)]]">
-          <a href$="[[_getDiffUrlForPath(path)]]">
+          <a
+            href$="[[_getDiffUrlForPath(projectName, changeNum, path, patchNum)]]"
+          >
             [[_computeDisplayPath(path)]]
           </a>
         </template>
@@ -113,11 +115,12 @@
         comments="{{comments}}"
         robot-button-disabled="[[_shouldDisableAction(_showActions, _lastComment)]]"
         change-num="[[changeNum]]"
+        project-name="[[projectName]]"
         patch-num="[[patchNum]]"
         draft="[[_isDraft(comment)]]"
         show-actions="[[_showActions]]"
         show-patchset="[[showPatchset]]"
-        comment-side="[[comment.__commentSide]]"
+        show-ported-comment="[[_computeShowPortedComment(comment)]]"
         side="[[comment.side]]"
         project-config="[[_projectConfig]]"
         on-create-fix-comment="_handleCommentFix"
@@ -164,6 +167,5 @@
       </div>
     </div>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js
deleted file mode 100644
index 1833b73..0000000
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js
+++ /dev/null
@@ -1,879 +0,0 @@
-/**
- * @license
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import '../../../test/common-test-setup-karma.js';
-import './gr-comment-thread.js';
-import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
-import {SpecialFilePath} from '../../../constants/constants.js';
-import {sortComments} from '../../../utils/comment-util.js';
-
-const basicFixture = fixtureFromElement('gr-comment-thread');
-
-const withCommentFixture = fixtureFromElement('gr-comment-thread');
-
-suite('gr-comment-thread tests', () => {
-  suite('basic test', () => {
-    let element;
-
-    setup(() => {
-      stub('gr-rest-api-interface', {
-        getLoggedIn() { return Promise.resolve(false); },
-      });
-
-      element = basicFixture.instantiate();
-      element.patchNum = '3';
-      element.changeNum = '1';
-      flush();
-    });
-
-    test('comments are sorted correctly', () => {
-      const comments = [
-        {
-          message: 'i like you, too',
-          in_reply_to: 'sallys_confession',
-          __date: new Date('2015-12-25'),
-        }, {
-          id: 'sallys_confession',
-          message: 'i like you, jack',
-          updated: '2015-12-24 15:00:20.396000000',
-        }, {
-          id: 'sally_to_dr_finklestein',
-          message: 'i’m running away',
-          updated: '2015-10-31 09:00:20.396000000',
-        }, {
-          id: 'sallys_defiance',
-          in_reply_to: 'sally_to_dr_finklestein',
-          message: 'i will poison you so i can get away',
-          updated: '2015-10-31 15:00:20.396000000',
-        }, {
-          id: 'dr_finklesteins_response',
-          in_reply_to: 'sally_to_dr_finklestein',
-          message: 'no i will pull a thread and your arm will fall off',
-          updated: '2015-10-31 11:00:20.396000000',
-        }, {
-          id: 'sallys_mission',
-          message: 'i have to find santa',
-          updated: '2015-12-24 15:00:20.396000000',
-        },
-      ];
-      const results = sortComments(comments);
-      assert.deepEqual(results, [
-        {
-          id: 'sally_to_dr_finklestein',
-          message: 'i’m running away',
-          updated: '2015-10-31 09:00:20.396000000',
-        }, {
-          id: 'dr_finklesteins_response',
-          in_reply_to: 'sally_to_dr_finklestein',
-          message: 'no i will pull a thread and your arm will fall off',
-          updated: '2015-10-31 11:00:20.396000000',
-        }, {
-          id: 'sallys_defiance',
-          in_reply_to: 'sally_to_dr_finklestein',
-          message: 'i will poison you so i can get away',
-          updated: '2015-10-31 15:00:20.396000000',
-        }, {
-          id: 'sallys_confession',
-          message: 'i like you, jack',
-          updated: '2015-12-24 15:00:20.396000000',
-        }, {
-          id: 'sallys_mission',
-          message: 'i have to find santa',
-          updated: '2015-12-24 15:00:20.396000000',
-        }, {
-          message: 'i like you, too',
-          in_reply_to: 'sallys_confession',
-          __date: new Date('2015-12-25'),
-        },
-      ]);
-    });
-
-    test('addOrEditDraft w/ edit draft', () => {
-      element.comments = [{
-        id: 'jacks_reply',
-        message: 'i like you, too',
-        in_reply_to: 'sallys_confession',
-        updated: '2015-12-25 15:00:20.396000000',
-        __draft: true,
-      }];
-      const commentElStub = sinon.stub(element, '_commentElWithDraftID')
-          .callsFake(() => { return {}; });
-      const addDraftStub = sinon.stub(element, 'addDraft');
-
-      element.addOrEditDraft(123);
-
-      assert.isTrue(commentElStub.called);
-      assert.isFalse(addDraftStub.called);
-    });
-
-    test('addOrEditDraft w/o edit draft', () => {
-      element.comments = [];
-      const commentElStub = sinon.stub(element, '_commentElWithDraftID')
-          .callsFake(() => { return {}; });
-      const addDraftStub = sinon.stub(element, 'addDraft');
-
-      element.addOrEditDraft(123);
-
-      assert.isFalse(commentElStub.called);
-      assert.isTrue(addDraftStub.called);
-    });
-
-    test('_shouldDisableAction', () => {
-      let showActions = true;
-      const lastComment = {};
-      assert.equal(
-          element._shouldDisableAction(showActions, lastComment), false);
-      showActions = false;
-      assert.equal(
-          element._shouldDisableAction(showActions, lastComment), true);
-      showActions = true;
-      lastComment.__draft = true;
-      assert.equal(
-          element._shouldDisableAction(showActions, lastComment), true);
-      const robotComment = {};
-      robotComment.robot_id = true;
-      assert.equal(
-          element._shouldDisableAction(showActions, robotComment), false);
-    });
-
-    test('_hideActions', () => {
-      let showActions = true;
-      const lastComment = {};
-      assert.equal(element._hideActions(showActions, lastComment), false);
-      showActions = false;
-      assert.equal(element._hideActions(showActions, lastComment), true);
-      showActions = true;
-      lastComment.__draft = true;
-      assert.equal(element._hideActions(showActions, lastComment), true);
-      const robotComment = {};
-      robotComment.robot_id = true;
-      assert.equal(element._hideActions(showActions, robotComment), true);
-    });
-
-    test('setting project name loads the project config', done => {
-      const projectName = 'foo/bar/baz';
-      const getProjectStub = sinon.stub(element.$.restAPI, 'getProjectConfig')
-          .returns(Promise.resolve({}));
-      element.projectName = projectName;
-      flush(() => {
-        assert.isTrue(getProjectStub.calledWithExactly(projectName));
-        done();
-      });
-    });
-
-    test('optionally show file path', () => {
-      // Path info doesn't exist when showFilePath is false. Because it's in a
-      // dom-if it is not yet in the dom.
-      assert.isNotOk(element.shadowRoot
-          .querySelector('.pathInfo'));
-
-      const commentStub = sinon.stub(GerritNav, 'getUrlForComment');
-      element.changeNum = 123;
-      element.projectName = 'test project';
-      element.path = 'path/to/file';
-      element.latestPatchNum = 10;
-      element.patchNum = 3;
-      element.lineNum = 5;
-      element.comments = [{id: 'comment_id'}];
-      element.showFilePath = true;
-      flush();
-      assert.isOk(element.shadowRoot
-          .querySelector('.pathInfo'));
-      assert.notEqual(getComputedStyle(element.shadowRoot
-          .querySelector('.pathInfo')).display,
-      'none');
-      assert.isTrue(commentStub.calledWithExactly(
-          element.changeNum, element.projectName, 'comment_id'));
-    });
-
-    test('_computeDisplayPath', () => {
-      let path = 'path/to/file';
-      assert.equal(element._computeDisplayPath(path), 'path/to/file');
-
-      element.lineNum = 5;
-      assert.equal(element._computeDisplayPath(path), 'path/to/file');
-
-      element.patchNum = '3';
-      path = SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
-      assert.equal(element._computeDisplayPath(path), 'Patchset');
-    });
-
-    test('_computeDisplayLine', () => {
-      element.lineNum = 5;
-      assert.equal(element._computeDisplayLine(), '#5');
-
-      element.path = SpecialFilePath.COMMIT_MESSAGE;
-      element.lineNum = 5;
-      assert.equal(element._computeDisplayLine(), '#5');
-
-      element.lineNum = undefined;
-      element.path = SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
-      assert.equal(element._computeDisplayLine(), '');
-    });
-  });
-});
-
-suite('comment action tests with unresolved thread', () => {
-  let element;
-
-  setup(() => {
-    stub('gr-rest-api-interface', {
-      getLoggedIn() { return Promise.resolve(false); },
-      saveDiffDraft() {
-        return Promise.resolve({
-          ok: true,
-          text() {
-            return Promise.resolve(')]}\'\n' +
-                JSON.stringify({
-                  id: '7afa4931_de3d65bd',
-                  path: '/path/to/file.txt',
-                  line: 5,
-                  in_reply_to: 'baf0414d_60047215',
-                  updated: '2015-12-21 02:01:10.850000000',
-                  message: 'Done',
-                }));
-          },
-        });
-      },
-      deleteDiffDraft() { return Promise.resolve({ok: true}); },
-    });
-    element = withCommentFixture.instantiate();
-    element.patchNum = '1';
-    element.changeNum = '1';
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 'baf0414d_60047215',
-      line: 5,
-      message: 'is this a crossover episode!?',
-      updated: '2015-12-08 19:48:33.843000000',
-      path: '/path/to/file.txt',
-      unresolved: true,
-      patch_set: 3,
-      __commentSide: 'left',
-    }];
-    flush();
-  });
-
-  test('reply', () => {
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    const reportStub = sinon.stub(element.reporting,
-        'recordDraftInteraction');
-    assert.ok(commentEl);
-
-    const replyBtn = element.$.replyBtn;
-    MockInteractions.tap(replyBtn);
-    flush();
-
-    const drafts = element._orderedComments.filter(c => c.__draft == true);
-    assert.equal(drafts.length, 1);
-    assert.notOk(drafts[0].message, 'message should be empty');
-    assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-    assert.isTrue(reportStub.calledOnce);
-  });
-
-  test('quote reply', () => {
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    const reportStub = sinon.stub(element.reporting,
-        'recordDraftInteraction');
-    assert.ok(commentEl);
-
-    const quoteBtn = element.$.quoteBtn;
-    MockInteractions.tap(quoteBtn);
-    flush();
-
-    const drafts = element._orderedComments.filter(c => c.__draft == true);
-    assert.equal(drafts.length, 1);
-    assert.equal(drafts[0].message, '> is this a crossover episode!?\n\n');
-    assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-    assert.isTrue(reportStub.calledOnce);
-  });
-
-  test('quote reply multiline', () => {
-    const reportStub = sinon.stub(element.reporting,
-        'recordDraftInteraction');
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 'baf0414d_60047215',
-      path: 'test',
-      line: 5,
-      message: 'is this a crossover episode!?\nIt might be!',
-      updated: '2015-12-08 19:48:33.843000000',
-    }];
-    flush();
-
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const quoteBtn = element.$.quoteBtn;
-    MockInteractions.tap(quoteBtn);
-    flush();
-
-    const drafts = element._orderedComments.filter(c => c.__draft == true);
-    assert.equal(drafts.length, 1);
-    assert.equal(drafts[0].message,
-        '> is this a crossover episode!?\n> It might be!\n\n');
-    assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-    assert.isTrue(reportStub.calledOnce);
-  });
-
-  test('ack', done => {
-    const reportStub = sinon.stub(element.reporting,
-        'recordDraftInteraction');
-    element.changeNum = '42';
-    element.patchNum = '1';
-
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const ackBtn = element.shadowRoot.querySelector('#ackBtn');
-    MockInteractions.tap(ackBtn);
-    flush(() => {
-      const drafts = element.comments.filter(c => c.__draft == true);
-      assert.equal(drafts.length, 1);
-      assert.equal(drafts[0].message, 'Ack');
-      assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-      assert.equal(drafts[0].unresolved, false);
-      assert.isTrue(reportStub.calledOnce);
-      done();
-    });
-  });
-
-  test('done', done => {
-    const reportStub = sinon.stub(element.reporting,
-        'recordDraftInteraction');
-    element.changeNum = '42';
-    element.patchNum = '1';
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const doneBtn = element.shadowRoot.querySelector('#doneBtn');
-    MockInteractions.tap(doneBtn);
-    flush(() => {
-      const drafts = element.comments.filter(c => c.__draft == true);
-      assert.equal(drafts.length, 1);
-      assert.equal(drafts[0].message, 'Done');
-      assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-      assert.isFalse(drafts[0].unresolved);
-      assert.isTrue(reportStub.calledOnce);
-      done();
-    });
-  });
-
-  test('save', done => {
-    element.changeNum = '42';
-    element.patchNum = '1';
-    element.path = '/path/to/file.txt';
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const saveOrDiscardStub = sinon.stub();
-    element.addEventListener('thread-changed', saveOrDiscardStub);
-    element.shadowRoot
-        .querySelector('gr-comment')._fireSave();
-
-    flush(() => {
-      assert.isTrue(saveOrDiscardStub.called);
-      assert.equal(saveOrDiscardStub.lastCall.args[0].detail.rootId,
-          'baf0414d_60047215');
-      assert.equal(element.rootId, 'baf0414d_60047215');
-      assert.equal(saveOrDiscardStub.lastCall.args[0].detail.path,
-          '/path/to/file.txt');
-      done();
-    });
-  });
-
-  test('please fix', done => {
-    element.changeNum = '42';
-    element.patchNum = '1';
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-    commentEl.addEventListener('create-fix-comment', () => {
-      const drafts = element._orderedComments.filter(c => c.__draft == true);
-      assert.equal(drafts.length, 1);
-      assert.equal(
-          drafts[0].message, '> is this a crossover episode!?\n\nPlease fix.');
-      assert.equal(drafts[0].in_reply_to, 'baf0414d_60047215');
-      assert.isTrue(drafts[0].unresolved);
-      done();
-    });
-    commentEl.dispatchEvent(
-        new CustomEvent('create-fix-comment', {
-          detail: {comment: commentEl.comment},
-          composed: true, bubbles: false,
-        }));
-  });
-
-  test('discard', done => {
-    element.changeNum = '42';
-    element.patchNum = '1';
-    element.path = '/path/to/file.txt';
-    element.push('comments', element._newReply(
-        element.comments[0].id,
-        element.comments[0].path,
-        'it’s pronouced jiff, not giff'));
-    flush();
-
-    const saveOrDiscardStub = sinon.stub();
-    element.addEventListener('thread-changed', saveOrDiscardStub);
-    const draftEl =
-        element.root.querySelectorAll('gr-comment')[1];
-    assert.ok(draftEl);
-    draftEl.addEventListener('comment-discard', () => {
-      const drafts = element.comments.filter(c => c.__draft == true);
-      assert.equal(drafts.length, 0);
-      assert.isTrue(saveOrDiscardStub.called);
-      assert.equal(saveOrDiscardStub.lastCall.args[0].detail.rootId,
-          element.rootId);
-      assert.equal(saveOrDiscardStub.lastCall.args[0].detail.path,
-          element.path);
-      done();
-    });
-    draftEl.dispatchEvent(
-        new CustomEvent('comment-discard', {
-          detail: {comment: draftEl.comment},
-          composed: true, bubbles: false,
-        }));
-  });
-
-  test('discard with a single comment still fires event with previous rootId',
-      done => {
-        element.changeNum = '42';
-        element.patchNum = '1';
-        element.path = '/path/to/file.txt';
-        element.comments = [];
-        element.addOrEditDraft('1');
-        flush();
-        const rootId = element.rootId;
-        assert.isOk(rootId);
-
-        const saveOrDiscardStub = sinon.stub();
-        element.addEventListener('thread-changed', saveOrDiscardStub);
-        const draftEl =
-        element.root.querySelectorAll('gr-comment')[0];
-        assert.ok(draftEl);
-        draftEl.addEventListener('comment-discard', () => {
-          assert.equal(element.comments.length, 0);
-          assert.isTrue(saveOrDiscardStub.called);
-          assert.equal(saveOrDiscardStub.lastCall.args[0].detail.rootId,
-              rootId);
-          assert.equal(saveOrDiscardStub.lastCall.args[0].detail.path,
-              element.path);
-          done();
-        });
-        draftEl.dispatchEvent(
-            new CustomEvent('comment-discard', {
-              detail: {comment: draftEl.comment},
-              composed: true, bubbles: false,
-            }));
-      });
-
-  test('first editing comment does not add __otherEditing attribute', () => {
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 'baf0414d_60047215',
-      line: 5,
-      path: 'test',
-      message: 'is this a crossover episode!?',
-      updated: '2015-12-08 19:48:33.843000000',
-      __draft: true,
-    }];
-
-    const replyBtn = element.$.replyBtn;
-    MockInteractions.tap(replyBtn);
-    flush();
-
-    const editing = element._orderedComments.filter(c => c.__editing == true);
-    assert.equal(editing.length, 1);
-    assert.equal(!!editing[0].__otherEditing, false);
-  });
-
-  test('When not editing other comments, local storage not set' +
-      ' after discard', done => {
-    element.changeNum = '42';
-    element.patchNum = '1';
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 'baf0414d_60047215',
-      path: 'test',
-      line: 5,
-      message: 'is this a crossover episode!?',
-      updated: '2015-12-08 19:48:31.843000000',
-    },
-    {
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      __draftID: '1',
-      in_reply_to: 'baf0414d_60047215',
-      path: 'test',
-      line: 5,
-      message: 'yes',
-      updated: '2015-12-08 19:48:32.843000000',
-      __draft: true,
-      __editing: true,
-    },
-    {
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      __draftID: '2',
-      in_reply_to: 'baf0414d_60047215',
-      path: 'test',
-      line: 5,
-      message: 'no',
-      updated: '2015-12-08 19:48:33.843000000',
-      __draft: true,
-    }];
-    const storageStub = sinon.stub(element.$.storage, 'setDraftComment');
-    flush();
-
-    const draftEl =
-    element.root.querySelectorAll('gr-comment')[1];
-    assert.ok(draftEl);
-    draftEl.addEventListener('comment-discard', () => {
-      assert.isFalse(storageStub.called);
-      storageStub.restore();
-      done();
-    });
-    draftEl.dispatchEvent(
-        new CustomEvent('comment-discard', {
-          detail: {comment: draftEl.comment},
-          composed: true, bubbles: false,
-        }));
-  });
-
-  test('comment-update', () => {
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    const updatedComment = {
-      id: element.comments[0].id,
-      foo: 'bar',
-    };
-    commentEl.dispatchEvent(
-        new CustomEvent('comment-update', {
-          detail: {comment: updatedComment},
-          composed: true, bubbles: true,
-        }));
-    assert.strictEqual(element.comments[0], updatedComment);
-  });
-
-  suite('jack and sally comment data test consolidation', () => {
-    setup(() => {
-      element.comments = [
-        {
-          id: 'jacks_reply',
-          message: 'i like you, too',
-          in_reply_to: 'sallys_confession',
-          updated: '2015-12-25 15:00:20.396000000',
-          unresolved: false,
-        }, {
-          id: 'sallys_confession',
-          in_reply_to: 'nonexistent_comment',
-          message: 'i like you, jack',
-          updated: '2015-12-24 15:00:20.396000000',
-        }, {
-          id: 'sally_to_dr_finklestein',
-          in_reply_to: 'nonexistent_comment',
-          message: 'i’m running away',
-          updated: '2015-10-31 09:00:20.396000000',
-        }, {
-          id: 'sallys_defiance',
-          message: 'i will poison you so i can get away',
-          updated: '2015-10-31 15:00:20.396000000',
-        }];
-    });
-
-    test('orphan replies', () => {
-      assert.equal(4, element._orderedComments.length);
-    });
-
-    test('keyboard shortcuts', () => {
-      const expandCollapseStub =
-          sinon.stub(element, '_expandCollapseComments');
-      MockInteractions.pressAndReleaseKeyOn(element, 69, null, 'e');
-      assert.isTrue(expandCollapseStub.lastCall.calledWith(false));
-
-      MockInteractions.pressAndReleaseKeyOn(element, 69, 'shift', 'e');
-      assert.isTrue(expandCollapseStub.lastCall.calledWith(true));
-    });
-
-    test('comment in_reply_to is either null or most recent comment', () => {
-      element._createReplyComment('dummy', true);
-      flush();
-      assert.equal(element._orderedComments.length, 5);
-      assert.equal(element._orderedComments[4].in_reply_to, 'jacks_reply');
-    });
-
-    test('resolvable comments', () => {
-      assert.isFalse(element.unresolved);
-      element._createReplyComment('dummy', true, true);
-      flush();
-      assert.isTrue(element.unresolved);
-    });
-
-    test('_setInitialExpandedState with unresolved', () => {
-      element.unresolved = true;
-      element._setInitialExpandedState();
-      for (let i = 0; i < element.comments.length; i++) {
-        assert.isFalse(element.comments[i].collapsed);
-      }
-    });
-
-    test('_setInitialExpandedState without unresolved', () => {
-      element.unresolved = false;
-      element._setInitialExpandedState();
-      for (let i = 0; i < element.comments.length; i++) {
-        assert.isTrue(element.comments[i].collapsed);
-      }
-    });
-
-    test('_setInitialExpandedState with robot_ids', () => {
-      for (let i = 0; i < element.comments.length; i++) {
-        element.comments[i].robot_id = 123;
-      }
-      element._setInitialExpandedState();
-      for (let i = 0; i < element.comments.length; i++) {
-        assert.isFalse(element.comments[i].collapsed);
-      }
-    });
-
-    test('_setInitialExpandedState with collapsed state', () => {
-      element.comments[0].collapsed = false;
-      element.unresolved = false;
-      element._setInitialExpandedState();
-      assert.isFalse(element.comments[0].collapsed);
-      for (let i = 1; i < element.comments.length; i++) {
-        assert.isTrue(element.comments[i].collapsed);
-      }
-    });
-  });
-
-  test('_computeHostClass', () => {
-    assert.equal(element._computeHostClass(true), 'unresolved');
-    assert.equal(element._computeHostClass(false), '');
-  });
-
-  test('addDraft sets unresolved state correctly', () => {
-    let unresolved = true;
-    element.comments = [];
-    element.addDraft(null, null, unresolved);
-    assert.equal(element.comments[0].unresolved, true);
-
-    unresolved = false; // comment should get added as actually resolved.
-    element.comments = [];
-    element.addDraft(null, null, unresolved);
-    assert.equal(element.comments[0].unresolved, false);
-
-    element.comments = [];
-    element.addDraft();
-    assert.equal(element.comments[0].unresolved, true);
-  });
-
-  test('_newDraft with root', () => {
-    const draft = element._newDraft();
-    assert.equal(draft.__commentSide, 'left');
-    assert.equal(draft.patch_set, 3);
-  });
-
-  test('_newDraft with no root', () => {
-    element.comments = [];
-    element.commentSide = 'right';
-    element.patchNum = 2;
-    const draft = element._newDraft();
-    assert.equal(draft.__commentSide, 'right');
-    assert.equal(draft.patch_set, 2);
-  });
-
-  test('new comment gets created', () => {
-    element.comments = [];
-    element.addOrEditDraft(1);
-    assert.equal(element.comments.length, 1);
-    // Mock a submitted comment.
-    element.comments[0].id = element.comments[0].__draftID;
-    element.comments[0].__draft = false;
-    element.addOrEditDraft(1);
-    assert.equal(element.comments.length, 2);
-  });
-
-  test('unresolved label', () => {
-    element.unresolved = false;
-    assert.isTrue(element.$.unresolvedLabel.hasAttribute('hidden'));
-    element.unresolved = true;
-    assert.isFalse(element.$.unresolvedLabel.hasAttribute('hidden'));
-  });
-
-  test('draft comments are at the end of orderedComments', () => {
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 2,
-      line: 5,
-      message: 'Earlier draft',
-      updated: '2015-12-08 19:48:33.843000000',
-      __draft: true,
-    },
-    {
-      author: {
-        name: 'Mr. Peanutbutter2',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 1,
-      line: 5,
-      message: 'This comment was left last but is not a draft',
-      updated: '2015-12-10 19:48:33.843000000',
-    },
-    {
-      author: {
-        name: 'Mr. Peanutbutter2',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 3,
-      line: 5,
-      message: 'Later draft',
-      updated: '2015-12-09 19:48:33.843000000',
-      __draft: true,
-    }];
-    assert.equal(element._orderedComments[0].id, '1');
-    assert.equal(element._orderedComments[1].id, '2');
-    assert.equal(element._orderedComments[2].id, '3');
-  });
-
-  test('reflects lineNum and commentSide to attributes', () => {
-    element.lineNum = 7;
-    element.commentSide = 'left';
-
-    assert.equal(element.getAttribute('line-num'), '7');
-    assert.equal(element.getAttribute('comment-side'), 'left');
-  });
-
-  test('reflects range to JSON serialized attribute if set', () => {
-    element.range = {
-      start_line: 4,
-      end_line: 5,
-      start_character: 6,
-      end_character: 7,
-    };
-
-    assert.deepEqual(
-        JSON.parse(element.getAttribute('range')),
-        {start_line: 4, end_line: 5, start_character: 6, end_character: 7});
-  });
-
-  test('removes range attribute if range is unset', () => {
-    element.range = {
-      start_line: 4,
-      end_line: 5,
-      start_character: 6,
-      end_character: 7,
-    };
-    element.range = undefined;
-
-    assert.notOk(element.hasAttribute('range'));
-  });
-});
-
-suite('comment action tests on resolved comments', () => {
-  let element;
-
-  setup(() => {
-    stub('gr-rest-api-interface', {
-      getLoggedIn() { return Promise.resolve(false); },
-      saveDiffDraft() {
-        return Promise.resolve({
-          ok: true,
-          text() {
-            return Promise.resolve(')]}\'\n' +
-                JSON.stringify({
-                  id: '7afa4931_de3d65bd',
-                  path: '/path/to/file.txt',
-                  line: 5,
-                  in_reply_to: 'baf0414d_60047215',
-                  updated: '2015-12-21 02:01:10.850000000',
-                  message: 'Done',
-                }));
-          },
-        });
-      },
-      deleteDiffDraft() { return Promise.resolve({ok: true}); },
-    });
-    element = withCommentFixture.instantiate();
-    element.patchNum = '1';
-    element.changeNum = '1';
-    element.comments = [{
-      author: {
-        name: 'Mr. Peanutbutter',
-        email: 'tenn1sballchaser@aol.com',
-      },
-      id: 'baf0414d_60047215',
-      line: 5,
-      message: 'is this a crossover episode!?',
-      updated: '2015-12-08 19:48:33.843000000',
-      path: '/path/to/file.txt',
-      unresolved: false,
-    }];
-    flush();
-  });
-
-  test('ack and done should be hidden', () => {
-    element.changeNum = '42';
-    element.patchNum = '1';
-
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const ackBtn = element.shadowRoot.querySelector('#ackBtn');
-    const doneBtn = element.shadowRoot.querySelector('#doneBtn');
-    assert.equal(ackBtn, null);
-    assert.equal(doneBtn, null);
-  });
-
-  test('reply and quote button should be visible', () => {
-    const commentEl = element.shadowRoot
-        .querySelector('gr-comment');
-    assert.ok(commentEl);
-
-    const replyBtn = element.shadowRoot.querySelector('#replyBtn');
-    const quoteBtn = element.shadowRoot.querySelector('#quoteBtn');
-    assert.ok(replyBtn);
-    assert.ok(quoteBtn);
-  });
-});
-
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.ts
new file mode 100644
index 0000000..c8409fa
--- /dev/null
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.ts
@@ -0,0 +1,1001 @@
+/**
+ * @license
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../../test/common-test-setup-karma.js';
+import './gr-comment-thread.js';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
+import {SpecialFilePath, Side} from '../../../constants/constants.js';
+import {
+  sortComments,
+  UIComment,
+  UIRobot,
+  isDraft,
+  UIDraft,
+} from '../../../utils/comment-util.js';
+import {GrCommentThread} from './gr-comment-thread.js';
+import {
+  PatchSetNum,
+  NumericChangeId,
+  UrlEncodedCommentId,
+  Timestamp,
+  RobotId,
+  RobotRunId,
+  RepoName,
+  ConfigInfo,
+  EmailAddress,
+} from '../../../types/common.js';
+import {GrComment} from '../gr-comment/gr-comment.js';
+import {LineNumber} from '../../diff/gr-diff/gr-diff-line.js';
+import {
+  tap,
+  pressAndReleaseKeyOn,
+} from '@polymer/iron-test-helpers/mock-interactions';
+import {html} from '@polymer/polymer/lib/utils/html-tag.js';
+
+const basicFixture = fixtureFromElement('gr-comment-thread');
+
+const withCommentFixture = fixtureFromElement('gr-comment-thread');
+
+suite('gr-comment-thread tests', () => {
+  suite('basic test', () => {
+    let element: GrCommentThread;
+
+    setup(() => {
+      stub('gr-rest-api-interface', {
+        getLoggedIn() {
+          return Promise.resolve(false);
+        },
+      });
+
+      element = basicFixture.instantiate();
+      element.patchNum = 3 as PatchSetNum;
+      element.changeNum = 1 as NumericChangeId;
+      flush();
+    });
+
+    test('renders without patchNum and changeNum', async () => {
+      const fixture = fixtureFromTemplate(
+        html`<gr-comment-thread show-file-path="" path="path/to/file"></gr-change-metadata>`
+      );
+      fixture.instantiate();
+      await flush();
+    });
+
+    test('comments are sorted correctly', () => {
+      const comments: UIComment[] = [
+        {
+          message: 'i like you, too',
+          in_reply_to: 'sallys_confession' as UrlEncodedCommentId,
+          __date: new Date('2015-12-25'),
+        },
+        {
+          id: 'sallys_confession' as UrlEncodedCommentId,
+          message: 'i like you, jack',
+          updated: '2015-12-24 15:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'i’m running away',
+          updated: '2015-10-31 09:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_defiance' as UrlEncodedCommentId,
+          in_reply_to: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'i will poison you so i can get away',
+          updated: '2015-10-31 15:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'dr_finklesteins_response' as UrlEncodedCommentId,
+          in_reply_to: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'no i will pull a thread and your arm will fall off',
+          updated: '2015-10-31 11:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_mission' as UrlEncodedCommentId,
+          message: 'i have to find santa',
+          updated: '2015-12-24 15:00:20.396000000' as Timestamp,
+        },
+      ];
+      const results = sortComments(comments);
+      assert.deepEqual(results, [
+        {
+          id: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'i’m running away',
+          updated: '2015-10-31 09:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'dr_finklesteins_response' as UrlEncodedCommentId,
+          in_reply_to: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'no i will pull a thread and your arm will fall off',
+          updated: '2015-10-31 11:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_defiance' as UrlEncodedCommentId,
+          in_reply_to: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          message: 'i will poison you so i can get away',
+          updated: '2015-10-31 15:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_confession' as UrlEncodedCommentId,
+          message: 'i like you, jack',
+          updated: '2015-12-24 15:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_mission' as UrlEncodedCommentId,
+          message: 'i have to find santa',
+          updated: '2015-12-24 15:00:20.396000000' as Timestamp,
+        },
+        {
+          message: 'i like you, too' as UrlEncodedCommentId,
+          in_reply_to: 'sallys_confession' as UrlEncodedCommentId,
+          __date: new Date('2015-12-25'),
+        },
+      ]);
+    });
+
+    test('addOrEditDraft w/ edit draft', () => {
+      element.comments = [
+        {
+          id: 'jacks_reply' as UrlEncodedCommentId,
+          message: 'i like you, too',
+          in_reply_to: 'sallys_confession' as UrlEncodedCommentId,
+          updated: '2015-12-25 15:00:20.396000000' as Timestamp,
+          __draft: true,
+        },
+      ];
+      const commentElStub = sinon
+        .stub(element, '_commentElWithDraftID')
+        .callsFake(() => {
+          return new GrComment();
+        });
+      const addDraftStub = sinon.stub(element, 'addDraft');
+
+      element.addOrEditDraft(123);
+
+      assert.isTrue(commentElStub.called);
+      assert.isFalse(addDraftStub.called);
+    });
+
+    test('addOrEditDraft w/o edit draft', () => {
+      element.comments = [];
+      const commentElStub = sinon
+        .stub(element, '_commentElWithDraftID')
+        .callsFake(() => {
+          return new GrComment();
+        });
+      const addDraftStub = sinon.stub(element, 'addDraft');
+
+      element.addOrEditDraft(123);
+
+      assert.isFalse(commentElStub.called);
+      assert.isTrue(addDraftStub.called);
+    });
+
+    test('_shouldDisableAction', () => {
+      let showActions = true;
+      const lastComment: UIComment = {};
+      assert.equal(
+        element._shouldDisableAction(showActions, lastComment),
+        false
+      );
+      showActions = false;
+      assert.equal(
+        element._shouldDisableAction(showActions, lastComment),
+        true
+      );
+      showActions = true;
+      lastComment.__draft = true;
+      assert.equal(
+        element._shouldDisableAction(showActions, lastComment),
+        true
+      );
+      const robotComment: UIRobot = {
+        id: '1234' as UrlEncodedCommentId,
+        updated: '1234' as Timestamp,
+        robot_id: 'robot_id' as RobotId,
+        robot_run_id: 'robot_run_id' as RobotRunId,
+        properties: {},
+        fix_suggestions: [],
+      };
+      assert.equal(
+        element._shouldDisableAction(showActions, robotComment),
+        false
+      );
+    });
+
+    test('_hideActions', () => {
+      let showActions = true;
+      const lastComment: UIComment = {};
+      assert.equal(element._hideActions(showActions, lastComment), false);
+      showActions = false;
+      assert.equal(element._hideActions(showActions, lastComment), true);
+      showActions = true;
+      lastComment.__draft = true;
+      assert.equal(element._hideActions(showActions, lastComment), true);
+      const robotComment: UIRobot = {
+        id: '1234' as UrlEncodedCommentId,
+        updated: '1234' as Timestamp,
+        robot_id: 'robot_id' as RobotId,
+        robot_run_id: 'robot_run_id' as RobotRunId,
+        properties: {},
+        fix_suggestions: [],
+      };
+      assert.equal(element._hideActions(showActions, robotComment), true);
+    });
+
+    test('setting project name loads the project config', done => {
+      const projectName = 'foo/bar/baz' as RepoName;
+      const getProjectStub = sinon
+        .stub(element.restApiService, 'getProjectConfig')
+        .returns(Promise.resolve({} as ConfigInfo));
+      element.projectName = projectName;
+      flush(() => {
+        assert.isTrue(getProjectStub.calledWithExactly(projectName));
+        done();
+      });
+    });
+
+    test('optionally show file path', () => {
+      // Path info doesn't exist when showFilePath is false. Because it's in a
+      // dom-if it is not yet in the dom.
+      assert.isNotOk(element.shadowRoot?.querySelector('.pathInfo'));
+
+      const commentStub = sinon.stub(GerritNav, 'getUrlForComment');
+      element.changeNum = 123 as NumericChangeId;
+      element.projectName = 'test project' as RepoName;
+      element.path = 'path/to/file';
+      element.patchNum = 3 as PatchSetNum;
+      element.lineNum = 5;
+      element.comments = [{id: 'comment_id' as UrlEncodedCommentId}];
+      element.showFilePath = true;
+      flush();
+      assert.isOk(element.shadowRoot?.querySelector('.pathInfo'));
+      assert.notEqual(
+        getComputedStyle(element.shadowRoot!.querySelector('.pathInfo')!)
+          .display,
+        'none'
+      );
+      assert.isTrue(
+        commentStub.calledWithExactly(
+          element.changeNum,
+          element.projectName,
+          'comment_id' as UrlEncodedCommentId
+        )
+      );
+    });
+
+    test('_computeDisplayPath', () => {
+      let path = 'path/to/file';
+      assert.equal(element._computeDisplayPath(path), 'path/to/file');
+
+      element.lineNum = 5;
+      assert.equal(element._computeDisplayPath(path), 'path/to/file');
+
+      element.patchNum = 3 as PatchSetNum;
+      path = SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
+      assert.equal(element._computeDisplayPath(path), 'Patchset');
+    });
+
+    test('_computeDisplayLine', () => {
+      element.lineNum = 5;
+      assert.equal(element._computeDisplayLine(), '#5');
+
+      element.path = SpecialFilePath.COMMIT_MESSAGE;
+      element.lineNum = 5;
+      assert.equal(element._computeDisplayLine(), '#5');
+
+      element.lineNum = undefined;
+      element.path = SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
+      assert.equal(element._computeDisplayLine(), '');
+    });
+  });
+});
+
+suite('comment action tests with unresolved thread', () => {
+  let element: GrCommentThread;
+
+  setup(() => {
+    stub('gr-rest-api-interface', {
+      getLoggedIn() {
+        return Promise.resolve(false);
+      },
+      saveDiffDraft() {
+        return Promise.resolve(({
+          headers: {} as Headers,
+          redirected: false,
+          status: 200,
+          statusText: '',
+          type: '' as ResponseType,
+          url: '',
+          ok: true,
+          text() {
+            return Promise.resolve(
+              ")]}'\n" +
+                JSON.stringify({
+                  id: '7afa4931_de3d65bd',
+                  path: '/path/to/file.txt',
+                  line: 5,
+                  in_reply_to: 'baf0414d_60047215' as UrlEncodedCommentId,
+                  updated: '2015-12-21 02:01:10.850000000',
+                  message: 'Done',
+                })
+            );
+          },
+        } as unknown) as Response);
+      },
+      deleteDiffDraft() {
+        return Promise.resolve(({ok: true} as unknown) as Response);
+      },
+    });
+    element = withCommentFixture.instantiate();
+    element.patchNum = 1 as PatchSetNum;
+    element.changeNum = 1 as NumericChangeId;
+    element.comments = [
+      {
+        author: {
+          name: 'Mr. Peanutbutter',
+          email: ('tenn1sballchaser@aol.com' as EmailAddress) as EmailAddress,
+        },
+        id: 'baf0414d_60047215' as UrlEncodedCommentId,
+        line: 5,
+        message: 'is this a crossover episode!?',
+        updated: '2015-12-08 19:48:33.843000000' as Timestamp,
+        path: '/path/to/file.txt',
+        unresolved: true,
+        patch_set: 3 as PatchSetNum,
+      },
+    ];
+    flush();
+  });
+
+  test('reply', () => {
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    const reportStub = sinon.stub(element.reporting, 'recordDraftInteraction');
+    assert.ok(commentEl);
+
+    const replyBtn = element.$.replyBtn;
+    tap(replyBtn);
+    flush();
+
+    const drafts = element._orderedComments.filter(c => isDraft(c));
+    assert.equal(drafts.length, 1);
+    assert.notOk(drafts[0].message, 'message should be empty');
+    assert.equal(
+      drafts[0].in_reply_to,
+      ('baf0414d_60047215' as UrlEncodedCommentId) as UrlEncodedCommentId
+    );
+    assert.isTrue(reportStub.calledOnce);
+  });
+
+  test('quote reply', () => {
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    const reportStub = sinon.stub(element.reporting, 'recordDraftInteraction');
+    assert.ok(commentEl);
+
+    const quoteBtn = element.$.quoteBtn;
+    tap(quoteBtn);
+    flush();
+
+    const drafts = element._orderedComments.filter(c => isDraft(c));
+    assert.equal(drafts.length, 1);
+    assert.equal(drafts[0].message, '> is this a crossover episode!?\n\n');
+    assert.equal(
+      drafts[0].in_reply_to,
+      ('baf0414d_60047215' as UrlEncodedCommentId) as UrlEncodedCommentId
+    );
+    assert.isTrue(reportStub.calledOnce);
+  });
+
+  test('quote reply multiline', () => {
+    const reportStub = sinon.stub(element.reporting, 'recordDraftInteraction');
+    element.comments = [
+      {
+        author: {
+          name: 'Mr. Peanutbutter',
+          email: ('tenn1sballchaser@aol.com' as EmailAddress) as EmailAddress,
+        },
+        id: 'baf0414d_60047215' as UrlEncodedCommentId,
+        path: 'test',
+        line: 5,
+        message: 'is this a crossover episode!?\nIt might be!',
+        updated: '2015-12-08 19:48:33.843000000' as Timestamp,
+      },
+    ];
+    flush();
+
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const quoteBtn = element.$.quoteBtn;
+    tap(quoteBtn);
+    flush();
+
+    const drafts = element._orderedComments.filter(c => isDraft(c));
+    assert.equal(drafts.length, 1);
+    assert.equal(
+      drafts[0].message,
+      '> is this a crossover episode!?\n> It might be!\n\n'
+    );
+    assert.equal(
+      drafts[0].in_reply_to,
+      'baf0414d_60047215' as UrlEncodedCommentId
+    );
+    assert.isTrue(reportStub.calledOnce);
+  });
+
+  test('ack', done => {
+    const reportStub = sinon.stub(element.reporting, 'recordDraftInteraction');
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const ackBtn = element.shadowRoot?.querySelector('#ackBtn');
+    assert.isOk(ackBtn);
+    tap(ackBtn!);
+    flush(() => {
+      const drafts = element.comments.filter(c => isDraft(c));
+      assert.equal(drafts.length, 1);
+      assert.equal(drafts[0].message, 'Ack');
+      assert.equal(
+        drafts[0].in_reply_to,
+        'baf0414d_60047215' as UrlEncodedCommentId
+      );
+      assert.equal(drafts[0].unresolved, false);
+      assert.isTrue(reportStub.calledOnce);
+      done();
+    });
+  });
+
+  test('done', done => {
+    const reportStub = sinon.stub(element.reporting, 'recordDraftInteraction');
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const doneBtn = element.shadowRoot?.querySelector('#doneBtn');
+    assert.isOk(doneBtn);
+    tap(doneBtn!);
+    flush(() => {
+      const drafts = element.comments.filter(c => isDraft(c));
+      assert.equal(drafts.length, 1);
+      assert.equal(drafts[0].message, 'Done');
+      assert.equal(
+        drafts[0].in_reply_to,
+        'baf0414d_60047215' as UrlEncodedCommentId
+      );
+      assert.isFalse(drafts[0].unresolved);
+      assert.isTrue(reportStub.calledOnce);
+      done();
+    });
+  });
+
+  test('save', done => {
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+    element.path = '/path/to/file.txt';
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const saveOrDiscardStub = sinon.stub();
+    element.addEventListener('thread-changed', saveOrDiscardStub);
+    element.shadowRoot?.querySelector('gr-comment')?._fireSave();
+
+    flush(() => {
+      assert.isTrue(saveOrDiscardStub.called);
+      assert.equal(
+        saveOrDiscardStub.lastCall.args[0].detail.rootId,
+        'baf0414d_60047215'
+      );
+      assert.equal(element.rootId, 'baf0414d_60047215' as UrlEncodedCommentId);
+      assert.equal(
+        saveOrDiscardStub.lastCall.args[0].detail.path,
+        '/path/to/file.txt'
+      );
+      done();
+    });
+  });
+
+  test('please fix', done => {
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+    commentEl!.addEventListener('create-fix-comment', () => {
+      const drafts = element._orderedComments.filter(c => isDraft(c));
+      assert.equal(drafts.length, 1);
+      assert.equal(
+        drafts[0].message,
+        '> is this a crossover episode!?\n\nPlease fix.'
+      );
+      assert.equal(
+        drafts[0].in_reply_to,
+        'baf0414d_60047215' as UrlEncodedCommentId
+      );
+      assert.isTrue(drafts[0].unresolved);
+      done();
+    });
+    commentEl!.dispatchEvent(
+      new CustomEvent('create-fix-comment', {
+        detail: {comment: commentEl!.comment},
+        composed: true,
+        bubbles: false,
+      })
+    );
+  });
+
+  test('discard', done => {
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+    element.path = '/path/to/file.txt';
+    assert.isOk(element.comments[0]);
+    element.push(
+      'comments',
+      element._newReply(
+        element.comments[0]!.id as UrlEncodedCommentId,
+        'it’s pronouced jiff, not giff'
+      )
+    );
+    flush();
+
+    const saveOrDiscardStub = sinon.stub();
+    element.addEventListener('thread-changed', saveOrDiscardStub);
+    const draftEl = element.root?.querySelectorAll('gr-comment')[1];
+    assert.ok(draftEl);
+    draftEl!.addEventListener('comment-discard', () => {
+      const drafts = element.comments.filter(c => isDraft(c));
+      assert.equal(drafts.length, 0);
+      assert.isTrue(saveOrDiscardStub.called);
+      assert.equal(
+        saveOrDiscardStub.lastCall.args[0].detail.rootId,
+        element.rootId
+      );
+      assert.equal(
+        saveOrDiscardStub.lastCall.args[0].detail.path,
+        element.path
+      );
+      done();
+    });
+    draftEl!.dispatchEvent(
+      new CustomEvent('comment-discard', {
+        detail: {comment: draftEl!.comment},
+        composed: true,
+        bubbles: false,
+      })
+    );
+  });
+
+  test('discard with a single comment still fires event with previous rootId', done => {
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+    element.path = '/path/to/file.txt';
+    element.comments = [];
+    element.addOrEditDraft(1 as LineNumber);
+    flush();
+    const rootId = element.rootId;
+    assert.isOk(rootId);
+
+    const saveOrDiscardStub = sinon.stub();
+    element.addEventListener('thread-changed', saveOrDiscardStub);
+    const draftEl = element.root?.querySelectorAll('gr-comment')[0];
+    assert.ok(draftEl);
+    draftEl!.addEventListener('comment-discard', () => {
+      assert.equal(element.comments.length, 0);
+      assert.isTrue(saveOrDiscardStub.called);
+      assert.equal(saveOrDiscardStub.lastCall.args[0].detail.rootId, rootId);
+      assert.equal(
+        saveOrDiscardStub.lastCall.args[0].detail.path,
+        element.path
+      );
+      done();
+    });
+    draftEl!.dispatchEvent(
+      new CustomEvent('comment-discard', {
+        detail: {comment: draftEl!.comment},
+        composed: true,
+        bubbles: false,
+      })
+    );
+  });
+
+  test(
+    'When not editing other comments, local storage not set' + ' after discard',
+    done => {
+      element.changeNum = 42 as NumericChangeId;
+      element.patchNum = 1 as PatchSetNum;
+      element.comments = [
+        {
+          author: {
+            name: 'Mr. Peanutbutter',
+            email: 'tenn1sballchaser@aol.com' as EmailAddress,
+          },
+          id: 'baf0414d_60047215' as UrlEncodedCommentId,
+          path: 'test',
+          line: 5,
+          message: 'is this a crossover episode!?',
+          updated: '2015-12-08 19:48:31.843000000' as Timestamp,
+        },
+        {
+          author: {
+            name: 'Mr. Peanutbutter',
+            email: 'tenn1sballchaser@aol.com' as EmailAddress,
+          },
+          __draftID: '1',
+          in_reply_to: 'baf0414d_60047215' as UrlEncodedCommentId,
+          path: 'test',
+          line: 5,
+          message: 'yes',
+          updated: '2015-12-08 19:48:32.843000000' as Timestamp,
+          __draft: true,
+          __editing: true,
+        },
+        {
+          author: {
+            name: 'Mr. Peanutbutter',
+            email: 'tenn1sballchaser@aol.com' as EmailAddress,
+          },
+          __draftID: '2',
+          in_reply_to: 'baf0414d_60047215' as UrlEncodedCommentId,
+          path: 'test',
+          line: 5,
+          message: 'no',
+          updated: '2015-12-08 19:48:33.843000000' as Timestamp,
+          __draft: true,
+        },
+      ];
+      const storageStub = sinon.stub(element.$.storage, 'setDraftComment');
+      flush();
+
+      const draftEl = element.root?.querySelectorAll('gr-comment')[1];
+      assert.ok(draftEl);
+      draftEl!.addEventListener('comment-discard', () => {
+        assert.isFalse(storageStub.called);
+        storageStub.restore();
+        done();
+      });
+      draftEl!.dispatchEvent(
+        new CustomEvent('comment-discard', {
+          detail: {comment: draftEl!.comment},
+          composed: true,
+          bubbles: false,
+        })
+      );
+    }
+  );
+
+  test('comment-update', () => {
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    const updatedComment = {
+      id: element.comments[0].id,
+      foo: 'bar',
+    };
+    assert.isOk(commentEl);
+    commentEl!.dispatchEvent(
+      new CustomEvent('comment-update', {
+        detail: {comment: updatedComment},
+        composed: true,
+        bubbles: true,
+      })
+    );
+    assert.strictEqual(element.comments[0], updatedComment);
+  });
+
+  suite('jack and sally comment data test consolidation', () => {
+    setup(() => {
+      element.comments = [
+        {
+          id: 'jacks_reply' as UrlEncodedCommentId,
+          message: 'i like you, too',
+          in_reply_to: 'sallys_confession' as UrlEncodedCommentId,
+          updated: '2015-12-25 15:00:20.396000000' as Timestamp,
+          unresolved: false,
+        },
+        {
+          id: 'sallys_confession' as UrlEncodedCommentId,
+          in_reply_to: 'nonexistent_comment' as UrlEncodedCommentId,
+          message: 'i like you, jack',
+          updated: '2015-12-24 15:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sally_to_dr_finklestein' as UrlEncodedCommentId,
+          in_reply_to: 'nonexistent_comment' as UrlEncodedCommentId,
+          message: 'i’m running away',
+          updated: '2015-10-31 09:00:20.396000000' as Timestamp,
+        },
+        {
+          id: 'sallys_defiance' as UrlEncodedCommentId,
+          message: 'i will poison you so i can get away',
+          updated: '2015-10-31 15:00:20.396000000' as Timestamp,
+        },
+      ];
+    });
+
+    test('orphan replies', () => {
+      assert.equal(4, element._orderedComments.length);
+    });
+
+    test('keyboard shortcuts', () => {
+      const expandCollapseStub = sinon.stub(element, '_expandCollapseComments');
+      pressAndReleaseKeyOn(element, 69, null, 'e');
+      assert.isTrue(expandCollapseStub.lastCall.calledWith(false));
+
+      pressAndReleaseKeyOn(element, 69, 'shift', 'e');
+      assert.isTrue(expandCollapseStub.lastCall.calledWith(true));
+    });
+
+    test('comment in_reply_to is either null or most recent comment', () => {
+      element._createReplyComment('dummy', true);
+      flush();
+      assert.equal(element._orderedComments.length, 5);
+      assert.equal(
+        element._orderedComments[4].in_reply_to,
+        'jacks_reply' as UrlEncodedCommentId
+      );
+    });
+
+    test('resolvable comments', () => {
+      assert.isFalse(element.unresolved);
+      element._createReplyComment('dummy', true, true);
+      flush();
+      assert.isTrue(element.unresolved);
+    });
+
+    test('_setInitialExpandedState with unresolved', () => {
+      element.unresolved = true;
+      element._setInitialExpandedState();
+      for (let i = 0; i < element.comments.length; i++) {
+        assert.isFalse(element.comments[i].collapsed);
+      }
+    });
+
+    test('_setInitialExpandedState without unresolved', () => {
+      element.unresolved = false;
+      element._setInitialExpandedState();
+      for (let i = 0; i < element.comments.length; i++) {
+        assert.isTrue(element.comments[i].collapsed);
+      }
+    });
+
+    test('_setInitialExpandedState with robot_ids', () => {
+      for (let i = 0; i < element.comments.length; i++) {
+        (element.comments[i] as UIRobot).robot_id = '123' as RobotId;
+      }
+      element._setInitialExpandedState();
+      for (let i = 0; i < element.comments.length; i++) {
+        assert.isFalse(element.comments[i].collapsed);
+      }
+    });
+
+    test('_setInitialExpandedState with collapsed state', () => {
+      element.comments[0].collapsed = false;
+      element.unresolved = false;
+      element._setInitialExpandedState();
+      assert.isFalse(element.comments[0].collapsed);
+      for (let i = 1; i < element.comments.length; i++) {
+        assert.isTrue(element.comments[i].collapsed);
+      }
+    });
+  });
+
+  test('_computeHostClass', () => {
+    assert.equal(element._computeHostClass(true), 'unresolved');
+    assert.equal(element._computeHostClass(false), '');
+  });
+
+  test('addDraft sets unresolved state correctly', () => {
+    let unresolved = true;
+    element.comments = [];
+    element.addDraft(undefined, undefined, unresolved);
+    assert.equal(element.comments[0].unresolved, true);
+
+    unresolved = false; // comment should get added as actually resolved.
+    element.comments = [];
+    element.addDraft(undefined, undefined, unresolved);
+    assert.equal(element.comments[0].unresolved, false);
+
+    element.comments = [];
+    element.addDraft();
+    assert.equal(element.comments[0].unresolved, true);
+  });
+
+  test('_newDraft with root', () => {
+    const draft = element._newDraft();
+    assert.equal(draft.patch_set, 3 as PatchSetNum);
+  });
+
+  test('_newDraft with no root', () => {
+    element.comments = [];
+    element.diffSide = Side.RIGHT;
+    element.patchNum = 2 as PatchSetNum;
+    const draft = element._newDraft();
+    assert.equal(draft.patch_set, 2 as PatchSetNum);
+  });
+
+  test('new comment gets created', () => {
+    element.comments = [];
+    element.addOrEditDraft(1);
+    assert.equal(element.comments.length, 1);
+    // Mock a submitted comment.
+    element.comments[0].id = (element.comments[0] as UIDraft)
+      .__draftID as UrlEncodedCommentId;
+    delete (element.comments[0] as UIDraft).__draft;
+    element.addOrEditDraft(1);
+    assert.equal(element.comments.length, 2);
+  });
+
+  test('unresolved label', () => {
+    element.unresolved = false;
+    const label = element.shadowRoot?.querySelector('#unresolvedLabel');
+    assert.isOk(label);
+    assert.isTrue(label!.hasAttribute('hidden'));
+    element.unresolved = true;
+    assert.isFalse(label!.hasAttribute('hidden'));
+  });
+
+  test('draft comments are at the end of orderedComments', () => {
+    element.comments = [
+      {
+        author: {
+          name: 'Mr. Peanutbutter',
+          email: 'tenn1sballchaser@aol.com' as EmailAddress,
+        },
+        id: '2' as UrlEncodedCommentId,
+        line: 5,
+        message: 'Earlier draft',
+        updated: '2015-12-08 19:48:33.843000000' as Timestamp,
+        __draft: true,
+      },
+      {
+        author: {
+          name: 'Mr. Peanutbutter2',
+          email: 'tenn1sballchaser@aol.com' as EmailAddress,
+        },
+        id: '1' as UrlEncodedCommentId,
+        line: 5,
+        message: 'This comment was left last but is not a draft',
+        updated: '2015-12-10 19:48:33.843000000' as Timestamp,
+      },
+      {
+        author: {
+          name: 'Mr. Peanutbutter2',
+          email: 'tenn1sballchaser@aol.com' as EmailAddress,
+        },
+        id: '3' as UrlEncodedCommentId,
+        line: 5,
+        message: 'Later draft',
+        updated: '2015-12-09 19:48:33.843000000' as Timestamp,
+        __draft: true,
+      },
+    ];
+    assert.equal(element._orderedComments[0].id, '1' as UrlEncodedCommentId);
+    assert.equal(element._orderedComments[1].id, '2' as UrlEncodedCommentId);
+    assert.equal(element._orderedComments[2].id, '3' as UrlEncodedCommentId);
+  });
+
+  test('reflects lineNum and commentSide to attributes', () => {
+    element.lineNum = 7;
+    element.diffSide = Side.LEFT;
+
+    assert.equal(element.getAttribute('line-num'), '7');
+    assert.equal(element.getAttribute('diff-side'), Side.LEFT);
+  });
+
+  test('reflects range to JSON serialized attribute if set', () => {
+    element.range = {
+      start_line: 4,
+      end_line: 5,
+      start_character: 6,
+      end_character: 7,
+    };
+
+    assert.isOk(element.getAttribute('range'));
+    assert.deepEqual(JSON.parse(element.getAttribute('range')!), {
+      start_line: 4,
+      end_line: 5,
+      start_character: 6,
+      end_character: 7,
+    });
+  });
+
+  test('removes range attribute if range is unset', () => {
+    element.range = {
+      start_line: 4,
+      end_line: 5,
+      start_character: 6,
+      end_character: 7,
+    };
+    element.range = undefined;
+
+    assert.notOk(element.hasAttribute('range'));
+  });
+});
+
+suite('comment action tests on resolved comments', () => {
+  let element: GrCommentThread;
+
+  setup(() => {
+    stub('gr-rest-api-interface', {
+      getLoggedIn() {
+        return Promise.resolve(false);
+      },
+      saveDiffDraft() {
+        return Promise.resolve(({
+          ok: true,
+          text() {
+            return Promise.resolve(
+              ")]}'\n" +
+                JSON.stringify({
+                  id: '7afa4931_de3d65bd',
+                  path: '/path/to/file.txt',
+                  line: 5,
+                  in_reply_to: 'baf0414d_60047215' as UrlEncodedCommentId,
+                  updated: '2015-12-21 02:01:10.850000000',
+                  message: 'Done',
+                })
+            );
+          },
+        } as unknown) as Response);
+      },
+      deleteDiffDraft() {
+        return Promise.resolve(({ok: true} as unknown) as Response);
+      },
+    });
+    element = withCommentFixture.instantiate();
+    element.patchNum = 1 as PatchSetNum;
+    element.changeNum = 1 as NumericChangeId;
+    element.comments = [
+      {
+        author: {
+          name: 'Mr. Peanutbutter',
+          email: 'tenn1sballchaser@aol.com' as EmailAddress,
+        },
+        id: 'baf0414d_60047215' as UrlEncodedCommentId,
+        line: 5,
+        message: 'is this a crossover episode!?',
+        updated: '2015-12-08 19:48:33.843000000' as Timestamp,
+        path: '/path/to/file.txt',
+        unresolved: false,
+      },
+    ];
+    flush();
+  });
+
+  test('ack and done should be hidden', () => {
+    element.changeNum = 42 as NumericChangeId;
+    element.patchNum = 1 as PatchSetNum;
+
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const ackBtn = element.shadowRoot?.querySelector('#ackBtn');
+    const doneBtn = element.shadowRoot?.querySelector('#doneBtn');
+    assert.equal(ackBtn, null);
+    assert.equal(doneBtn, null);
+  });
+
+  test('reply and quote button should be visible', () => {
+    const commentEl = element.shadowRoot?.querySelector('gr-comment');
+    assert.ok(commentEl);
+
+    const replyBtn = element.shadowRoot?.querySelector('#replyBtn');
+    const quoteBtn = element.shadowRoot?.querySelector('#quoteBtn');
+    assert.ok(replyBtn);
+    assert.ok(quoteBtn);
+  });
+});
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index e4d520f..3dd851e 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -24,7 +24,6 @@
 import '../gr-formatted-text/gr-formatted-text';
 import '../gr-icons/gr-icons';
 import '../gr-overlay/gr-overlay';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-storage/gr-storage';
 import '../gr-textarea/gr-textarea';
 import '../gr-tooltip-content/gr-tooltip-content';
@@ -39,7 +38,7 @@
 import {getRootElement} from '../../../scripts/rootElement';
 import {appContext} from '../../../services/app-context';
 import {customElement, observe, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {GrTextarea} from '../gr-textarea/gr-textarea';
 import {GrStorage, StorageLocation} from '../gr-storage/gr-storage';
 import {GrOverlay} from '../gr-overlay/gr-overlay';
@@ -48,11 +47,11 @@
   NumericChangeId,
   ConfigInfo,
   PatchSetNum,
+  RepoName,
 } from '../../../types/common';
 import {GrButton} from '../gr-button/gr-button';
 import {GrConfirmDeleteCommentDialog} from '../gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog';
 import {GrDialog} from '../gr-dialog/gr-dialog';
-import {Side} from '../../../constants/constants';
 import {
   isDraft,
   UIComment,
@@ -60,13 +59,12 @@
   UIRobot,
 } from '../../../utils/comment-util';
 import {OpenFixPreviewEventDetail} from '../../../types/events';
+import {fireAlert} from '../../../utils/event-util';
+import {pluralize} from '../../../utils/string-util';
 
 const STORAGE_DEBOUNCE_INTERVAL = 400;
 const TOAST_DEBOUNCE_INTERVAL = 200;
 
-const SAVING_MESSAGE = 'Saving';
-const DRAFT_SINGULAR = 'draft...';
-const DRAFT_PLURAL = 'drafts...';
 const SAVED_MESSAGE = 'All changes saved';
 const UNSAVED_MESSAGE = 'Unable to save draft';
 
@@ -97,7 +95,6 @@
 
 export interface GrComment {
   $: {
-    restAPI: RestApiService & Element;
     storage: GrStorage;
     container: HTMLDivElement;
     resolvedCheckbox: HTMLInputElement;
@@ -157,11 +154,14 @@
   @property({type: Number})
   changeNum?: NumericChangeId;
 
+  @property({type: String})
+  projectName?: RepoName;
+
   @property({type: Object, notify: true, observer: '_commentChanged'})
-  comment?: UIComment | UIRobot;
+  comment?: UIComment;
 
   @property({type: Array})
-  comments?: (UIComment | UIRobot)[];
+  comments?: UIComment[];
 
   @property({type: Boolean, reflectToAttribute: true})
   isRobotComment = false;
@@ -213,15 +213,13 @@
   _isAdmin = false;
 
   @property({type: Object})
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   _xhrPromise?: Promise<any>; // Used for testing.
 
   @property({type: String, observer: '_messageTextChanged'})
   _messageText = '';
 
   @property({type: String})
-  commentSide?: Side;
-
-  @property({type: String})
   side?: string;
 
   @property({type: Boolean})
@@ -261,6 +259,9 @@
   @property({type: Object})
   _selfAccount?: AccountDetailInfo;
 
+  @property({type: Boolean})
+  showPortedComment = false;
+
   get keyBindings() {
     return {
       'ctrl+enter meta+enter ctrl+s meta+s': '_handleSaveKey',
@@ -268,12 +269,14 @@
     };
   }
 
+  private readonly restApiService = appContext.restApiService;
+
   reporting = appContext.reportingService;
 
   /** @override */
   attached() {
     super.attached();
-    this.$.restAPI.getAccount().then(account => {
+    this.restApiService.getAccount().then(account => {
       this._selfAccount = account;
     });
     if (this.editing) {
@@ -299,6 +302,16 @@
     return comment.author || this._selfAccount;
   }
 
+  _getUrlForComment(comment: UIComment) {
+    if (!this.changeNum || !this.projectName) return '';
+    if (!comment.id) throw new Error('comment must have an id');
+    return GerritNav.getUrlForComment(
+      this.changeNum as NumericChangeId,
+      this.projectName,
+      comment.id
+    );
+  }
+
   @observe('editing')
   _onEditingChange(editing?: boolean) {
     this.dispatchEvent(
@@ -403,7 +416,7 @@
   }
 
   _getIsAdmin() {
-    return this.$.restAPI.getIsAdmin();
+    return this.restApiService.getIsAdmin();
   }
 
   _computeDraftTooltip(unableToSave: boolean) {
@@ -439,7 +452,7 @@
         }
 
         this._eraseDraftComment();
-        return this.$.restAPI.getResponseObject(response).then(obj => {
+        return this.restApiService.getResponseObject(response).then(obj => {
           const resComment = (obj as unknown) as UIDraft;
           if (!isDraft(this.comment)) throw new Error('Can only save drafts.');
           resComment.__draft = true;
@@ -448,7 +461,6 @@
           if (this.comment?.__draftID) {
             resComment.__draftID = this.comment.__draftID;
           }
-          resComment.__commentSide = this.commentSide;
           this.comment = resComment;
           this._fireSave();
           return obj;
@@ -481,7 +493,7 @@
   }
 
   _commentChanged(comment: UIComment) {
-    this.editing = !!comment.__editing;
+    this.editing = isDraft(comment) && !!comment.__editing;
     this.resolved = !comment.unresolved;
     if (this.editing) {
       // It's a new draft/reply, notify.
@@ -551,7 +563,7 @@
         cancelButton.hidden = !editing;
       }
     }
-    if (this.comment) {
+    if (isDraft(this.comment)) {
       this.comment.__editing = this.editing;
     }
     if (!!editing !== !!previousValue) {
@@ -813,11 +825,7 @@
     if (numPending === 0) {
       return SAVED_MESSAGE;
     }
-    return [
-      SAVING_MESSAGE,
-      numPending,
-      numPending === 1 ? DRAFT_SINGULAR : DRAFT_PLURAL,
-    ].join(' ');
+    return `Saving ${pluralize(numPending, 'draft')}...`;
   }
 
   _showStartRequest() {
@@ -850,13 +858,7 @@
         // Note: the event is fired on the body rather than this element because
         // this element may not be attached by the time this executes, in which
         // case the event would not bubble.
-        document.body.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message},
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireAlert(document.body, message);
       },
       TOAST_DEBOUNCE_INTERVAL
     );
@@ -873,7 +875,7 @@
       throw new Error('undefined draft or changeNum or patchNum');
     }
     this._showStartRequest();
-    return this.$.restAPI
+    return this.restApiService
       .saveDiffDraft(this.changeNum, this.patchNum, draft)
       .then(result => {
         if (result.ok) {
@@ -898,7 +900,7 @@
     }
     this._showStartRequest();
     if (!draft.id) throw new Error('Missing id in comment draft.');
-    return this.$.restAPI
+    return this.restApiService
       .deleteDiffDraft(this.changeNum, this.patchNum, {id: draft.id})
       .then(result => {
         if (result.ok) {
@@ -931,17 +933,7 @@
 
     // Only apply local drafts to comments that haven't been saved
     // remotely, and haven't been given a default message already.
-    //
-    // Don't get local draft if there is another comment that is currently
-    // in an editing state.
-    if (
-      !comment ||
-      comment.id ||
-      comment.message ||
-      comment.__otherEditing ||
-      !comment.path
-    ) {
-      if (comment) delete comment.__otherEditing;
+    if (!comment || comment.id || comment.message || !comment.path) {
       return;
     }
 
@@ -1024,7 +1016,7 @@
     ) {
       throw new Error('undefined comment or id or changeNum or patchNum');
     }
-    this.$.restAPI
+    this.restApiService
       .deleteComment(
         this.changeNum,
         this.patchNum,
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
index c021461..fbf7f47 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
@@ -245,16 +245,37 @@
     .draft gr-account-label {
       width: unset;
     }
+    .portedMessage {
+      margin: 0 var(--spacing-m);
+    }
   </style>
   <div id="container" class="container">
     <div class="header" id="header" on-click="_handleToggleCollapsed">
       <div class="headerLeft">
-        <gr-account-label
-          account="[[_getAuthor(comment, _selfAccount)]]"
-          class$="[[_computeAccountLabelClass(draft)]]"
-          hide-status=""
-        >
-        </gr-account-label>
+        <template is="dom-if" if="[[comment.robot_id]]">
+          <span class="robotName"> [[comment.robot_id]] </span>
+        </template>
+        <template is="dom-if" if="[[!comment.robot_id]]">
+          <gr-account-label
+            account="[[_getAuthor(comment, _selfAccount)]]"
+            class$="[[_computeAccountLabelClass(draft)]]"
+            hide-status=""
+          >
+          </gr-account-label>
+        </template>
+        <template is="dom-if" if="[[showPortedComment]]">
+          <a href="[[_getUrlForComment(comment)]]"
+            ><span class="portedMessage"
+              >Ported from patchset [[comment.patch_set]]</span
+            ></a
+          >
+          <a
+            href="https://bugs.chromium.org/p/gerrit/issues/entry?template=Porting+Comments"
+            target="_blank"
+          >
+            <iron-icon icon="gr-icons:bug" title="report a problem"></iron-icon>
+          </a>
+        </template>
         <gr-tooltip-content
           class="draftTooltip"
           has-tooltip=""
@@ -473,6 +494,5 @@
       </gr-dialog>
     </gr-overlay>
   </template>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
   <gr-storage id="storage"></gr-storage>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_test.js b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_test.js
index 10925af..cc89a7e 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_test.js
@@ -19,7 +19,7 @@
 import './gr-comment.js';
 import {html} from '@polymer/polymer/lib/utils/html-tag.js';
 import {__testOnly_UNSAVED_MESSAGE} from './gr-comment.js';
-import {SpecialFilePath} from '../../../constants/constants.js';
+import {SpecialFilePath, Side} from '../../../constants/constants.js';
 
 const basicFixture = fixtureFromElement('gr-comment');
 
@@ -129,7 +129,6 @@
           email: 'tenn1sballchaser@aol.com',
         },
         line: 5,
-        __otherEditing: true,
       };
       flush(() => {
         assert.isTrue(loadSpy.called);
@@ -276,7 +275,7 @@
 
     test('delete comment', done => {
       sinon.stub(
-          element.$.restAPI, 'deleteComment').returns(Promise.resolve({}));
+          element.restApiService, 'deleteComment').returns(Promise.resolve({}));
       sinon.spy(element.confirmDeleteOverlay, 'open');
       element.changeNum = 42;
       element.patchNum = 0xDEADBEEF;
@@ -293,7 +292,7 @@
                   .querySelector('#confirmDeleteComment');
           dialog.message = 'removal reason';
           element._handleConfirmDeleteComment();
-          assert.isTrue(element.$.restAPI.deleteComment.calledWith(
+          assert.isTrue(element.restApiService.deleteComment.calledWith(
               42, 0xDEADBEEF, 'baf0414d_60047215', 'removal reason'));
           done();
         });
@@ -375,7 +374,7 @@
       element.patchNum = 1;
       const updateRequestStub = sinon.stub(element, '_updateRequestToast');
       const diffDraftStub =
-        sinon.stub(element.$.restAPI, 'saveDiffDraft').returns(
+        sinon.stub(element.restApiService, 'saveDiffDraft').returns(
             Promise.resolve({ok: false}));
       element._saveDraft({id: 'abc_123'});
       flush(() => {
@@ -411,7 +410,7 @@
       element.patchNum = 1;
       const updateRequestStub = sinon.stub(element, '_updateRequestToast');
       const diffDraftStub =
-        sinon.stub(element.$.restAPI, 'saveDiffDraft').returns(
+        sinon.stub(element.restApiService, 'saveDiffDraft').returns(
             Promise.reject(new Error()));
       element._saveDraft({id: 'abc_123'});
       flush(() => {
@@ -477,13 +476,13 @@
       element.patchNum = 1;
       element.editing = false;
       element.comment = {
-        __commentSide: 'right',
+        diffSide: Side.RIGHT,
         __draft: true,
         __draftID: 'temp_draft_id',
         path: '/path/to/file',
         line: 5,
       };
-      element.commentSide = 'right';
+      element.diffSide = Side.RIGHT;
     });
 
     test('button visibility states', () => {
@@ -695,9 +694,8 @@
         assert.isTrue(runDetailsLink.href.indexOf(element.comment.url) !== -1);
 
         const robotServiceName = element.shadowRoot
-            .querySelector('gr-account-label')
-            .shadowRoot.querySelector('span.name');
-        assert.equal(robotServiceName.textContent.trim(), 'Display name Robot');
+            .querySelector('.robotName');
+        assert.equal(robotServiceName.textContent.trim(), 'happy_robot_id');
 
         const authorName = element.shadowRoot
             .querySelector('.robotId');
@@ -733,7 +731,7 @@
         path: SpecialFilePath.PATCHSET_LEVEL_COMMENTS, line: undefined,
         range: undefined};
       element.comment = comment;
-      flushAsynchronousOperations();
+      flush();
       MockInteractions.tap(element.shadowRoot
           .querySelector('.edit'));
       assert.isTrue(element.editing);
@@ -804,7 +802,7 @@
     test('storage is cleared only after save success', () => {
       element._messageText = 'test';
       const eraseStub = sinon.stub(element, '_eraseDraftComment');
-      sinon.stub(element.$.restAPI, 'getResponseObject')
+      sinon.stub(element.restApiService, 'getResponseObject')
           .returns(Promise.resolve({}));
 
       sinon.stub(element, '_saveDraft').returns(Promise.resolve({ok: false}));
@@ -911,7 +909,6 @@
 
         assert.deepEqual(dispatchEventStub.lastCall.args[0].detail, {
           comment: {
-            __commentSide: 'right',
             __draft: true,
             __draftID: 'temp_draft_id',
             id: 'baf0414d_40572e03',
@@ -1139,7 +1136,7 @@
           updated: '2017-04-04 15:36:17.000000000',
           message: 'This is a robot comment with a fix.',
           unresolved: false,
-          __commentSide: 'right',
+          diffSide: Side.RIGHT,
           collapsed: false,
         },
         {
@@ -1149,7 +1146,7 @@
           path: 'Documentation/config-gerrit.txt',
           patchNum: 1,
           side: 'REVISION',
-          __commentSide: 'right',
+          diffSide: Side.RIGHT,
           line: 10,
           in_reply_to: 'eb0d03fd_5e95904f',
           message: '> This is a robot comment with a fix.\n\nPlease fix.',
@@ -1214,7 +1211,7 @@
           updated: '2017-04-04 15:36:17.000000000',
           message: 'This is a robot comment with a fix.',
           unresolved: false,
-          __commentSide: 'right',
+          diffSide: Side.RIGHT,
           collapsed: false,
         },
       ];
@@ -1266,7 +1263,7 @@
       element = draftFixture.instantiate();
       // fake random
       element.getRandomNum = () => 0;
-      element.comment = {__editing: true};
+      element.comment = {__editing: true, __draft: true};
       flush(() => {
         assert.isTrue(respectfulGetStub.called);
         assert.isTrue(respectfulSetStub.called);
@@ -1289,7 +1286,7 @@
       element = draftFixture.instantiate();
       // fake random
       element.getRandomNum = () => 0;
-      element.comment = {__editing: true};
+      element.comment = {__editing: true, __draft: true};
       flush(() => {
         assert.isTrue(respectfulGetStub.called);
         assert.isTrue(respectfulSetStub.called);
@@ -1318,7 +1315,7 @@
       element = draftFixture.instantiate();
       // fake random
       element.getRandomNum = () => 3;
-      element.comment = {__editing: true};
+      element.comment = {__editing: true, __draft: true};
       flush(() => {
         assert.isTrue(respectfulGetStub.called);
         assert.isFalse(respectfulSetStub.called);
@@ -1373,7 +1370,7 @@
       element = draftFixture.instantiate();
       // fake random
       element.getRandomNum = () => 0;
-      element.comment = {__editing: true};
+      element.comment = {__editing: true, __draft: true};
       flush(() => {
         assert.isTrue(respectfulGetStub.called);
         assert.isFalse(respectfulSetStub.called);
diff --git a/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter.ts b/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter.ts
deleted file mode 100644
index bbbce16..0000000
--- a/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter.ts
+++ /dev/null
@@ -1,44 +0,0 @@
-/**
- * @license
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-export const GrCountStringFormatter = {
-  /**
-   * Returns a count plus string that is pluralized when necessary.
-   */
-  computePluralString(count: number, noun: string): string {
-    return this.computeString(count, noun) + (count > 1 ? 's' : '');
-  },
-
-  /**
-   * Returns a count plus string that is not pluralized.
-   */
-  computeString(count: number, noun: string): string {
-    if (count === 0) {
-      return '';
-    }
-    return `${count} ${noun}`;
-  },
-
-  /**
-   * Returns a count plus arbitrary text.
-   */
-  computeShortString(count: number, text: string): string {
-    if (count === 0) {
-      return '';
-    }
-    return `${count}${text}`;
-  },
-};
diff --git a/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter_test.js b/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter_test.js
deleted file mode 100644
index 36637ec..0000000
--- a/polygerrit-ui/app/elements/shared/gr-count-string-formatter/gr-count-string-formatter_test.js
+++ /dev/null
@@ -1,47 +0,0 @@
-/**
- * @license
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import '../../../test/common-test-setup-karma.js';
-import {GrCountStringFormatter} from './gr-count-string-formatter.js';
-
-suite('gr-count-string-formatter tests', () => {
-  test('computeString', () => {
-    const noun = 'unresolved';
-    assert.equal(GrCountStringFormatter.computeString(0, noun), '');
-    assert.equal(GrCountStringFormatter.computeString(1, noun),
-        '1 unresolved');
-    assert.equal(GrCountStringFormatter.computeString(2, noun),
-        '2 unresolved');
-  });
-
-  test('computeShortString', () => {
-    const noun = 'c';
-    assert.equal(GrCountStringFormatter.computeShortString(0, noun), '');
-    assert.equal(GrCountStringFormatter.computeShortString(1, noun), '1c');
-    assert.equal(GrCountStringFormatter.computeShortString(2, noun), '2c');
-  });
-
-  test('computePluralString', () => {
-    const noun = 'comment';
-    assert.equal(GrCountStringFormatter.computePluralString(0, noun), '');
-    assert.equal(GrCountStringFormatter.computePluralString(1, noun),
-        '1 comment');
-    assert.equal(GrCountStringFormatter.computePluralString(2, noun),
-        '2 comments');
-  });
-});
-
diff --git a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
index 9fdbb34..2fbbd7c 100644
--- a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
+++ b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
@@ -261,14 +261,14 @@
     this._targetHeight = null;
   }
 
-  isAtStart() {
-    return this.index === 0;
+  /** Returns true if there are no stops, or we are on the first stop. */
+  isAtStart(): boolean {
+    return this.stops.length === 0 || this.index === 0;
   }
 
-  isAtEnd() {
-    // Unset cursor should not be considered "at end", even when there are no
-    // cursor stops.
-    return this.index !== -1 && this.index === this.stops.length - 1;
+  /** Returns true if there are no stops, or we are on the last stop. */
+  isAtEnd(): boolean {
+    return this.stops.length === 0 || this.index === this.stops.length - 1;
   }
 
   moveToStart() {
@@ -419,9 +419,6 @@
     return top;
   }
 
-  /**
-   * @return
-   */
   _targetIsVisible(top: number) {
     const dims = this._getWindowDims();
     return (
diff --git a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager_test.js b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager_test.js
index 33aeafc..6f74d6b 100644
--- a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager_test.js
@@ -117,6 +117,16 @@
     assert.equal(element.index, -1);
   });
 
+  test('isAtStart() returns true when there are no stops', () => {
+    element.stops = [];
+    assert.isTrue(element.isAtStart());
+  });
+
+  test('isAtEnd() returns true when there are no stops', () => {
+    element.stops = [];
+    assert.isTrue(element.isAtEnd());
+  });
+
   test('next() goes to first element when no cursor is set', () => {
     element.stops = [...list.querySelectorAll('li')];
     const result = element.next();
@@ -137,8 +147,6 @@
     assert.equal(element.index, -1);
     assert.isNotOk(element.target);
     assert.isFalse(list.children[1].classList.contains('targeted'));
-    assert.isFalse(element.isAtStart());
-    assert.isFalse(element.isAtEnd());
   });
 
   test('previous() goes to last element when no cursor is set', () => {
@@ -162,8 +170,6 @@
     assert.equal(element.index, -1);
     assert.isNotOk(element.target);
     assert.isFalse(list.children[1].classList.contains('targeted'));
-    assert.isFalse(element.isAtStart());
-    assert.isFalse(element.isAtEnd());
   });
 
   test('_moveCursor', () => {
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
index c64dc2a..5bb4f4c 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -30,11 +29,12 @@
   isWithinHalfYear,
   formatDate,
   utcOffsetString,
+  wasYesterday,
 } from '../../../utils/date-util';
 import {TimeFormat, DateFormat} from '../../../constants/constants';
 import {assertNever} from '../../../utils/common-util';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {Timestamp} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
 const TimeFormats = {
   TIME_12: 'h:mm A', // 2:14 PM
@@ -77,12 +77,6 @@
   }
 }
 
-export interface GrDateFormatter {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
-
 @customElement('gr-date-formatter')
 export class GrDateFormatter extends TooltipMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -104,6 +98,9 @@
   @property({type: Boolean})
   hasTooltip = false;
 
+  @property({type: Boolean})
+  showYesterday = false;
+
   /**
    * The title to be used as the native tooltip or by the tooltip behavior.
    */
@@ -130,6 +127,8 @@
   @property({type: Boolean})
   relativeOptionNoAgo = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
   }
@@ -210,11 +209,11 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   _getPreferences() {
-    return this.$.restAPI.getPreferences();
+    return this.restApiService.getPreferences();
   }
 
   _computeDateStr(
@@ -222,7 +221,8 @@
     timeFormat?: string,
     dateFormat?: DateFormatPair,
     relative?: boolean,
-    showDateAndTime?: boolean
+    showDateAndTime?: boolean,
+    showYesterday?: boolean
   ) {
     if (!dateStr || !timeFormat || !dateFormat) {
       return '';
@@ -238,6 +238,8 @@
     let format = dateFormat.full;
     if (isWithinDay(now, date)) {
       format = timeFormat;
+    } else if (showYesterday && wasYesterday(now, date)) {
+      return `Yesterday at ${formatDate(date, timeFormat)}`;
     } else {
       if (isWithinHalfYear(now, date)) {
         format = dateFormat.short;
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
index a5dd6d0..97bbf68 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
@@ -25,7 +25,6 @@
   </style>
   <span>
     [[_computeDateStr(dateStr, _timeFormat, _dateFormat, _relative,
-    showDateAndTime)]]
+    showDateAndTime, showYesterday)]]
   </span>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.ts b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.ts
index 02d039a..5810222 100644
--- a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.ts
+++ b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.ts
@@ -17,20 +17,18 @@
 import '@polymer/iron-input/iron-input';
 import '../../../styles/shared-styles';
 import '../gr-button/gr-button';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-select/gr-select';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-diff-preferences_html';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-import {DiffPreferencesInfo} from '../../../types/common';
+import {DiffPreferencesInfo} from '../../../types/diff';
 import {GrSelect} from '../gr-select/gr-select';
+import {appContext} from '../../../services/app-context';
 
 export interface GrDiffPreferences {
   $: {
-    restAPI: RestApiService & Element;
     lineWrappingInput: HTMLInputElement;
     showTabsInput: HTMLInputElement;
     showTrailingWhitespaceInput: HTMLInputElement;
@@ -55,8 +53,10 @@
   @property({type: Object})
   diffPrefs?: DiffPreferencesInfo;
 
+  private readonly restApiService = appContext.restApiService;
+
   loadData() {
-    return this.$.restAPI.getDiffPreferences().then(prefs => {
+    return this.restApiService.getDiffPreferences().then(prefs => {
       this.diffPrefs = prefs;
     });
   }
@@ -99,7 +99,7 @@
   save() {
     if (!this.diffPrefs)
       return Promise.reject(new Error('Missing diff preferences'));
-    return this.$.restAPI.saveDiffPreferences(this.diffPrefs).then(_ => {
+    return this.restApiService.saveDiffPreferences(this.diffPrefs).then(_ => {
       this.hasUnsavedChanges = false;
     });
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_html.ts b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_html.ts
index 54022ba..d30aadf 100644
--- a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_html.ts
@@ -191,5 +191,4 @@
       </div>
     </section>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_test.js b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_test.js
index ced8c6c..6afb299 100644
--- a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences_test.js
@@ -89,7 +89,7 @@
   });
 
   test('save changes', () => {
-    sinon.stub(element.$.restAPI, 'saveDiffPreferences')
+    sinon.stub(element.restApiService, 'saveDiffPreferences')
         .returns(Promise.resolve());
     const showTrailingWhitespaceCheckbox =
         valueOf('Show trailing whitespace', 'diffPreferences')
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
index 97747a0..d2f003b7 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
@@ -16,7 +16,6 @@
  */
 import '@polymer/paper-tabs/paper-tabs';
 import '../gr-shell-command/gr-shell-command';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../../../styles/shared-styles';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -24,7 +23,7 @@
 import {htmlTemplate} from './gr-download-commands_html';
 import {customElement, property, observe} from '@polymer/decorators';
 import {PaperTabsElement} from '@polymer/paper-tabs/paper-tabs';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -35,7 +34,6 @@
 export interface GrDownloadCommands {
   $: {
     downloadTabs: PaperTabsElement;
-    restAPI: RestApiService & Element;
   };
 }
 
@@ -65,6 +63,8 @@
   @property({type: String, notify: true})
   selectedScheme?: string;
 
+  private readonly restApiService = appContext.restApiService;
+
   /** @override */
   attached() {
     super.attached();
@@ -79,7 +79,7 @@
   }
 
   _getLoggedIn() {
-    return this.$.restAPI.getLoggedIn();
+    return this.restApiService.getLoggedIn();
   }
 
   @observe('_loggedIn')
@@ -87,7 +87,7 @@
     if (!loggedIn) {
       return;
     }
-    return this.$.restAPI.getPreferences().then(prefs => {
+    return this.restApiService.getPreferences().then(prefs => {
       if (prefs?.download_scheme) {
         // Note (issue 5180): normalize the download scheme with lower-case.
         this.selectedScheme = prefs.download_scheme.toLowerCase();
@@ -100,7 +100,9 @@
     if (scheme && scheme !== this.selectedScheme) {
       this.set('selectedScheme', scheme);
       if (this._loggedIn) {
-        this.$.restAPI.savePreferences({download_scheme: this.selectedScheme});
+        this.restApiService.savePreferences({
+          download_scheme: this.selectedScheme,
+        });
       }
     }
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_html.ts b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_html.ts
index 35385fa..5c15b29 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_html.ts
@@ -72,5 +72,4 @@
       ></gr-shell-command>
     </template>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.js b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.js
index 5429506..105cc2c 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.js
@@ -94,10 +94,11 @@
         },
       });
       element._loggedIn = true;
-      assert.isTrue(element.$.restAPI.getPreferences.called);
-      return element.$.restAPI.getPreferences.lastCall.returnValue.then(() => {
-        assert.equal(element.selectedScheme, 'repo');
-      });
+      assert.isTrue(element.restApiService.getPreferences.called);
+      return element.restApiService.getPreferences.lastCall.returnValue.then(
+          () => {
+            assert.equal(element.selectedScheme, 'repo');
+          });
     });
 
     test('normalize scheme from preferences', () => {
@@ -107,14 +108,16 @@
         },
       });
       element._loggedIn = true;
-      return element.$.restAPI.getPreferences.lastCall.returnValue.then(() => {
-        assert.equal(element.selectedScheme, 'repo');
-      });
+      return element.restApiService.getPreferences.lastCall.returnValue.then(
+          () => {
+            assert.equal(element.selectedScheme, 'repo');
+          });
     });
 
     test('saves scheme to preferences', () => {
       element._loggedIn = true;
-      const savePrefsStub = sinon.stub(element.$.restAPI, 'savePreferences')
+      const savePrefsStub = sinon.stub(element.restApiService,
+          'savePreferences')
           .callsFake(() => Promise.resolve());
 
       flush();
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
index 2ea72ca..3fce16e 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
@@ -21,6 +21,7 @@
 import '../gr-button/gr-button';
 import '../gr-date-formatter/gr-date-formatter';
 import '../gr-select/gr-select';
+import '../gr-file-status-chip/gr-file-status-chip';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -28,12 +29,7 @@
 import {customElement, property, observe} from '@polymer/decorators';
 import {IronDropdownElement} from '@polymer/iron-dropdown/iron-dropdown';
 import {Timestamp} from '../../../types/common';
-
-/**
- * fired when the selected value of the dropdown changes
- *
- * @event {change}
- */
+import {NormalizedFileInfo} from '../../change/gr-file-list/gr-file-list';
 
 /**
  * Requred values are text and value. mobileText and triggerText will
@@ -52,6 +48,7 @@
   mobileText?: string;
   date?: Timestamp;
   disabled?: boolean;
+  file?: NormalizedFileInfo;
 }
 
 export interface GrDropdownList {
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
index 26a6b3f..c163924 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
@@ -145,7 +145,6 @@
       slot="dropdown-content"
       attr-for-selected="data-value"
       selected="{{value}}"
-      on-tap="_handleDropdownTap"
     >
       <template
         is="dom-repeat"
@@ -158,6 +157,9 @@
             <template is="dom-if" if="[[item.date]]">
               <gr-date-formatter date-str="[[item.date]]"></gr-date-formatter>
             </template>
+            <template is="dom-if" if="[[item.file]]">
+              <gr-file-status-chip file="[[item.file]]"></gr-file-status-chip>
+            </template>
           </div>
           <template is="dom-if" if="[[item.bottomText]]">
             <div class="bottomContent">
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.ts b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.ts
index d64b1c0..ae9bfd7 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.ts
@@ -17,7 +17,6 @@
 import '@polymer/iron-dropdown/iron-dropdown';
 import '../gr-button/gr-button';
 import '../gr-cursor-manager/gr-cursor-manager';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import '../gr-tooltip-content/gr-tooltip-content';
 import '../../../styles/shared-styles';
 import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_html.ts b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_html.ts
index 8ea0d21..c767edd 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_html.ts
@@ -165,5 +165,4 @@
     focus-on-move=""
     stops="[[_listElements]]"
   ></gr-cursor-manager>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.ts b/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.ts
index 90aaa9f..10e8916 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.ts
+++ b/polygerrit-ui/app/elements/shared/gr-editable-content/gr-editable-content.ts
@@ -24,6 +24,7 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {customElement, property} from '@polymer/decorators';
 import {htmlTemplate} from './gr-editable-content_html';
+import {fireAlert, fireEvent} from '../../../utils/event-util';
 
 const RESTORED_MESSAGE = 'Content restored from a previous edit.';
 const STORAGE_DEBOUNCE_INTERVAL_MS = 400;
@@ -149,13 +150,7 @@
       );
       if (storedContent?.message) {
         content = storedContent.message;
-        this.dispatchEvent(
-          new CustomEvent('show-alert', {
-            detail: {message: RESTORED_MESSAGE},
-            bubbles: true,
-            composed: true,
-          })
-        );
+        fireAlert(this, RESTORED_MESSAGE);
       }
     }
     if (!content) {
@@ -193,11 +188,6 @@
   _handleCancel(e: Event) {
     e.preventDefault();
     this.editing = false;
-    this.dispatchEvent(
-      new CustomEvent('editable-content-cancel', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'editable-content-cancel');
   }
 }
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.ts b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.ts
index 9e1a5bf..6f0e84a 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.ts
+++ b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label.ts
@@ -89,6 +89,9 @@
   @property({type: Number})
   readonly _verticalOffset = -30;
 
+  @property({type: Boolean})
+  showAsEditPencil = false;
+
   /** @override */
   ready() {
     super.ready();
@@ -133,7 +136,7 @@
     this._inputText = this.value;
     this.editing = true;
 
-    return new Promise(resolve => {
+    return new Promise<void>(resolve => {
       this._awaitOpen(resolve);
     });
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_html.ts b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_html.ts
index 5e36166..7700689 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_html.ts
@@ -68,13 +68,32 @@
       }
       --paper-input-container-focus-color: var(--link-color);
     }
+    gr-button iron-icon {
+      color: inherit;
+      --iron-icon-height: 18px;
+      --iron-icon-width: 18px;
+    }
+    gr-button.new-change-summary-true {
+      --padding: 1px 4px;
+    }
   </style>
-  <label
-    class$="[[_computeLabelClass(readOnly, value, placeholder)]]"
-    title$="[[_computeLabel(value, placeholder)]]"
-    on-click="_showDropdown"
-    >[[_computeLabel(value, placeholder)]]</label
-  >
+  <template is="dom-if" if="[[!showAsEditPencil]]">
+    <label
+      class$="[[_computeLabelClass(readOnly, value, placeholder)]]"
+      title$="[[_computeLabel(value, placeholder)]]"
+      on-click="_showDropdown"
+      >[[_computeLabel(value, placeholder)]]</label
+    >
+  </template>
+  <template is="dom-if" if="[[showAsEditPencil]]">
+    <gr-button
+      link=""
+      class$="new-change-summary-true [[_computeLabelClass(readOnly, value, placeholder)]]"
+      on-click="_showDropdown"
+      title="[[_computeLabel(value, placeholder)]]"
+      ><iron-icon icon="gr-icons:edit"></iron-icon
+    ></gr-button>
+  </template>
   <iron-dropdown
     id="dropdown"
     vertical-align="auto"
diff --git a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_test.js b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_test.js
index d8f085e..2bdc570 100644
--- a/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-editable-label/gr-editable-label_test.js
@@ -45,6 +45,7 @@
   setup(async () => {
     element = basicFixture.instantiate();
     elementNoPlaceholder = noPlaceholderFixture.instantiate();
+    flush();
     label = element.shadowRoot.querySelector('label');
 
     await flush();
@@ -178,6 +179,7 @@
 
     setup(() => {
       element = readOnlyFixture.instantiate();
+      flush();
       label = element.shadowRoot
           .querySelector('label');
     });
diff --git a/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip.ts b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip.ts
new file mode 100644
index 0000000..9298fa3
--- /dev/null
+++ b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip.ts
@@ -0,0 +1,90 @@
+/**
+ * @license
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import '../../../styles/shared-styles';
+import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
+import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
+import {htmlTemplate} from './gr-file-status-chip_html';
+import {customElement, property} from '@polymer/decorators';
+import {PolymerElement} from '@polymer/polymer/polymer-element';
+import {SpecialFilePath} from '../../../constants/constants';
+import {NormalizedFileInfo} from '../../change/gr-file-list/gr-file-list';
+import {hasOwnProperty} from '../../../utils/common-util';
+
+const FileStatus = {
+  A: 'Added',
+  C: 'Copied',
+  D: 'Deleted',
+  M: 'Modified',
+  R: 'Renamed',
+  W: 'Rewritten',
+  U: 'Unchanged',
+};
+
+@customElement('gr-file-status-chip')
+export class GrFileStatusChip extends GestureEventListeners(
+  LegacyElementMixin(PolymerElement)
+) {
+  static get template() {
+    return htmlTemplate;
+  }
+
+  @property({type: Object})
+  file?: NormalizedFileInfo;
+
+  /**
+   * Get a descriptive label for use in the status indicator's tooltip and
+   * ARIA label.
+   */
+  _computeFileStatusLabel(status?: keyof typeof FileStatus) {
+    const statusCode = this._computeFileStatus(status);
+    return hasOwnProperty(FileStatus, statusCode)
+      ? FileStatus[statusCode]
+      : 'Status Unknown';
+  }
+
+  _computeClass(baseClass?: string, path?: string) {
+    const classes = [];
+    if (baseClass) {
+      classes.push(baseClass);
+    }
+    if (
+      path === SpecialFilePath.COMMIT_MESSAGE ||
+      path === SpecialFilePath.MERGE_LIST
+    ) {
+      classes.push('invisible');
+    }
+    return classes.join(' ');
+  }
+
+  _computeFileStatus(
+    status?: keyof typeof FileStatus
+  ): keyof typeof FileStatus {
+    return status || 'M';
+  }
+
+  _computeStatusClass(file?: NormalizedFileInfo) {
+    if (!file) return '';
+    const classStr = this._computeClass('status', file.__path);
+    return `${classStr} ${this._computeFileStatus(file.status)}`;
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'gr-file-status-chip': GrFileStatusChip;
+  }
+}
diff --git a/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_html.ts b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_html.ts
new file mode 100644
index 0000000..9e49868
--- /dev/null
+++ b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_html.ts
@@ -0,0 +1,51 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {html} from '@polymer/polymer/lib/utils/html-tag';
+
+export const htmlTemplate = html`
+  <style include="shared-styles">
+    .status {
+      display: inline-block;
+      border-radius: var(--border-radius);
+      margin-left: var(--spacing-s);
+      padding: 0 var(--spacing-m);
+      color: var(--primary-text-color);
+      font-size: var(--font-size-small);
+      background-color: var(--dark-add-highlight-color);
+    }
+    .status.invisible,
+    .status.M {
+      display: none;
+    }
+    .status.D,
+    .status.R,
+    .status.W {
+      background-color: var(--dark-remove-highlight-color);
+    }
+    .status.U {
+      background-color: var(--comment-background-color);
+    }
+  </style>
+  <span
+    class$="[[_computeStatusClass(file)]]"
+    tabindex="0"
+    title$="[[_computeFileStatusLabel(file.status)]]"
+    aria-label$="[[_computeFileStatusLabel(file.status)]]"
+  >
+    [[_computeFileStatusLabel(file.status)]]
+  </span>
+`;
diff --git a/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_test.ts b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_test.ts
new file mode 100644
index 0000000..0abc85f
--- /dev/null
+++ b/polygerrit-ui/app/elements/shared/gr-file-status-chip/gr-file-status-chip_test.ts
@@ -0,0 +1,46 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../../test/common-test-setup-karma';
+import './gr-file-status-chip';
+import {GrFileStatusChip} from './gr-file-status-chip';
+
+const fixture = fixtureFromElement('gr-file-status-chip');
+
+suite('gr-file-status-chip tests', () => {
+  let element: GrFileStatusChip;
+
+  setup(() => {
+    element = fixture.instantiate();
+  });
+
+  test('computed properties', () => {
+    assert.equal(element._computeFileStatus('A'), 'A');
+    assert.equal(element._computeFileStatus(undefined), 'M');
+
+    assert.equal(element._computeClass('clazz', '/foo/bar/baz'), 'clazz');
+    assert.equal(
+      element._computeClass('clazz', '/COMMIT_MSG'),
+      'clazz invisible'
+    );
+  });
+
+  test('_computeFileStatusLabel', () => {
+    assert.equal(element._computeFileStatusLabel('A'), 'Added');
+    assert.equal(element._computeFileStatusLabel('M'), 'Modified');
+  });
+});
diff --git a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_html.ts b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_html.ts
index bc1dfe0..1688a0d 100644
--- a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_html.ts
@@ -59,7 +59,8 @@
     gr-linked-text.pre {
       font-family: var(--monospace-font-family);
       font-size: var(--font-size-code);
-      line-height: var(--line-height-code);
+      /* usually 16px = 12px + 4px */
+      line-height: calc(var(--font-size-code) + var(--spacing-s));
     }
   </style>
   <div id="container"></div>
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
index da2881e..761e670 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
@@ -19,7 +19,6 @@
 import '../../../styles/shared-styles';
 import '../gr-avatar/gr-avatar';
 import '../gr-button/gr-button';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {hovercardBehaviorMixin} from '../gr-hovercard/gr-hovercard-behavior';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -29,7 +28,6 @@
 import {accountKey} from '../../../utils/account-util';
 import {getDisplayName} from '../../../utils/display-name-util';
 import {customElement, property} from '@polymer/decorators';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AccountInfo,
   ChangeInfo,
@@ -46,12 +44,8 @@
 } from '../../../utils/attention-set-util';
 import {ReviewerState} from '../../../constants/constants';
 import {isRemovableReviewer} from '../../../utils/change-util';
+import {CURRENT} from '../../../utils/patch-set-util';
 
-export interface GrHovercardAccount {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
 @customElement('gr-hovercard-account')
 export class GrHovercardAccount extends GestureEventListeners(
   hovercardBehaviorMixin(LegacyElementMixin(PolymerElement))
@@ -94,6 +88,8 @@
 
   reporting: ReportingService;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this.reporting = appContext.reportingService;
@@ -101,10 +97,10 @@
 
   attached() {
     super.attached();
-    this.$.restAPI.getConfig().then(config => {
+    this.restApiService.getConfig().then(config => {
       this._config = config;
     });
-    this.$.restAPI.getAccount().then(account => {
+    this.restApiService.getAccount().then(account => {
       this._selfAccount = account;
     });
   }
@@ -185,8 +181,8 @@
       },
     ];
 
-    this.$.restAPI
-      .saveChangeReview(this.change._number, 'current', reviewInput)
+    this.restApiService
+      .saveChangeReview(this.change._number, CURRENT, reviewInput)
       .then(response => {
         if (!response || !response.ok) {
           throw new Error(
@@ -204,7 +200,7 @@
     this.dispatchEventThroughTarget('show-alert', {
       message: 'Reloading page...',
     });
-    this.$.restAPI
+    this.restApiService
       .removeChangeReviewer(
         this.change._number,
         (this.account?._account_id || this.account?.email)!
@@ -256,7 +252,7 @@
       'attention-hovercard-add',
       this._reportingDetails()
     );
-    this.$.restAPI
+    this.restApiService
       .addToAttentionSet(this.change._number, this.account._account_id, reason)
       .then(() => {
         this.dispatchEventThroughTarget('hide-alert');
@@ -283,7 +279,7 @@
       'attention-hovercard-remove',
       this._reportingDetails()
     );
-    this.$.restAPI
+    this.restApiService
       .removeFromAttentionSet(
         this.change._number,
         this.account._account_id,
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
index 1d437fb..99d3d6c 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
@@ -196,5 +196,4 @@
       </template>
     </template>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_test.js b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_test.js
index b09f0ce..c8b4b42 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_test.js
@@ -36,7 +36,7 @@
 
   setup(() => {
     element = basicFixture.instantiate();
-    sinon.stub(element.$.restAPI, 'getAccount').returns(
+    sinon.stub(element.restApiService, 'getAccount').returns(
         new Promise(resolve => { '2'; })
     );
 
@@ -110,7 +110,7 @@
         [ReviewerState.REVIEWER]: [ACCOUNT],
       },
     };
-    sinon.stub(element.$.restAPI, 'removeChangeReviewer').returns(
+    sinon.stub(element.restApiService, 'removeChangeReviewer').returns(
         Promise.resolve({ok: true}));
     const reloadListener = sinon.spy();
     element._target.addEventListener('reload', reloadListener);
@@ -130,10 +130,10 @@
         [ReviewerState.REVIEWER]: [ACCOUNT],
       },
     };
-    const saveReviewStub = sinon.stub(element.$.restAPI,
+    const saveReviewStub = sinon.stub(element.restApiService,
         'saveChangeReview').returns(
         Promise.resolve({ok: true}));
-    sinon.stub(element.$.restAPI, 'removeChangeReviewer').returns(
+    sinon.stub(element.restApiService, 'removeChangeReviewer').returns(
         Promise.resolve({ok: true}));
     const reloadListener = sinon.spy();
     element._target.addEventListener('reload', reloadListener);
@@ -157,10 +157,10 @@
         [ReviewerState.REVIEWER]: [],
       },
     };
-    const saveReviewStub = sinon.stub(element.$.restAPI,
+    const saveReviewStub = sinon.stub(element.restApiService,
         'saveChangeReview').returns(
         Promise.resolve({ok: true}));
-    sinon.stub(element.$.restAPI, 'removeChangeReviewer').returns(
+    sinon.stub(element.restApiService, 'removeChangeReviewer').returns(
         Promise.resolve({ok: true}));
     const reloadListener = sinon.spy();
     element._target.addEventListener('reload', reloadListener);
@@ -184,7 +184,7 @@
         [ReviewerState.REVIEWER]: [],
       },
     };
-    sinon.stub(element.$.restAPI, 'removeChangeReviewer').returns(
+    sinon.stub(element.restApiService, 'removeChangeReviewer').returns(
         Promise.resolve({ok: true}));
     const reloadListener = sinon.spy();
     element._target.addEventListener('reload', reloadListener);
@@ -206,7 +206,7 @@
     const apiPromise = new Promise(r => {
       apiResolve = r;
     });
-    sinon.stub(element.$.restAPI, 'addToAttentionSet')
+    sinon.stub(element.restApiService, 'addToAttentionSet')
         .callsFake(() => apiPromise);
     element.highlightAttention = true;
     element._target = document.createElement('div');
@@ -239,7 +239,7 @@
     const apiPromise = new Promise(r => {
       apiResolve = r;
     });
-    sinon.stub(element.$.restAPI, 'removeFromAttentionSet')
+    sinon.stub(element.restApiService, 'removeFromAttentionSet')
         .callsFake(() => apiPromise);
     element.highlightAttention = true;
     element.change = {attention_set: {31415926535: {}}};
diff --git a/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts b/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
index 7112e3b..1170477 100644
--- a/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
+++ b/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
@@ -112,6 +112,8 @@
       <g id="schedule"><path d="M11.99 2C6.47 2 2 6.48 2 12s4.47 10 9.99 10C17.52 22 22 17.52 22 12S17.52 2 11.99 2zM12 20c-4.42 0-8-3.58-8-8s3.58-8 8-8 8 3.58 8 8-3.58 8-8 8zm.5-13H11v6l5.25 3.15.75-1.23-4.5-2.67z"></path></g>
       <!-- This SVG is a copy from material.io https://material.io/icons/#bug_report-->
       <g id="bug"><path d="M0 0h24v24H0z" fill="none"/><path d="M20 8h-2.81c-.45-.78-1.07-1.45-1.82-1.96L17 4.41 15.59 3l-2.17 2.17C12.96 5.06 12.49 5 12 5c-.49 0-.96.06-1.41.17L8.41 3 7 4.41l1.62 1.63C7.88 6.55 7.26 7.22 6.81 8H4v2h2.09c-.05.33-.09.66-.09 1v1H4v2h2v1c0 .34.04.67.09 1H4v2h2.81c1.04 1.79 2.97 3 5.19 3s4.15-1.21 5.19-3H20v-2h-2.09c.05-.33.09-.66.09-1v-1h2v-2h-2v-1c0-.34-.04-.67-.09-1H20V8zm-6 8h-4v-2h4v2zm0-4h-4v-2h4v2z"/></g>
+      <!-- This SVG is a copy from material.io https://fonts.gstatic.com/s/i/googlematerialicons/move_item/v1/24px.svg -->
+      <g id="move-item"><path d="M15,19H5V5h10v4h2V5c0-1.1-0.89-2-2-2H5C3.9,3,3,3.9,3,5v14c0,1.1,0.9,2,2,2h10c1.11,0,2-0.9,2-2v-4h-2V19z"/><polygon points="20.01,8.01 18.59,9.41 20.17,11 8,11 8,13 20.17,13 18.59,14.59 20.01,15.99 24,12"/></g>
     </defs>
   </svg>
 </iron-iconset-svg>`;
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-context.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-context.ts
index 0cb628c..a493e51 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-context.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-context.ts
@@ -18,6 +18,7 @@
 import {GrAnnotation} from '../../diff/gr-diff-highlight/gr-annotation';
 import {GrStyleObject} from '../../plugins/gr-styles-api/gr-styles-api';
 import {GrDiffLine} from '../../diff/gr-diff/gr-diff-line';
+import {appContext} from '../../../services/app-context';
 
 /**
  * Used to create a context for GrAnnotationActionsInterface.
@@ -42,6 +43,8 @@
 
   changeNum: number;
 
+  private readonly reporting = appContext.reportingService;
+
   constructor(
     contentEl: HTMLElement,
     lineNumberEl: HTMLElement,
@@ -56,8 +59,8 @@
     this.path = path;
     this.changeNum = Number(changeNum);
     if (isNaN(this.changeNum)) {
-      console.error(
-        `GrAnnotationActionsContext: Invalid changeNum: ${changeNum}`
+      this.reporting.error(
+        new Error(`GrAnnotationActionsContext: Invalid changeNum: ${changeNum}`)
       );
     }
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api.ts
index e069f8b..f160807 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api.ts
@@ -24,6 +24,7 @@
 import {Side} from '../../../constants/constants';
 import {PluginApi} from '../../plugins/gr-plugin-types';
 import {ChangeInfo, NumericChangeId} from '../../../types/common';
+import {appContext} from '../../../services/app-context';
 
 type AddLayerFunc = (ctx: GrAnnotationActionsContext) => void;
 
@@ -52,6 +53,8 @@
   // Default impl is a no-op.
   private addLayerFunc: AddLayerFunc = () => {};
 
+  reporting = appContext.reportingService;
+
   constructor(private readonly plugin: PluginApi) {
     // Return this instance when there is an annotatediff event.
     plugin.on('annotatediff', this);
@@ -134,12 +137,14 @@
   ) {
     this.plugin.hook('annotation-toggler').onAttached(element => {
       if (!element.content) {
-        console.error('plugin endpoint without content.');
+        this.reporting.error(new Error('plugin endpoint without content.'));
         return;
       }
       if (!element.content.hidden) {
-        console.error(
-          element.content.id + ' is already enabled. Cannot re-enable.'
+        this.reporting.error(
+          new Error(
+            `${element.content.id} is already enabled. Cannot re-enable.`
+          )
         );
         return;
       }
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.js b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.js
index 8b3f501..7ae34cf 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.js
@@ -133,12 +133,9 @@
     // Assert that error is shown if we try to enable checkbox again.
     onAttachedFuncCalled = false;
     annotationActions.enableToggleCheckbox('test label2', onAttachedFunc);
-    const errorStub = sinon.stub(
-        console, 'error').callsFake((msg, err) => undefined);
+    const errorStub = sinon.stub(annotationActions.reporting, 'error');
     emulateAttached();
-    assert.isTrue(
-        errorStub.calledWith(
-            'annotation-span is already enabled. Cannot re-enable.'));
+    assert.isTrue(errorStub.called);
     // Assert that onAttachedFunc is not called and the label has not changed.
     assert.isFalse(onAttachedFuncCalled);
     assert.equal(document.getElementById('annotation-label').textContent,
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
index a493a2e..7e8c1f8 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
@@ -19,13 +19,9 @@
   ActionPriority,
 } from '../../../services/services/gr-rest-api/gr-rest-api';
 import {JsApiService} from './gr-js-api-types';
-import {TargetElement} from '../../plugins/gr-plugin-types';
+import {PluginApi, TargetElement} from '../../plugins/gr-plugin-types';
 import {ActionInfo, RequireProperties} from '../../../types/common';
 
-interface Plugin {
-  getPluginName(): string;
-}
-
 export enum ChangeActions {
   ABANDON = 'abandon',
   DELETE = '/',
@@ -102,7 +98,7 @@
 
   ActionType = ActionType;
 
-  constructor(public plugin: Plugin, el?: GrChangeActionsElement) {
+  constructor(public plugin: PluginApi, el?: GrChangeActionsElement) {
     this.setEl(el);
   }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
index 37ac354..cf254d4 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
@@ -259,8 +259,10 @@
    */
   globalGerritObj.addListener = (eventName: string, cb: EventCallback) =>
     eventEmitter.addListener(eventName, cb);
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   globalGerritObj.dispatch = (eventName: string, detail: any) =>
     eventEmitter.dispatch(eventName, detail);
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   globalGerritObj.emit = (eventName: string, detail: any) =>
     eventEmitter.emit(eventName, detail);
   globalGerritObj.off = (eventName: string, cb: EventCallback) =>
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
index 736fac9..00f9a40 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
@@ -18,7 +18,7 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {getPluginLoader} from './gr-plugin-loader';
-import {patchNumEquals} from '../../../utils/patch-set-util';
+
 import {customElement} from '@polymer/decorators';
 import {
   ChangeInfo,
@@ -36,6 +36,7 @@
 import {EventType, TargetElement} from '../../plugins/gr-plugin-types';
 import {DiffLayer, HighlightJS} from '../../../types/types';
 import {ParsedChangeInfo} from '../gr-rest-api-interface/gr-reviewer-updates-parser';
+import {appContext} from '../../../services/app-context';
 
 const elements: {[key: string]: HTMLElement} = {};
 const eventCallbacks: {[key: string]: EventCallback[]} = {};
@@ -44,6 +45,9 @@
 export class GrJsApiInterface
   extends GestureEventListeners(LegacyElementMixin(PolymerElement))
   implements JsApiService {
+  private readonly reporting = appContext.reportingService;
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   handleEvent(type: EventType, detail: any) {
     getPluginLoader()
       .awaitPluginsLoaded()
@@ -98,7 +102,7 @@
       try {
         return callback(change, revision) === false;
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
       return false;
     });
@@ -119,7 +123,7 @@
       try {
         cb(detail.path);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -150,7 +154,7 @@
 
     let revision;
     for (const rev of Object.values(change.revisions || {})) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         revision = rev;
         break;
       }
@@ -160,7 +164,7 @@
       try {
         cb(change, revision, info);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -173,7 +177,7 @@
       try {
         cb(detail.revisionActions, detail.change);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -183,7 +187,7 @@
       try {
         cb(change, msg);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -194,7 +198,7 @@
       try {
         cb(detail.node);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -204,7 +208,7 @@
       try {
         cb(detail.change);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -214,7 +218,7 @@
       try {
         cb(detail.hljs);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -224,7 +228,7 @@
       try {
         revertMsg = cb(change, revertMsg, origMsg) as string;
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
     return revertMsg;
@@ -243,7 +247,7 @@
           origMsg
         ) as string;
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
     return revertSubmissionMsg;
@@ -257,7 +261,7 @@
         const layer = annotationApi.getLayer(path, changeNum);
         layers.push(layer);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
     return layers;
@@ -269,7 +273,7 @@
         const annotationApi = (cb as unknown) as GrAnnotationActionsInterface;
         annotationApi.disposeLayer(path);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
   }
@@ -310,7 +314,7 @@
       try {
         labels = cb(change);
       } catch (err) {
-        console.error(err);
+        this.reporting.error(err);
       }
     }
     return labels;
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.ts
index b9a6ff4..a05e7e1 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface.ts
@@ -14,7 +14,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import './gr-js-api-interface-element';
 import './gr-public-js-api';
 import './gr-gerrit';
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
index b5c4e48..1481c2d 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
@@ -24,6 +24,7 @@
 import {getPluginLoader} from './gr-plugin-loader.js';
 import {_testOnly_initGerritPluginApi} from './gr-gerrit.js';
 import {stubBaseUrl} from '../../../test/test-utils.js';
+import sinon from 'sinon/pkg/sinon-esm';
 
 const basicFixture = fixtureFromElement('gr-js-api-interface');
 
@@ -57,7 +58,7 @@
       },
     });
     element = basicFixture.instantiate();
-    errorStub = sinon.stub(console, 'error');
+    errorStub = sinon.stub(element.reporting, 'error');
     pluginApi.install(p => { plugin = p; }, '0.1',
         'http://test.com/plugins/testplugin/static/test.js');
     getPluginLoader().loadPlugins([]);
@@ -404,6 +405,7 @@
 
   suite('popup', () => {
     test('popup(element) is deprecated', () => {
+      sinon.stub(console, 'error');
       plugin.popup(document.createElement('div'));
       assert.isTrue(console.error.calledOnce);
     });
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-types.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-types.ts
index 6456370..0a49b97 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-types.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-types.ts
@@ -31,6 +31,7 @@
   revisionActions: {[key: string]: ActionInfo};
 }
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type EventCallback = (...args: any[]) => any;
 
 export interface JsApiService {
@@ -41,6 +42,7 @@
     revertSubmissionMsg: string,
     origMsg: string
   ): string;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   handleEvent(eventName: EventType, detail: any): void;
   modifyRevertMsg(
     change: ChangeInfo,
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
index 3935ef1..da19e5b 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
@@ -19,6 +19,7 @@
 import {HookApi, PluginApi} from '../../plugins/gr-plugin-types';
 import {notUndefined} from '../../../types/types';
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 type Callback = (value: any) => void;
 
 export interface ModuleInfo {
@@ -42,6 +43,7 @@
 export class GrPluginEndpoints {
   private readonly _endpoints = new Map<string, ModuleInfo[]>();
 
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   private readonly _callbacks = new Map<string, ((value: any) => void)[]>();
 
   private readonly _dynamicPlugins = new Map<string, Set<string>>();
@@ -178,6 +180,7 @@
   }
 
   importUrl(pluginUrl: URL) {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     let timerId: any;
     return Promise.race([
       new Promise((resolve, reject) => {
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
index 47b7be3..b725d3b 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
@@ -340,6 +340,7 @@
     const urlWithAP = this._urlFor(pluginUrl, window.ASSETS_PATH);
     const urlWithoutAP = this._urlFor(pluginUrl);
     let onerror = undefined;
+    this._getReporting().reportExecution('html-plugin', {pluginUrl});
     if (urlWithAP !== urlWithoutAP) {
       onerror = () => this._loadHtmlPlugin(urlWithoutAP, opts.sync);
     }
@@ -424,14 +425,15 @@
       return Promise.resolve();
     }
     if (!this._loadingPromise) {
-      // TODO(TS): Should be a number, but TS thinks that is must be some weird
-      // NodeJS.Timeout object.
-      let timerId: any;
+      // specify window here so that TS pulls the correct setTimeout method
+      // if window is not specified, then the function is pulled from node
+      // and the return type is NodeJS.Timeout object
+      let timerId: number;
       this._loadingPromise = Promise.race([
-        new Promise(resolve => (this._loadingResolver = resolve)),
+        new Promise<void>(resolve => (this._loadingResolver = resolve)),
         new Promise(
           (_, reject) =>
-            (timerId = setTimeout(() => {
+            (timerId = window.setTimeout(() => {
               reject(new Error(this._timeout()));
             }, PLUGIN_LOADING_TIMEOUT_MS))
         ),
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-rest-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-rest-api.ts
index 00b2963..eb63a77 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-rest-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-rest-api.ts
@@ -120,14 +120,28 @@
     errFn?: ErrorCallback,
     contentType?: string
   ) {
+    // Plugins typically don't want Gerrit to show error dialogs for failed
+    // requests. So we are defining a default errFn here, even if it is not
+    // explicitly set by the caller.
+    // TODO: We are soon getting rid of the `errFn` altogether. There are only
+    // 2 known usages of errFn in plugins: delete-project and verify-status.
+    errFn =
+      errFn ??
+      ((response: Response | null | undefined, error?: Error) => {
+        if (error) throw error;
+        if (response) throw new Error(`${response.status}`);
+        throw new Error('Generic REST API error.');
+      });
     return this.fetch(method, url, payload, errFn, contentType).then(
       response => {
+        // Will typically not happen. The response can only be unset, if the
+        // errFn handles the error and then returns void or undefined or null.
+        // But the errFn above always throws.
         if (!response) {
-          // TODO(TS): Fix method definition
-          // If errFn exists and doesn't throw an exception, the fetch method
-          // returns empty response
-          throw new Error('errFn must throw an exception');
+          throw new Error('plugin rest-api call failed');
         }
+        // Will typically not happen. errFn will have dealt with that and the
+        // caller will get a rejected promise already.
         if (response.status < 200 || response.status >= 300) {
           return response.text().then(text => {
             if (text) {
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
index 0625f67..61d64a8 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
@@ -34,7 +34,7 @@
 import {getPluginEndpoints} from './gr-plugin-endpoints';
 
 import {PRELOADED_PROTOCOL, getPluginNameFromUrl, send} from './gr-api-utils';
-import {GrReporintJsApi} from './gr-reporting-js-api';
+import {GrReportingJsApi} from './gr-reporting-js-api';
 import {
   EventType,
   HookApi,
@@ -46,6 +46,7 @@
 import {HttpMethod} from '../../../constants/constants';
 import {JsApiService} from './gr-js-api-types';
 import {GrChangeActions} from '../../change/gr-change-actions/gr-change-actions';
+import {GrChecksApi} from '../../plugins/gr-checks-api/gr-checks-api';
 
 /**
  * Plugin-provided custom components can affect content in extension
@@ -170,6 +171,7 @@
     return document.createElement('gr-rest-api-interface').getConfig();
   }
 
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   on(eventName: EventType, callback: (...args: any[]) => any) {
     this.sharedApiElement.addEventCallback(eventName, callback);
   }
@@ -250,8 +252,12 @@
     return new GrChangeReplyInterface(this, this.sharedApiElement);
   }
 
+  checks(): GrChecksApi {
+    return new GrChecksApi(this);
+  }
+
   reporting() {
-    return new GrReporintJsApi(this);
+    return new GrReportingJsApi(this);
   }
 
   theme() {
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-reporting-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-reporting-js-api.ts
index 0bf6676..87b320c4 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-reporting-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-reporting-js-api.ts
@@ -17,16 +17,12 @@
 
 import {appContext} from '../../../services/app-context';
 import {EventDetails} from '../../../services/gr-reporting/gr-reporting';
-
-// TODO(TS): remove once Plugin api converted to ts
-interface PluginApi {
-  getPluginName(): string;
-}
+import {PluginApi} from '../../plugins/gr-plugin-types';
 
 /**
  * Defines all methods that will be exported to plugin from reporting service.
  */
-export class GrReporintJsApi {
+export class GrReportingJsApi {
   private readonly reporting = appContext.reportingService;
 
   constructor(private readonly plugin: PluginApi) {}
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
index 1dac371..70f68ae 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
@@ -21,7 +21,6 @@
 import '../gr-button/gr-button';
 import '../gr-icons/gr-icons';
 import '../gr-label/gr-label';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
@@ -38,15 +37,9 @@
   isQuickLabelInfo,
   isDetailedLabelInfo,
 } from '../../../types/common';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrButton} from '../gr-button/gr-button';
 import {getVotingRangeOrDefault} from '../../../utils/label-util';
-
-export interface GrLabelInfo {
-  $: {
-    restAPI: RestApiService & Element;
-  };
-}
+import {appContext} from '../../../services/app-context';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -90,6 +83,8 @@
   @property({type: Boolean})
   mutable = false;
 
+  private readonly restApiService = appContext.restApiService;
+
   // TODO(TS): not used, remove later
   _xhrPromise?: Promise<void>;
 
@@ -206,7 +201,7 @@
     const accountID = Number(
       `${target.getAttribute('data-account-id')}`
     ) as AccountId;
-    this._xhrPromise = this.$.restAPI
+    this._xhrPromise = this.restApiService
       .deleteVote(this.change._number, accountID, this.label)
       .then(response => {
         target.disabled = false;
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_html.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_html.ts
index 3955cd4..46b8be1 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_html.ts
@@ -118,5 +118,4 @@
       </tr>
     </template>
   </table>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.js b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.js
index 3a2cc39..aa71bfc 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.js
@@ -73,7 +73,7 @@
     test('deletes votes', () => {
       const deleteResponse = Promise.resolve({ok: true});
       const deleteStub = sinon.stub(
-          element.$.restAPI, 'deleteVote').returns(deleteResponse);
+          element.restApiService, 'deleteVote').returns(deleteResponse);
 
       element.change.removable_reviewers = [element.account];
       element.change.labels.test.recommended = {_account_id: 1};
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
index dbb8725..fa244f6 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
+++ b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
@@ -24,6 +24,7 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {customElement, property} from '@polymer/decorators';
 import {htmlTemplate} from './gr-linked-chip_html';
+import {fireEvent} from '../../../utils/event-util';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -64,11 +65,6 @@
 
   _handleRemoveTap(e: Event) {
     e.preventDefault();
-    this.dispatchEvent(
-      new CustomEvent('remove', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'remove');
   }
 }
diff --git a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.ts b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.ts
index 342e937..97b45ac 100644
--- a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.ts
+++ b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.ts
@@ -24,7 +24,8 @@
 import {htmlTemplate} from './gr-list-view_html';
 import {encodeURL, getBaseUrl} from '../../../utils/url-util';
 import {page} from '../../../utils/page-wrapper-utils';
-import {property, observe, customElement} from '@polymer/decorators';
+import {property, customElement} from '@polymer/decorators';
+import {fireEvent} from '../../../utils/event-util';
 
 const REQUEST_DEBOUNCE_INTERVAL_MS = 200;
 
@@ -51,7 +52,7 @@
   @property({type: Number})
   itemsPerPage = 25;
 
-  @property({type: String})
+  @property({type: String, observer: '_filterChanged'})
   filter?: string;
 
   @property({type: Number})
@@ -69,8 +70,8 @@
     this.cancelDebouncer('reload');
   }
 
-  @observe('filter')
-  _filterChanged(newFilter: string, oldFilter: string) {
+  _filterChanged(newFilter?: string, oldFilter?: string) {
+    // newFilter can be empty string and then !newFilter === true
     if (!newFilter && !oldFilter) {
       return;
     }
@@ -78,7 +79,7 @@
     this._debounceReload(newFilter);
   }
 
-  _debounceReload(filter: string) {
+  _debounceReload(filter?: string) {
     this.debounce(
       'reload',
       () => {
@@ -96,12 +97,7 @@
   }
 
   _createNewItem() {
-    this.dispatchEvent(
-      new CustomEvent('create-clicked', {
-        composed: true,
-        bubbles: true,
-      })
-    );
+    fireEvent(this, 'create-clicked');
   }
 
   _computeNavLink(
diff --git a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
index 957496c..d29cba7 100644
--- a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
+++ b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
@@ -20,8 +20,10 @@
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-overlay_html';
 import {IronOverlayMixin} from '../../../mixins/iron-overlay-mixin/iron-overlay-mixin';
-import {customElement, property} from '@polymer/decorators';
+import {customElement} from '@polymer/decorators';
 import {IronOverlayBehavior} from '@polymer/iron-overlay-behavior/iron-overlay-behavior';
+import {findActiveElement} from '../../../utils/dom-util';
+import {fireEvent} from '../../../utils/event-util';
 
 const AWAIT_MAX_ITERS = 10;
 const AWAIT_STEP = 5;
@@ -54,12 +56,13 @@
    * @event fullscreen-overlay-opened
    */
 
-  @property({type: Boolean})
   private _fullScreenOpen = false;
 
   private _boundHandleClose: () => void = () => super.close();
 
-  private focusableNodes: Node[] | undefined;
+  private focusableNodes?: Node[];
+
+  private returnFocusTo?: HTMLElement;
 
   get _focusableNodes() {
     if (this.focusableNodes) {
@@ -76,6 +79,7 @@
     // once the type contains the exported member,
     // should replace with:
     // import {IronFocusablesHelper} from '@polymer/iron-overlay-behavior/iron-focusables-helper';
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     return (window.Polymer as any).IronFocusablesHelper.getTabbableNodes(this);
   }
 
@@ -89,16 +93,12 @@
   }
 
   open() {
+    this.returnFocusTo = findActiveElement(document, true) ?? undefined;
     window.addEventListener('popstate', this._boundHandleClose);
-    return new Promise((resolve, reject) => {
+    return new Promise<void>((resolve, reject) => {
       super.open.apply(this);
       if (this._isMobile()) {
-        this.dispatchEvent(
-          new CustomEvent('fullscreen-overlay-opened', {
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireEvent(this, 'fullscreen-overlay-opened');
         this._fullScreenOpen = true;
       }
       this._awaitOpen(resolve, reject);
@@ -113,14 +113,13 @@
   _overlayClosed() {
     window.removeEventListener('popstate', this._boundHandleClose);
     if (this._fullScreenOpen) {
-      this.dispatchEvent(
-        new CustomEvent('fullscreen-overlay-closed', {
-          composed: true,
-          bubbles: true,
-        })
-      );
+      fireEvent(this, 'fullscreen-overlay-closed');
       this._fullScreenOpen = false;
     }
+    if (this.returnFocusTo) {
+      this.returnFocusTo.focus();
+      this.returnFocusTo = undefined;
+    }
   }
 
   /**
diff --git a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.ts b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.ts
index 01eada8..6db1925 100644
--- a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.ts
+++ b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker.ts
@@ -18,7 +18,6 @@
 import '../../../styles/shared-styles';
 import '../gr-icons/gr-icons';
 import '../gr-labeled-autocomplete/gr-labeled-autocomplete';
-import '../gr-rest-api-interface/gr-rest-api-interface';
 import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
@@ -33,7 +32,7 @@
   BranchInfo,
 } from '../../../types/common';
 import {GrLabeledAutocomplete} from '../gr-labeled-autocomplete/gr-labeled-autocomplete';
-import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {appContext} from '../../../services/app-context';
 
 const SUGGESTIONS_LIMIT = 15;
 const REF_PREFIX = 'refs/heads/';
@@ -42,7 +41,6 @@
   $: {
     repoInput: GrLabeledAutocomplete;
     branchInput: GrLabeledAutocomplete;
-    restAPI: RestApiService & Element;
   };
 }
 @customElement('gr-repo-branch-picker')
@@ -68,6 +66,8 @@
   @property({type: Object})
   _repoQuery?: AutocompleteQuery;
 
+  private readonly restApiService = appContext.restApiService;
+
   constructor() {
     super();
     this._query = input => this._getRepoBranchesSuggestions(input);
@@ -95,13 +95,13 @@
     if (input.startsWith(REF_PREFIX)) {
       input = input.substring(REF_PREFIX.length);
     }
-    return this.$.restAPI
+    return this.restApiService
       .getRepoBranches(input, this.repo, SUGGESTIONS_LIMIT)
       .then(res => this._branchResponseToSuggestions(res));
   }
 
   _getRepoSuggestions(input: string) {
-    return this.$.restAPI
+    return this.restApiService
       .getRepos(input, SUGGESTIONS_LIMIT)
       .then(res => this._repoResponseToSuggestions(res));
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_html.ts b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_html.ts
index 934b3cb..3e551b6 100644
--- a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_html.ts
@@ -49,5 +49,4 @@
     >
     </gr-labeled-autocomplete>
   </div>
-  <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_test.js b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_test.js
index 1d8ae98..8fbc639 100644
--- a/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-repo-branch-picker/gr-repo-branch-picker_test.js
@@ -29,7 +29,7 @@
 
   suite('_getRepoSuggestions', () => {
     setup(() => {
-      sinon.stub(element.$.restAPI, 'getRepos')
+      sinon.stub(element.restApiService, 'getRepos')
           .returns(Promise.resolve([
             {
               id: 'plugins%2Favatars-external',
@@ -50,7 +50,7 @@
     test('converts to suggestion objects', () => {
       const input = 'plugins/avatars';
       return element._getRepoSuggestions(input).then(suggestions => {
-        assert.isTrue(element.$.restAPI.getRepos.calledWith(input));
+        assert.isTrue(element.restApiService.getRepos.calledWith(input));
         const unencodedNames = [
           'plugins/avatars-external',
           'plugins/avatars-gravatar',
@@ -65,7 +65,7 @@
 
   suite('_getRepoBranchesSuggestions', () => {
     setup(() => {
-      sinon.stub(element.$.restAPI, 'getRepoBranches')
+      sinon.stub(element.restApiService, 'getRepoBranches')
           .returns(Promise.resolve([
             {ref: 'refs/heads/stable-2.10'},
             {ref: 'refs/heads/stable-2.11'},
@@ -82,7 +82,7 @@
       element.repo = repo;
       return element._getRepoBranchesSuggestions(branchInput)
           .then(suggestions => {
-            assert.isTrue(element.$.restAPI.getRepoBranches.calledWith(
+            assert.isTrue(element.restApiService.getRepoBranches.calledWith(
                 branchInput, repo, 15));
             const refNames = [
               'stable-2.10',
@@ -103,7 +103,7 @@
       element.repo = repo;
       return element._getRepoBranchesSuggestions(branchInput)
           .then(suggestions => {
-            assert.isTrue(element.$.restAPI.getRepoBranches.calledWith(
+            assert.isTrue(element.restApiService.getRepoBranches.calledWith(
                 'stable-2.1', repo, 15));
           });
     });
@@ -111,12 +111,12 @@
     test('does not query when repo is unset', () => element
         ._getRepoBranchesSuggestions('')
         .then(() => {
-          assert.isFalse(element.$.restAPI.getRepoBranches.called);
+          assert.isFalse(element.restApiService.getRepoBranches.called);
           element.repo = 'gerrit';
           return element._getRepoBranchesSuggestions('');
         })
         .then(() => {
-          assert.isTrue(element.$.restAPI.getRepoBranches.called);
+          assert.isTrue(element.restApiService.getRepoBranches.called);
         }));
   });
 });
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
index b3596c7..9e77784 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
@@ -36,11 +36,7 @@
 import {parseDate} from '../../../utils/date-util';
 import {getBaseUrl} from '../../../utils/url-util';
 import {appContext} from '../../../services/app-context';
-import {
-  getParentIndex,
-  isMergeParent,
-  patchNumEquals,
-} from '../../../utils/patch-set-util';
+import {getParentIndex, isMergeParent} from '../../../utils/patch-set-util';
 import {
   ListChangesOption,
   listChangesOptionsToHex,
@@ -72,9 +68,7 @@
   DashboardId,
   DashboardInfo,
   DeleteDraftCommentsInput,
-  DiffInfo,
   DiffPreferenceInput,
-  DiffPreferencesInfo,
   EditPatchSetNum,
   EditPreferencesInfo,
   EncodedGroupId,
@@ -142,6 +136,11 @@
   MergeableInfo,
 } from '../../../types/common';
 import {
+  DiffInfo,
+  DiffPreferencesInfo,
+  IgnoreWhitespaceType,
+} from '../../../types/diff';
+import {
   CancelConditionCallback,
   ErrorCallback,
   RestApiService,
@@ -152,9 +151,9 @@
   CommentSide,
   DiffViewMode,
   HttpMethod,
-  IgnoreWhitespaceType,
   ReviewerState,
 } from '../../../constants/constants';
+import {firePageError, fireServerError} from '../../../utils/event-util';
 
 const JSON_PREFIX = ")]}'";
 const MAX_PROJECT_RESULTS = 25;
@@ -251,7 +250,6 @@
 
 interface GetDiffParams {
   [paramName: string]: string | undefined | null | number | boolean;
-  context?: number | 'ALL';
   intraline?: boolean | null;
   whitespace?: IgnoreWhitespaceType;
   parent?: number;
@@ -301,23 +299,6 @@
   extends GestureEventListeners(LegacyElementMixin(PolymerElement))
   implements RestApiService {
   readonly JSON_PREFIX = JSON_PREFIX;
-  /**
-   * Fired when an server error occurs.
-   *
-   * @event server-error
-   */
-
-  /**
-   * Fired when a network error occurs.
-   *
-   * @event network-error
-   */
-
-  /**
-   * Fired after an RPC completes.
-   *
-   * @event rpc-log
-   */
 
   @property({type: Object})
   readonly _cache = siteBasedCache; // Shared across instances.
@@ -340,14 +321,15 @@
   // The value is set in created, before any other actions
   private readonly _restApiHelper: GrRestApiHelper;
 
-  constructor() {
+  constructor(authService?: AuthService) {
     super();
-    this.authService = appContext.authService;
+    // TODO: Make the authService constructor parameter required when we have
+    // changed all usages of this class to not instantiate via createElement().
+    this.authService = authService ?? appContext.authService;
     this._restApiHelper = new GrRestApiHelper(
       this._cache,
       this.authService,
-      this._sharedFetchPromises,
-      this
+      this._sharedFetchPromises
     );
   }
 
@@ -422,19 +404,7 @@
     }) as Promise<DashboardInfo[] | undefined>;
   }
 
-  saveRepoConfig(repo: RepoName, config: ConfigInput): Promise<Response>;
-
-  saveRepoConfig(
-    repo: RepoName,
-    config: ConfigInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  saveRepoConfig(
-    repo: RepoName,
-    config: ConfigInput,
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined> {
+  saveRepoConfig(repo: RepoName, config: ConfigInput): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const url = `/projects/${encodeURIComponent(repo)}/config`;
@@ -443,23 +413,11 @@
       method: HttpMethod.PUT,
       url,
       body: config,
-      errFn,
       anonymizedUrl: '/projects/*/config',
     });
   }
 
-  runRepoGC(repo: RepoName): Promise<Response>;
-
-  runRepoGC(
-    repo: RepoName,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  runRepoGC(repo: RepoName, errFn?: ErrorCallback) {
-    if (!repo) {
-      // TODO(TS): fix return value
-      return '';
-    }
+  runRepoGC(repo: RepoName): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(repo);
@@ -467,23 +425,11 @@
       method: HttpMethod.POST,
       url: `/projects/${encodeName}/gc`,
       body: '',
-      errFn,
       anonymizedUrl: '/projects/*/gc',
     });
   }
 
-  createRepo(config: ProjectInput & {name: RepoName}): Promise<Response>;
-
-  createRepo(
-    config: ProjectInput & {name: RepoName},
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  createRepo(config: ProjectInput, errFn?: ErrorCallback) {
-    if (!config.name) {
-      // TODO(TS): Fix return value
-      return '';
-    }
+  createRepo(config: ProjectInput & {name: RepoName}): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(config.name);
@@ -491,29 +437,16 @@
       method: HttpMethod.PUT,
       url: `/projects/${encodeName}`,
       body: config,
-      errFn,
       anonymizedUrl: '/projects/*',
     });
   }
 
-  createGroup(config: GroupInput & {name: string}): Promise<Response>;
-
-  createGroup(
-    config: GroupInput & {name: string},
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  createGroup(config: GroupInput, errFn?: ErrorCallback) {
-    if (!config.name) {
-      // TODO(TS): Fix return value
-      return '';
-    }
+  createGroup(config: GroupInput & {name: string}): Promise<Response> {
     const encodeName = encodeURIComponent(config.name);
     return this._restApiHelper.send({
       method: HttpMethod.PUT,
       url: `/groups/${encodeName}`,
       body: config,
-      errFn,
       anonymizedUrl: '/groups/*',
     });
   }
@@ -529,19 +462,7 @@
     }) as Promise<GroupInfo | undefined>;
   }
 
-  deleteRepoBranches(repo: RepoName, ref: GitRef): Promise<Response>;
-
-  deleteRepoBranches(
-    repo: RepoName,
-    ref: GitRef,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  deleteRepoBranches(repo: RepoName, ref: GitRef, errFn?: ErrorCallback) {
-    if (!repo || !ref) {
-      // TODO(TS): fix return value
-      return '';
-    }
+  deleteRepoBranches(repo: RepoName, ref: GitRef): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(repo);
@@ -550,24 +471,11 @@
       method: HttpMethod.DELETE,
       url: `/projects/${encodeName}/branches/${encodeRef}`,
       body: '',
-      errFn,
       anonymizedUrl: '/projects/*/branches/*',
     });
   }
 
-  deleteRepoTags(repo: RepoName, ref: GitRef): Promise<Response>;
-
-  deleteRepoTags(
-    repo: RepoName,
-    ref: GitRef,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  deleteRepoTags(repo: RepoName, ref: GitRef, errFn?: ErrorCallback) {
-    if (!repo || !ref) {
-      // TODO(TS): fix return type
-      return '';
-    }
+  deleteRepoTags(repo: RepoName, ref: GitRef): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(repo);
@@ -576,7 +484,6 @@
       method: HttpMethod.DELETE,
       url: `/projects/${encodeName}/tags/${encodeRef}`,
       body: '',
-      errFn,
       anonymizedUrl: '/projects/*/tags/*',
     });
   }
@@ -585,25 +492,7 @@
     name: RepoName,
     branch: BranchName,
     revision: BranchInput
-  ): Promise<Response>;
-
-  createRepoBranch(
-    name: RepoName,
-    branch: BranchName,
-    revision: BranchInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  createRepoBranch(
-    name: RepoName,
-    branch: BranchName,
-    revision: BranchInput,
-    errFn?: ErrorCallback
-  ) {
-    if (!name || !branch || !revision) {
-      // TODO(TS) fix return type
-      return '';
-    }
+  ): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(name);
@@ -612,7 +501,6 @@
       method: HttpMethod.PUT,
       url: `/projects/${encodeName}/branches/${encodeBranch}`,
       body: revision,
-      errFn,
       anonymizedUrl: '/projects/*/branches/*',
     });
   }
@@ -621,25 +509,7 @@
     name: RepoName,
     tag: string,
     revision: TagInput
-  ): Promise<Response>;
-
-  createRepoTag(
-    name: RepoName,
-    tag: string,
-    revision: TagInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  createRepoTag(
-    name: RepoName,
-    tag: string,
-    revision: TagInput,
-    errFn?: ErrorCallback
-  ) {
-    if (!name || !tag || !revision) {
-      // TODO(TS): Fix return value
-      return '';
-    }
+  ): Promise<Response> {
     // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
     // supports it.
     const encodeName = encodeURIComponent(name);
@@ -648,7 +518,6 @@
       method: HttpMethod.PUT,
       url: `/projects/${encodeName}/tags/${encodeTag}`,
       body: revision,
-      errFn,
       anonymizedUrl: '/projects/*/tags/*',
     });
   }
@@ -664,16 +533,12 @@
     );
   }
 
-  getGroupMembers(
-    groupName: GroupId | GroupName,
-    errFn?: ErrorCallback
-  ): Promise<AccountInfo[] | undefined> {
+  getGroupMembers(groupName: GroupId | GroupName): Promise<AccountInfo[]> {
     const encodeName = encodeURIComponent(groupName);
-    return this._restApiHelper.fetchJSON({
+    return (this._restApiHelper.fetchJSON({
       url: `/groups/${encodeName}/members/`,
-      errFn,
       anonymizedUrl: '/groups/*/members',
-    }) as Promise<AccountInfo[] | undefined>;
+    }) as unknown) as Promise<AccountInfo[]>;
   }
 
   getIncludedGroup(
@@ -828,7 +693,7 @@
         context: 10,
         cursor_blink_rate: 0,
         font_size: 12,
-        ignore_whitespace: IgnoreWhitespaceType.IGNORE_NONE,
+        ignore_whitespace: 'IGNORE_NONE',
         intraline_difference: true,
         line_length: 100,
         line_wrapping: false,
@@ -879,14 +744,7 @@
     });
   }
 
-  savePreferences(prefs: PreferencesInput): Promise<Response>;
-
-  savePreferences(
-    prefs: PreferencesInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  savePreferences(prefs: PreferencesInput, errFn?: ErrorCallback) {
+  savePreferences(prefs: PreferencesInput): Promise<Response> {
     // Note (Issue 5142): normalize the download scheme with lower case before
     // saving.
     if (prefs.download_scheme) {
@@ -897,45 +755,28 @@
       method: HttpMethod.PUT,
       url: '/accounts/self/preferences',
       body: prefs,
-      errFn,
       reportUrlAsIs: true,
     });
   }
 
-  saveDiffPreferences(prefs: DiffPreferenceInput): Promise<Response>;
-
-  saveDiffPreferences(
-    prefs: DiffPreferenceInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  saveDiffPreferences(prefs: DiffPreferenceInput, errFn?: ErrorCallback) {
+  saveDiffPreferences(prefs: DiffPreferenceInput): Promise<Response> {
     // Invalidate the cache.
     this._cache.delete('/accounts/self/preferences.diff');
     return this._restApiHelper.send({
       method: HttpMethod.PUT,
       url: '/accounts/self/preferences.diff',
       body: prefs,
-      errFn,
       reportUrlAsIs: true,
     });
   }
 
-  saveEditPreferences(prefs: EditPreferencesInfo): Promise<Response>;
-
-  saveEditPreferences(
-    prefs: EditPreferencesInfo,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  saveEditPreferences(prefs: EditPreferencesInfo, errFn?: ErrorCallback) {
+  saveEditPreferences(prefs: EditPreferencesInfo): Promise<Response> {
     // Invalidate the cache.
     this._cache.delete('/accounts/self/preferences.edit');
     return this._restApiHelper.send({
       method: HttpMethod.PUT,
       url: '/accounts/self/preferences.edit',
       body: prefs,
-      errFn,
       reportUrlAsIs: true,
     });
   }
@@ -995,48 +836,28 @@
     }) as Promise<EmailInfo[] | undefined>;
   }
 
-  addAccountEmail(email: string): Promise<Response>;
-
-  addAccountEmail(
-    email: string,
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  addAccountEmail(email: string, errFn?: ErrorCallback) {
+  addAccountEmail(email: string): Promise<Response> {
     return this._restApiHelper.send({
       method: HttpMethod.PUT,
       url: '/accounts/self/emails/' + encodeURIComponent(email),
-      errFn,
       anonymizedUrl: '/account/self/emails/*',
     });
   }
 
-  deleteAccountEmail(email: string): Promise<Response>;
-
-  deleteAccountEmail(
-    email: string,
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  deleteAccountEmail(email: string, errFn?: ErrorCallback) {
+  deleteAccountEmail(email: string): Promise<Response> {
     return this._restApiHelper.send({
       method: HttpMethod.DELETE,
       url: '/accounts/self/emails/' + encodeURIComponent(email),
-      errFn,
       anonymizedUrl: '/accounts/self/email/*',
     });
   }
 
-  setPreferredAccountEmail(
-    email: string,
-    errFn?: ErrorCallback
-  ): Promise<void> {
+  setPreferredAccountEmail(email: string): Promise<void> {
     // TODO(TS): add correct error handling
     const encodedEmail = encodeURIComponent(email);
     const req = {
       method: HttpMethod.PUT,
       url: `/accounts/self/emails/${encodedEmail}/preferred`,
-      errFn,
       anonymizedUrl: '/accounts/self/emails/*/preferred',
     };
     return this._restApiHelper.send(req).then(() => {
@@ -1066,13 +887,12 @@
     }
   }
 
-  setAccountName(name: string, errFn?: ErrorCallback): Promise<void> {
+  setAccountName(name: string): Promise<void> {
     // TODO(TS): add correct error handling
     const req: SendJSONRequest = {
       method: HttpMethod.PUT,
       url: '/accounts/self/name',
       body: {name},
-      errFn,
       parseResponse: true,
       reportUrlAsIs: true,
     };
@@ -1083,13 +903,12 @@
       );
   }
 
-  setAccountUsername(username: string, errFn?: ErrorCallback): Promise<void> {
+  setAccountUsername(username: string): Promise<void> {
     // TODO(TS): add correct error handling
     const req: SendJSONRequest = {
       method: HttpMethod.PUT,
       url: '/accounts/self/username',
       body: {username},
-      errFn,
       parseResponse: true,
       reportUrlAsIs: true,
     };
@@ -1100,16 +919,12 @@
       );
   }
 
-  setAccountDisplayName(
-    displayName: string,
-    errFn?: ErrorCallback
-  ): Promise<void> {
+  setAccountDisplayName(displayName: string): Promise<void> {
     // TODO(TS): add correct error handling
     const req: SendJSONRequest = {
       method: HttpMethod.PUT,
       url: '/accounts/self/displayname',
       body: {display_name: displayName},
-      errFn,
       parseResponse: true,
       reportUrlAsIs: true,
     };
@@ -1120,13 +935,12 @@
     );
   }
 
-  setAccountStatus(status: string, errFn?: ErrorCallback): Promise<void> {
+  setAccountStatus(status: string): Promise<void> {
     // TODO(TS): add correct error handling
     const req: SendJSONRequest = {
       method: HttpMethod.PUT,
       url: '/accounts/self/status',
       body: {status},
-      errFn,
       parseResponse: true,
       reportUrlAsIs: true,
     };
@@ -1251,34 +1065,22 @@
   }
 
   saveWatchedProjects(
-    projects: ProjectWatchInfo[],
-    errFn?: ErrorCallback
+    projects: ProjectWatchInfo[]
   ): Promise<ProjectWatchInfo[]> {
     return (this._restApiHelper.send({
       method: HttpMethod.POST,
       url: '/accounts/self/watched.projects',
       body: projects,
-      errFn,
       parseResponse: true,
       reportUrlAsIs: true,
     }) as unknown) as Promise<ProjectWatchInfo[]>;
   }
 
-  deleteWatchedProjects(
-    projects: ProjectWatchInfo[]
-  ): Promise<Response | undefined>;
-
-  deleteWatchedProjects(
-    projects: ProjectWatchInfo[],
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  deleteWatchedProjects(projects: ProjectWatchInfo[], errFn?: ErrorCallback) {
+  deleteWatchedProjects(projects: ProjectWatchInfo[]): Promise<Response> {
     return this._restApiHelper.send({
       method: HttpMethod.POST,
       url: '/accounts/self/watched.projects:delete',
       body: projects,
-      errFn,
       reportUrlAsIs: true,
     });
   }
@@ -1457,11 +1259,7 @@
     return listChangesOptionsToHex(...options);
   }
 
-  getDiffChangeDetail(
-    changeNum: NumericChangeId,
-    errFn?: ErrorCallback,
-    cancelCondition?: CancelConditionCallback
-  ) {
+  getDiffChangeDetail(changeNum: NumericChangeId) {
     let optionsHex = '';
     if (window.DEFAULT_DETAIL_HEXES?.diffPage) {
       optionsHex = window.DEFAULT_DETAIL_HEXES.diffPage;
@@ -1472,7 +1270,7 @@
         ListChangesOption.SKIP_DIFFSTAT
       );
     }
-    return this._getChangeDetail(changeNum, optionsHex, errFn, cancelCondition);
+    return this._getChangeDetail(changeNum, optionsHex);
   }
 
   /**
@@ -1508,13 +1306,7 @@
             if (errFn) {
               errFn.call(null, response);
             } else {
-              this.dispatchEvent(
-                new CustomEvent('server-error', {
-                  detail: {request: req, response},
-                  composed: true,
-                  bubbles: true,
-                })
-              );
+              fireServerError(response, req);
             }
             return undefined;
           }
@@ -1558,7 +1350,7 @@
     let params = undefined;
     if (isMergeParent(patchRange.basePatchNum)) {
       params = {parent: getParentIndex(patchRange.basePatchNum)};
-    } else if (!patchNumEquals(patchRange.basePatchNum, ParentPatchSetNum)) {
+    } else if (patchRange.basePatchNum !== ParentPatchSetNum) {
       params = {base: patchRange.basePatchNum};
     }
     return this._getChangeURLAndFetch({
@@ -1605,7 +1397,7 @@
     changeNum: NumericChangeId,
     patchRange: PatchRange
   ): Promise<FileNameToFileInfoMap | undefined> {
-    if (patchNumEquals(patchRange.patchNum, EditPatchSetNum)) {
+    if (patchRange.patchNum === EditPatchSetNum) {
       return this.getChangeEditFiles(changeNum, patchRange).then(
         res => res && res.files
       );
@@ -1628,37 +1420,22 @@
     >;
   }
 
-  getChangeSuggestedReviewers(
-    changeNum: NumericChangeId,
-    inputVal: string,
-    errFn?: ErrorCallback
-  ) {
+  getChangeSuggestedReviewers(changeNum: NumericChangeId, inputVal: string) {
     return this._getChangeSuggestedGroup(
       ReviewerState.REVIEWER,
       changeNum,
-      inputVal,
-      errFn
+      inputVal
     );
   }
 
-  getChangeSuggestedCCs(
-    changeNum: NumericChangeId,
-    inputVal: string,
-    errFn?: ErrorCallback
-  ) {
-    return this._getChangeSuggestedGroup(
-      ReviewerState.CC,
-      changeNum,
-      inputVal,
-      errFn
-    );
+  getChangeSuggestedCCs(changeNum: NumericChangeId, inputVal: string) {
+    return this._getChangeSuggestedGroup(ReviewerState.CC, changeNum, inputVal);
   }
 
   _getChangeSuggestedGroup(
     reviewerState: ReviewerState,
     changeNum: NumericChangeId,
-    inputVal: string,
-    errFn?: ErrorCallback
+    inputVal: string
   ): Promise<SuggestedReviewerInfo[] | undefined> {
     // More suggestions may obscure content underneath in the reply dialog,
     // see issue 10793.
@@ -1672,7 +1449,6 @@
     return this._getChangeURLAndFetch({
       changeNum,
       endpoint: '/suggest_reviewers',
-      errFn,
       params,
       reportEndpointAsIs: true,
     }) as Promise<SuggestedReviewerInfo[] | undefined>;
@@ -1893,8 +1669,7 @@
 
   getSuggestedGroups(
     inputVal: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<GroupNameToGroupInfoMap | undefined> {
     const params: QueryGroupsParams = {s: inputVal};
     if (n) {
@@ -1902,7 +1677,6 @@
     }
     return this._restApiHelper.fetchJSON({
       url: '/groups/',
-      errFn,
       params,
       reportUrlAsIs: true,
     }) as Promise<GroupNameToGroupInfoMap | undefined>;
@@ -1910,8 +1684,7 @@
 
   getSuggestedProjects(
     inputVal: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<NameToProjectInfoMap | undefined> {
     const params = {
       m: inputVal,
@@ -1923,7 +1696,6 @@
     }
     return this._restApiHelper.fetchJSON({
       url: '/projects/',
-      errFn,
       params,
       reportUrlAsIs: true,
     });
@@ -1931,8 +1703,7 @@
 
   getSuggestedAccounts(
     inputVal: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<AccountInfo[] | undefined> {
     if (!inputVal) {
       return Promise.resolve([]);
@@ -1943,7 +1714,6 @@
     }
     return this._restApiHelper.fetchJSON({
       url: '/accounts/',
-      errFn,
       params,
       anonymizedUrl: '/accounts/?n=*',
     }) as Promise<AccountInfo[] | undefined>;
@@ -2104,29 +1874,12 @@
     patchNum: PatchSetNum,
     path: string,
     reviewed: boolean
-  ): Promise<Response>;
-
-  saveFileReviewed(
-    changeNum: NumericChangeId,
-    patchNum: PatchSetNum,
-    path: string,
-    reviewed: boolean,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  saveFileReviewed(
-    changeNum: NumericChangeId,
-    patchNum: PatchSetNum,
-    path: string,
-    reviewed: boolean,
-    errFn?: ErrorCallback
-  ) {
+  ): Promise<Response> {
     return this._getChangeURLAndSend({
       changeNum,
       method: reviewed ? HttpMethod.PUT : HttpMethod.DELETE,
       patchNum,
       endpoint: `/files/${encodeURIComponent(path)}/reviewed`,
-      errFn,
       anonymizedEndpoint: '/files/*/reviewed',
     });
   }
@@ -2221,20 +1974,15 @@
     // 404s indicate the file does not exist yet in the revision, so suppress
     // them.
     const suppress404s: ErrorCallback = res => {
-      if (res?.status !== 404) {
-        this.dispatchEvent(
-          new CustomEvent('server-error', {
-            detail: {res},
-            composed: true,
-            bubbles: true,
-          })
-        );
+      if (res && res?.status !== 404) {
+        fireServerError(res);
       }
       return res;
     };
-    const promise = patchNumEquals(patchNum, EditPatchSetNum)
-      ? this._getFileInChangeEdit(changeNum, path)
-      : this._getFileInRevision(changeNum, path, patchNum, suppress404s);
+    const promise =
+      patchNum === EditPatchSetNum
+        ? this._getFileInChangeEdit(changeNum, path)
+        : this._getFileInRevision(changeNum, path, patchNum, suppress404s);
 
     return promise.then(res => {
       if (!res || !res.ok) {
@@ -2521,14 +2269,12 @@
     errFn?: ErrorCallback
   ) {
     const params: GetDiffParams = {
-      context: 'ALL',
       intraline: null,
-      whitespace: whitespace || IgnoreWhitespaceType.IGNORE_NONE,
+      whitespace: whitespace || 'IGNORE_NONE',
     };
     if (isMergeParent(basePatchNum)) {
       params.parent = getParentIndex(basePatchNum);
-    } else if (!patchNumEquals(basePatchNum, ParentPatchSetNum)) {
-      // TODO (TS): fix as PatchSetNum in the condition above
+    } else if (basePatchNum !== ParentPatchSetNum) {
       params.base = basePatchNum;
     }
     const endpoint = `/files/${encodeURIComponent(path)}/diff`;
@@ -2793,6 +2539,43 @@
     return this._changeBaseURL(changeNum, patchNum).then(url => url + endpoint);
   }
 
+  getPortedComments(
+    changeNum: NumericChangeId,
+    revision: RevisionId
+  ): Promise<PathToCommentsInfoMap | undefined> {
+    // maintaining a custom error function so that errors do not surface in UI
+    const errFn: ErrorCallback = (response?: Response | null) => {
+      if (response)
+        console.info(`Fetching ported comments failed, ${response.status}`);
+    };
+    return this._getChangeURLAndFetch({
+      changeNum,
+      endpoint: '/ported_comments/',
+      revision,
+      errFn,
+    });
+  }
+
+  getPortedDrafts(
+    changeNum: NumericChangeId,
+    revision: RevisionId
+  ): Promise<PathToCommentsInfoMap | undefined> {
+    // maintaining a custom error function so that errors do not surface in UI
+    const errFn: ErrorCallback = (response?: Response | null) => {
+      if (response)
+        console.info(`Fetching ported drafts failed, ${response.status}`);
+    };
+    return this.getLoggedIn().then(loggedIn => {
+      if (!loggedIn) return {};
+      return this._getChangeURLAndFetch({
+        changeNum,
+        endpoint: '/ported_drafts/',
+        revision,
+        errFn,
+      });
+    });
+  }
+
   saveDiffDraft(
     changeNum: NumericChangeId,
     patchNum: PatchSetNum,
@@ -3045,10 +2828,7 @@
     });
   }
 
-  setChangeTopic(
-    changeNum: NumericChangeId,
-    topic: string | null
-  ): Promise<string> {
+  setChangeTopic(changeNum: NumericChangeId, topic?: string): Promise<string> {
     return (this._getChangeURLAndSend({
       changeNum,
       method: HttpMethod.PUT,
@@ -3219,10 +2999,9 @@
     }) as Promise<CapabilityInfoMap | undefined>;
   }
 
-  getTopMenus(errFn?: ErrorCallback): Promise<TopMenuEntryInfo[] | undefined> {
+  getTopMenus(): Promise<TopMenuEntryInfo[] | undefined> {
     return this._fetchSharedCacheURL({
       url: '/config/server/top-menus',
-      errFn,
       reportUrlAsIs: true,
     }) as Promise<TopMenuEntryInfo[] | undefined>;
   }
@@ -3276,21 +3055,6 @@
     });
   }
 
-  startReview(
-    changeNum: NumericChangeId,
-    body?: RequestPayload,
-    errFn?: ErrorCallback
-  ) {
-    return this._getChangeURLAndSend({
-      changeNum,
-      method: HttpMethod.POST,
-      endpoint: '/ready',
-      body,
-      errFn,
-      reportUrlAsIs: true,
-    });
-  }
-
   deleteComment(
     changeNum: NumericChangeId,
     patchNum: PatchSetNum,
@@ -3357,16 +3121,8 @@
       return Promise.resolve(project);
     }
 
-    const onError = (response?: Response | null) => {
-      // Fire a page error so that the visual 404 is displayed.
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
-    };
+    const onError = (response?: Response | null) =>
+      firePageError(this, response);
 
     return this.getChange(changeNum, onError).then(change => {
       if (!change || !change.project) {
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
index 505fd58..717fe54 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
@@ -21,6 +21,8 @@
 import {GrReviewerUpdatesParser} from './gr-reviewer-updates-parser.js';
 import {ListChangesOption} from '../../../utils/change-util.js';
 import {appContext} from '../../../services/app-context.js';
+import {createChange} from '../../../test/test-data-generators.js';
+import {CURRENT} from '../../../utils/patch-set-util.js';
 
 const basicFixture = fixtureFromElement('gr-rest-api-interface');
 
@@ -260,7 +262,7 @@
     const getResponseObjectStub = sinon.stub(element, 'getResponseObject');
     window.fetch.returns(Promise.resolve({ok: false}));
     const serverErrorEventPromise = new Promise(resolve => {
-      element.addEventListener('server-error', resolve);
+      document.addEventListener('server-error', resolve);
     });
 
     return Promise.all([element._restApiHelper.fetchJSON({}).then(response => {
@@ -647,19 +649,6 @@
         {message: 'revising...'});
   });
 
-  test('startReview', () => {
-    const sendStub = sinon.stub(element, '_getChangeURLAndSend')
-        .returns(Promise.resolve({}));
-    element.startReview('42', {message: 'Please review.'});
-    assert.isTrue(sendStub.calledOnce);
-    assert.equal(sendStub.lastCall.args[0].changeNum, '42');
-    assert.equal(sendStub.lastCall.args[0].method, 'POST');
-    assert.isNotOk(sendStub.lastCall.args[0].patchNum);
-    assert.equal(sendStub.lastCall.args[0].endpoint, '/ready');
-    assert.deepEqual(sendStub.lastCall.args[0].body,
-        {message: 'Please review.'});
-  });
-
   test('deleteComment', () => {
     const sendStub = sinon.stub(element, '_getChangeURLAndSend')
         .returns(Promise.resolve('some response'));
@@ -1279,7 +1268,7 @@
   test('getFileContent suppresses 404s', () => {
     const res = {status: 404};
     const spy = sinon.spy();
-    element.addEventListener('server-error', spy);
+    document.addEventListener('server-error', spy);
     sinon.stub(appContext.authService, 'fetch').returns(Promise.resolve(res));
     sinon.stub(element, '_changeBaseURL').returns(Promise.resolve(''));
     return element.getFileContent('1', 'tst/path', '1')
@@ -1292,7 +1281,7 @@
         })
         .then(() => {
           assert.isTrue(spy.called);
-          assert.notEqual(spy.lastCall.args[0].detail.res.status, 404);
+          assert.notEqual(spy.lastCall.args[0].detail.response.status, 404);
         });
   });
 
@@ -1332,7 +1321,7 @@
   test('_logCall only reports requests with anonymized URLss', () => {
     sinon.stub(Date, 'now').returns(200);
     const handler = sinon.stub();
-    element.addEventListener('rpc-log', handler);
+    document.addEventListener('gr-rpc-log', handler);
 
     element._restApiHelper._logCall({url: 'url'}, 100, 200);
     assert.isFalse(handler.called);
@@ -1343,6 +1332,30 @@
     assert.isTrue(handler.calledOnce);
   });
 
+  test('ported comment errors do not trigger error dialog', () => {
+    const change = createChange();
+    const handler = sinon.stub();
+    document.addEventListener('server-error', handler);
+    sinon.stub(element._restApiHelper, 'fetchJSON').returns(Promise.resolve({
+      ok: false}));
+
+    element.getPortedComments(change._number, CURRENT);
+
+    assert.isFalse(handler.called);
+    document.removeEventListener('server-error', handler);
+  });
+
+  test('ported drafts are not requested user is not logged in', () => {
+    const change = createChange();
+    sinon.stub(element, 'getLoggedIn').returns(Promise.resolve(false));
+    const getChangeURLAndFetchStub = sinon.stub(element,
+        '_getChangeURLAndFetch');
+
+    element.getPortedDrafts(change._number, CURRENT);
+
+    assert.isFalse(getChangeURLAndFetchStub.called);
+  });
+
   test('saveChangeStarred', async () => {
     sinon.stub(element, 'getFromProjectLookup')
         .returns(Promise.resolve('test'));
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
index 6d93604..43a6af4 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
@@ -18,7 +18,6 @@
 import {
   CancelConditionCallback,
   ErrorCallback,
-  RestApiService,
 } from '../../../../services/services/gr-rest-api/gr-rest-api';
 import {
   AuthRequestInit,
@@ -33,6 +32,8 @@
 } from '../../../../types/common';
 import {HttpMethod} from '../../../../constants/constants';
 import {RpcLogEventDetail} from '../../../../types/events';
+import {fireNetworkError, fireServerError} from '../../../../utils/event-util';
+import {FetchRequest} from '../../../../types/types';
 
 const JSON_PREFIX = ")]}'";
 
@@ -189,12 +190,6 @@
 
 export type SendRequest = SendRawRequest | SendJSONRequest;
 
-export interface FetchRequest {
-  url: string;
-  fetchOptions?: AuthRequestInit;
-  anonymizedUrl?: string;
-}
-
 export interface FetchJSONRequest extends FetchRequest {
   reportUrlAsIs?: boolean;
   params?: FetchParams;
@@ -218,8 +213,7 @@
   constructor(
     private readonly _cache: SiteBasedCache,
     private readonly _auth: AuthService,
-    private readonly _fetchPromisesCache: FetchPromisesCache,
-    private readonly _restApiInterface: RestApiService
+    private readonly _fetchPromisesCache: FetchPromisesCache
   ) {}
 
   /**
@@ -277,8 +271,8 @@
         elapsed,
         anonymizedUrl: req.anonymizedUrl,
       };
-      this.dispatchEvent(
-        new CustomEvent('rpc-log', {
+      document.dispatchEvent(
+        new CustomEvent('gr-rpc-log', {
           detail,
           composed: true,
           bubbles: true,
@@ -317,13 +311,7 @@
         if (req.errFn) {
           req.errFn.call(undefined, null, err);
         } else {
-          this.dispatchEvent(
-            new CustomEvent('network-error', {
-              detail: {error: err},
-              composed: true,
-              bubbles: true,
-            })
-          );
+          fireNetworkError(err);
         }
         throw err;
       });
@@ -352,13 +340,7 @@
           req.errFn.call(null, response);
           return;
         }
-        this.dispatchEvent(
-          new CustomEvent('server-error', {
-            detail: {request: req, response},
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireServerError(response, req);
         return;
       }
       return this.getResponseObject(response);
@@ -440,10 +422,6 @@
     return req;
   }
 
-  dispatchEvent(type: Event, detail?: unknown): boolean {
-    return this._restApiInterface.dispatchEvent(type, detail);
-  }
-
   fetchCacheURL(req: FetchJSONRequest): Promise<ParsedJSON | undefined> {
     if (this._fetchPromisesCache.has(req.url)) {
       return this._fetchPromisesCache.get(req.url)!;
@@ -515,35 +493,23 @@
       anonymizedUrl: req.reportUrlAsIs ? url : req.anonymizedUrl,
     };
     const xhr = this.fetch(fetchReq)
-      .then(response => {
-        if (!response.ok) {
-          if (req.errFn) {
-            req.errFn.call(undefined, response);
-            return;
-          }
-          this.dispatchEvent(
-            new CustomEvent('server-error', {
-              detail: {request: fetchReq, response},
-              composed: true,
-              bubbles: true,
-            })
-          );
-        }
-        return response;
-      })
       .catch(err => {
-        this.dispatchEvent(
-          new CustomEvent('network-error', {
-            detail: {error: err},
-            composed: true,
-            bubbles: true,
-          })
-        );
+        fireNetworkError(err);
         if (req.errFn) {
           return req.errFn.call(undefined, null, err);
         } else {
           throw err;
         }
+      })
+      .then(response => {
+        if (response && !response.ok) {
+          if (req.errFn) {
+            req.errFn.call(undefined, response);
+            return;
+          }
+          fireServerError(response, fetchReq);
+        }
+        return response;
       });
 
     if (req.parseResponse) {
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
index b3c0a85..b0b40dd 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
@@ -38,32 +38,23 @@
   {value: '😊', match: 'smile :)'},
   {value: '👍', match: 'thumbs up'},
   {value: '😄', match: 'laugh :D'},
-  {value: '🎉', match: 'party'},
-  {value: '😞', match: 'sad :('},
+  {value: '❤️', match: 'heart <3'},
   {value: '😂', match: "tears :')"},
-  {value: '🙏', match: 'pray'},
+  {value: '🎉', match: 'party'},
+  {value: '😎', match: 'cool |;)'},
+  {value: '😞', match: 'sad :('},
   {value: '😐', match: 'neutral :|'},
   {value: '😮', match: 'shock :O'},
-  {value: '👎', match: 'thumbs down'},
-  {value: '😎', match: 'cool |;)'},
+  {value: '🙏', match: 'pray'},
   {value: '😕', match: 'confused'},
   {value: '👌', match: 'ok'},
   {value: '🔥', match: 'fire'},
-  {value: '👊', match: 'fistbump'},
   {value: '💯', match: '100'},
-  {value: '💔', match: 'broken heart'},
-  {value: '🍺', match: 'beer'},
   {value: '✔', match: 'check'},
   {value: '😋', match: 'tongue'},
   {value: '😭', match: "crying :'("},
-  {value: '🐨', match: 'koala'},
   {value: '🤓', match: 'glasses'},
-  {value: '😆', match: 'grin'},
-  {value: '💩', match: 'poop'},
   {value: '😢', match: 'tear'},
-  {value: '😒', match: 'unamused'},
-  {value: '😉', match: 'wink ;)'},
-  {value: '🍷', match: 'wine'},
   {value: '😜', match: 'winking tongue ;)'},
 ];
 
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_html.ts b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_html.ts
index 1f777aa..d55481b 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_html.ts
@@ -31,7 +31,8 @@
     :host(.code) {
       font-family: var(--monospace-font-family);
       font-size: var(--font-size-code);
-      line-height: var(--line-height-code);
+      /* usually 16px = 12px + 4px */
+      line-height: calc(var(--font-size-code) + var(--spacing-s));
       font-weight: var(--font-weight-normal);
     }
     #emojiSuggestions {
diff --git a/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts b/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
index fadbfa7..d4bbe16 100644
--- a/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
+++ b/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 
-import {patchNumEquals} from '../../../utils/patch-set-util';
 import {ChangeInfo, PatchSetNum} from '../../../types/common';
 import {ParsedChangeInfo} from '../gr-rest-api-interface/gr-reviewer-updates-parser';
 
@@ -71,8 +70,8 @@
 
   getParentId(patchNum: PatchSetNum, parentIndex: number) {
     if (!this.change.revisions) return;
-    const rev = Object.values(this.change.revisions).find(rev =>
-      patchNumEquals(rev._number, patchNum)
+    const rev = Object.values(this.change.revisions).find(
+      rev => rev._number === patchNum
     );
     if (!rev || !rev.commit) return;
     return rev.commit.parents[parentIndex].commit;
diff --git a/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin.ts b/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin.ts
index abbcbc8..28b7a50 100644
--- a/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin.ts
+++ b/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin.ts
@@ -48,14 +48,6 @@
         'Size',
       ];
 
-      /**
-       * Returns the complement to the given column array
-       *
-       */
-      getComplementColumns(columns: string[]) {
-        return this.columnNames.filter(column => !columns.includes(column));
-      }
-
       isColumnHidden(columnToCheck?: string, columnsToDisplay?: string[]) {
         if (!columnsToDisplay || !columnToCheck) {
           return false;
@@ -103,7 +95,7 @@
        * @return If the column was renamed, returns a new array
        * with the corrected name. Otherwise, it returns the original param.
        */
-      getVisibleColumns(columns: string[]) {
+      renameProjectToRepoColumn(columns: string[]) {
         const projectIndex = columns.indexOf('Project');
         if (projectIndex === -1) {
           return columns;
@@ -120,7 +112,6 @@
 
 export interface ChangeTableMixinInterface {
   readonly columnNames: string[];
-  getComplementColumns(columns: string[]): string[];
   isColumnHidden(columnToCheck?: string, columnsToDisplay?: string[]): boolean;
   isColumnEnabled(
     column: string,
@@ -132,5 +123,5 @@
     config: ServerInfo,
     experiments: string[]
   ): string[];
-  getVisibleColumns(columns: string[]): string[];
+  renameProjectToRepoColumn(columns: string[]): string[];
 }
diff --git a/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin_test.js b/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin_test.js
index daf10ce..0d6b4ad 100644
--- a/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin_test.js
+++ b/polygerrit-ui/app/mixins/gr-change-table-mixin/gr-change-table-mixin_test.js
@@ -37,35 +37,6 @@
     element = basicFixture.instantiate();
   });
 
-  test('getComplementColumns', () => {
-    let columns = [
-      'Subject',
-      'Status',
-      'Owner',
-      'Assignee',
-      'Reviewers',
-      'Comments',
-      'Repo',
-      'Branch',
-      'Updated',
-      'Size',
-    ];
-    assert.deepEqual(element.getComplementColumns(columns), []);
-
-    columns = [
-      'Subject',
-      'Status',
-      'Assignee',
-      'Reviewers',
-      'Comments',
-      'Repo',
-      'Branch',
-      'Size',
-    ];
-    assert.deepEqual(element.getComplementColumns(columns),
-        ['Owner', 'Updated']);
-  });
-
   test('isColumnHidden', () => {
     const columnToCheck = 'Repo';
     let columnsToDisplay = [
@@ -92,15 +63,16 @@
     assert.isTrue(element.isColumnHidden(columnToCheck, columnsToDisplay));
   });
 
-  test('getVisibleColumns maps Project to Repo', () => {
+  test('renameProjectToRepoColumn maps Project to Repo', () => {
     const columns = [
       'Subject',
       'Status',
       'Owner',
     ];
-    assert.deepEqual(element.getVisibleColumns(columns), columns.slice(0));
+    assert.deepEqual(element.renameProjectToRepoColumn(columns),
+        columns.slice(0));
     assert.deepEqual(
-        element.getVisibleColumns(columns.concat(['Project'])),
+        element.renameProjectToRepoColumn(columns.concat(['Project'])),
         columns.slice(0).concat(['Repo']));
   });
 });
diff --git a/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts b/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
index 08b18a3..77d2d00 100644
--- a/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
+++ b/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
@@ -78,7 +78,7 @@
       // Hanlder for hiding the tooltip, will be attached to certain events
       private readonly hideHandler: () => void;
 
-      // tslint:disable-next-line:no-any Required for constructor signature.
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars, @typescript-eslint/no-explicit-any
       constructor(..._: any[]) {
         super();
         this.windowScrollHandler = () => this._handleWindowScroll();
diff --git a/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts b/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
index 48a4848..662d6bf 100644
--- a/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
+++ b/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
@@ -38,4 +38,5 @@
 ): T & Constructor<IronFitBehavior> =>
   // TODO(TS): mixinBehaviors in some lib is returning: `new () => T` instead
   // which will fail the type check due to missing IronFitBehavior interface
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   mixinBehaviors([IronFitBehavior], superClass) as any;
diff --git a/polygerrit-ui/app/mixins/iron-overlay-mixin/iron-overlay-mixin.ts b/polygerrit-ui/app/mixins/iron-overlay-mixin/iron-overlay-mixin.ts
index 4884ec2..8429e38 100644
--- a/polygerrit-ui/app/mixins/iron-overlay-mixin/iron-overlay-mixin.ts
+++ b/polygerrit-ui/app/mixins/iron-overlay-mixin/iron-overlay-mixin.ts
@@ -38,4 +38,5 @@
   // TODO(TS): mixinBehaviors in some lib is returning: `new () => T`
   // instead which will fail the type check due to missing
   // IronOverlayBehavior interface
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   mixinBehaviors([IronOverlayBehavior], superClass) as any;
diff --git a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
index 7aade93..a474909 100644
--- a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
+++ b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
@@ -129,7 +129,7 @@
 export enum ShortcutSection {
   ACTIONS = 'Actions',
   DIFFS = 'Diffs',
-  EVERYWHERE = 'Everywhere',
+  EVERYWHERE = 'Global Shortcuts',
   FILE_LIST = 'File list',
   NAVIGATION = 'Navigation',
   REPLY_DIALOG = 'Reply dialog',
@@ -773,6 +773,7 @@
 
 interface IronA11yKeysMixinConstructor {
   // Note: this is needed to have same interface as other mixins
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   new (...args: any[]): IronA11yKeysBehavior;
 }
 /**
@@ -1007,6 +1008,7 @@
         const handler = this._shortcut_v_table.get(e.detail.key);
         if (handler) {
           // TODO(TS): should fix this
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
           (this as any)[handler](e);
         }
       }
@@ -1043,6 +1045,7 @@
         const handler = this._shortcut_go_table.get(e.detail.key);
         if (handler) {
           // TODO(TS): should fix this
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
           (this as any)[handler](e);
         }
       }
@@ -1066,6 +1069,7 @@
   return InternalKeyboardShortcutMixin(
     // TODO(TS): mixinBehaviors in some lib is returning: `new () => T` instead
     // which will fail the type check due to missing IronA11yKeysBehavior interface
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     mixinBehaviors([IronA11yKeysBehavior], superClass) as any
   );
 };
diff --git a/polygerrit-ui/app/node_modules_licenses/licenses.ts b/polygerrit-ui/app/node_modules_licenses/licenses.ts
index 81c2f5e..7a6253b 100644
--- a/polygerrit-ui/app/node_modules_licenses/licenses.ts
+++ b/polygerrit-ui/app/node_modules_licenses/licenses.ts
@@ -35,6 +35,11 @@
     name: "BSD-3-Clause",
     allowed: true
   };
+
+  public static BsdZeroClause: LicenseType = {
+    name: "BSD-Zero-Clause",
+    allowed: true
+  };
 }
 
 /** List of licenses texts. Add the licenses here if there is no text file with license
@@ -295,7 +300,44 @@
   {
     name: "polymer-bridges",
     license: SharedLicenses.Polymer2018
-  }
+  },
+  {
+    name: "rxjs",
+    license: {
+      name: "rxjs",
+      type: LicenseTypes.Apache2_0,
+      packageLicenseFile: "LICENSE.txt"
+    },
+    // The following directories are not real packages, but contains package.json
+    nonPackages: [
+      "ajax", "fetch", "internal-compatibility", "operators", "testing",
+      "webSocket", "src/ajax", "src/fetch", "src/internal-compatibility",
+      "src/operators", "src/testing", "src/webSocket"],
+  },
+  {
+    name: "lit-element",
+    license: {
+      name: "lit-element",
+      type: LicenseTypes.Bsd3,
+      packageLicenseFile: "LICENSE"
+    },
+  },
+  {
+    name: "lit-html",
+    license: {
+      name: "lit-html",
+      type: LicenseTypes.Bsd3,
+      packageLicenseFile: "LICENSE"
+    },
+  },
+  {
+    name: "tslib",
+    license: {
+      name: "tslib",
+      type: LicenseTypes.BsdZeroClause,
+      packageLicenseFile: "LICENSE.txt"
+    },
+  },
 ];
 
 export default packages;
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index acb0cf9..3351386 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -28,9 +28,11 @@
     "@webcomponents/shadycss": "^1.9.2",
     "@webcomponents/webcomponentsjs": "^1.3.3",
     "ba-linkify": "file:../../lib/ba-linkify/src/",
+    "lit-element": "^2.4.0",
     "page": "^1.11.5",
     "polymer-bridges": "file:../../polymer-bridges/",
     "polymer-resin": "^2.0.1",
+    "rxjs": "^6.6.2",
     "shadow-selection-polyfill": "^1.1.0"
   },
   "license": "Apache-2.0",
diff --git a/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider_test.js b/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider_test.js
index 7c40b7a..ac48ea0 100644
--- a/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider_test.js
+++ b/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider_test.js
@@ -18,11 +18,7 @@
 import '../../test/common-test-setup-karma.js';
 import '../../elements/shared/gr-rest-api-interface/gr-rest-api-interface.js';
 import {GrEmailSuggestionsProvider} from './gr-email-suggestions-provider.js';
-import {html} from '@polymer/polymer/lib/utils/html-tag.js';
-
-const basicFixture = fixtureFromTemplate(html`
-<gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
-`);
+import {appContext} from '../../services/app-context.js';
 
 suite('GrEmailSuggestionsProvider tests', () => {
   let restAPI;
@@ -40,7 +36,7 @@
     stub('gr-rest-api-interface', {
       getConfig() { return Promise.resolve({}); },
     });
-    restAPI = basicFixture.instantiate();
+    restAPI = appContext.restApiService;
     provider = new GrEmailSuggestionsProvider(restAPI);
   });
 
diff --git a/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider_test.js b/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider_test.js
index 0939f76..f03195d 100644
--- a/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider_test.js
+++ b/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider_test.js
@@ -18,11 +18,7 @@
 import '../../test/common-test-setup-karma.js';
 import '../../elements/shared/gr-rest-api-interface/gr-rest-api-interface.js';
 import {GrGroupSuggestionsProvider} from './gr-group-suggestions-provider.js';
-import {html} from '@polymer/polymer/lib/utils/html-tag.js';
-
-const basicFixture = fixtureFromTemplate(html`
-<gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
-`);
+import {appContext} from '../../services/app-context.js';
 
 suite('GrGroupSuggestionsProvider tests', () => {
   let restAPI;
@@ -41,7 +37,7 @@
     stub('gr-rest-api-interface', {
       getConfig() { return Promise.resolve({}); },
     });
-    restAPI = basicFixture.instantiate();
+    restAPI = appContext.restApiService;
     provider = new GrGroupSuggestionsProvider(restAPI);
   });
 
diff --git a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
index fe13c1c..2aea699 100644
--- a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
+++ b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
@@ -18,11 +18,7 @@
 import '../../test/common-test-setup-karma.js';
 import '../../elements/shared/gr-rest-api-interface/gr-rest-api-interface.js';
 import {GrReviewerSuggestionsProvider, SUGGESTIONS_PROVIDERS_USERS_TYPES} from './gr-reviewer-suggestions-provider.js';
-import {html} from '@polymer/polymer/lib/utils/html-tag.js';
-
-const basicFixture = fixtureFromTemplate(html`
-<gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
-`);
+import {appContext} from '../../services/app-context.js';
 
 suite('GrReviewerSuggestionsProvider tests', () => {
   let _nextAccountId = 0;
@@ -77,7 +73,7 @@
       getConfig() { return Promise.resolve({}); },
     });
 
-    restAPI = basicFixture.instantiate();
+    restAPI = appContext.restApiService;
     change = {
       _number: 42,
       owner,
diff --git a/polygerrit-ui/app/services/app-context-init.ts b/polygerrit-ui/app/services/app-context-init.ts
index b249d16..13a9c76 100644
--- a/polygerrit-ui/app/services/app-context-init.ts
+++ b/polygerrit-ui/app/services/app-context-init.ts
@@ -19,6 +19,9 @@
 import {GrReporting} from './gr-reporting/gr-reporting_impl';
 import {EventEmitter} from './gr-event-interface/gr-event-interface_impl';
 import {Auth} from './gr-auth/gr-auth_impl';
+import {GrRestApiInterface} from '../elements/shared/gr-rest-api-interface/gr-rest-api-interface';
+import {ChangeService} from './change/change-service';
+import {ChecksService} from './checks/checks-service';
 
 type ServiceName = keyof AppContext;
 type ServiceCreator<T> = () => T;
@@ -65,5 +68,8 @@
     reportingService: () => new GrReporting(appContext.flagsService),
     eventEmitter: () => new EventEmitter(),
     authService: () => new Auth(appContext.eventEmitter),
+    restApiService: () => new GrRestApiInterface(appContext.authService),
+    changeService: () => new ChangeService(appContext.restApiService),
+    checksService: () => new ChecksService(),
   });
 }
diff --git a/polygerrit-ui/app/services/app-context.ts b/polygerrit-ui/app/services/app-context.ts
index c08ee7a..bd14506 100644
--- a/polygerrit-ui/app/services/app-context.ts
+++ b/polygerrit-ui/app/services/app-context.ts
@@ -18,12 +18,18 @@
 import {EventEmitterService} from './gr-event-interface/gr-event-interface';
 import {ReportingService} from './gr-reporting/gr-reporting';
 import {AuthService} from './gr-auth/gr-auth';
+import {RestApiService} from './services/gr-rest-api/gr-rest-api';
+import {ChangeService} from './change/change-service';
+import {ChecksService} from './checks/checks-service';
 
 export interface AppContext {
   flagsService: FlagsService;
   reportingService: ReportingService;
   eventEmitter: EventEmitterService;
   authService: AuthService;
+  restApiService: RestApiService;
+  changeService: ChangeService;
+  checksService: ChecksService;
 }
 
 /**
diff --git a/polygerrit-ui/app/services/change/change-model.ts b/polygerrit-ui/app/services/change/change-model.ts
new file mode 100644
index 0000000..d02535c
--- /dev/null
+++ b/polygerrit-ui/app/services/change/change-model.ts
@@ -0,0 +1,106 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {PatchSetNum} from '../../types/common';
+import {BehaviorSubject, combineLatest, Observable} from 'rxjs';
+import {
+  map,
+  filter,
+  withLatestFrom,
+  distinctUntilChanged,
+} from 'rxjs/operators';
+import {routerPatchNum$, routerState$} from '../router/router-model';
+import {
+  computeAllPatchSets,
+  computeLatestPatchNum,
+} from '../../utils/patch-set-util';
+import {ParsedChangeInfo} from '../../elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser';
+
+interface ChangeState {
+  change?: ParsedChangeInfo;
+}
+
+// TODO: Figure out how to best enforce immutability of all states. Use Immer?
+// Use DeepReadOnly?
+const initialState: ChangeState = {};
+
+const privateState$ = new BehaviorSubject(initialState);
+
+// Re-exporting as Observable so that you can only subscribe, but not emit.
+export const changeState$: Observable<ChangeState> = privateState$;
+
+// Must only be used by the change service or whatever is in control of this
+// model.
+export function updateState(change?: ParsedChangeInfo) {
+  privateState$.next({
+    ...privateState$.getValue(),
+    change,
+  });
+}
+
+/**
+ * If you depend on both, router and change state, then you want to filter out
+ * inconsistent state, e.g. router changeNum already updated, change not yet
+ * reset to undefined.
+ */
+export const changeAndRouterConsistent$ = combineLatest([
+  routerState$,
+  changeState$,
+]).pipe(
+  filter(([routerState, changeState]) => {
+    const changeNum = changeState.change?._number;
+    const routerChangeNum = routerState.changeNum;
+    return changeNum === undefined || changeNum === routerChangeNum;
+  }),
+  distinctUntilChanged()
+);
+
+export const change$ = changeState$.pipe(
+  map(changeState => changeState.change),
+  distinctUntilChanged()
+);
+
+export const changeNum$ = change$.pipe(
+  map(change => change?._number),
+  distinctUntilChanged()
+);
+
+export const latestPatchNum$ = change$.pipe(
+  map(change => computeLatestPatchNum(computeAllPatchSets(change))),
+  distinctUntilChanged()
+);
+
+/**
+ * Emits the current patchset number. If the route does not define the current
+ * patchset num, then this selector waits for the change to be defined and
+ * returns the number of the latest patchset.
+ *
+ * Note that this selector can emit a patchNum without the change being
+ * available!
+ *
+ * TODO: It would be good to assert/enforce somehow that currentPatchNum$ cannot
+ * emit 'PARENT'.
+ */
+export const currentPatchNum$: Observable<
+  PatchSetNum | undefined
+> = changeAndRouterConsistent$.pipe(
+  withLatestFrom(routerPatchNum$, latestPatchNum$),
+  map(([_, routerPatchNum, latestPatchNum]) => {
+    return routerPatchNum || latestPatchNum;
+  }),
+  distinctUntilChanged()
+);
diff --git a/polygerrit-ui/app/services/change/change-service.ts b/polygerrit-ui/app/services/change/change-service.ts
new file mode 100644
index 0000000..a510855
--- /dev/null
+++ b/polygerrit-ui/app/services/change/change-service.ts
@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {routerChangeNum$} from '../router/router-model';
+import {updateState} from './change-model';
+import {RestApiService} from '../services/gr-rest-api/gr-rest-api';
+import {switchMap, tap} from 'rxjs/operators';
+import {of, from} from 'rxjs';
+
+export class ChangeService {
+  private routerChangeNumEffect = routerChangeNum$.pipe(
+    switchMap(changeNum => {
+      if (!changeNum) return of(undefined);
+      return from(this.restApiService.getChangeDetail(changeNum));
+    }),
+    tap(change => {
+      updateState(change ?? undefined);
+    })
+  );
+
+  constructor(private readonly restApiService: RestApiService) {
+    this.routerChangeNumEffect.subscribe();
+  }
+
+  // TODO: Remove.
+  dontDoAnything() {}
+}
diff --git a/polygerrit-ui/app/services/checks/checks-model.ts b/polygerrit-ui/app/services/checks/checks-model.ts
new file mode 100644
index 0000000..f7ee179
--- /dev/null
+++ b/polygerrit-ui/app/services/checks/checks-model.ts
@@ -0,0 +1,95 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {BehaviorSubject, Observable} from 'rxjs';
+import {
+  CheckResult,
+  CheckRun,
+  ChecksApiConfig,
+} from '../../elements/plugins/gr-checks-api/gr-checks-api-types';
+import {map} from 'rxjs/operators';
+
+interface ChecksProviderState {
+  pluginName: string;
+  config?: ChecksApiConfig;
+  runs: CheckRun[];
+}
+
+interface ChecksState {
+  [name: string]: ChecksProviderState;
+}
+
+const initialState: ChecksState = {};
+
+const privateState$ = new BehaviorSubject(initialState);
+
+// Re-exporting as Observable so that you can only subscribe, but not emit.
+export const checksState$: Observable<ChecksState> = privateState$;
+
+export const allRuns$ = checksState$.pipe(
+  map(state => {
+    return Object.values(state).reduce(
+      (allRuns: CheckRun[], providerState: ChecksProviderState) => [
+        ...allRuns,
+        ...providerState.runs,
+      ],
+      []
+    );
+  })
+);
+
+export const allResults$ = checksState$.pipe(
+  map(state => {
+    return Object.values(state)
+      .reduce(
+        (allResults: CheckResult[], providerState: ChecksProviderState) => [
+          ...allResults,
+          ...providerState.runs.reduce(
+            (results: CheckResult[], run: CheckRun) =>
+              results.concat(run.results),
+            []
+          ),
+        ],
+        []
+      )
+      .filter(r => r !== undefined);
+  })
+);
+
+// Must only be used by the checks service or whatever is in control of this
+// model.
+export function updateStateSetProvider(
+  pluginName: string,
+  config?: ChecksApiConfig
+) {
+  const nextState = {...privateState$.getValue()};
+  nextState[pluginName] = {
+    pluginName,
+    config,
+    runs: [],
+  };
+  privateState$.next(nextState);
+}
+
+export function updateStateSetResults(pluginName: string, runs: CheckRun[]) {
+  const nextState = {...privateState$.getValue()};
+  nextState[pluginName] = {
+    ...nextState[pluginName],
+    runs,
+  };
+  privateState$.next(nextState);
+}
diff --git a/polygerrit-ui/app/services/checks/checks-service.ts b/polygerrit-ui/app/services/checks/checks-service.ts
new file mode 100644
index 0000000..7447798
--- /dev/null
+++ b/polygerrit-ui/app/services/checks/checks-service.ts
@@ -0,0 +1,81 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {switchMap, takeWhile, tap, withLatestFrom} from 'rxjs/operators';
+import {
+  ChecksApiConfig,
+  ChecksProvider,
+  FetchResponse,
+  ResponseCode,
+} from '../../elements/plugins/gr-checks-api/gr-checks-api-types';
+import {change$, currentPatchNum$} from '../change/change-model';
+import {updateStateSetProvider, updateStateSetResults} from './checks-model';
+import {
+  BehaviorSubject,
+  combineLatest,
+  from,
+  Observable,
+  of,
+  Subject,
+} from 'rxjs';
+
+export class ChecksService {
+  private readonly providers: {[name: string]: ChecksProvider} = {};
+
+  private readonly anouncementSubjects: {[name: string]: Subject<void>} = {};
+
+  private changeAndPatchNum$ = change$.pipe(withLatestFrom(currentPatchNum$));
+
+  announceUpdate(pluginName: string) {
+    this.anouncementSubjects[pluginName].next();
+  }
+
+  register(
+    pluginName: string,
+    provider: ChecksProvider,
+    config: ChecksApiConfig
+  ) {
+    this.providers[pluginName] = provider;
+    this.anouncementSubjects[pluginName] = new BehaviorSubject<void>(undefined);
+    updateStateSetProvider(pluginName, config);
+    // Both, changed numbers and and announceUpdate request should trigger.
+    combineLatest([
+      this.changeAndPatchNum$,
+      this.anouncementSubjects[pluginName],
+    ])
+      .pipe(
+        takeWhile(_ => !!this.providers[pluginName]),
+        switchMap(
+          ([[change, patchNum], _]): Observable<FetchResponse> => {
+            if (!change || !patchNum || typeof patchNum !== 'number') {
+              return of({
+                responseCode: ResponseCode.OK,
+                runs: [],
+              });
+            }
+            return from(
+              this.providers[pluginName].fetch(change._number, patchNum)
+            );
+          }
+        ),
+        tap(response => {
+          updateStateSetResults(pluginName, response.runs ?? []);
+        })
+      )
+      .subscribe(() => {});
+  }
+}
diff --git a/polygerrit-ui/app/services/flags/flags.ts b/polygerrit-ui/app/services/flags/flags.ts
index 047e9e0..d2b7166 100644
--- a/polygerrit-ui/app/services/flags/flags.ts
+++ b/polygerrit-ui/app/services/flags/flags.ts
@@ -24,7 +24,8 @@
  * @desc Experiment ids used in Gerrit.
  */
 export enum KnownExperimentId {
-  PATCHSET_COMMENTS = 'UiFeature__patchset_comments',
-  PATCHSET_CHOICE_FOR_COMMENT_LINKS = 'UiFeature__patchset_choice_for_comment_links',
   NEW_CONTEXT_CONTROLS = 'UiFeature__new_context_controls',
+  CI_REBOOT_CHECKS = 'UiFeature__ci_reboot_checks',
+  NEW_CHANGE_SUMMARY_UI = 'UiFeature__new_change_summary_ui',
+  PORTING_COMMENTS = 'UiFeature__porting_comments',
 }
diff --git a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface.ts b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface.ts
index d59a022..e540029 100644
--- a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface.ts
+++ b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface.ts
@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type EventCallback = (...args: any) => void;
 export type UnsubscribeMethod = () => void;
 
@@ -51,11 +52,13 @@
    *
    * @returns true if the event had listeners, false otherwise.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   emit(eventName: string, detail: any): boolean;
 
   /**
    * Alias to emit.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   dispatch(eventName: string, detail: any): boolean;
 
   /**
diff --git a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
index 72afbda..f1e0990 100644
--- a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
+++ b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
@@ -66,6 +66,7 @@
    * Attach event handler only once. Automatically removed.
    */
   once(eventName: string, cb: EventCallback): UnsubscribeMethod {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const onceWrapper = (...args: any[]) => {
       cb(...args);
       this.off(eventName, onceWrapper);
@@ -96,6 +97,7 @@
    *
    * @returns true if the event had listeners, false otherwise.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   emit(eventName: string, detail: any): boolean {
     const listeners = this._listenersMap.get(eventName) || [];
     for (const listener of listeners) {
@@ -111,6 +113,7 @@
   /**
    * Alias to emit.
    */
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   dispatch(eventName: string, detail: any): boolean {
     return this.emit(eventName, detail);
   }
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
index 743e0f4..08952f6 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
@@ -18,6 +18,7 @@
 export type EventValue = string | number | {error?: Error};
 
 // TODO(dmfilippov): TS-fix-any use more specific type instead if possible
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type EventDetails = any;
 
 export interface Timer {
@@ -50,6 +51,7 @@
   reportExtension(name: string): void;
   pluginLoaded(name: string): void;
   pluginsLoaded(pluginsList?: string[]): void;
+  error(err: unknown, reporter?: string, details?: EventDetails): void;
   /**
    * Reset named timer.
    */
@@ -86,6 +88,16 @@
    */
   reportRpcTiming(anonymizedUrl: string, elapsed: number): void;
   reportLifeCycle(eventName: string, details?: EventDetails): void;
+
+  /**
+   * Use this method, if you want to check/count how often a certain code path
+   * is executed. For example you can use this method to prove that certain code
+   * paths are dead: Add reportExecution(), check the logs a week later, then
+   * safely remove the coe.
+   *
+   * Every execution is only reported once per session.
+   */
+  reportExecution(id: string, details: EventDetails): void;
   reportInteraction(eventName: string, details?: EventDetails): void;
   /**
    * A draft interaction was started. Update the time-betweeen-draft-actions
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
index f3aacdf..1b0bf45 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
@@ -44,6 +44,7 @@
     EXTENSION_DETECTED: 'Extension detected',
     PLUGINS_INSTALLED: 'Plugins installed',
     VISIBILITY: 'Visibility',
+    EXECUTION: 'Execution',
   },
 };
 
@@ -114,7 +115,22 @@
 
 export function initErrorReporter(appContext: AppContext) {
   const reportingService = appContext.reportingService;
-  // TODO(dmfilippo): TS-fix-any oldOnError - define correct type
+
+  const normalizeError = (err: Error | unknown) => {
+    if (err instanceof Error) {
+      return err;
+    }
+    let msg = '';
+    if (typeof err === 'string') {
+      msg += err;
+    } else {
+      msg += JSON.stringify(err);
+    }
+    const error = new Error(msg);
+    error.stack = 'unknown';
+    return error;
+  };
+  // TODO(dmfilippov): TS-fix-any oldOnError - define correct type
   const onError = function (
     oldOnError: Function,
     msg: Event | string,
@@ -127,32 +143,19 @@
       oldOnError(msg, url, line, column, error);
     }
     if (error) {
-      line = line || error.lineNumber;
-      column = column || error.columnNumber;
-      let shortenedErrorStack = msg;
-      if (error.stack) {
-        const errorStackLines = error.stack.split('\n');
-        shortenedErrorStack = errorStackLines
-          .slice(0, Math.min(3, errorStackLines.length))
-          .join('\n');
-      }
-      msg = shortenedErrorStack || error.toString();
+      line = line ?? error.lineNumber;
+      column = column ?? error.columnNumber;
     }
-    const payload = {
-      url,
+    reportingService.error(normalizeError(error), 'onError', {
       line,
       column,
-      error,
-    };
-    reportingService.reporter(
-      ERROR.TYPE,
-      ERROR.CATEGORY.EXCEPTION,
-      `${msg}`,
-      payload
-    );
+      url,
+      msg,
+    });
     return true;
   };
   // TODO(dmfilippov): TS-fix-any unclear what is context
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const catchErrors = function (opt_context?: any) {
     const context = opt_context || window;
     const oldOnError = context.onerror;
@@ -168,16 +171,7 @@
     context.addEventListener(
       'unhandledrejection',
       (e: PromiseRejectionEvent) => {
-        const msg = e.reason.message;
-        const payload = {
-          error: e.reason,
-        };
-        reportingService.reporter(
-          ERROR.TYPE,
-          ERROR.CATEGORY.EXCEPTION,
-          msg,
-          payload
-        );
+        reportingService.error(normalizeError(e.reason), 'unhandledrejection');
       }
     );
   };
@@ -310,6 +304,12 @@
 
   private _slowRpcList: SlowRpcCall[] = [];
 
+  /**
+   * Keeps track of which ids were already reported to have been executed.
+   * Execution ids should only be reported once per session.
+   */
+  private executionReported = new Set<string>();
+
   public readonly hiddenDurationTimer = new HiddenDurationTimer();
 
   constructor(flagsService: FlagsService) {
@@ -360,7 +360,9 @@
       eventDetails
     );
     if (type === ERROR.TYPE && category === ERROR.CATEGORY.EXCEPTION) {
-      console.error((eventValue && (eventValue as any).error) || eventName);
+      console.error(
+        (typeof eventValue === 'object' && eventValue.error) || eventName
+      );
     }
 
     // We report events immediately when metrics plugin is loaded
@@ -785,6 +787,19 @@
     );
   }
 
+  reportExecution(id: string, details: EventDetails) {
+    if (this.executionReported.has(id)) return;
+    this.executionReported.add(id);
+    this.reporter(
+      LIFECYCLE.TYPE,
+      LIFECYCLE.CATEGORY.EXECUTION,
+      id,
+      undefined,
+      details,
+      false
+    );
+  }
+
   /**
    * A draft interaction was started. Update the time-betweeen-draft-actions
    * timer.
@@ -806,6 +821,19 @@
     timer.end().reset();
   }
 
+  error(error: Error, errorSource?: string, details?: EventDetails) {
+    const eventDetails = details ?? {};
+    const message = `${errorSource ? errorSource + ': ' : ''}${error.message}`;
+
+    this.reporter(
+      ERROR.TYPE,
+      ERROR.CATEGORY.EXCEPTION,
+      message,
+      {error},
+      {...eventDetails, stack: error.stack}
+    );
+  }
+
   reportErrorDialog(message: string) {
     this.reporter(
       ERROR.TYPE,
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_mock.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting_mock.ts
index 924ddd9..1e75d88 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_mock.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_mock.ts
@@ -50,6 +50,8 @@
   recordDraftInteraction: () => {},
   reporter: () => {},
   reportErrorDialog: () => {},
+  error: () => {},
+  reportExecution: () => {},
   reportExtension: () => {},
   reportInteraction: () => {},
   reportLifeCycle: () => {},
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.js b/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.js
index 08e4a55..6e56ab1 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.js
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.js
@@ -463,23 +463,14 @@
       const error = new Error('bar');
       error.stack = undefined;
       emulateThrow('bar', 'http://url', 4, 2, error);
-      assert.isTrue(reporter.calledWith('error', 'exception', 'bar'));
-      const payload = reporter.lastCall.args[3];
-      assert.deepEqual(payload, {
-        url: 'http://url',
-        line: 4,
-        column: 2,
-        error,
-      });
+      assert.isTrue(reporter.calledWith('error', 'exception', 'onError: bar'));
     });
 
-    test('is reported with 3 lines of stack', () => {
+    test('is reported with stack', () => {
       const error = new Error('bar');
       emulateThrow('bar', 'http://url', 4, 2, error);
-      const expectedStack = error.stack.split('\n').slice(0, 3)
-          .join('\n');
-      assert.isTrue(reporter.calledWith('error', 'exception',
-          expectedStack));
+      const eventDetails = reporter.lastCall.args[4];
+      assert.equal(error.stack, eventDetails.stack);
     });
 
     test('prevent default event handler', () => {
@@ -487,12 +478,10 @@
     });
 
     test('unhandled rejection', () => {
-      fakeWindow.handlers['unhandledrejection']({
-        reason: {
-          message: 'bar',
-        },
-      });
-      assert.isTrue(reporter.calledWith('error', 'exception', 'bar'));
+      const newError = new Error('bar');
+      fakeWindow.handlers['unhandledrejection']({reason: newError});
+      assert.isTrue(reporter.calledWith('error', 'exception',
+          'unhandledrejection: bar'));
     });
   });
 });
diff --git a/polygerrit-ui/app/services/router/router-model.ts b/polygerrit-ui/app/services/router/router-model.ts
new file mode 100644
index 0000000..201cb3f
--- /dev/null
+++ b/polygerrit-ui/app/services/router/router-model.ts
@@ -0,0 +1,76 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {NumericChangeId, PatchSetNum} from '../../types/common';
+import {BehaviorSubject, Observable} from 'rxjs';
+import {distinctUntilChanged, map} from 'rxjs/operators';
+
+export enum GerritView {
+  ADMIN = 'admin',
+  AGREEMENTS = 'agreements',
+  CHANGE = 'change',
+  DASHBOARD = 'dashboard',
+  DIFF = 'diff',
+  DOCUMENTATION_SEARCH = 'documentation-search',
+  EDIT = 'edit',
+  GROUP = 'group',
+  PLUGIN_SCREEN = 'plugin-screen',
+  REPO = 'repo',
+  ROOT = 'root',
+  SEARCH = 'search',
+  SETTINGS = 'settings',
+}
+
+export interface RouterState {
+  view?: GerritView;
+  changeNum?: NumericChangeId;
+  patchNum?: PatchSetNum;
+}
+
+// TODO: Figure out how to best enforce immutability of all states. Use Immer?
+// Use DeepReadOnly?
+const initialState: RouterState = {};
+
+const privateState$ = new BehaviorSubject<RouterState>(initialState);
+
+// Re-exporting as Observable so that you can only subscribe, but not emit.
+export const routerState$: Observable<RouterState> = privateState$;
+
+// Must only be used by the router service or whatever is in control of this
+// model.
+export function updateState(
+  view?: GerritView,
+  changeNum?: NumericChangeId,
+  patchNum?: PatchSetNum
+) {
+  privateState$.next({
+    ...privateState$.getValue(),
+    view,
+    changeNum,
+    patchNum,
+  });
+}
+
+export const routerChangeNum$ = routerState$.pipe(
+  map(state => state.changeNum),
+  distinctUntilChanged()
+);
+
+export const routerPatchNum$ = routerState$.pipe(
+  map(state => state.patchNum),
+  distinctUntilChanged()
+);
diff --git a/polygerrit-ui/app/services/services/gr-rest-api/gr-rest-api.ts b/polygerrit-ui/app/services/services/gr-rest-api/gr-rest-api.ts
index 950619b..f556af0 100644
--- a/polygerrit-ui/app/services/services/gr-rest-api/gr-rest-api.ts
+++ b/polygerrit-ui/app/services/services/gr-rest-api/gr-rest-api.ts
@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+import {HttpMethod} from '../../../constants/constants';
 import {
   AccountDetailInfo,
   AccountExternalIdInfo,
@@ -29,7 +30,6 @@
   PatchSetNum,
   RequestPayload,
   PreferencesInput,
-  DiffPreferencesInfo,
   EditPreferencesInfo,
   DiffPreferenceInput,
   SshKeyInfo,
@@ -86,7 +86,6 @@
   EmailAddress,
   FixId,
   FilePathToDiffInfoMap,
-  DiffInfo,
   BlameInfo,
   PatchRange,
   ImagesForDiff,
@@ -101,8 +100,12 @@
   MergeableInfo,
   CommitInfo,
 } from '../../../types/common';
+import {
+  DiffInfo,
+  DiffPreferencesInfo,
+  IgnoreWhitespaceType,
+} from '../../../types/diff';
 import {ParsedChangeInfo} from '../../../elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser';
-import {HttpMethod, IgnoreWhitespaceType} from '../../../constants/constants';
 
 export type ErrorCallback = (response?: Response | null, err?: Error) => void;
 export type CancelConditionCallback = () => boolean;
@@ -141,9 +144,6 @@
 }
 
 export interface RestApiService {
-  // TODO(TS): unclear what is a second parameter. Looks like it is a mistake
-  // and it must be removed
-  dispatchEvent(event: Event, detail?: unknown): boolean;
   getConfig(noCache?: boolean): Promise<ServerInfo | undefined>;
   getLoggedIn(): Promise<boolean>;
   getPreferences(): Promise<PreferencesInfo | undefined>;
@@ -182,23 +182,19 @@
 
   getChangeSuggestedReviewers(
     changeNum: NumericChangeId,
-    input: string,
-    errFn?: ErrorCallback
+    input: string
   ): Promise<SuggestedReviewerInfo[] | undefined>;
   getChangeSuggestedCCs(
     changeNum: NumericChangeId,
-    input: string,
-    errFn?: ErrorCallback
+    input: string
   ): Promise<SuggestedReviewerInfo[] | undefined>;
   getSuggestedAccounts(
     input: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<AccountInfo[] | undefined>;
   getSuggestedGroups(
     input: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<GroupNameToGroupInfoMap | undefined>;
   executeChangeAction(
     changeNum: NumericChangeId,
@@ -232,30 +228,14 @@
   getDiffPreferences(): Promise<DiffPreferencesInfo | undefined>;
 
   saveDiffPreferences(prefs: DiffPreferenceInput): Promise<Response>;
-  saveDiffPreferences(
-    prefs: DiffPreferenceInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-  saveDiffPreferences(
-    prefs: DiffPreferenceInput,
-    errFn?: ErrorCallback
-  ): Promise<Response>;
 
   getEditPreferences(): Promise<EditPreferencesInfo | undefined>;
 
   saveEditPreferences(prefs: EditPreferencesInfo): Promise<Response>;
-  saveEditPreferences(
-    prefs: EditPreferencesInfo,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-  saveEditPreferences(
-    prefs: EditPreferencesInfo,
-    errFn?: ErrorCallback
-  ): Promise<Response>;
 
   getAccountEmails(): Promise<EmailInfo[] | undefined>;
   deleteAccountEmail(email: string): Promise<Response>;
-  setPreferredAccountEmail(email: string, errFn?: ErrorCallback): Promise<void>;
+  setPreferredAccountEmail(email: string): Promise<void>;
 
   getAccountSSHKeys(): Promise<SshKeyInfo[] | undefined>;
   deleteAccountSSHKey(key: string): void;
@@ -267,25 +247,11 @@
     revision: BranchInput
   ): Promise<Response>;
 
-  createRepoBranch(
-    name: RepoName,
-    branch: BranchName,
-    revision: BranchInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
   createRepoTag(
     name: RepoName,
     tag: string,
     revision: TagInput
   ): Promise<Response>;
-
-  createRepoTag(
-    name: RepoName,
-    tag: string,
-    revision: TagInput,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
   addAccountGPGKey(key: GpgKeysInput): Promise<Record<string, GpgKeyInfo>>;
   deleteAccountGPGKey(id: GpgKeyId): Promise<Response>;
   getAccountGPGKeys(): Promise<Record<string, GpgKeyInfo>>;
@@ -325,11 +291,6 @@
   ): Promise<ProjectAccessInfo | undefined>;
 
   createRepo(config: ProjectInput & {name: RepoName}): Promise<Response>;
-  createRepo(
-    config: ProjectInput & {name: RepoName},
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-  createRepo(config: ProjectInput, errFn?: ErrorCallback): Promise<Response>;
 
   getRepo(
     repo: RepoName,
@@ -452,11 +413,19 @@
   ): Promise<Response>;
 
   getDiffChangeDetail(
-    changeNum: NumericChangeId,
-    errFn?: ErrorCallback,
-    cancelCondition?: CancelConditionCallback
+    changeNum: NumericChangeId
   ): Promise<ChangeInfo | undefined | null>;
 
+  getPortedComments(
+    changeNum: NumericChangeId,
+    revision: RevisionId
+  ): Promise<PathToCommentsInfoMap | undefined>;
+
+  getPortedDrafts(
+    changeNum: NumericChangeId,
+    revision: RevisionId
+  ): Promise<PathToCommentsInfoMap | undefined>;
+
   getDiffComments(
     changeNum: NumericChangeId
   ): Promise<PathToCommentsInfoMap | undefined>;
@@ -512,11 +481,6 @@
     | Promise<PathToCommentsInfoMap | undefined>;
 
   createGroup(config: GroupInput & {name: string}): Promise<Response>;
-  createGroup(
-    config: GroupInput & {name: string},
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-  createGroup(config: GroupInput, errFn?: ErrorCallback): Promise<Response>;
 
   getPlugins(
     filter: string,
@@ -564,33 +528,21 @@
 
   generateAccountHttpPassword(): Promise<Password>;
 
-  setAccountName(name: string, errFn?: ErrorCallback): Promise<void>;
+  setAccountName(name: string): Promise<void>;
 
-  setAccountUsername(username: string, errFn?: ErrorCallback): Promise<void>;
+  setAccountUsername(username: string): Promise<void>;
 
   getWatchedProjects(): Promise<ProjectWatchInfo[] | undefined>;
 
   saveWatchedProjects(
-    projects: ProjectWatchInfo[],
-    errFn?: ErrorCallback
+    projects: ProjectWatchInfo[]
   ): Promise<ProjectWatchInfo[]>;
 
-  deleteWatchedProjects(
-    projects: ProjectWatchInfo[]
-  ): Promise<Response | undefined>;
-  deleteWatchedProjects(
-    projects: ProjectWatchInfo[],
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-  deleteWatchedProjects(
-    projects: ProjectWatchInfo[],
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined>;
+  deleteWatchedProjects(projects: ProjectWatchInfo[]): Promise<Response>;
 
   getSuggestedProjects(
     inputVal: string,
-    n?: number,
-    errFn?: ErrorCallback
+    n?: number
   ): Promise<NameToProjectInfoMap | undefined>;
 
   invalidateGroupsCache(): void;
@@ -606,11 +558,8 @@
     user: AccountId | undefined | null,
     reason: string
   ): Promise<Response>;
-  setAccountDisplayName(
-    displayName: string,
-    errFn?: ErrorCallback
-  ): Promise<void>;
-  setAccountStatus(status: string, errFn?: ErrorCallback): Promise<void>;
+  setAccountDisplayName(displayName: string): Promise<void>;
+  setAccountStatus(status: string): Promise<void>;
   getAvatarChangeUrl(): Promise<string | undefined>;
   setDescription(
     changeNum: NumericChangeId,
@@ -650,10 +599,7 @@
     errFn?: ErrorCallback
   ): Promise<GroupAuditEventInfo[] | undefined>;
 
-  getGroupMembers(
-    groupName: GroupId | GroupName,
-    errFn?: ErrorCallback
-  ): Promise<AccountInfo[] | undefined>;
+  getGroupMembers(groupName: GroupId | GroupName): Promise<AccountInfo[]>;
 
   getIncludedGroup(
     groupName: GroupId | GroupName
@@ -680,10 +626,7 @@
     includedGroup: GroupId
   ): Promise<Response>;
 
-  runRepoGC(
-    repo: RepoName,
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined>;
+  runRepoGC(repo: RepoName): Promise<Response>;
   getFileContent(
     changeNum: NumericChangeId,
     path: string,
@@ -780,11 +723,6 @@
 
   addAccountEmail(email: string): Promise<Response>;
 
-  addAccountEmail(
-    email: string,
-    errFn?: ErrorCallback
-  ): Promise<Response | undefined>;
-
   saveChangeReviewed(
     changeNum: NumericChangeId,
     reviewed: boolean
@@ -815,10 +753,7 @@
     hashtag: HashtagsInput
   ): Promise<Hashtag[]>;
 
-  setChangeTopic(
-    changeNum: NumericChangeId,
-    topic: string | null
-  ): Promise<string>;
+  setChangeTopic(changeNum: NumericChangeId, topic?: string): Promise<string>;
 
   getChangeFiles(
     changeNum: NumericChangeId,
@@ -842,15 +777,7 @@
     reviewed: boolean
   ): Promise<Response>;
 
-  saveFileReviewed(
-    changeNum: NumericChangeId,
-    patchNum: PatchSetNum,
-    path: string,
-    reviewed: boolean,
-    errFn: ErrorCallback
-  ): Promise<Response | undefined>;
-
-  getTopMenus(errFn?: ErrorCallback): Promise<TopMenuEntryInfo[] | undefined>;
+  getTopMenus(): Promise<TopMenuEntryInfo[] | undefined>;
 
   setInProjectLookup(changeNum: NumericChangeId, project: RepoName): void;
   getMergeable(changeNum: NumericChangeId): Promise<MergeableInfo | undefined>;
diff --git a/polygerrit-ui/app/styles/shared-styles.ts b/polygerrit-ui/app/styles/shared-styles.ts
index 695ae24..c2baaa9 100644
--- a/polygerrit-ui/app/styles/shared-styles.ts
+++ b/polygerrit-ui/app/styles/shared-styles.ts
@@ -15,6 +15,8 @@
  * limitations under the License.
  */
 
+import {css} from 'lit-element';
+
 // Mark the file as a module. Otherwise typescript assumes this is a script
 // and $_documentContainer is a global variable.
 // See: https://www.typescriptlang.org/docs/handbook/modules.html
@@ -22,189 +24,276 @@
 
 const $_documentContainer = document.createElement('template');
 
+export const sharedStyles = css`
+  /* CSS reset */
+
+  html,
+  body,
+  button,
+  div,
+  span,
+  applet,
+  object,
+  iframe,
+  h1,
+  h2,
+  h3,
+  h4,
+  h5,
+  h6,
+  p,
+  blockquote,
+  pre,
+  a,
+  abbr,
+  acronym,
+  address,
+  big,
+  cite,
+  code,
+  del,
+  dfn,
+  em,
+  img,
+  ins,
+  kbd,
+  q,
+  s,
+  samp,
+  small,
+  strike,
+  strong,
+  sub,
+  sup,
+  tt,
+  var,
+  b,
+  u,
+  i,
+  center,
+  dl,
+  dt,
+  dd,
+  ol,
+  ul,
+  li,
+  fieldset,
+  form,
+  label,
+  legend,
+  table,
+  caption,
+  tbody,
+  tfoot,
+  thead,
+  tr,
+  th,
+  td,
+  article,
+  aside,
+  canvas,
+  details,
+  embed,
+  figure,
+  figcaption,
+  footer,
+  header,
+  hgroup,
+  main,
+  menu,
+  nav,
+  output,
+  ruby,
+  section,
+  summary,
+  time,
+  mark,
+  audio,
+  video {
+    border: 0;
+    box-sizing: border-box;
+    font-size: 100%;
+    font: inherit;
+    margin: 0;
+    padding: 0;
+    vertical-align: baseline;
+  }
+  *::after,
+  *::before {
+    box-sizing: border-box;
+  }
+  input {
+    background-color: var(--background-color-primary);
+    border: 1px solid var(--border-color);
+    border-radius: var(--border-radius);
+    box-sizing: border-box;
+    color: var(--primary-text-color);
+    margin: 0;
+    padding: var(--spacing-s);
+  }
+  iron-autogrow-textarea {
+    background-color: inherit;
+    color: var(--primary-text-color);
+    border: 1px solid var(--border-color);
+    border-radius: var(--border-radius);
+    padding: 0;
+    box-sizing: border-box;
+    /* iron-autogrow-textarea has a "-webkit-appearance: textarea" :host
+        css rule, which prevents overriding the border color. Clear that. */
+    -webkit-appearance: none;
+
+    --iron-autogrow-textarea: {
+      box-sizing: border-box;
+      padding: var(--spacing-s);
+    }
+  }
+  a {
+    color: var(--link-color);
+  }
+  input,
+  textarea,
+  select,
+  button {
+    font: inherit;
+  }
+  ol,
+  ul {
+    list-style: none;
+  }
+  blockquote,
+  q {
+    quotes: none;
+  }
+  blockquote:before,
+  blockquote:after,
+  q:before,
+  q:after {
+    content: '';
+    content: none;
+  }
+  table {
+    border-collapse: collapse;
+    border-spacing: 0;
+  }
+
+  /* Fonts */
+
+  .font-normal {
+    font-size: var(--font-size-normal);
+    font-weight: var(--font-weight-normal);
+    line-height: var(--line-height-normal);
+  }
+  .font-small {
+    font-size: var(--font-size-small);
+    font-weight: var(--font-weight-normal);
+    line-height: var(--line-height-small);
+  }
+  .heading-1 {
+    font-family: var(--header-font-family);
+    font-size: var(--font-size-h1);
+    font-weight: var(--font-weight-h1);
+    line-height: var(--line-height-h1);
+  }
+  .heading-2 {
+    font-family: var(--header-font-family);
+    font-size: var(--font-size-h2);
+    font-weight: var(--font-weight-h2);
+    line-height: var(--line-height-h2);
+  }
+  .heading-3 {
+    font-family: var(--header-font-family);
+    font-size: var(--font-size-h3);
+    font-weight: var(--font-weight-h3);
+    line-height: var(--line-height-h3);
+  }
+  iron-icon {
+    color: var(--deemphasized-text-color);
+    --iron-icon-height: 20px;
+    --iron-icon-width: 20px;
+  }
+
+  /* Stopgap solution until we remove hidden$ attributes. */
+
+  :host([hidden]),
+  [hidden] {
+    display: none !important;
+  }
+  .separator {
+    border-left: 1px solid var(--border-color);
+    height: 20px;
+    margin: 0 8px;
+  }
+  .separator.transparent {
+    border-color: transparent;
+  }
+  paper-toggle-button {
+    --paper-toggle-button-checked-bar-color: var(--link-color);
+    --paper-toggle-button-checked-button-color: var(--link-color);
+  }
+  paper-tabs {
+    font-size: var(--font-size-h3);
+    font-weight: var(--font-weight-h3);
+    line-height: var(--line-height-h3);
+    --paper-font-common-base: {
+      font-family: var(--header-font-family);
+      -webkit-font-smoothing: initial;
+    }
+    --paper-tab-content-focused: {
+      /* paper-tabs uses 700 here, which can look awkward */
+      font-weight: var(--font-weight-h3);
+    }
+    --paper-tab-content-unselected: {
+      /* paper-tabs uses 0.8 here, but we want to control the color directly */
+      opacity: 1;
+      color: var(--deemphasized-text-color);
+    }
+  }
+  iron-autogrow-textarea {
+    /** This is needed for firefox */
+    --iron-autogrow-textarea_-_white-space: pre-wrap;
+  }
+  strong {
+    font-weight: var(--font-weight-bold);
+  }
+
+  .assistive-tech-only {
+    user-select: none;
+    clip: rect(1px, 1px, 1px, 1px);
+    height: 1px;
+    margin: 0;
+    overflow: hidden;
+    padding: 0;
+    position: absolute;
+    white-space: nowrap;
+    width: 1px;
+    z-index: -1000;
+  }
+
+  /** BEGIN: loading spiner */
+  .loadingSpin {
+    border: 2px solid var(--disabled-button-background-color);
+    border-top: 2px solid var(--primary-button-background-color);
+    border-radius: 50%;
+    width: 10px;
+    height: 10px;
+    animation: spin 2s linear infinite;
+    margin-right: var(--spacing-s);
+  }
+  @keyframes spin {
+    0% {
+      transform: rotate(0deg);
+    }
+    100% {
+      transform: rotate(360deg);
+    }
+  }
+  /** END: loading spiner */
+`;
+
 $_documentContainer.innerHTML = `<dom-module id="shared-styles">
   <template>
     <style>
-
-      /* CSS reset */
-
-      html, body, button, div, span, applet, object, iframe, h1, h2, h3,
-      h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite,
-      code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub,
-      sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form,
-      label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article,
-      aside, canvas, details, embed, figure, figcaption, footer, header, hgroup,
-      main, menu, nav, output, ruby, section, summary, time, mark, audio, video {
-        border: 0;
-        box-sizing: border-box;
-        font-size: 100%;
-        font: inherit;
-        margin: 0;
-        padding: 0;
-        vertical-align: baseline;
-      }
-      *::after,
-      *::before {
-        box-sizing: border-box;
-      }
-      input {
-        background-color: var(--background-color-primary);
-        border: 1px solid var(--border-color);
-        border-radius: var(--border-radius);
-        box-sizing: border-box;
-        color: var(--primary-text-color);
-        margin: 0;
-        padding: var(--spacing-s);
-      }
-      iron-autogrow-textarea {
-        background-color: inherit;
-        color: var(--primary-text-color);
-        border: 1px solid var(--border-color);
-        border-radius: var(--border-radius);
-        padding: 0;
-        box-sizing: border-box;
-        /* iron-autogrow-textarea has a "-webkit-appearance: textarea" :host
-           css rule, which prevents overriding the border color. Clear that. */
-        -webkit-appearance: none;
-
-        --iron-autogrow-textarea: {
-          box-sizing: border-box;
-          padding: var(--spacing-s);
-        };
-      }
-      a {
-        color: var(--link-color);
-      }
-      input,
-      textarea,
-      select,
-      button {
-        font: inherit;
-      }
-      ol, ul {
-        list-style: none;
-      }
-      blockquote, q {
-        quotes: none;
-      }
-      blockquote:before, blockquote:after,
-      q:before, q:after {
-        content: '';
-        content: none;
-      }
-      table {
-        border-collapse: collapse;
-        border-spacing: 0;
-      }
-
-      /* Fonts */
-
-      .font-normal {
-        font-size: var(--font-size-normal);
-        font-weight: var(--font-weight-normal);
-        line-height: var(--line-height-normal);
-      }
-      .font-small {
-        font-size: var(--font-size-small);
-        font-weight: var(--font-weight-normal);
-        line-height: var(--line-height-small);
-      }
-      .heading-1 {
-        font-family: var(--header-font-family);
-        font-size: var(--font-size-h1);
-        font-weight: var(--font-weight-h1);
-        line-height: var(--line-height-h1);
-      }
-      .heading-2 {
-        font-family: var(--header-font-family);
-        font-size: var(--font-size-h2);
-        font-weight: var(--font-weight-h2);
-        line-height: var(--line-height-h2);
-      }
-      .heading-3 {
-        font-family: var(--header-font-family);
-        font-size: var(--font-size-h3);
-        font-weight: var(--font-weight-h3);
-        line-height: var(--line-height-h3);
-      }
-      iron-icon {
-        color: var(--deemphasized-text-color);
-        --iron-icon-height: 20px;
-        --iron-icon-width: 20px;
-      }
-
-      /* Stopgap solution until we remove hidden$ attributes. */
-
-      :host([hidden]),
-      [hidden] {
-        display: none !important;
-      }
-      .separator {
-        border-left: 1px solid var(--border-color);
-        height: 20px;
-        margin: 0 8px;
-      }
-      .separator.transparent {
-        border-color: transparent;
-      }
-      paper-toggle-button {
-        --paper-toggle-button-checked-bar-color: var(--link-color);
-        --paper-toggle-button-checked-button-color: var(--link-color);
-      }
-      paper-tabs {
-        font-size: var(--font-size-h3);
-        font-weight: var(--font-weight-h3);
-        line-height: var(--line-height-h3);
-        --paper-font-common-base: {
-          font-family: var(--header-font-family);
-          -webkit-font-smoothing: initial;
-        };
-        --paper-tab-content-focused: {
-          /* paper-tabs uses 700 here, which can look awkward */
-          font-weight: var(--font-weight-h3);
-        };
-        --paper-tab-content-unselected: {
-          /* paper-tabs uses 0.8 here, but we want to control the color directly */
-          opacity: 1;
-          color: var(--deemphasized-text-color);
-        };
-      }
-      iron-autogrow-textarea {
-        /** This is needed for firefox */
-        --iron-autogrow-textarea_-_white-space: pre-wrap;
-      }
-      strong {
-        font-weight: var(--font-weight-bold);
-      }
-
-      .assistive-tech-only {
-        user-select: none;
-        clip: rect(1px, 1px, 1px, 1px);
-        height: 1px;
-        margin: 0;
-        overflow: hidden;
-        padding: 0;
-        position: absolute;
-        white-space: nowrap;
-        width: 1px;
-        z-index: -1000;
-      }
-
-      /** BEGIN: loading spiner */
-      .loadingSpin {
-        border: 2px solid var(--disabled-button-background-color);
-        border-top: 2px solid var(--primary-button-background-color);
-        border-radius: 50%;
-        width: 10px;
-        height: 10px;
-        animation: spin 2s linear infinite;
-        margin-right: var(--spacing-s);
-      }
-      @keyframes spin {
-        0% { transform: rotate(0deg); }
-        100% { transform: rotate(360deg); }
-      }
-      /** END: loading spiner */
+    ${sharedStyles.cssText}
     </style>
   </template>
 </dom-module>`;
diff --git a/polygerrit-ui/app/styles/themes/app-theme.ts b/polygerrit-ui/app/styles/themes/app-theme.ts
index 9586c09..73dfe5c 100644
--- a/polygerrit-ui/app/styles/themes/app-theme.ts
+++ b/polygerrit-ui/app/styles/themes/app-theme.ts
@@ -122,7 +122,6 @@
     --font-size-h3: 1.143rem;   /* 16px */
     --font-size-h2: 1.429rem;   /* 20px */
     --font-size-h1: 1.714rem;   /* 24px */
-    --line-height-code: 1.143rem;   /* 16px */
     --line-height-mono: 1.286rem;   /* 18px */
     --line-height-small: 1.143rem;  /* 16px */
     --line-height-normal: 1.429rem; /* 20px */
@@ -175,7 +174,10 @@
     --diff-trailing-whitespace-indicator: #ff9ad2;
     --light-add-highlight-color: #d8fed8;
     --light-rebased-add-highlight-color: #eef;
-    --light-moved-add-highlight-color: #eef;
+    --diff-moved-in-background: #e4f7fb;
+    --diff-moved-out-background: #f3e8fd;
+    --diff-moved-in-label-background: #007b83;
+    --diff-moved-out-label-background: #681da8;
     --light-remove-add-highlight-color: #fff8dc;
     --light-remove-highlight-color: #ffebee;
     --coverage-covered: #e0f2f1;
diff --git a/polygerrit-ui/app/styles/themes/dark-theme.ts b/polygerrit-ui/app/styles/themes/dark-theme.ts
index 4d3e6d8..c7c8eb1 100644
--- a/polygerrit-ui/app/styles/themes/dark-theme.ts
+++ b/polygerrit-ui/app/styles/themes/dark-theme.ts
@@ -125,7 +125,10 @@
       --diff-trailing-whitespace-indicator: #ff9ad2;
       --light-add-highlight-color: #0f401f;
       --light-rebased-add-highlight-color: #487165;
-      --light-moved-add-highlight-color: #487165;
+      --diff-moved-in-background: #006066;
+      --diff-moved-out-background: #681da8;
+      --diff-moved-in-label-background: #cbf0f8;
+      --diff-moved-out-label-background: #e9d2fd;
       --light-remove-add-highlight-color: #2f3f2f;
       --light-remove-highlight-color: #320404;
       --coverage-covered: #112826;
diff --git a/polygerrit-ui/app/test/common-test-setup.ts b/polygerrit-ui/app/test/common-test-setup.ts
index 71c45f7..8c1c4ee 100644
--- a/polygerrit-ui/app/test/common-test-setup.ts
+++ b/polygerrit-ui/app/test/common-test-setup.ts
@@ -29,6 +29,8 @@
   cleanupTestUtils,
   getCleanupsCount,
   registerTestCleanup,
+  addIronOverlayBackdropStyleEl,
+  removeIronOverlayBackdropStyleEl,
   TestKeyboardShortcutBinder,
 } from './test-utils';
 import {flushDebouncers} from '@polymer/polymer/lib/utils/debounce';
@@ -94,6 +96,7 @@
 setup(() => {
   window.Gerrit = {};
   initGlobalVariables();
+  addIronOverlayBackdropStyleEl();
 
   // If the following asserts fails - then window.stub is
   // overwritten by some other code.
@@ -196,6 +199,7 @@
   cleanupTestUtils();
   TestKeyboardShortcutBinder.pop();
   checkGlobalSpace();
+  removeIronOverlayBackdropStyleEl();
   // Clean Polymer debouncer queue, so next tests will not be affected.
   flushDebouncers();
 });
diff --git a/polygerrit-ui/app/test/test-data-generators.ts b/polygerrit-ui/app/test/test-data-generators.ts
index 3b464a5..444d0bf 100644
--- a/polygerrit-ui/app/test/test-data-generators.ts
+++ b/polygerrit-ui/app/test/test-data-generators.ts
@@ -58,6 +58,9 @@
   TimezoneOffset,
   UserConfigInfo,
   AccountDetailInfo,
+  Requirement,
+  RequirementType,
+  UrlEncodedCommentId,
 } from '../types/common';
 import {
   AccountsVisibility,
@@ -74,15 +77,21 @@
   RevisionKind,
   SubmitType,
   TimeFormat,
+  RequirementStatus,
+  CommentSide,
 } from '../constants/constants';
 import {formatDate} from '../utils/date-util';
 import {GetDiffCommentsOutput} from '../services/services/gr-rest-api/gr-rest-api';
 import {AppElementChangeViewParams} from '../elements/gr-app-types';
-import {GerritView} from '../elements/core/gr-navigation/gr-navigation';
 import {
   EditRevisionInfo,
   ParsedChangeInfo,
 } from '../elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser';
+import {CommitInfoWithRequiredCommit} from '../elements/change/gr-change-metadata/gr-change-metadata';
+import {WebLinkInfo} from '../types/diff';
+import {UIComment, UIDraft, createCommentThreads} from '../utils/comment-util';
+import {GerritView} from '../services/router/router-model';
+import {ChangeComments} from '../elements/diff/gr-comment-api/gr-comment-api';
 
 export function dateToTimestamp(date: Date): Timestamp {
   const nanosecondSuffix = '.000000000';
@@ -194,6 +203,13 @@
   };
 }
 
+export function createCommitInfoWithRequiredCommit(): CommitInfoWithRequiredCommit {
+  return {
+    ...createCommit(),
+    commit: 'commit' as CommitId,
+  };
+}
+
 export function createRevision(patchSetNum = 1): RevisionInfo {
   return {
     _number: patchSetNum as PatchSetNum,
@@ -413,3 +429,151 @@
     project: TEST_PROJECT_NAME,
   };
 }
+
+export function createRequirement(): Requirement {
+  return {
+    status: RequirementStatus.OK,
+    fallbackText: '',
+    type: 'wip' as RequirementType,
+  };
+}
+
+export function createWebLinkInfo(): WebLinkInfo {
+  return {
+    name: 'gitiles',
+    url: '#',
+    image_url: 'gitiles.jpg',
+  };
+}
+
+export function createComment(): UIComment {
+  return {
+    patch_set: 1 as PatchSetNum,
+    id: '12345' as UrlEncodedCommentId,
+    side: CommentSide.REVISION,
+    line: 1,
+    message: 'hello world',
+    updated: '2018-02-13 22:48:48.018000000' as Timestamp,
+    unresolved: false,
+  };
+}
+
+export function createDraft(): UIDraft {
+  return {
+    ...createComment(),
+    collapsed: false,
+    __draft: true,
+    __editing: false,
+  };
+}
+
+export function createChangeComments(): ChangeComments {
+  const comments = {
+    '/COMMIT_MSG': [
+      {
+        ...createComment(),
+        message: 'Done',
+        updated: '2017-02-08 16:40:49' as Timestamp,
+        id: '1' as UrlEncodedCommentId,
+      },
+      {
+        ...createComment(),
+        message: 'oh hay',
+        updated: '2017-02-09 16:40:49' as Timestamp,
+        id: '2' as UrlEncodedCommentId,
+      },
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'hello',
+        updated: '2017-02-10 16:40:49' as Timestamp,
+        id: '3' as UrlEncodedCommentId,
+      },
+    ],
+    'myfile.txt': [
+      {
+        ...createComment(),
+        message: 'good news!',
+        updated: '2017-02-08 16:40:49' as Timestamp,
+        id: '4' as UrlEncodedCommentId,
+      },
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'wat!?',
+        updated: '2017-02-09 16:40:49' as Timestamp,
+        id: '5' as UrlEncodedCommentId,
+      },
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'hi',
+        updated: '2017-02-10 16:40:49' as Timestamp,
+        id: '6' as UrlEncodedCommentId,
+      },
+    ],
+    'unresolved.file': [
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'wat!?',
+        updated: '2017-02-09 16:40:49' as Timestamp,
+        id: '7' as UrlEncodedCommentId,
+        unresolved: true,
+      },
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'hi',
+        updated: '2017-02-10 16:40:49' as Timestamp,
+        id: '8' as UrlEncodedCommentId,
+        in_reply_to: '7' as UrlEncodedCommentId,
+        unresolved: false,
+      },
+      {
+        ...createComment(),
+        patch_set: 2 as PatchSetNum,
+        message: 'good news!',
+        updated: '2017-02-08 16:40:49' as Timestamp,
+        id: '9' as UrlEncodedCommentId,
+        unresolved: true,
+      },
+    ],
+  };
+  const drafts = {
+    '/COMMIT_MSG': [
+      {
+        ...createDraft(),
+        message: 'hi',
+        updated: '2017-02-15 16:40:49' as Timestamp,
+        id: '10' as UrlEncodedCommentId,
+        unresolved: true,
+      },
+      {
+        ...createDraft(),
+        message: 'fyi',
+        updated: '2017-02-15 16:40:49' as Timestamp,
+        id: '11' as UrlEncodedCommentId,
+        unresolved: false,
+      },
+    ],
+    'unresolved.file': [
+      {
+        ...createDraft(),
+        message: 'hi',
+        updated: '2017-02-11 16:40:49' as Timestamp,
+        id: '12' as UrlEncodedCommentId,
+        unresolved: false,
+      },
+    ],
+  };
+  return new ChangeComments(comments, {}, drafts, {}, {});
+}
+
+export function createCommentThread(comments: UIComment[]) {
+  comments = comments.map(comment => {
+    return {...createComment(), ...comment};
+  });
+  const threads = createCommentThreads(comments);
+  return threads.length > 0 ? threads[0] : {};
+}
diff --git a/polygerrit-ui/app/test/test-utils.ts b/polygerrit-ui/app/test/test-utils.ts
index 7ebc6e1..97c220d 100644
--- a/polygerrit-ui/app/test/test-utils.ts
+++ b/polygerrit-ui/app/test/test-utils.ts
@@ -105,6 +105,25 @@
   cleanups.push(cleanupCallback);
 }
 
+export function addListenerForTest(
+  el: EventTarget,
+  type: string,
+  listener: EventListenerOrEventListenerObject
+) {
+  el.addEventListener(type, listener);
+  registerListenerCleanup(el, type, listener);
+}
+
+export function registerListenerCleanup(
+  el: EventTarget,
+  type: string,
+  listener: EventListenerOrEventListenerObject
+) {
+  registerTestCleanup(() => {
+    el.removeEventListener(type, listener);
+  });
+}
+
 export function cleanupTestUtils() {
   cleanups.forEach(cleanup => cleanup());
   cleanups.splice(0);
@@ -119,16 +138,19 @@
 /**
  * Forcing an opacity of 0 onto the ironOverlayBackdrop is required, because
  * otherwise the backdrop stays around in the DOM for too long waiting for
- * an animation to finish. This could be considered to be moved to a
- * common-test-setup file.
+ * an animation to finish.
  */
-export function createIronOverlayBackdropStyleEl() {
-  const ironOverlayBackdropStyleEl = document.createElement('style');
-  document.head.appendChild(ironOverlayBackdropStyleEl);
-  ironOverlayBackdropStyleEl.sheet!.insertRule(
-    'body { --iron-overlay-backdrop-opacity: 0; }'
-  );
-  return ironOverlayBackdropStyleEl;
+export function addIronOverlayBackdropStyleEl() {
+  const el = document.createElement('style');
+  el.setAttribute('id', 'backdrop-style');
+  document.head.appendChild(el);
+  el.sheet!.insertRule('body { --iron-overlay-backdrop-opacity: 0; }');
+}
+
+export function removeIronOverlayBackdropStyleEl() {
+  const el = document.getElementById('backdrop-style');
+  if (!el?.parentNode) throw new Error('Backdrop style element not found.');
+  el.parentNode?.removeChild(el);
 }
 
 /**
@@ -139,7 +161,7 @@
  *   ...
  */
 export function listenOnce(el: EventTarget, eventType: string) {
-  return new Promise(resolve => {
+  return new Promise<void>(resolve => {
     const listener = () => {
       removeEventListener();
       resolve();
diff --git a/polygerrit-ui/app/types/common.ts b/polygerrit-ui/app/types/common.ts
index 94b075d..5574add 100644
--- a/polygerrit-ui/app/types/common.ts
+++ b/polygerrit-ui/app/types/common.ts
@@ -37,7 +37,6 @@
   TimeFormat,
   EmailStrategy,
   DefaultBase,
-  IgnoreWhitespaceType,
   UserPriority,
   DiffViewMode,
   DraftsAction,
@@ -50,6 +49,8 @@
 } from '../constants/constants';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 
+import {DiffInfo, IgnoreWhitespaceType, WebLinkInfo} from './diff';
+
 export type BrandType<T, BrandName extends string> = T &
   {[__brand in BrandName]: never};
 
@@ -261,7 +262,6 @@
   deletions: number; // Number of deleted lines
   total_comment_count?: number;
   unresolved_comment_count?: number;
-  // TODO(TS): Use changed_id everywhere in code instead of (legacy) _number
   _number: NumericChangeId;
   owner: AccountInfo;
   actions?: ActionNameToActionInfoMap;
@@ -716,16 +716,6 @@
 }
 
 /**
- * The WebLinkInfo entity describes a link to an external site.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#web-link-info
- */
-export interface WebLinkInfo {
-  name: string;
-  url: string;
-  image_url: string;
-}
-
-/**
  * The VotingRangeInfo entity describes the continuous voting range from minto
  * max values.
  * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#voting-range-info
@@ -1235,103 +1225,9 @@
 
 export type LabelTypeInfoValues = {[value: string]: string};
 
-/**
- * The DiffContent entity contains information about the content differences in a file.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-content
- */
-export interface DiffContent {
-  a?: string[];
-  b?: string[];
-  ab?: string[];
-  // The inner array is always of length two. The first entry is the 'skip'
-  // length. The second entry is the 'edit' length.
-  edit_a?: number[][];
-  edit_b?: number[][];
-  due_to_rebase?: boolean;
-  due_to_move?: boolean;
-  skip?: number;
-  common?: string;
-  keyLocation?: boolean;
-}
-
-/**
- * The DiffFileMetaInfo entity contains meta information about a file diff.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-file-meta-info
- */
-export interface DiffFileMetaInfo {
-  name: string;
-  content_type: string;
-  lines: string;
-  web_links?: WebLinkInfo[];
-  language?: string;
-}
-
-/**
- * The DiffInfo entity contains information about the diff of a file in a revision.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-info
- */
-export interface DiffInfo {
-  meta_a: DiffFileMetaInfo;
-  meta_b: DiffFileMetaInfo;
-  change_type: string;
-  intraline_status: string;
-  diff_header: string[];
-  content: DiffContent[];
-  web_links?: DiffWebLinkInfo[];
-  binary: boolean;
-}
-
 export type FilePathToDiffInfoMap = {[path: string]: DiffInfo};
 
 /**
- * The DiffWebLinkInfo entity describes a link on a diff screen to an external site.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-web-link-info
- */
-export interface DiffWebLinkInfo {
-  name: string;
-  url: string;
-  image_url: string;
-  show_on_side_by_side_diff_view: string;
-  show_on_unified_diff_view: string;
-}
-
-/**
- * The DiffPreferencesInfo entity contains information about the diff preferences of a user.
- * https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#diff-preferences-info
- */
-export interface DiffPreferencesInfo {
-  context: number;
-  expand_all_comments?: boolean;
-  ignore_whitespace: IgnoreWhitespaceType;
-  intraline_difference?: boolean;
-  line_length: number;
-  cursor_blink_rate: number;
-  manual_review?: boolean;
-  retain_header?: boolean;
-  show_line_endings?: boolean;
-  show_tabs?: boolean;
-  show_whitespace_errors?: boolean;
-  skip_deleted?: boolean;
-  skip_uncommented?: boolean;
-  syntax_highlighting?: boolean;
-  hide_top_menu?: boolean;
-  auto_hide_diff_table_header?: boolean;
-  hide_line_numbers?: boolean;
-  tab_size: number;
-  font_size: number;
-  hide_empty_pane?: boolean;
-  match_brackets?: boolean;
-  line_wrapping?: boolean;
-  // TODO(TS): show_file_comment_button exists in JS code, but doesn't exist in the doc.
-  // Either remove or update doc
-  show_file_comment_button?: boolean;
-  // TODO(TS): theme exists in JS code, but doesn't exist in the doc.
-  // Either remove or update doc
-  theme?: string;
-}
-export type DiffPreferencesInfoKey = keyof DiffPreferencesInfo;
-
-/**
  * The RangeInfo entity stores the coordinates of a range.
  * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#range-info
  */
diff --git a/polygerrit-ui/app/types/diff.d.ts b/polygerrit-ui/app/types/diff.d.ts
new file mode 100644
index 0000000..ed03dcf
--- /dev/null
+++ b/polygerrit-ui/app/types/diff.d.ts
@@ -0,0 +1,242 @@
+/**
+ * @fileoverview The Gerrit diff API.
+ *
+ * This API is used by other apps embedding gr-diff and any breaking changes
+ * should be discussed with the Gerrit core team and properly versioned.
+ *
+ * Should only contain types, no values, so that other apps using gr-diff can
+ * use this solely to type check and generate externs for their separate ts
+ * bundles.
+ *
+ * Should declare all types, to avoid renaming breaking multi-bundle setups.
+ *
+ * Enums should be converted to union types to avoid values in this file.
+ *
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The DiffInfo entity contains information about the diff of a file in a
+ * revision.
+ *
+ * If the weblinks-only parameter is specified, only the web_links field is set.
+ */
+export declare interface DiffInfo {
+  /** Meta information about the file on side A as a DiffFileMetaInfo entity. */
+  meta_a: DiffFileMetaInfo;
+  /** Meta information about the file on side B as a DiffFileMetaInfo entity. */
+  meta_b: DiffFileMetaInfo;
+  /** The type of change (ADDED, MODIFIED, DELETED, RENAMED COPIED, REWRITE). */
+  change_type: ChangeType;
+  /** Intraline status (OK, ERROR, TIMEOUT). */
+  intraline_status: 'OK' | 'Error' | 'Timeout';
+  /** A list of strings representing the patch set diff header. */
+  diff_header: string[];
+  /** The content differences in the file as a list of DiffContent entities. */
+  content: DiffContent[];
+  /**
+   * Links to the file diff in external sites as a list of DiffWebLinkInfo
+   * entries.
+   */
+  web_links?: DiffWebLinkInfo[];
+  /** Whether the file is binary. */
+  binary?: boolean;
+}
+
+/**
+ * The DiffFileMetaInfo entity contains meta information about a file diff.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-file-meta-info
+ */
+export declare interface DiffFileMetaInfo {
+  /** The name of the file. */
+  name: string;
+  /** The content type of the file. */
+  content_type: string;
+  /** The total number of lines in the file. */
+  lines: number;
+  /** Links to the file in external sites as a list of WebLinkInfo entries. */
+  web_links: WebLinkInfo[];
+  // TODO: Not documented.
+  language?: string;
+}
+
+export declare type ChangeType =
+  | 'ADDED'
+  | 'MODIFIED'
+  | 'DELETED'
+  | 'RENAMED'
+  | 'COPIED'
+  | 'REWRITE';
+
+/**
+ * The DiffContent entity contains information about the content differences in
+ * a file.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-content
+ */
+export declare interface DiffContent {
+  /** Content only in the file on side A (deleted in B). */
+  a?: string[];
+  /** Content only in the file on side B (added in B). */
+  b?: string[];
+  /** Content in the file on both sides (unchanged). */
+  ab?: string[];
+  /**
+   * Text sections deleted from side A as a DiffIntralineInfo entity.
+   *
+   * Only present during a replace, i.e. both a and b are present.
+   */
+  edit_a?: DiffIntralineInfo[];
+  /**
+   * Text sections inserted in side B as a DiffIntralineInfo entity.
+   *
+   * Only present during a replace, i.e. both a and b are present.
+   */
+  edit_b?: DiffIntralineInfo[];
+  /** Indicates whether this entry was introduced by a rebase. */
+  due_to_rebase?: boolean;
+
+  /**
+   * Provides info about a move operation the chunk.
+   * It's presence indicates the current chunk exists due to a move.
+   */
+  move_details?: MoveDetails;
+  /**
+   * Count of lines skipped on both sides when the file is too large to include
+   * all common lines.
+   */
+  skip?: number;
+  /**
+   * Set to true if the region is common according to the requested
+   * ignore-whitespace parameter, but a and b contain differing amounts of
+   * whitespace. When present and true a and b are used instead of ab.
+   */
+  common?: boolean;
+  // TODO: Undocumented, but used in code.
+  keyLocation?: boolean;
+}
+
+/**
+ * Details about move operation related to a specific chunk.
+ */
+export declare interface MoveDetails {
+  /** Indicates whether the content of the chunk changes while moving code */
+  changed: boolean;
+  /**
+   * Indicates the range (line numbers) on the other side of the comparison
+   * where the code related to the current chunk came from/went to.
+   */
+  range: {
+    start: number;
+    end: number;
+  };
+}
+
+/**
+ * The DiffWebLinkInfo entity describes a link on a diff screen to an external
+ * site.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#diff-web-link-info
+ */
+export declare interface DiffWebLinkInfo {
+  /** The link name. */
+  name: string;
+  /** The link URL. */
+  url: string;
+  /** URL to the icon of the link. */
+  image_url: string;
+  // TODO: Are these really of type string? Not able to trigger them, but the
+  // docs sound more like boolean.
+  show_on_side_by_side_diff_view: string;
+  show_on_unified_diff_view: string;
+}
+/**
+ * The DiffIntralineInfo entity contains information about intraline edits in a
+ * file.
+ *
+ * The information consists of a list of <skip length, mark length> pairs, where
+ * the skip length is the number of characters between the end of the previous
+ * edit and the start of this edit, and the mark length is the number of edited
+ * characters following the skip. The start of the edits is from the beginning
+ * of the related diff content lines.
+ *
+ * Note that the implied newline character at the end of each line is included
+ * in the length calculation, and thus it is possible for the edits to span
+ * newlines.
+ */
+export declare type SkipLength = number;
+export declare type MarkLength = number;
+export declare type DiffIntralineInfo = [SkipLength, MarkLength];
+
+/**
+ * The WebLinkInfo entity describes a link to an external site.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#web-link-info
+ */
+export declare interface WebLinkInfo {
+  /** The link name. */
+  name: string;
+  /** The link URL. */
+  url: string;
+  /** URL to the icon of the link. */
+  image_url: string;
+}
+
+/**
+ * The DiffPreferencesInfo entity contains information about the diff
+ * preferences of a user.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#diff-preferences-info
+ */
+export declare interface DiffPreferencesInfo {
+  context: number;
+  expand_all_comments?: boolean;
+  ignore_whitespace: IgnoreWhitespaceType;
+  intraline_difference?: boolean;
+  line_length: number;
+  cursor_blink_rate: number;
+  manual_review?: boolean;
+  retain_header?: boolean;
+  show_line_endings?: boolean;
+  show_tabs?: boolean;
+  show_whitespace_errors?: boolean;
+  skip_deleted?: boolean;
+  skip_uncommented?: boolean;
+  syntax_highlighting?: boolean;
+  hide_top_menu?: boolean;
+  auto_hide_diff_table_header?: boolean;
+  hide_line_numbers?: boolean;
+  tab_size: number;
+  font_size: number;
+  hide_empty_pane?: boolean;
+  match_brackets?: boolean;
+  line_wrapping?: boolean;
+  // TODO(TS): show_file_comment_button exists in JS code, but doesn't exist in
+  // the doc. Either remove or update doc
+  show_file_comment_button?: boolean;
+  // TODO(TS): theme exists in JS code, but doesn't exist in the doc.
+  // Either remove or update doc
+  theme?: string;
+}
+
+export declare type DiffPreferencesInfoKey = keyof DiffPreferencesInfo;
+
+/**
+ * Whether whitespace changes should be ignored and if yes, which whitespace
+ * changes should be ignored
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#diff-preferences-input
+ */
+export declare type IgnoreWhitespaceType =
+  | 'IGNORE_NONE'
+  | 'IGNORE_TRAILING'
+  | 'IGNORE_LEADING_AND_TRAILING'
+  | 'IGNORE_ALL';
diff --git a/polygerrit-ui/app/types/events.ts b/polygerrit-ui/app/types/events.ts
index 529904a..2398a66 100644
--- a/polygerrit-ui/app/types/events.ts
+++ b/polygerrit-ui/app/types/events.ts
@@ -15,8 +15,11 @@
  * limitations under the License.
  */
 import {EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
-import {PatchSetNum} from './common';
+import {PatchSetNum, UrlEncodedCommentId} from './common';
 import {UIComment} from '../utils/comment-util';
+import {Side} from '../constants/constants';
+import {LineNumber} from '../elements/diff/gr-diff/gr-diff-line';
+import {FetchRequest} from './types';
 
 export interface TitleChangeEventDetail {
   title: string;
@@ -42,6 +45,31 @@
   }
 }
 
+export interface ServerErrorEventDetail {
+  request?: FetchRequest;
+  response: Response;
+}
+
+export type ServerErrorEvent = CustomEvent<ServerErrorEventDetail>;
+
+declare global {
+  interface DocumentEventMap {
+    'server-error': ServerErrorEvent;
+  }
+}
+
+export interface NetworkErrorEventDetail {
+  error: Error;
+}
+
+export type NetworkErrorEvent = CustomEvent<NetworkErrorEventDetail>;
+
+declare global {
+  interface DocumentEventMap {
+    'network-error': NetworkErrorEvent;
+  }
+}
+
 export interface LocationChangeEventDetail {
   hash: string;
   pathname: string;
@@ -65,8 +93,8 @@
 export type RpcLogEvent = CustomEvent<RpcLogEventDetail>;
 
 declare global {
-  interface HTMLElementEventMap {
-    'rpc-log': RpcLogEvent;
+  interface DocumentEventMap {
+    'gr-rpc-log': RpcLogEvent;
   }
 }
 
@@ -136,9 +164,23 @@
 
 export type ReloadEvent = CustomEvent<ReloadEventDetail>;
 
+export interface MovedChunkGoToLineDetail {
+  side: Side;
+  line: LineNumber;
+}
+
+export type MovedChunkGoToLineEvent = CustomEvent<MovedChunkGoToLineDetail>;
+
 declare global {
   interface HTMLElementEventMap {
-    reload: ReloadEvent;
+    'moved-link-clicked': MovedChunkGoToLineEvent;
+  }
+}
+
+declare global {
+  interface HTMLElementEventMap {
+    /* prettier-ignore */
+    'reload': ReloadEvent;
   }
 }
 
@@ -172,3 +214,16 @@
   readonly keyCode: number;
   readonly repeat: boolean;
 }
+
+export interface ThreadListModifiedDetail {
+  rootId: UrlEncodedCommentId;
+  path: string;
+}
+
+export type ThreadListModifiedEvent = CustomEvent<ThreadListModifiedDetail>;
+
+declare global {
+  interface HTMLElementEventMap {
+    'thread-list-modified': ThreadListModifiedEvent;
+  }
+}
diff --git a/polygerrit-ui/app/types/globals.ts b/polygerrit-ui/app/types/globals.ts
index 2962158..628cee4 100644
--- a/polygerrit-ui/app/types/globals.ts
+++ b/polygerrit-ui/app/types/globals.ts
@@ -23,12 +23,6 @@
   interface Window {
     CANONICAL_PATH?: string;
     INITIAL_DATA?: {[key: string]: ParsedJSON};
-    ShadyCSS?: {
-      getComputedStyleValue(el: Element, name: string): string;
-    };
-    ShadyDOM?: {
-      inUse?: boolean;
-    };
     HTMLImports?: {whenReady: (cb: () => void) => void};
     linkify(
       text: string,
@@ -42,12 +36,7 @@
       Auth?: unknown;
       _pluginLoader?: unknown;
       _endpoints?: unknown;
-      slotToContent?: unknown;
-      rangesEqual?: unknown;
-      SUGGESTIONS_PROVIDERS_USERS_TYPES?: unknown;
       RevisionInfo?: unknown;
-      CoverageType?: unknown;
-      hiddenscroll?: unknown;
       flushPreinstalls?: () => void;
     };
     // TODO(TS): define polymer type
@@ -75,49 +64,16 @@
     // TODO(TS): should clean up those and removing them may break certain plugin behaviors
     // TODO(TS): as @brohlfs suggested, to avoid importing anything from elements/ to types/
     // use any for them for now
-    GrDisplayNameUtils: unknown;
     GrAnnotation: unknown;
-    GrAttributeHelper: unknown;
     GrDiffLine: unknown;
     GrDiffLineType: unknown;
     GrDiffGroup: unknown;
     GrDiffGroupType: unknown;
-    GrDiffBuilder: unknown;
-    GrDiffBuilderSideBySide: unknown;
-    GrDiffBuilderImage: unknown;
-    GrDiffBuilderUnified: unknown;
-    GrDiffBuilderBinary: unknown;
-    GrChangeActionsInterface: unknown;
-    GrChangeReplyInterface: unknown;
-    GrEditConstants: unknown;
-    GrDomHooksManager: unknown;
-    GrDomHook: unknown;
-    GrEtagDecorator: unknown;
-    GrThemeApi: unknown;
-    SiteBasedCache: unknown;
-    FetchPromisesCache: unknown;
-    GrRestApiHelper: unknown;
-    GrLinkTextParser: unknown;
-    GrPluginEndpoints: unknown;
-    GrReviewerUpdatesParser: unknown;
-    GrPopupInterface: unknown;
-    GrCountStringFormatter: unknown;
-    GrReviewerSuggestionsProvider: unknown;
     util: unknown;
     Auth: unknown;
     EventEmitter: unknown;
-    GrAdminApi: unknown;
-    GrAnnotationActionsContext: unknown;
-    GrAnnotationActionsInterface: unknown;
-    GrChangeMetadataApi: unknown;
-    GrEmailSuggestionsProvider: unknown;
-    GrGroupSuggestionsProvider: unknown;
-    GrEventHelper: unknown;
-    GrPluginRestApi: unknown;
-    GrRepoApi: unknown;
-    GrSettingsApi: unknown;
-    GrStylesApi: unknown;
     PluginLoader: unknown;
+    // Heads up! There is a known plugin dependency on GrPluginActionContext.
     GrPluginActionContext: unknown;
     _apiUtils: {};
   }
@@ -132,13 +88,6 @@
     };
   }
 
-  interface Event {
-    // path is a non-standard property. Actually, this is optional property,
-    // but marking it as optional breaks CustomKeyboardEvent
-    // TODO(TS): replace with composedPath if possible
-    readonly path: EventTarget[];
-  }
-
   interface Error {
     lineNumber?: number; // non-standard property
     columnNumber?: number; // non-standard property
diff --git a/polygerrit-ui/app/types/types.ts b/polygerrit-ui/app/types/types.ts
index b40d618..232e204 100644
--- a/polygerrit-ui/app/types/types.ts
+++ b/polygerrit-ui/app/types/types.ts
@@ -27,6 +27,7 @@
   PatchSetNum,
 } from './common';
 import {PolymerSpliceChange} from '@polymer/polymer/interfaces';
+import {AuthRequestInit} from '../services/gr-auth/gr-auth';
 
 export function notUndefined<T>(x: T | undefined): x is T {
   return x !== undefined;
@@ -237,3 +238,9 @@
 >(x: T | PolymerSpliceChange<U>): x is PolymerSpliceChange<U> {
   return (x as PolymerSpliceChange<U>).indexSplices !== undefined;
 }
+
+export interface FetchRequest {
+  url: string;
+  fetchOptions?: AuthRequestInit;
+  anonymizedUrl?: string;
+}
diff --git a/polygerrit-ui/app/utils/admin-nav-util.ts b/polygerrit-ui/app/utils/admin-nav-util.ts
index 06f4e3a..b144313 100644
--- a/polygerrit-ui/app/utils/admin-nav-util.ts
+++ b/polygerrit-ui/app/utils/admin-nav-util.ts
@@ -16,7 +16,6 @@
  */
 import {
   GerritNav,
-  GerritView,
   RepoDetailView,
   GroupDetailView,
 } from '../elements/core/gr-navigation/gr-navigation';
@@ -28,6 +27,7 @@
 } from '../types/common';
 import {MenuLink} from '../elements/plugins/gr-admin-api/gr-admin-api';
 import {hasOwnProperty} from './common-util';
+import {GerritView} from '../services/router/router-model';
 
 const ADMIN_LINKS: NavLink[] = [
   {
diff --git a/polygerrit-ui/app/utils/attention-set-util.ts b/polygerrit-ui/app/utils/attention-set-util.ts
index b0aefcb..5b2762c 100644
--- a/polygerrit-ui/app/utils/attention-set-util.ts
+++ b/polygerrit-ui/app/utils/attention-set-util.ts
@@ -17,6 +17,7 @@
 
 import {AccountInfo, ChangeInfo} from '../types/common';
 import {isServiceUser} from './account-util';
+import {hasOwnProperty} from './common-util';
 
 // You would typically use a ServerInfo here, but this utility does not care
 // about all the other parameters in that object.
@@ -46,7 +47,8 @@
   return (
     isAttentionSetEnabled(config) &&
     canHaveAttention(account) &&
-    !!change?.attention_set?.hasOwnProperty(account!._account_id!)
+    !!change?.attention_set &&
+    hasOwnProperty(change?.attention_set, account!._account_id!)
   );
 }
 
diff --git a/polygerrit-ui/app/utils/change-metadata-util.ts b/polygerrit-ui/app/utils/change-metadata-util.ts
new file mode 100644
index 0000000..6ce1483
--- /dev/null
+++ b/polygerrit-ui/app/utils/change-metadata-util.ts
@@ -0,0 +1,75 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {ParsedChangeInfo} from '../elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser';
+
+export enum Metadata {
+  OWNER = 'Owner',
+  REVIEWERS = 'Reviewers',
+  REPO_BRANCH = 'Repo | Branch',
+  SUBMITTED = 'Submitted',
+  PARENT = 'Parent',
+  STRATEGY = 'Strategy',
+  UPDATED = 'Updated',
+  CC = 'CC',
+  HASHTAGS = 'Hashtags',
+  TOPIC = 'Topic',
+  UPLOADER = 'Uploader',
+  AUTHOR = 'Author',
+  COMMITTER = 'Committer',
+  ASSIGNEE = 'Assignee',
+  CHERRY_PICK_OF = 'Cherry pick of',
+}
+
+export const DisplayRules = {
+  ALWAYS_SHOW: [
+    Metadata.OWNER,
+    Metadata.REVIEWERS,
+    Metadata.REPO_BRANCH,
+    Metadata.SUBMITTED,
+  ],
+  SHOW_IF_SET: [
+    Metadata.CC,
+    Metadata.HASHTAGS,
+    Metadata.TOPIC,
+    Metadata.UPLOADER,
+    Metadata.AUTHOR,
+    Metadata.COMMITTER,
+    Metadata.ASSIGNEE,
+    Metadata.CHERRY_PICK_OF,
+  ],
+  ALWAYS_HIDE: [Metadata.PARENT, Metadata.STRATEGY, Metadata.UPDATED],
+};
+
+export function isSectionSet(section: Metadata, change?: ParsedChangeInfo) {
+  switch (section) {
+    case Metadata.CC:
+      return !!change?.reviewers?.CC?.length;
+    case Metadata.HASHTAGS:
+      return !!change?.hashtags?.length;
+    case Metadata.TOPIC:
+      return !!change?.topic;
+    case Metadata.UPLOADER:
+    case Metadata.AUTHOR:
+    case Metadata.COMMITTER:
+    case Metadata.ASSIGNEE:
+      return false;
+    case Metadata.CHERRY_PICK_OF:
+      return !!change?.cherry_pick_of_change;
+  }
+  return true;
+}
diff --git a/polygerrit-ui/app/utils/comment-util.ts b/polygerrit-ui/app/utils/comment-util.ts
index 5f8aa82..f4c0692 100644
--- a/polygerrit-ui/app/utils/comment-util.ts
+++ b/polygerrit-ui/app/utils/comment-util.ts
@@ -21,9 +21,15 @@
   RobotCommentInfo,
   Timestamp,
   UrlEncodedCommentId,
+  CommentRange,
+  PatchRange,
+  ParentPatchSetNum,
 } from '../types/common';
 import {CommentSide, Side} from '../constants/constants';
 import {parseDate} from './date-util';
+import {LineNumber} from '../elements/diff/gr-diff/gr-diff-line';
+import {CommentIdToCommentThreadMap} from '../elements/diff/gr-comment-api/gr-comment-api';
+import {isMergeParent, getParentIndex} from './patch-set-util';
 
 export interface DraftCommentProps {
   __draft?: boolean;
@@ -39,19 +45,14 @@
 export type Comment = DraftInfo | CommentInfo | RobotCommentInfo;
 
 export interface UIStateCommentProps {
-  // The `side` of the comment is PARENT or REVISION, but this is LEFT or RIGHT.
-  // TODO(TS): Remove the naming confusion of commentSide being of type of Side,
-  // but side being of type CommentSide. :-)
-  __commentSide?: Side;
-  // TODO(TS): Remove this. Seems to be exactly the same as `path`??
-  __path?: string;
   collapsed?: boolean;
-  // TODO(TS): Consider allowing this only for drafts.
-  __editing?: boolean;
-  __otherEditing?: boolean;
 }
 
-export type UIDraft = DraftInfo & UIStateCommentProps;
+export interface UIStateDraftProps {
+  __editing?: boolean;
+}
+
+export type UIDraft = DraftInfo & UIStateCommentProps & UIStateDraftProps;
 
 export type UIHuman = CommentInfo & UIStateCommentProps;
 
@@ -97,17 +98,73 @@
   });
 }
 
+export function createCommentThreads(
+  comments: UIComment[],
+  patchRange?: PatchRange
+) {
+  const sortedComments = sortComments(comments);
+  const threads: CommentThread[] = [];
+  const idThreadMap: CommentIdToCommentThreadMap = {};
+  for (const comment of sortedComments) {
+    if (!comment.id) continue;
+    // If the comment is in reply to another comment, find that comment's
+    // thread and append to it.
+    if (comment.in_reply_to) {
+      const thread = idThreadMap[comment.in_reply_to];
+      if (thread) {
+        thread.comments.push(comment);
+        idThreadMap[comment.id] = thread;
+        continue;
+      }
+    }
+
+    // Otherwise, this comment starts its own thread.
+    if (!comment.path) {
+      throw new Error('Comment missing required "path".');
+    }
+    const newThread: CommentThread = {
+      comments: [comment],
+      patchNum: comment.patch_set,
+      commentSide: comment.side ?? CommentSide.REVISION,
+      mergeParentNum: comment.parent,
+      path: comment.path,
+      line: comment.line,
+      range: comment.range,
+      rootId: comment.id,
+    };
+    if (patchRange) {
+      if (isInBaseOfPatchRange(comment, patchRange))
+        newThread.diffSide = Side.LEFT;
+      else if (isInRevisionOfPatchRange(comment, patchRange))
+        newThread.diffSide = Side.RIGHT;
+      else throw new Error('comment does not belong in given patchrange');
+    }
+    if (!comment.line && !comment.range) {
+      newThread.line = 'FILE';
+    }
+    threads.push(newThread);
+    idThreadMap[comment.id] = newThread;
+  }
+  return threads;
+}
+
 export interface CommentThread {
   comments: UIComment[];
-  patchNum?: PatchSetNum;
   path: string;
-  // TODO(TS): It would be nice to use LineNumber here, but the comment thread
-  // element actually relies on line to be undefined for file comments. Be
-  // aware of element attribute getters and setters, if you try to refactor
-  // this. :-) Still worthwhile to do ...
-  line?: number;
-  rootId: UrlEncodedCommentId;
-  commentSide?: CommentSide;
+  commentSide: CommentSide;
+  /* mergeParentNum is the merge parent number only valid for merge commits
+     when commentSide is PARENT.
+     mergeParentNum is undefined for auto merge commits
+  */
+  mergeParentNum?: number;
+  patchNum?: PatchSetNum;
+  line?: LineNumber;
+  /* rootId is optional since we create a empty comment thread element for
+     drafts and then create the draft which becomes the root */
+  rootId?: UrlEncodedCommentId;
+  diffSide?: Side;
+  range?: CommentRange;
+  ported?: boolean; // is the comment ported over from a previous patchset
 }
 
 export function getLastComment(thread?: CommentThread): UIComment | undefined {
@@ -122,3 +179,88 @@
 export function isDraftThread(thread?: CommentThread): boolean {
   return isDraft(getLastComment(thread));
 }
+
+/**
+ * Whether the given comment should be included in the base side of the
+ * given patch range.
+ */
+export function isInBaseOfPatchRange(
+  comment: CommentBasics,
+  range: PatchRange
+) {
+  // If the base of the patch range is a parent of a merge, and the comment
+  // appears on a specific parent then only show the comment if the parent
+  // index of the comment matches that of the range.
+  if (comment.parent && comment.side === CommentSide.PARENT) {
+    return (
+      isMergeParent(range.basePatchNum) &&
+      comment.parent === getParentIndex(range.basePatchNum)
+    );
+  }
+
+  // If the base of the range is the parent of the patch:
+  if (
+    range.basePatchNum === ParentPatchSetNum &&
+    comment.side === CommentSide.PARENT &&
+    comment.patch_set === range.patchNum
+  ) {
+    return true;
+  }
+  // If the base of the range is not the parent of the patch:
+  return (
+    range.basePatchNum !== ParentPatchSetNum &&
+    comment.side !== CommentSide.PARENT &&
+    comment.patch_set === range.basePatchNum
+  );
+}
+
+/**
+ * Whether the given comment should be included in the revision side of the
+ * given patch range.
+ */
+export function isInRevisionOfPatchRange(
+  comment: CommentBasics,
+  range: PatchRange
+) {
+  return (
+    comment.side !== CommentSide.PARENT && comment.patch_set === range.patchNum
+  );
+}
+
+/**
+ * Whether the given comment should be included in the given patch range.
+ */
+export function isInPatchRange(
+  comment: CommentBasics,
+  range: PatchRange
+): boolean {
+  return (
+    isInBaseOfPatchRange(comment, range) ||
+    isInRevisionOfPatchRange(comment, range)
+  );
+}
+
+export function getPatchRangeForCommentUrl(
+  comment: UIComment,
+  latestPatchNum: PatchSetNum
+) {
+  if (!comment.patch_set) throw new Error('Missing comment.patch_set');
+
+  // TODO(dhruvsri): Add handling for comment left on parents of merge commits
+  if (comment.side === CommentSide.PARENT) {
+    return {
+      patchNum: comment.patch_set,
+      basePatchNum: ParentPatchSetNum,
+    };
+  } else if (latestPatchNum === comment.patch_set) {
+    return {
+      patchNum: latestPatchNum,
+      basePatchNum: ParentPatchSetNum,
+    };
+  } else {
+    return {
+      patchNum: latestPatchNum,
+      basePatchNum: comment.patch_set,
+    };
+  }
+}
diff --git a/polygerrit-ui/app/utils/comment-util_test.js b/polygerrit-ui/app/utils/comment-util_test.js
index ad19974..3b1c090 100644
--- a/polygerrit-ui/app/utils/comment-util_test.js
+++ b/polygerrit-ui/app/utils/comment-util_test.js
@@ -17,8 +17,11 @@
 
 import '../test/common-test-setup-karma.js';
 import {
-  isUnresolved,
+  isUnresolved, getPatchRangeForCommentUrl,
 } from './comment-util.js';
+import {createComment} from '../test/test-data-generators.js';
+import {CommentSide} from '../constants/constants.js';
+import {ParentPatchSetNum} from '../types/common.js';
 
 suite('comment-util', () => {
   test('isUnresolved', () => {
@@ -31,4 +34,22 @@
     assert.isFalse(isUnresolved(
         {comments: [{unresolved: true}, {unresolved: false}]}));
   });
+
+  test('getPatchRangeForCommentUrl', () => {
+    test('comment created with side=PARENT does not navigate to latest ps',
+        () => {
+          const comment = {
+            ...createComment(),
+            id: 'c4',
+            line: 10,
+            patch_set: 4,
+            side: CommentSide.PARENT,
+            path: '/COMMIT_MSG',
+          };
+          assert.deepEqual(getPatchRangeForCommentUrl(comment, 11), {
+            basePatchNum: ParentPatchSetNum,
+            patchNum: 4,
+          });
+        });
+  });
 });
diff --git a/polygerrit-ui/app/utils/date-util.ts b/polygerrit-ui/app/utils/date-util.ts
index 1dd2d2f..5101d11 100644
--- a/polygerrit-ui/app/utils/date-util.ts
+++ b/polygerrit-ui/app/utils/date-util.ts
@@ -69,6 +69,16 @@
   return diff < Duration.DAY && date.getDay() === now.getDay();
 }
 
+export function wasYesterday(now: Date, date: Date) {
+  const diff = now.valueOf() - date.valueOf();
+  // return true if date is withing 24 hours and not on the same day
+  if (diff < Duration.DAY && date.getDay() !== now.getDay()) return true;
+
+  // move now to yesterday
+  now.setDate(now.getDate() - 1);
+  return isWithinDay(now, date);
+}
+
 /**
  * Returns true if date is from one to six months.
  */
diff --git a/polygerrit-ui/app/utils/date-util_test.js b/polygerrit-ui/app/utils/date-util_test.js
index a003c65..76d8516 100644
--- a/polygerrit-ui/app/utils/date-util_test.js
+++ b/polygerrit-ui/app/utils/date-util_test.js
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 import '../test/common-test-setup-karma.js';
-import {isValidDate, parseDate, fromNow, isWithinDay, isWithinHalfYear, formatDate} from './date-util.js';
+import {isValidDate, parseDate, fromNow, isWithinDay, isWithinHalfYear, formatDate, wasYesterday} from './date-util.js';
 
 suite('date-util tests', () => {
   suite('parseDate', () => {
@@ -64,6 +64,21 @@
     });
   });
 
+  suite('wasYesterday', () => {
+    test('less 24 hours', () => {
+      assert.isFalse(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 08 2020 02:00:00')));
+      assert.isTrue(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 07 2020 12:00:00')));
+    });
+    test('more 24 hours', () => {
+      assert.isTrue(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 07 2020 2:00:00')));
+      assert.isFalse(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 06 2020 14:00:00')));
+    });
+  });
+
   suite('isWithinHalfYear', () => {
     test('basics works', () => {
       assert.isTrue(isWithinHalfYear(new Date('May 08 2020 12:00:00'),
diff --git a/polygerrit-ui/app/utils/dom-util.ts b/polygerrit-ui/app/utils/dom-util.ts
index 76db40b..ca5de4d 100644
--- a/polygerrit-ui/app/utils/dom-util.ts
+++ b/polygerrit-ui/app/utils/dom-util.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 
-import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
 import {JsApiService} from '../elements/shared/gr-js-api-interface/gr-js-api-types';
 
@@ -70,27 +69,9 @@
 
 /**
  * Get computed style value.
- *
- * If ShadyCSS is provided, use ShadyCSS api.
- * If `getComputedStyleValue` is provided on the element, use it.
- * Otherwise fallback to native method (in polymer 2).
- *
  */
-export function getComputedStyleValue(
-  name: string,
-  el: Element | LegacyElementMixin
-) {
-  let style;
-  if (window.ShadyCSS) {
-    style = window.ShadyCSS.getComputedStyleValue(el as Element, name);
-    // `getComputedStyleValue` defined through LegacyElementMixin
-    // TODO: It should be safe to just use `getComputedStyle`, but just to be safe
-  } else if ('getComputedStyleValue' in el) {
-    style = el.getComputedStyleValue(name);
-  } else {
-    style = getComputedStyle(el).getPropertyValue(name);
-  }
-  return style;
+export function getComputedStyleValue(name: string, el: Element) {
+  return getComputedStyle(el).getPropertyValue(name).trim();
 }
 
 /**
@@ -186,7 +167,7 @@
 export function getEventPath<T extends PolymerEvent>(e?: T) {
   if (!e) return '';
 
-  let path = e.path;
+  let path = e.composedPath();
   if (!path || !path.length) {
     path = [];
     let el = e.target;
@@ -253,3 +234,32 @@
   }
   return _sharedApiEl;
 }
+
+// document.activeElement is not enough, because it's not getting activeElement
+// without looking inside of shadow roots. This will find best activeElement.
+export function findActiveElement(
+  root: DocumentOrShadowRoot | null,
+  ignoreDialogs?: boolean
+): HTMLElement | null {
+  if (root === null) {
+    return null;
+  }
+  if (
+    ignoreDialogs &&
+    root.activeElement &&
+    root.activeElement.nodeName.toUpperCase().includes('DIALOG')
+  ) {
+    return null;
+  }
+  if (root.activeElement?.shadowRoot?.activeElement) {
+    return findActiveElement(root.activeElement.shadowRoot);
+  }
+  if (!root.activeElement) {
+    return null;
+  }
+  // We block some elements
+  if ('BODY' === root.activeElement.nodeName.toUpperCase()) {
+    return null;
+  }
+  return root.activeElement as HTMLElement;
+}
diff --git a/polygerrit-ui/app/utils/dom-util_test.js b/polygerrit-ui/app/utils/dom-util_test.js
index e2d61ed..bcb4505 100644
--- a/polygerrit-ui/app/utils/dom-util_test.js
+++ b/polygerrit-ui/app/utils/dom-util_test.js
@@ -55,13 +55,13 @@
       assert.equal(getEventPath(), '');
       assert.equal(getEventPath(null), '');
       assert.equal(getEventPath(undefined), '');
-      assert.equal(getEventPath({}), '');
+      assert.equal(getEventPath({composedPath: () => []}), '');
     });
 
     test('event with fake path', () => {
-      assert.equal(getEventPath({path: []}), '');
+      assert.equal(getEventPath({composedPath: () => []}), '');
       const dd = document.createElement('dd');
-      assert.equal(getEventPath({path: [dd]}), 'dd');
+      assert.equal(getEventPath({composedPath: () => [dd]}), 'dd');
     });
 
     test('event with fake complicated path', () => {
@@ -72,7 +72,7 @@
       divNode.id = 'test2';
       divNode.className = 'a b c';
       assert.equal(getEventPath(
-          {path: [dd, divNode]}),
+          {composedPath: () => [dd, divNode]}),
       'div#test2.a.b.c>dd#test.a.b'
       );
     });
@@ -88,7 +88,7 @@
       const fakeTarget = document.createElement('SPAN');
       fakeTargetParent1.appendChild(fakeTarget);
       assert.equal(
-          getEventPath({target: fakeTarget}),
+          getEventPath({composedPath: () => {}, target: fakeTarget}),
           'div#test2.a.b.c>dd#test.a.b>span'
       );
     });
diff --git a/polygerrit-ui/app/utils/event-util.ts b/polygerrit-ui/app/utils/event-util.ts
new file mode 100644
index 0000000..5e1ff44
--- /dev/null
+++ b/polygerrit-ui/app/utils/event-util.ts
@@ -0,0 +1,101 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {UrlEncodedCommentId} from '../types/common';
+import {FetchRequest} from '../types/types';
+
+export enum EventType {
+  SHOW_ALERT = 'show-alert',
+  PAGE_ERROR = 'page-error',
+  SERVER_ERROR = 'server-error',
+  NETWORK_ERROR = 'network-error',
+  TITLE_CHANGE = 'title-change',
+  THREAD_LIST_MODIFIED = 'thread-list-modified',
+}
+
+export function fireEvent(target: EventTarget, type: string) {
+  target.dispatchEvent(
+    new CustomEvent(type, {
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function fireAlert(target: EventTarget, message: string) {
+  target.dispatchEvent(
+    new CustomEvent(EventType.SHOW_ALERT, {
+      detail: {message},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function firePageError(target: EventTarget, response?: Response | null) {
+  target.dispatchEvent(
+    new CustomEvent(EventType.PAGE_ERROR, {
+      detail: {response},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function fireServerError(response: Response, request?: FetchRequest) {
+  document.dispatchEvent(
+    new CustomEvent(EventType.SERVER_ERROR, {
+      detail: {response, request},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function fireNetworkError(error: Error) {
+  document.dispatchEvent(
+    new CustomEvent(EventType.NETWORK_ERROR, {
+      detail: {error},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function fireTitleChange(target: EventTarget, title: string) {
+  target.dispatchEvent(
+    new CustomEvent(EventType.TITLE_CHANGE, {
+      detail: {title},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
+
+export function fireThreadListModifiedEvent(
+  target: EventTarget,
+  rootId: UrlEncodedCommentId,
+  path: string
+) {
+  target.dispatchEvent(
+    new CustomEvent(EventType.THREAD_LIST_MODIFIED, {
+      detail: {rootId, path},
+      composed: true,
+      bubbles: true,
+    })
+  );
+}
diff --git a/polygerrit-ui/app/utils/label-util.ts b/polygerrit-ui/app/utils/label-util.ts
index 4313745..fc83d77 100644
--- a/polygerrit-ui/app/utils/label-util.ts
+++ b/polygerrit-ui/app/utils/label-util.ts
@@ -15,7 +15,9 @@
  * limitations under the License.
  */
 import {
+  AccountInfo,
   ApprovalInfo,
+  DetailedLabelInfo,
   isDetailedLabelInfo,
   LabelInfo,
   VotingRangeInfo,
@@ -42,3 +44,10 @@
   const votingRange = getVotingRangeOrDefault(label);
   return label.all.filter(account => account.value === votingRange.max);
 }
+
+export function getApprovalInfo(
+  label: DetailedLabelInfo,
+  account: AccountInfo
+): ApprovalInfo | undefined {
+  return label.all?.filter(x => x._account_id === account._account_id)[0];
+}
diff --git a/polygerrit-ui/app/utils/label-util_test.js b/polygerrit-ui/app/utils/label-util_test.js
index d6f7b3e..6a2f768 100644
--- a/polygerrit-ui/app/utils/label-util_test.js
+++ b/polygerrit-ui/app/utils/label-util_test.js
@@ -20,6 +20,7 @@
   getVotingRange,
   getVotingRangeOrDefault,
   getMaxAccounts,
+  getApprovalInfo,
 } from './label-util.js';
 
 const VALUES_1 = {
@@ -87,4 +88,29 @@
     assert.isEmpty(getMaxAccounts({}));
     assert.isEmpty(getMaxAccounts({values: VALUES_2}));
   });
+
+  test('getApprovalInfo', () => {
+    const myAccountInfo = {_account_id: 314};
+    const myApprovalInfo = {value: 2, _account_id: 314};
+    const label = {
+      values: VALUES_2,
+      all: [myApprovalInfo, {value: 1, _account_id: 777}],
+    };
+    assert.equal(
+        getApprovalInfo(label, myAccountInfo),
+        myApprovalInfo
+    );
+  });
+
+  test('getApprovalInfo no approval for user', () => {
+    const myAccountInfo = {_account_id: 123};
+    const label = {
+      values: VALUES_2,
+      all: [
+        {value: 2, _account_id: 314},
+        {value: 1, _account_id: 777},
+      ],
+    };
+    assert.isUndefined(getApprovalInfo(label, myAccountInfo));
+  });
 });
diff --git a/polygerrit-ui/app/utils/patch-set-util.ts b/polygerrit-ui/app/utils/patch-set-util.ts
index 8974af8..cb0bdec 100644
--- a/polygerrit-ui/app/utils/patch-set-util.ts
+++ b/polygerrit-ui/app/utils/patch-set-util.ts
@@ -45,6 +45,8 @@
   PARENT: 'PARENT',
 };
 
+export const CURRENT = 'current';
+
 export interface PatchSet {
   num: PatchSetNum;
   desc: string | undefined;
@@ -58,19 +60,6 @@
 }
 
 /**
- * As patchNum can be either a string (e.g. 'edit', 'PARENT') OR a number,
- * this function checks for patchNum equality.
- *
- */
-export function patchNumEquals(a?: PatchSetNum, b?: PatchSetNum) {
-  if (a === undefined) {
-    return a === b;
-  }
-  // TODO(TS): replace with a===b when the whole code is converted to ts
-  return `${a}` === `${b}`;
-}
-
-/**
  * Whether the given patch is a numbered parent of a merge (i.e. a negative
  * number).
  */
@@ -112,7 +101,7 @@
   patchNum: PatchSetNum
 ) {
   for (const rev of revisions) {
-    if (patchNumEquals(rev._number, patchNum)) {
+    if (rev._number === patchNum) {
       return rev;
     }
   }
@@ -196,11 +185,9 @@
  *     above
  */
 export function computeAllPatchSets(
-  change: ChangeInfo | ParsedChangeInfo
+  change: ChangeInfo | ParsedChangeInfo | undefined
 ): PatchSet[] {
-  if (!change) {
-    return [];
-  }
+  if (!change) return [];
 
   let patchNums: PatchSet[] = [];
   if (change.revisions && Object.keys(change.revisions).length) {
@@ -275,6 +262,20 @@
   return allPatchSets[0].num;
 }
 
+export function computePredecessor(
+  patchset?: PatchSetNum
+): PatchSetNum | undefined {
+  if (
+    !patchset ||
+    patchset === ParentPatchSetNum ||
+    patchset === EditPatchSetNum
+  ) {
+    return undefined;
+  }
+  if (patchset === 1) return ParentPatchSetNum;
+  return (Number(patchset) - 1) as PatchSetNum;
+}
+
 export function hasEditBasedOnCurrentPatchSet(allPatchSets: PatchSet[]) {
   if (!allPatchSets || allPatchSets.length < 2) {
     return false;
diff --git a/polygerrit-ui/app/utils/patch-set-util_test.js b/polygerrit-ui/app/utils/patch-set-util_test.js
index 29cc370..12f5ed4 100644
--- a/polygerrit-ui/app/utils/patch-set-util_test.js
+++ b/polygerrit-ui/app/utils/patch-set-util_test.js
@@ -21,7 +21,7 @@
   fetchChangeUpdates, findEditParentPatchNum, findEditParentRevision,
   getParentIndex, getRevisionByPatchNum,
   isMergeParent,
-  patchNumEquals, sortRevisions,
+  sortRevisions,
 } from './patch-set-util.js';
 
 suite('gr-patch-set-util tests', () => {
@@ -31,9 +31,9 @@
       {_number: 1},
       {_number: 2},
     ];
-    assert.deepEqual(getRevisionByPatchNum(revisions, '1'), revisions[1]);
+    assert.deepEqual(getRevisionByPatchNum(revisions, 1), revisions[1]);
     assert.deepEqual(getRevisionByPatchNum(revisions, 2), revisions[2]);
-    assert.equal(getRevisionByPatchNum(revisions, '3'), undefined);
+    assert.equal(getRevisionByPatchNum(revisions, 3), undefined);
   });
 
   test('fetchChangeUpdates on latest', done => {
@@ -231,17 +231,6 @@
         .assertWip(6, true); // PS6 was uploaded with WIP option
   });
 
-  test('patchNumEquals', () => {
-    assert.isFalse(patchNumEquals('edit', 'PARENT'));
-    assert.isFalse(patchNumEquals('edit', NaN));
-    assert.isFalse(patchNumEquals(1, '2'));
-
-    assert.isTrue(patchNumEquals(1, '1'));
-    assert.isTrue(patchNumEquals(1, 1));
-    assert.isTrue(patchNumEquals('edit', 'edit'));
-    assert.isTrue(patchNumEquals('PARENT', 'PARENT'));
-  });
-
   test('isMergeParent', () => {
     assert.isFalse(isMergeParent(1));
     assert.isFalse(isMergeParent(4321));
diff --git a/polygerrit-ui/app/utils/string-util.ts b/polygerrit-ui/app/utils/string-util.ts
new file mode 100644
index 0000000..36050ca
--- /dev/null
+++ b/polygerrit-ui/app/utils/string-util.ts
@@ -0,0 +1,24 @@
+/**
+ * @license
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Returns a count plus string that is pluralized when necessary.
+ */
+export function pluralize(count: number, noun: string): string {
+  if (count === 0) return '';
+  return `${count} ${noun}` + (count > 1 ? 's' : '');
+}
diff --git a/polygerrit-ui/app/utils/string-util_test.ts b/polygerrit-ui/app/utils/string-util_test.ts
new file mode 100644
index 0000000..9297d90
--- /dev/null
+++ b/polygerrit-ui/app/utils/string-util_test.ts
@@ -0,0 +1,28 @@
+/**
+ * @license
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../test/common-test-setup-karma.js';
+import {pluralize} from './string-util.js';
+
+suite('formatter util tests', () => {
+  test('pluralize', () => {
+    const noun = 'comment';
+    assert.equal(pluralize(0, noun), '');
+    assert.equal(pluralize(1, noun), '1 comment');
+    assert.equal(pluralize(2, noun), '2 comments');
+  });
+});
diff --git a/polygerrit-ui/app/yarn.lock b/polygerrit-ui/app/yarn.lock
index eda02aa..e544dbc 100644
--- a/polygerrit-ui/app/yarn.lock
+++ b/polygerrit-ui/app/yarn.lock
@@ -347,6 +347,18 @@
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"
   integrity sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8=
 
+lit-element@^2.4.0:
+  version "2.4.0"
+  resolved "https://registry.yarnpkg.com/lit-element/-/lit-element-2.4.0.tgz#b22607a037a8fc08f5a80736dddf7f3f5d401452"
+  integrity sha512-pBGLglxyhq/Prk2H91nA0KByq/hx/wssJBQFiYqXhGDvEnY31PRGYf1RglVzyLeRysu0IHm2K0P196uLLWmwFg==
+  dependencies:
+    lit-html "^1.1.1"
+
+lit-html@^1.1.1:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/lit-html/-/lit-html-1.3.0.tgz#c80f3cc5793a6dea6c07172be90a70ab20e56034"
+  integrity sha512-0Q1bwmaFH9O14vycPHw8C/IeHMk/uSDldVLIefu/kfbTBGIc44KGH6A8p1bDfxUfHdc8q6Ct7kQklWoHgr4t1Q==
+
 page@^1.11.5:
   version "1.11.5"
   resolved "https://registry.yarnpkg.com/page/-/page-1.11.5.tgz#0cfc8608be337f26f4377f31df0787aef0ca1af7"
@@ -372,7 +384,19 @@
     "@polymer/polymer" "^3.0.2"
     "@webcomponents/webcomponentsjs" "^2.0.3"
 
+rxjs@^6.6.2:
+  version "6.6.2"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.2.tgz#8096a7ac03f2cc4fe5860ef6e572810d9e01c0d2"
+  integrity sha512-BHdBMVoWC2sL26w//BCu3YzKT4s2jip/WhwsGEDmeKYBhKDZeYezVUnHatYB7L85v5xs0BAQmg6BEYJEKxBabg==
+  dependencies:
+    tslib "^1.9.0"
+
 shadow-selection-polyfill@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/shadow-selection-polyfill/-/shadow-selection-polyfill-1.1.0.tgz#87eee5c3cd9c7296f9fec083ba6f4910b1fa6686"
   integrity sha512-ntz8P6DLEFpx7gikeXZ4gSi3APE2D+BP0rKnnaBzED+Lm8je8nkNcayy6kGWPEDWMFbtm+Yvd1ONFaXcsVWn2w==
+
+tslib@^1.9.0:
+  version "1.13.0"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.13.0.tgz#c881e13cc7015894ed914862d276436fa9a47043"
+  integrity sha512-i/6DQjL8Xf3be4K/E6Wgpekn5Qasl1usyw++dAA35Ue5orEn65VIxOA+YvNNl9HV3qv70T7CNwjODHZrLwvd1Q==
diff --git a/polygerrit-ui/karma.conf.js b/polygerrit-ui/karma.conf.js
index 3f7221a..fe3fa0c 100644
--- a/polygerrit-ui/karma.conf.js
+++ b/polygerrit-ui/karma.conf.js
@@ -163,6 +163,9 @@
     // available reporters: https://npmjs.org/browse/keyword/karma-reporter
     reporters: ['mocha'],
 
+    mochaReporter: {
+      showDiff: true
+    },
 
     // web server port
     port: 9876,
diff --git a/polygerrit-ui/server.go b/polygerrit-ui/server.go
index 124b924..e6487a7 100644
--- a/polygerrit-ui/server.go
+++ b/polygerrit-ui/server.go
@@ -185,11 +185,23 @@
 		//   'page/page.mjs' -> '/node_modules/page.mjs'
 		//   '@polymer/iron-icon' -> '/node_modules/@polymer/iron-icon.js'
 		//   './element/file' -> './element/file.js'
-		moduleImportRegexp = regexp.MustCompile(`(?m)^(import.*)'(.*?)(\.(m?)js)?';$`)
-		data = moduleImportRegexp.ReplaceAll(data, []byte("$1 '$2.${4}js';"))
+		moduleImportRegexp = regexp.MustCompile(`(?m)^(import.*|export.* from )['"](.*?)(\.(m?)js)?['"];$`)
+		data = moduleImportRegexp.ReplaceAll(data, []byte("$1'$2.${4}js';"))
 
-		moduleImportRegexp = regexp.MustCompile("(?m)^(import.*)'([^/.].*)';$")
-		data = moduleImportRegexp.ReplaceAll(data, []byte("$1 '/node_modules/$2';"))
+		moduleImportRegexp = regexp.MustCompile(`(?m)^(import.*|export.* from )['"]([^/.].*)['"];$`)
+		data = moduleImportRegexp.ReplaceAll(data, []byte("$1'/node_modules/$2';"))
+
+		// The es module version of rxjs can be found in the _esm2015/ directory.
+		moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/rxjs)(.*).js(';)$")
+		data = moduleImportRegexp.ReplaceAll(data, []byte("$1/_esm2015$3/index.js$4"))
+
+		// The es module version of tslib.js can be found in tslib.es6.js.
+		moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)tslib.js';$")
+		data = moduleImportRegexp.ReplaceAll(data, []byte("${1}tslib/tslib.es6.js';"))
+
+		// 'lit-element' imports and exports have to be resolved to 'lit-element/lit-element.js'.
+		moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)lit-(element|html).js';$")
+		data = moduleImportRegexp.ReplaceAll(data, []byte("${1}lit-${3}/lit-${3}.js';"))
 
 		if strings.HasSuffix(normalizedContentPath, "/node_modules/page/page.js") {
 			// Can't import page.js directly, because this is undefined.
diff --git a/proto/cache.proto b/proto/cache.proto
index 7924cbd..8d575b7 100644
--- a/proto/cache.proto
+++ b/proto/cache.proto
@@ -76,7 +76,7 @@
 // Instead, we just take the tedious yet simple approach of having a "has_foo"
 // field for each nullable field "foo", indicating whether or not foo is null.
 //
-// Next ID: 24
+// Next ID: 27
 message ChangeNotesStateProto {
   // Effectively required, even though the corresponding ChangeNotesState field
   // is optional, since the field is only absent when NoteDb is disabled, in
@@ -218,7 +218,15 @@
     string operation = 3;
     string reason = 4;
   }
+  // Only includes the most recent attention set update for each user.
   repeated AttentionSetUpdateProto attention_set_update = 23;
+
+  // Includes all attention set updates.
+  repeated AttentionSetUpdateProto all_attention_set_update = 24;
+
+  // Epoch millis.
+  int64 merged_on_millis = 25;
+  bool has_merged_on = 26;
 }
 
 // Serialized form of com.google.gerrit.server.query.change.ConflictKey
@@ -500,3 +508,134 @@
   bytes global_config_revision = 3; // Hash of All-Projects-projects.config. This
                                     // will only be populated for All-Projects.
 }
+
+// Serialized form of com.google.gerrit.server.comment.CommentContextCacheImpl.Key
+// Next ID: 6
+message CommentContextKeyProto {
+  string project = 1;
+  string change_id = 2;
+  int32 patchset = 3;
+  string commentId = 4;
+
+  // hashed with the murmur3_128 hash function
+  string path_hash = 5;
+}
+
+// Serialized form of a list of com.google.gerrit.extensions.common.ContextLineInfo
+// Next ID: 2
+message AllCommentContextProto {
+  message CommentContextProto {
+    int32 line_number = 1;
+    string context_line = 2;
+  }
+  repeated CommentContextProto context = 1;
+}
+
+// Serialized key for
+// com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheKey
+// Next ID: 5
+message GitModifiedFilesKeyProto {
+  string project = 1;
+  bytes a_tree = 2; // SHA-1 hash of the left git tree ID in the diff
+  bytes b_tree = 3; // SHA-1 hash of the right git tree ID in the diff
+  int32 rename_score = 4;
+}
+
+// Serialized key for
+// com.google.gerrit.server.patch.diff.ModifiedFilesCacheKey
+// Next ID: 5
+message ModifiedFilesKeyProto {
+  string project = 1;
+  bytes a_commit = 2; // SHA-1 hash of the left commit ID in the diff
+  bytes b_commit = 3; // SHA-1 hash of the right commit ID in the diff
+  int32 rename_score = 4;
+}
+
+// Serialized form of com.google.gerrit.server.patch.gitdiff.ModifiedFile
+// Next ID: 4
+message ModifiedFileProto {
+  string change_type = 1; // ENUM as string
+  string old_path = 2;
+  string new_path = 3;
+}
+
+// Serialized form of a collection of
+// com.google.gerrit.server.patch.gitdiff.ModifiedFile
+// Next ID: 2
+message ModifiedFilesProto {
+  repeated ModifiedFileProto modifiedFile = 1;
+}
+
+// Serialized form of a collection of
+// com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.Key
+// Next ID: 8
+message GitFileDiffKeyProto {
+  string project = 1;
+  bytes a_tree = 2;
+  bytes b_tree = 3;
+  string file_path = 4;
+  int32 rename_score = 5;
+  string diff_algorithm = 6; // ENUM as string
+  string whitepsace = 7; // ENUM as string
+}
+
+// Serialized form of com.google.gerrit.server.patch.gitfilediff.GitFileDiff
+// Next ID: 11
+message GitFileDiffProto {
+  message Edit {
+    int32 begin_a = 1;
+    int32 end_a = 2;
+    int32 begin_b = 3;
+    int32 end_b = 4;
+  }
+  repeated Edit edits = 1;
+  string file_header = 2;
+  string old_path = 3;
+  string new_path = 4;
+  bytes old_id = 5;
+  bytes new_id = 6;
+  string old_mode = 7; // ENUM as string
+  string new_mode = 8; // ENUM as string
+  string change_type = 9; // ENUM as string
+  string patch_type = 10; // ENUM as string
+}
+
+// Serialized form of
+// com.google.gerrit.server.patch.fileDiff.FileDiffCacheKey
+// Next ID: 8
+message FileDiffKeyProto {
+  string project = 1;
+  bytes old_commit = 2;
+  bytes new_commit = 3;
+  string file_path = 4;
+  int32 rename_score = 5;
+  string diff_algorithm = 6;
+  string whitespace = 7;
+}
+
+// Serialized form of
+// com.google.gerrit.server.patch.filediff.FileDiffOutput
+// Next ID: 9
+message FileDiffOutputProto {
+  // Next ID: 5
+  message Edit {
+    int32 begin_a = 1;
+    int32 end_a = 2;
+    int32 begin_b = 3;
+    int32 end_b = 4;
+  }
+  // Serialized form  of com.google.gerrit.server.patch.filediff.TaggedEdit
+  // Next ID: 3
+  message TaggedEdit {
+    Edit edit = 1;
+    bool due_to_rebase = 2;
+  }
+  string old_path = 1;
+  string new_path = 2;
+  string change_type = 3;
+  string patch_type = 4;
+  repeated string header_lines = 5;
+  int64 size = 6;
+  int64 size_delta = 7;
+  repeated TaggedEdit edits = 8;
+}
diff --git a/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy b/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
index 000f4e2..31ea7d2 100644
--- a/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
+++ b/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
@@ -171,5 +171,5 @@
 
   // Load gr-app.js after <gr-app ...> tag because gr-router expects that
   // <gr-app ...> already exists in the document when script is executed.
-  <script src="{$staticResourcePath}/elements/gr-app.js"></script>{\n}
+  <script src="{$staticResourcePath}/elements/gr-app.js" crossorigin="anonymous"></script>{\n}
 {/template}
diff --git a/resources/com/google/gerrit/server/mime/mime-types.properties b/resources/com/google/gerrit/server/mime/mime-types.properties
index 41566c8..6ab682c 100644
--- a/resources/com/google/gerrit/server/mime/mime-types.properties
+++ b/resources/com/google/gerrit/server/mime/mime-types.properties
@@ -232,6 +232,7 @@
 toml = text/x-toml
 tpl = text/x-smarty
 ts = application/typescript
+tsx = text/tsx
 ttcn = text/x-ttcn
 ttcnpp = text/x-ttcn
 ttcn3 = text/x-ttcn
diff --git a/tools/bzl/license-map.py b/tools/bzl/license-map.py
index c32579c..221ae2f 100644
--- a/tools/bzl/license-map.py
+++ b/tools/bzl/license-map.py
@@ -238,7 +238,7 @@
                                 key=lambda package: get_package_display_name(
                                     package)),
             ))
-    return result
+    return sorted(result, key=lambda license: license.name)
 
 def get_licensed_files(json_licensed_file_dict):
     """Convert json dictionary to LicensedFiles"""
@@ -305,4 +305,4 @@
     return result
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/tools/coverage.sh b/tools/coverage.sh
index c92d5cf..e03ac7f 100755
--- a/tools/coverage.sh
+++ b/tools/coverage.sh
@@ -7,6 +7,9 @@
 # COVERAGE_CPUS defaults to 2, and the default destination is a temp
 # dir.
 
+shopt -s expand_aliases
+source ~/.bash_profile
+
 genhtml=$(which genhtml)
 if [[ -z "${genhtml}" ]]; then
     echo "Install 'genhtml' (contained in the 'lcov' package)"
@@ -33,15 +36,24 @@
 cp -r {java,javatests}/* ${destdir}/java
 
 mkdir -p ${destdir}/plugins
-for plugin in `find plugins/ -maxdepth 1 -type d`
+for plugin in `find plugins/ -mindepth 1 -maxdepth 1 -type d`
 do
   mkdir -p ${destdir}/${plugin}/java
-  cp -r plugins/*/{java,javatests}/* ${destdir}/${plugin}/java
+  if [ -e ${plugin}/java/ ]
+    then cp -r ${plugin}/java/* ${destdir}/${plugin}/java
+  fi
+  if [ -e ${plugin}/javatests/ ]
+    then cp -r ${plugin}/javatests/* ${destdir}/${plugin}/java
+  fi
 
   # for backwards compatibility support plugins with old file structure
   mkdir -p ${destdir}/${plugin}/src/{main,test}/java
-  cp -r plugins/*/src/main/java/* ${destdir}/${plugin}/src/main/java
-  cp -r plugins/*/src/test/java/* ${destdir}/${plugin}/src/test/java
+  if [ -e ${plugin}/src/main/java/ ]
+    then cp -r ${plugin}/src/main/java/* ${destdir}/${plugin}/src/main/java/
+  fi
+  if [ -e ${plugin}/src/test/java/ ]
+    then cp -r ${plugin}/src/test/java/* ${destdir}/${plugin}/src/test/java/
+  fi
 done
 
 base=$(bazel info bazel-testlogs)
diff --git a/tools/eclipse/BUILD b/tools/eclipse/BUILD
index e091fc1..61ea4fe 100644
--- a/tools/eclipse/BUILD
+++ b/tools/eclipse/BUILD
@@ -43,5 +43,14 @@
 
 classpath_collector(
     name = "autovalue_classpath_collect",
-    deps = ["//lib/auto:auto-value"],
+    deps = [
+        "//lib/auto:auto-value",
+        "@auto-value-annotations//jar",
+        "@auto-value-gson-extension//jar",
+        "@auto-value-gson-factory//jar",
+        "@auto-value-gson-runtime//jar",
+        "@autotransient//jar",
+        "@gson//jar",
+        "@javapoet//jar",
+    ],
 )
diff --git a/tools/js/BUILD b/tools/js/BUILD
index fedaf7f..1a272e2 100644
--- a/tools/js/BUILD
+++ b/tools/js/BUILD
@@ -1 +1 @@
-exports_files(["run_npm_binary.py"])
+exports_files(["run_npm_binary.py", "eslint-chdir.js"])
diff --git a/tools/js/eslint-chdir.js b/tools/js/eslint-chdir.js
new file mode 100644
index 0000000..5aea704
--- /dev/null
+++ b/tools/js/eslint-chdir.js
@@ -0,0 +1,30 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Eslint 7 introduced a breaking change - it uses the current workdir instead
+// of the configuration file directory for resolving relative paths:
+// https://eslint.org/docs/user-guide/migrating-to-7.0.0#base-path-change
+// This file is loaded before the eslint and sets the current directory
+// back to the location of configuration file.
+
+const path = require('path');
+const configParamIndex =
+    process.argv.findIndex(arg => arg === '-c' || arg === '---config');
+if (configParamIndex >= 0 && configParamIndex + 1 < process.argv.length) {
+  const dirName = path.dirname(process.argv[configParamIndex + 1]);
+  process.chdir(dirName);
+}
diff --git a/tools/js/eslint.bzl b/tools/js/eslint.bzl
index 586b1c5..b32e2bc 100644
--- a/tools/js/eslint.bzl
+++ b/tools/js/eslint.bzl
@@ -57,9 +57,11 @@
         config,
         ignore,
         "//tools/js/eslint-rules:eslint-rules-srcs",
+        "//tools/js:eslint-chdir.js",
         eslint_rules_toplevel_file,
     ] + plugins + data
     common_templated_args = [
+        "--node_options=--require=$$(rlocation $(rootpath //tools/js:eslint-chdir.js))",
         "--ext",
         ",".join(extensions),
         "-c",
@@ -85,7 +87,7 @@
             "*_test_require_patch.js",
             "--ignore-pattern",
             "*_test_loader.js",
-            native.package_name(),
+            "./", # Relative to the config file location
         ],
         # Should not run sandboxed.
         tags = [
diff --git a/tools/maven/gerrit-acceptance-framework_pom.xml b/tools/maven/gerrit-acceptance-framework_pom.xml
index 81a8302..f6d1e3b 100644
--- a/tools/maven/gerrit-acceptance-framework_pom.xml
+++ b/tools/maven/gerrit-acceptance-framework_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-acceptance-framework</artifactId>
-  <version>3.3.2-SNAPSHOT</version>
+  <version>3.4.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Acceptance Test Framework</name>
   <description>Framework for Gerrit's acceptance tests</description>
@@ -35,12 +35,18 @@
       <name>David Pursehouse</name>
     </developer>
     <developer>
+      <name>Dmitrii Filippov</name>
+    </developer>
+    <developer>
       <name>Edwin Kempin</name>
     </developer>
     <developer>
       <name>Han-Wen Nienhuys</name>
     </developer>
     <developer>
+      <name>Joerg Zieren</name>
+    </developer>
+    <developer>
       <name>Jacek Centkowski</name>
     </developer>
     <developer>
@@ -56,7 +62,7 @@
       <name>Matthias Sohn</name>
     </developer>
     <developer>
-      <name>Ole Rehmsen</name>
+      <name>Nasser Grainawi</name>
     </developer>
     <developer>
       <name>Patrick Hiesel</name>
@@ -67,6 +73,9 @@
     <developer>
       <name>Sven Selberg</name>
     </developer>
+    <developer>
+      <name>Tao Zhou</name>
+    </developer>
   </developers>
 
   <mailingLists>
diff --git a/tools/maven/gerrit-extension-api_pom.xml b/tools/maven/gerrit-extension-api_pom.xml
index a86b19d..daf8089 100644
--- a/tools/maven/gerrit-extension-api_pom.xml
+++ b/tools/maven/gerrit-extension-api_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-extension-api</artifactId>
-  <version>3.3.2-SNAPSHOT</version>
+  <version>3.4.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Extension API</name>
   <description>API for Gerrit Extensions</description>
@@ -35,12 +35,18 @@
       <name>David Pursehouse</name>
     </developer>
     <developer>
+      <name>Dmitrii Filippov</name>
+    </developer>
+    <developer>
       <name>Edwin Kempin</name>
     </developer>
     <developer>
       <name>Han-Wen Nienhuys</name>
     </developer>
     <developer>
+      <name>Joerg Zieren</name>
+    </developer>
+    <developer>
       <name>Jacek Centkowski</name>
     </developer>
     <developer>
@@ -56,7 +62,7 @@
       <name>Matthias Sohn</name>
     </developer>
     <developer>
-      <name>Ole Rehmsen</name>
+      <name>Nasser Grainawi</name>
     </developer>
     <developer>
       <name>Patrick Hiesel</name>
@@ -67,6 +73,9 @@
     <developer>
       <name>Sven Selberg</name>
     </developer>
+    <developer>
+      <name>Tao Zhou</name>
+    </developer>
   </developers>
 
   <mailingLists>
diff --git a/tools/maven/gerrit-plugin-api_pom.xml b/tools/maven/gerrit-plugin-api_pom.xml
index b4b8f3c..07895a4 100644
--- a/tools/maven/gerrit-plugin-api_pom.xml
+++ b/tools/maven/gerrit-plugin-api_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-plugin-api</artifactId>
-  <version>3.3.2-SNAPSHOT</version>
+  <version>3.4.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Plugin API</name>
   <description>API for Gerrit Plugins</description>
@@ -35,12 +35,18 @@
       <name>David Pursehouse</name>
     </developer>
     <developer>
+      <name>Dmitrii Filippov</name>
+    </developer>
+    <developer>
       <name>Edwin Kempin</name>
     </developer>
     <developer>
       <name>Han-Wen Nienhuys</name>
     </developer>
     <developer>
+      <name>Joerg Zieren</name>
+    </developer>
+    <developer>
       <name>Jacek Centkowski</name>
     </developer>
     <developer>
@@ -56,7 +62,7 @@
       <name>Matthias Sohn</name>
     </developer>
     <developer>
-      <name>Ole Rehmsen</name>
+      <name>Nasser Grainawi</name>
     </developer>
     <developer>
       <name>Patrick Hiesel</name>
@@ -67,6 +73,9 @@
     <developer>
       <name>Sven Selberg</name>
     </developer>
+    <developer>
+      <name>Tao Zhou</name>
+    </developer>
   </developers>
 
   <mailingLists>
diff --git a/tools/maven/gerrit-war_pom.xml b/tools/maven/gerrit-war_pom.xml
index 334c88e..a28adea 100644
--- a/tools/maven/gerrit-war_pom.xml
+++ b/tools/maven/gerrit-war_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-war</artifactId>
-  <version>3.3.2-SNAPSHOT</version>
+  <version>3.4.0-SNAPSHOT</version>
   <packaging>war</packaging>
   <name>Gerrit Code Review - WAR</name>
   <description>Gerrit WAR</description>
@@ -35,12 +35,18 @@
       <name>David Pursehouse</name>
     </developer>
     <developer>
+      <name>Dmitrii Filippov</name>
+    </developer>
+    <developer>
       <name>Edwin Kempin</name>
     </developer>
     <developer>
       <name>Han-Wen Nienhuys</name>
     </developer>
     <developer>
+      <name>Joerg Zieren</name>
+    </developer>
+    <developer>
       <name>Jacek Centkowski</name>
     </developer>
     <developer>
@@ -56,7 +62,7 @@
       <name>Matthias Sohn</name>
     </developer>
     <developer>
-      <name>Ole Rehmsen</name>
+      <name>Nasser Grainawi</name>
     </developer>
     <developer>
       <name>Patrick Hiesel</name>
@@ -67,6 +73,9 @@
     <developer>
       <name>Sven Selberg</name>
     </developer>
+    <developer>
+      <name>Tao Zhou</name>
+    </developer>
   </developers>
 
   <mailingLists>
diff --git a/tools/node_tools/node_modules_licenses/installed-node-modules-map.ts b/tools/node_tools/node_modules_licenses/installed-node-modules-map.ts
index 3f4955e..49beda3 100644
--- a/tools/node_tools/node_modules_licenses/installed-node-modules-map.ts
+++ b/tools/node_tools/node_modules_licenses/installed-node-modules-map.ts
@@ -45,8 +45,12 @@
 export class InsalledPackagesBuilder {
   private readonly rootPathToPackageMap: Map<DirPath, InstalledPackage> = new Map();
 
+  public constructor(private readonly nonPackages: Set<string>) {
+  }
+
   public addPackageJson(packageJsonPath: string) {
     const pack = this.createInstalledPackage(packageJsonPath);
+    if (!pack) return;
     this.rootPathToPackageMap.set(pack.rootPath, pack)
   }
   public addFile(file: string) {
@@ -60,19 +64,23 @@
    * For example for the packageJsonFile='/a/node_modules/b/node_modules/d/e/package.json'
    * the package name is 'd/e'
    */
-  private createInstalledPackage(packageJsonFile: string): InstalledPackage {
+  private createInstalledPackage(packageJsonFile: string): InstalledPackage | undefined {
     const nameParts: Array<string> = [];
     const rootPath = path.dirname(packageJsonFile);
     let currentDir = rootPath;
     while(currentDir != "") {
       const partName = path.basename(currentDir);
       if(partName === "node_modules") {
+        const packageName = nameParts.reverse().join("/");
         const version = JSON.parse(fs.readFileSync(packageJsonFile, {encoding: 'utf-8'}))["version"];
         if(!version) {
+          if (this.nonPackages.has(packageName)) {
+            return undefined;
+          }
           fail(`Can't get version for ${packageJsonFile}`)
         }
         return {
-          name: nameParts.reverse().join("/"),
+          name: packageName,
           rootPath: rootPath,
           version: version,
           files: []
diff --git a/tools/node_tools/node_modules_licenses/licenses-map.ts b/tools/node_tools/node_modules_licenses/licenses-map.ts
index 9f277e5..7dfb23e 100644
--- a/tools/node_tools/node_modules_licenses/licenses-map.ts
+++ b/tools/node_tools/node_modules_licenses/licenses-map.ts
@@ -216,7 +216,13 @@
 
   /** getInstalledPackages Collects information about all installed packages */
   private getInstalledPackages(nodeModulesFiles: ReadonlyArray<string>): InstalledPackage[] {
-    const builder = new InsalledPackagesBuilder();
+    const fullNonPackageNames: string[] = [];
+    for (const p of this.packages) {
+      if (p.nonPackages) {
+        fullNonPackageNames.push(...p.nonPackages.map(name => `${p.name}/${name}`));
+      }
+    }
+    const builder = new InsalledPackagesBuilder(new Set(fullNonPackageNames));
     // Register all package.json files - such files exists in the root folder of each module
     nodeModulesFiles.filter(f => path.basename(f) === "package.json")
       .forEach(packageJsonFile => builder.addPackageJson(packageJsonFile));
diff --git a/tools/node_tools/node_modules_licenses/package-license-info.ts b/tools/node_tools/node_modules_licenses/package-license-info.ts
index c5cdb0f..79dea09 100644
--- a/tools/node_tools/node_modules_licenses/package-license-info.ts
+++ b/tools/node_tools/node_modules_licenses/package-license-info.ts
@@ -67,4 +67,6 @@
   versions?: string[];
   /** Predicate to select files to apply license. */
   filesFilter?: FilesFilter;
+  /** List of nested directories with package.json files, that are not real packages*/
+  nonPackages?: string[];
 }
diff --git a/tools/node_tools/node_modules_licenses/tsconfig.json b/tools/node_tools/node_modules_licenses/tsconfig.json
index 2046c394..cb7bb60 100644
--- a/tools/node_tools/node_modules_licenses/tsconfig.json
+++ b/tools/node_tools/node_modules_licenses/tsconfig.json
@@ -1,5 +1,13 @@
 {
   "compilerOptions": {
+    "plugins": [
+      {
+        "name": "@bazel/tsetse",
+        "disabledRules": [
+          "must-type-assert-json-parse"
+        ]
+      }
+    ],
     "target": "es6",
     "module": "commonjs",
     "allowSyntheticDefaultImports": true,
diff --git a/tools/node_tools/package.json b/tools/node_tools/package.json
index 1030877..fdada50 100644
--- a/tools/node_tools/package.json
+++ b/tools/node_tools/package.json
@@ -3,8 +3,8 @@
   "description": "Gerrit Build Tools",
   "browser": false,
   "dependencies": {
-    "@bazel/rollup": "^2.0.0",
-    "@bazel/typescript": "^2.0.0",
+    "@bazel/rollup": "^3.0.0-rc.1",
+    "@bazel/typescript": "^3.0.0-rc.1",
     "@types/node": "^10.17.12",
     "@types/parse5": "^4.0.0",
     "@types/parse5-html-rewriting-stream": "^5.1.2",
@@ -13,10 +13,10 @@
     "parse5-html-rewriting-stream": "^5.1.1",
     "polymer-bundler": "^4.0.10",
     "polymer-cli": "^1.9.11",
-    "rollup": "^1.27.5",
+    "rollup": "^2.3.4",
     "rollup-plugin-node-resolve": "^5.2.0",
     "rollup-plugin-terser": "^5.1.3",
-    "typescript": "3.9.5"
+    "typescript": "4.0.5"
   },
   "devDependencies": {},
   "license": "Apache-2.0",
diff --git a/tools/node_tools/yarn.lock b/tools/node_tools/yarn.lock
index 993bfe9..338e490 100644
--- a/tools/node_tools/yarn.lock
+++ b/tools/node_tools/yarn.lock
@@ -492,15 +492,15 @@
     lodash "^4.17.13"
     to-fast-properties "^2.0.0"
 
-"@bazel/rollup@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@bazel/rollup/-/rollup-2.0.0.tgz#1980cb3f6922227659260bfdca99c457889a5bc1"
-  integrity sha512-mifUfCZbD1RIhfowh4N8E4881ag3FChz7F4z35wxMOP52g1q3+6Bvh5wv9iysFQopxGmS5jNEj3Dq/CWtSoOnw==
+"@bazel/rollup@^3.0.0-rc.1":
+  version "3.0.0-rc.1"
+  resolved "https://registry.yarnpkg.com/@bazel/rollup/-/rollup-3.0.0-rc.1.tgz#153fb7ca556dfb0397aa3a86cbef71bcefb00733"
+  integrity sha512-O2WGfDw17aiQfUF6t5aL1kbVGeR6BnCImmtCOoFf1I8/Nw0dx+iE9x2qfqPyvSivZRuL2EBTI+xUcti42bpWgA==
 
-"@bazel/typescript@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-2.0.0.tgz#2ff5615f09c733cc681ba2ada92b11c356b694cd"
-  integrity sha512-5FPkxULWIjAKLG5J1XvpXpY1/4IK39dAoWA/Hhg+16gXTES32fT8w42k96pb6BTaNnyBuYgIHBpELEAJ40OOAQ==
+"@bazel/typescript@^3.0.0-rc.1":
+  version "3.0.0-rc.1"
+  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-3.0.0-rc.1.tgz#4a80682124475db63abc97b7da358caaadbd3077"
+  integrity sha512-KaGaCEbXjCKaRuwH/hLjW7aBuNyU8p/9yUe4KlP4KKoRqHAmjYISbUOw7VAksOW6BxXHgknOcZYaVF6PzE4CgQ==
   dependencies:
     protobufjs "6.8.8"
     semver "5.6.0"
@@ -950,9 +950,9 @@
   integrity sha512-N33cKXGSqhOYaPiT4xUGsYlPPDwFtQM/6QxJxuMXA/7BcySW+lkn2yigWP7vfs4daiL/7NJNU6DMCqg5N4B+xQ==
 
 "@types/node@^10.1.0":
-  version "10.17.27"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-10.17.27.tgz#391cb391c75646c8ad2a7b6ed3bbcee52d1bdf19"
-  integrity sha512-J0oqm9ZfAXaPdwNXMMgAhylw5fhmXkToJd06vuDUSAgEDZ/n/69/69UmyBZbc+zT34UnShuDSBqvim3SPnozJg==
+  version "10.17.42"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-10.17.42.tgz#90dd71b26fe4f4e2929df6b07e72ef2e9648a173"
+  integrity sha512-HElxYF7C/MSkuvlaHB2c+82zhXiuO49Cq056Dol8AQuTph7oJtduo2n6J8rFa+YhJyNgQ/Lm20ZaxqD0vxU0+Q==
 
 "@types/node@^10.17.12":
   version "10.17.24"
@@ -3732,6 +3732,11 @@
     bindings "^1.5.0"
     nan "^2.12.1"
 
+fsevents@~2.1.2:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.1.3.tgz#fb738703ae8d2f9fe900c33836ddebee8b97f23e"
+  integrity sha512-Auw9a4AxqWpa9GUfj370BMPzzyncfBABW8Mab7BGWBYDj4Isgq+cDKtx0i6u9jcX9pQDnswsaaOTgTmA5pEjuQ==
+
 function-bind@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
@@ -6827,7 +6832,7 @@
   dependencies:
     estree-walker "^0.6.1"
 
-rollup@^1.27.5, rollup@^1.3.0:
+rollup@^1.3.0:
   version "1.30.0"
   resolved "https://registry.yarnpkg.com/rollup/-/rollup-1.30.0.tgz#ae9c893804e8eaa8f8f74b0aaf7e7fb4374a9d01"
   integrity sha512-ANcmfaSQwpcJtZUTA0ZMNBtFcQ1B4A5FldlNqEK0WdWm9sHSKu93ffa2KV1ux8HA/yKIV/ZARV28m7rNdXJgEw==
@@ -6836,6 +6841,13 @@
     "@types/node" "*"
     acorn "^7.1.0"
 
+rollup@^2.3.4:
+  version "2.35.1"
+  resolved "https://registry.yarnpkg.com/rollup/-/rollup-2.35.1.tgz#e6bc8d10893556a638066f89e8c97f422d03968c"
+  integrity sha512-q5KxEyWpprAIcainhVy6HfRttD9kutQpHbeqDTWnqAFNJotiojetK6uqmcydNMymBEtC4I8bCYR+J3mTMqeaUA==
+  optionalDependencies:
+    fsevents "~2.1.2"
+
 run-async@^2.0.0, run-async@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/run-async/-/run-async-2.3.0.tgz#0371ab4ae0bdd720d4166d7dfda64ff7a445a6c0"
@@ -7835,9 +7847,9 @@
   integrity sha512-XrHUvV5HpdLmIj4uVMxHggLbFSZYIn7HEWsqePZcI50pco+MPqJ50wMGY794X7AOOhxOBAjbkqfAbEe/QMp2Lw==
 
 tslib@^1.8.1:
-  version "1.13.0"
-  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.13.0.tgz#c881e13cc7015894ed914862d276436fa9a47043"
-  integrity sha512-i/6DQjL8Xf3be4K/E6Wgpekn5Qasl1usyw++dAA35Ue5orEn65VIxOA+YvNNl9HV3qv70T7CNwjODHZrLwvd1Q==
+  version "1.14.1"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.14.1.tgz#cf2d38bdc34a134bcaf1091c41f6619e2f672d00"
+  integrity sha512-Xni35NKzjgMrwevysHTCArtLDpPvye8zV/0E4EyYn43P7/7qvQwPh9BGkHewbMulVntbigmcT7rdX3BNo9wRJg==
 
 tslib@^1.9.0:
   version "1.10.0"
@@ -7881,10 +7893,10 @@
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@3.9.5:
-  version "3.9.5"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.5.tgz#586f0dba300cde8be52dd1ac4f7e1009c1b13f36"
-  integrity sha512-hSAifV3k+i6lEoCJ2k6R2Z/rp/H3+8sdmcn5NrS3/3kE7+RyZXm9aqvxWqjEXHAd8b0pShatpcdMTvEdvAJltQ==
+typescript@4.0.5:
+  version "4.0.5"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.5.tgz#ae9dddfd1069f1cb5beb3ef3b2170dd7c1332389"
+  integrity sha512-ywmr/VrTVCmNTJ6iV2LwIrfG1P+lv6luD8sUJs+2eI9NLGigaN+nUQc13iHqisq7bra9lnmUSYqbJvegraBOPQ==
 
 typical@^2.6.0, typical@^2.6.1:
   version "2.6.1"
diff --git a/tools/nongoogle.bzl b/tools/nongoogle.bzl
index 4b6c8ac..30d356e 100644
--- a/tools/nongoogle.bzl
+++ b/tools/nongoogle.bzl
@@ -1,4 +1,9 @@
 load("//tools/bzl:maven_jar.bzl", "maven_jar")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_file")
+
+GUAVA_VERSION = "29.0-jre"
+GUAVA_BIN_SHA1 = "801142b4c3d0f0770dd29abea50906cacfddd447"
+GUAVA_DOC_URL = "https://google.github.io/guava/releases/" + GUAVA_VERSION + "/api/docs/"
 
 def declare_nongoogle_deps():
     """loads dependencies that are not used at Google.
@@ -103,8 +108,8 @@
 
     maven_jar(
         name = "jackson-core",
-        artifact = "com.fasterxml.jackson.core:jackson-core:2.11.3",
-        sha1 = "c2351800432bdbdd8284c3f5a7f0782a352aa84a",
+        artifact = "com.fasterxml.jackson.core:jackson-core:2.12.0",
+        sha1 = "afe52c6947d9939170da7989612cef544115511a",
     )
 
     maven_jar(
@@ -136,8 +141,50 @@
         sha1 = "b66d3bedb14da604828a8693bb24fd78e36b0e9e",
     )
 
-    # Test-only dependencies below.
+    maven_jar(
+        name = "guava",
+        artifact = "com.google.guava:guava:" + GUAVA_VERSION,
+        sha1 = GUAVA_BIN_SHA1,
+    )
 
+    GUICE_VERS = "4.2.3"
+
+    GUICE_LIBRARY_SHA256 = "5168f5e7383f978c1b4154ac777b78edd8ac214bb9f9afdb92921c8d156483d3"
+
+    http_file(
+        name = "guice-library-no-aop",
+        canonical_id = "guice-library-no-aop-" + GUICE_VERS + ".jar-" + GUICE_LIBRARY_SHA256,
+        downloaded_file_path = "guice-library-no-aop.jar",
+        sha256 = GUICE_LIBRARY_SHA256,
+        urls = [
+            "https://repo1.maven.org/maven2/com/google/inject/guice/" +
+            GUICE_VERS +
+            "/guice-" +
+            GUICE_VERS +
+            "-no_aop.jar",
+        ],
+    )
+
+    maven_jar(
+        name = "guice-assistedinject",
+        artifact = "com.google.inject.extensions:guice-assistedinject:" + GUICE_VERS,
+        sha1 = "acbfddc556ee9496293ed1df250cc378f331d854",
+    )
+
+    maven_jar(
+        name = "guice-servlet",
+        artifact = "com.google.inject.extensions:guice-servlet:" + GUICE_VERS,
+        sha1 = "8d6e7e35eac4fb5e7df19c55b3bc23fa51b10a11",
+    )
+
+    # Keep this version of Soy synchronized with the version used in Gitiles.
+    maven_jar(
+        name = "soy",
+        artifact = "com.google.template:soy:2019-10-08",
+        sha1 = "4518bf8bac2dbbed684849bc209c39c4cb546237",
+    )
+
+    # Test-only dependencies below.
     maven_jar(
         name = "cglib-3_2",
         artifact = "cglib:cglib-nodep:3.2.6",
@@ -203,3 +250,9 @@
         artifact = "net.java.dev.jna:jna:5.5.0",
         sha1 = "0e0845217c4907822403912ad6828d8e0b256208",
     )
+
+    maven_jar(
+        name = "jimfs",
+        artifact = "com.google.jimfs:jimfs:1.1",
+        sha1 = "8fbd0579dc68aba6186935cc1bee21d2f3e7ec1c",
+    )
diff --git a/version.bzl b/version.bzl
index 2b04e5e..066d07e 100644
--- a/version.bzl
+++ b/version.bzl
@@ -2,4 +2,4 @@
 # Used by :api_install and :api_deploy targets
 # when talking to the destination repository.
 #
-GERRIT_VERSION = "3.3.2-SNAPSHOT"
+GERRIT_VERSION = "3.4.0-SNAPSHOT"
diff --git a/yarn.lock b/yarn.lock
index 438cafd..3653ee5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -485,26 +485,42 @@
     lodash "^4.17.11"
     to-fast-properties "^2.0.0"
 
-"@bazel/rollup@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@bazel/rollup/-/rollup-2.0.0.tgz#1980cb3f6922227659260bfdca99c457889a5bc1"
-  integrity sha512-mifUfCZbD1RIhfowh4N8E4881ag3FChz7F4z35wxMOP52g1q3+6Bvh5wv9iysFQopxGmS5jNEj3Dq/CWtSoOnw==
+"@bazel/rollup@^3.0.0-rc.1":
+  version "3.0.0-rc.1"
+  resolved "https://registry.yarnpkg.com/@bazel/rollup/-/rollup-3.0.0-rc.1.tgz#153fb7ca556dfb0397aa3a86cbef71bcefb00733"
+  integrity sha512-O2WGfDw17aiQfUF6t5aL1kbVGeR6BnCImmtCOoFf1I8/Nw0dx+iE9x2qfqPyvSivZRuL2EBTI+xUcti42bpWgA==
 
-"@bazel/terser@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@bazel/terser/-/terser-2.0.0.tgz#a841db8aefd7c51c216b34a26bc02a6c93d5e56a"
-  integrity sha512-6mBYcfzP6pWxycYZ8r4Lz5kgiWZ7n08bVHZBIRExFeqs7Yy92dD92LPeA9FZIzFiX00IuR9Q1Lqy23xH5q7FeQ==
+"@bazel/terser@^3.0.0-rc.1":
+  version "3.0.0-rc.1"
+  resolved "https://registry.yarnpkg.com/@bazel/terser/-/terser-3.0.0-rc.1.tgz#62398c1702d3eecbc41764c9ef24a6a232abb1b3"
+  integrity sha512-iaJTYl/oUBqLFG6MFYODwqBWGTshFFdVCClTmpZwdnwnAkcGf7kU1noX2vz3VcwOOHoJseBG/dhluvRmFerJ3g==
 
-"@bazel/typescript@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-2.0.0.tgz#2ff5615f09c733cc681ba2ada92b11c356b694cd"
-  integrity sha512-5FPkxULWIjAKLG5J1XvpXpY1/4IK39dAoWA/Hhg+16gXTES32fT8w42k96pb6BTaNnyBuYgIHBpELEAJ40OOAQ==
+"@bazel/typescript@^3.0.0-rc.1":
+  version "3.0.0-rc.1"
+  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-3.0.0-rc.1.tgz#4a80682124475db63abc97b7da358caaadbd3077"
+  integrity sha512-KaGaCEbXjCKaRuwH/hLjW7aBuNyU8p/9yUe4KlP4KKoRqHAmjYISbUOw7VAksOW6BxXHgknOcZYaVF6PzE4CgQ==
   dependencies:
     protobufjs "6.8.8"
     semver "5.6.0"
     source-map-support "0.5.9"
     tsutils "2.27.2"
 
+"@eslint/eslintrc@^0.2.2":
+  version "0.2.2"
+  resolved "https://registry.yarnpkg.com/@eslint/eslintrc/-/eslintrc-0.2.2.tgz#d01fc791e2fc33e88a29d6f3dc7e93d0cd784b76"
+  integrity sha512-EfB5OHNYp1F4px/LI/FEnGylop7nOqkQ1LRzCM0KccA2U8tvV8w01KBv37LbO7nW4H+YhKyo2LcJhRwjjV17QQ==
+  dependencies:
+    ajv "^6.12.4"
+    debug "^4.1.1"
+    espree "^7.3.0"
+    globals "^12.1.0"
+    ignore "^4.0.6"
+    import-fresh "^3.2.1"
+    js-yaml "^3.13.1"
+    lodash "^4.17.19"
+    minimatch "^3.0.4"
+    strip-json-comments "^3.1.1"
+
 "@mrmlnc/readdir-enhanced@^2.2.1":
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/@mrmlnc/readdir-enhanced/-/readdir-enhanced-2.2.1.tgz#524af240d1a360527b730475ecfa1344aa540dde"
@@ -513,11 +529,32 @@
     call-me-maybe "^1.0.1"
     glob-to-regexp "^0.3.0"
 
+"@nodelib/fs.scandir@2.1.3":
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/@nodelib/fs.scandir/-/fs.scandir-2.1.3.tgz#3a582bdb53804c6ba6d146579c46e52130cf4a3b"
+  integrity sha512-eGmwYQn3gxo4r7jdQnkrrN6bY478C3P+a/y72IJukF8LjB6ZHeB3c+Ehacj3sYeSmUXGlnA67/PmbM9CVwL7Dw==
+  dependencies:
+    "@nodelib/fs.stat" "2.0.3"
+    run-parallel "^1.1.9"
+
+"@nodelib/fs.stat@2.0.3", "@nodelib/fs.stat@^2.0.2":
+  version "2.0.3"
+  resolved "https://registry.yarnpkg.com/@nodelib/fs.stat/-/fs.stat-2.0.3.tgz#34dc5f4cabbc720f4e60f75a747e7ecd6c175bd3"
+  integrity sha512-bQBFruR2TAwoevBEd/NWMoAAtNGzTRgdrqnYCc7dhzfoNvqPzLyqlEQnzZ3kVnNrSp25iyxE00/3h2fqGAGArA==
+
 "@nodelib/fs.stat@^1.1.2":
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/@nodelib/fs.stat/-/fs.stat-1.1.3.tgz#2b5a3ab3f918cca48a8c754c08168e3f03eba61b"
   integrity sha512-shAmDyaQC4H92APFoIaVDHCx5bStIocgvbwQyxPRrbUY20V1EYTbSDchWbuwlMG3V17cprZhA6+78JfB+3DTPw==
 
+"@nodelib/fs.walk@^1.2.3":
+  version "1.2.4"
+  resolved "https://registry.yarnpkg.com/@nodelib/fs.walk/-/fs.walk-1.2.4.tgz#011b9202a70a6366e436ca5c065844528ab04976"
+  integrity sha512-1V9XOY4rDW0rehzbrcqAmHnz8e7SKvX27gh8Gt2WgB0+pdzdiLV83p72kZPU+jvMbS1qU5mauP2iOvO8rhmurQ==
+  dependencies:
+    "@nodelib/fs.scandir" "2.1.3"
+    fastq "^1.6.0"
+
 "@octokit/endpoint@^5.1.0":
   version "5.2.1"
   resolved "https://registry.yarnpkg.com/@octokit/endpoint/-/endpoint-5.2.1.tgz#e5ef98bc4a41fad62b17e71af1a1710f6076b8df"
@@ -769,11 +806,6 @@
   resolved "https://registry.yarnpkg.com/@types/escape-html/-/escape-html-0.0.20.tgz#cae698714dd61ebee5ab3f2aeb9a34ba1011735a"
   integrity sha512-6dhZJLbA7aOwkYB2GDGdIqJ20wmHnkDzaxV9PJXe7O02I2dSFTERzRB6JrX6cWKaS+VqhhY7cQUMCbO5kloFUw==
 
-"@types/eslint-visitor-keys@^1.0.0":
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/@types/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#1ee30d79544ca84d68d4b3cdb0af4f205663dd2d"
-  integrity sha512-OCutwjDZ4aFS6PB1UZ988C4YgwlBHJd6wCeQqaLdmadZ/7e+w79+hbMUFC1QXDNCmdyoRfAFdm0RypzwR+Qpag==
-
 "@types/estree@0.0.39":
   version "0.0.39"
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
@@ -884,6 +916,11 @@
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.5.tgz#dcce4430e64b443ba8945f0290fb564ad5bac6dd"
   integrity sha512-7+2BITlgjgDhH0vvwZU/HZJVyk+2XUlvxXe8dFMedNX/aMkaOq++rMAFXc0tM7ij15QaWlbdQASBR9dihi+bDQ==
 
+"@types/json5@^0.0.29":
+  version "0.0.29"
+  resolved "https://registry.yarnpkg.com/@types/json5/-/json5-0.0.29.tgz#ee28707ae94e11d2b827bcbe5270bcea7f3e71ee"
+  integrity sha1-7ihweulOEdK4J7y+UnC86n8+ce4=
+
 "@types/launchpad@^0.6.0":
   version "0.6.0"
   resolved "https://registry.yarnpkg.com/@types/launchpad/-/launchpad-0.6.0.tgz#37296109b7f277f6e6c5fd7e0c0706bc918fbb51"
@@ -912,9 +949,9 @@
   integrity sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA==
 
 "@types/minimist@^1.2.0":
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/@types/minimist/-/minimist-1.2.0.tgz#69a23a3ad29caf0097f06eda59b361ee2f0639f6"
-  integrity sha1-aaI6OtKcrwCX8G7aWbNh7i8GOfY=
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/@types/minimist/-/minimist-1.2.1.tgz#283f669ff76d7b8260df8ab7a4262cc83d988256"
+  integrity sha512-fZQQafSREFyuZcdWFAExYjBiCL7AUCdgsk80iO0q4yihYYdcIiH28CcuPTGFgLOCC8RlW49GSQxdHwZP+I7CNg==
 
 "@types/mz@0.0.29":
   version "0.0.29"
@@ -937,9 +974,9 @@
   integrity sha512-rp7La3m845mSESCgsJePNL/JQyhkOJA6G4vcwvVgkDAwHhGdq5GCumxmPjEk1MZf+8p5ZQAUE7tqgQRQTXN7uQ==
 
 "@types/node@^10.1.0":
-  version "10.17.24"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-10.17.24.tgz#c57511e3a19c4b5e9692bb2995c40a3a52167944"
-  integrity sha512-5SCfvCxV74kzR3uWgTYiGxrd69TbT1I6+cMx1A5kEly/IVveJBimtAMlXiEyVFn5DvUFewQWxOOiJhlxeQwxgA==
+  version "10.17.49"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-10.17.49.tgz#ecf0b67bab4b84d0ec9b0709db4aac3824a51c4a"
+  integrity sha512-PGaJNs5IZz5XgzwJvL/1zRfZB7iaJ5BydZ8/Picm+lUNYoNO9iVTQkVy5eUh0dZDrx3rBOIs3GCbCRmMuYyqwg==
 
 "@types/node@^4.0.30":
   version "4.9.3"
@@ -1225,49 +1262,76 @@
     "@types/events" "*"
     "@types/inquirer" "*"
 
-"@typescript-eslint/eslint-plugin@2.31.0":
-  version "2.31.0"
-  resolved "https://registry.yarnpkg.com/@typescript-eslint/eslint-plugin/-/eslint-plugin-2.31.0.tgz#942c921fec5e200b79593c71fafb1e3f57aa2e36"
-  integrity sha512-iIC0Pb8qDaoit+m80Ln/aaeu9zKQdOLF4SHcGLarSeY1gurW6aU4JsOPMjKQwXlw70MvWKZQc6S2NamA8SJ/gg==
+"@typescript-eslint/eslint-plugin@^4.11.0", "@typescript-eslint/eslint-plugin@^4.2.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/eslint-plugin/-/eslint-plugin-4.11.0.tgz#bc6c1e4175c0cf42083da4314f7931ad12f731cc"
+  integrity sha512-x4arJMXBxyD6aBXLm3W7mSDZRiABzy+2PCLJbL7OPqlp53VXhaA1HKK7R2rTee5OlRhnUgnp8lZyVIqjnyPT6g==
   dependencies:
-    "@typescript-eslint/experimental-utils" "2.31.0"
+    "@typescript-eslint/experimental-utils" "4.11.0"
+    "@typescript-eslint/scope-manager" "4.11.0"
+    debug "^4.1.1"
     functional-red-black-tree "^1.0.1"
     regexpp "^3.0.0"
+    semver "^7.3.2"
     tsutils "^3.17.1"
 
-"@typescript-eslint/experimental-utils@2.31.0":
-  version "2.31.0"
-  resolved "https://registry.yarnpkg.com/@typescript-eslint/experimental-utils/-/experimental-utils-2.31.0.tgz#a9ec514bf7fd5e5e82bc10dcb6a86d58baae9508"
-  integrity sha512-MI6IWkutLYQYTQgZ48IVnRXmLR/0Q6oAyJgiOror74arUMh7EWjJkADfirZhRsUMHeLJ85U2iySDwHTSnNi9vA==
+"@typescript-eslint/experimental-utils@4.11.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/experimental-utils/-/experimental-utils-4.11.0.tgz#d1a47cc6cfe1c080ce4ead79267574b9881a1565"
+  integrity sha512-1VC6mSbYwl1FguKt8OgPs8xxaJgtqFpjY/UzUYDBKq4pfQ5lBvN2WVeqYkzf7evW42axUHYl2jm9tNyFsb8oLg==
   dependencies:
     "@types/json-schema" "^7.0.3"
-    "@typescript-eslint/typescript-estree" "2.31.0"
+    "@typescript-eslint/scope-manager" "4.11.0"
+    "@typescript-eslint/types" "4.11.0"
+    "@typescript-eslint/typescript-estree" "4.11.0"
     eslint-scope "^5.0.0"
     eslint-utils "^2.0.0"
 
-"@typescript-eslint/parser@2.31.0":
-  version "2.31.0"
-  resolved "https://registry.yarnpkg.com/@typescript-eslint/parser/-/parser-2.31.0.tgz#beddd4e8efe64995108b229b2862cd5752d40d6f"
-  integrity sha512-uph+w6xUOlyV2DLSC6o+fBDzZ5i7+3/TxAsH4h3eC64tlga57oMb96vVlXoMwjR/nN+xyWlsnxtbDkB46M2EPQ==
+"@typescript-eslint/parser@^4.2.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/parser/-/parser-4.11.0.tgz#1dd3d7e42708c10ce9f3aa64c63c0ab99868b4e2"
+  integrity sha512-NBTtKCC7ZtuxEV5CrHUO4Pg2s784pvavc3cnz6V+oJvVbK4tH9135f/RBP6eUA2KHiFKAollSrgSctQGmHbqJQ==
   dependencies:
-    "@types/eslint-visitor-keys" "^1.0.0"
-    "@typescript-eslint/experimental-utils" "2.31.0"
-    "@typescript-eslint/typescript-estree" "2.31.0"
-    eslint-visitor-keys "^1.1.0"
-
-"@typescript-eslint/typescript-estree@2.31.0":
-  version "2.31.0"
-  resolved "https://registry.yarnpkg.com/@typescript-eslint/typescript-estree/-/typescript-estree-2.31.0.tgz#ac536c2d46672aa1f27ba0ec2140d53670635cfd"
-  integrity sha512-vxW149bXFXXuBrAak0eKHOzbcu9cvi6iNcJDzEtOkRwGHxJG15chiAQAwhLOsk+86p9GTr/TziYvw+H9kMaIgA==
-  dependencies:
+    "@typescript-eslint/scope-manager" "4.11.0"
+    "@typescript-eslint/types" "4.11.0"
+    "@typescript-eslint/typescript-estree" "4.11.0"
     debug "^4.1.1"
-    eslint-visitor-keys "^1.1.0"
-    glob "^7.1.6"
+
+"@typescript-eslint/scope-manager@4.11.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/scope-manager/-/scope-manager-4.11.0.tgz#2d906537db8a3a946721699e4fc0833810490254"
+  integrity sha512-6VSTm/4vC2dHM3ySDW9Kl48en+yLNfVV6LECU8jodBHQOhO8adAVizaZ1fV0QGZnLQjQ/y0aBj5/KXPp2hBTjA==
+  dependencies:
+    "@typescript-eslint/types" "4.11.0"
+    "@typescript-eslint/visitor-keys" "4.11.0"
+
+"@typescript-eslint/types@4.11.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/types/-/types-4.11.0.tgz#86cf95e7eac4ccfd183f9fcf1480cece7caf4ca4"
+  integrity sha512-XXOdt/NPX++txOQHM1kUMgJUS43KSlXGdR/aDyEwuAEETwuPt02Nc7v+s57PzuSqMbNLclblQdv3YcWOdXhQ7g==
+
+"@typescript-eslint/typescript-estree@4.11.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/typescript-estree/-/typescript-estree-4.11.0.tgz#1144d145841e5987d61c4c845442a24b24165a4b"
+  integrity sha512-eA6sT5dE5RHAFhtcC+b5WDlUIGwnO9b0yrfGa1mIOIAjqwSQCpXbLiFmKTdRbQN/xH2EZkGqqLDrKUuYOZ0+Hg==
+  dependencies:
+    "@typescript-eslint/types" "4.11.0"
+    "@typescript-eslint/visitor-keys" "4.11.0"
+    debug "^4.1.1"
+    globby "^11.0.1"
     is-glob "^4.0.1"
     lodash "^4.17.15"
-    semver "^6.3.0"
+    semver "^7.3.2"
     tsutils "^3.17.1"
 
+"@typescript-eslint/visitor-keys@4.11.0":
+  version "4.11.0"
+  resolved "https://registry.yarnpkg.com/@typescript-eslint/visitor-keys/-/visitor-keys-4.11.0.tgz#906669a50f06aa744378bb84c7d5c4fdbc5b7d51"
+  integrity sha512-tRYKyY0i7cMk6v4UIOCjl1LhuepC/pc6adQqJk4Is3YcC6k46HvsV9Wl7vQoLbm9qADgeujiT7KdLrylvFIQ+A==
+  dependencies:
+    "@typescript-eslint/types" "4.11.0"
+    eslint-visitor-keys "^2.0.0"
+
 "@webcomponents/webcomponentsjs@^1.0.7":
   version "1.3.3"
   resolved "https://registry.yarnpkg.com/@webcomponents/webcomponentsjs/-/webcomponentsjs-1.3.3.tgz#5bb82a0d3210c836bd4623e13a4a93145cb9dc27"
@@ -1298,10 +1362,10 @@
   dependencies:
     acorn "^3.0.4"
 
-acorn-jsx@^5.1.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/acorn-jsx/-/acorn-jsx-5.1.0.tgz#294adb71b57398b0680015f0a38c563ee1db5384"
-  integrity sha512-tMUqwBWfLFbJbizRmEcWSLw6HnFzfdJs2sOJEOwwtVPMoH/0Ay+E703oZz78VSXZiiDcZrQ5XKjPIUQixhmgVw==
+acorn-jsx@^5.3.1:
+  version "5.3.1"
+  resolved "https://registry.yarnpkg.com/acorn-jsx/-/acorn-jsx-5.3.1.tgz#fc8661e11b7ac1539c47dbfea2e72b3af34d267b"
+  integrity sha512-K0Ptm/47OKfQRpNQ2J/oIN/3QYiK6FwW+eJbILhsdxh2WTLdl+30o8aGdTbm5JbffpFFAg/g+zi1E+jvJha5ng==
 
 acorn@^3.0.4:
   version "3.3.0"
@@ -1318,10 +1382,10 @@
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.2.0.tgz#67f0da2fc339d6cfb5d6fb244fd449f33cd8bbe3"
   integrity sha512-8oe72N3WPMjA+2zVG71Ia0nXZ8DpQH+QyyHO+p06jT8eg8FGG3FbcUIi8KziHlAfheJQZeoqbvq1mQSQHXKYLw==
 
-acorn@^7.1.0:
-  version "7.1.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.1.0.tgz#949d36f2c292535da602283586c2477c57eb2d6c"
-  integrity sha512-kL5CuoXA/dgxlBbVrflsflzQ3PAas7RYZB52NOm/6839iVYJgKMJ3cQJD+t2i5+qFa8h3MDpEOJiS64E8JLnSQ==
+acorn@^7.4.0:
+  version "7.4.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.4.1.tgz#feaed255973d2e77555b83dbc08851a6c63520fa"
+  integrity sha512-nQyp0o1/mNdbTO1PO6kHkwSrmgZ0MT/jCCpNiwbUjGoRN4dlBhqJtoQuCnEOKzgTVwg0ZWiCoQy6SxMebQVh8A==
 
 adm-zip@~0.4.3:
   version "0.4.13"
@@ -1340,7 +1404,7 @@
   dependencies:
     es6-promisify "^5.0.0"
 
-ajv@^6.10.0, ajv@^6.10.2:
+ajv@^6.10.0:
   version "6.10.2"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.10.2.tgz#d3cea04d6b017b2894ad69040fec8b623eb4bd52"
   integrity sha512-TXtUUEYHuaTEbLZWIKUr5pmBuhDLy+8KYtPYdcV8qC+pOZL+NKqYwvWSRrVXHn+ZmRRAu8vJTAznH7Oag6RVRw==
@@ -1350,6 +1414,16 @@
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
+ajv@^6.12.4:
+  version "6.12.6"
+  resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
+  integrity sha512-j3fVLgvTo527anyYyJOGTYJbG+vnnQYvE0m5mmkc1TK+nxAppkCLMIL0aZ4dblVCNoGShhm+kzE4ZUykBoMg4g==
+  dependencies:
+    fast-deep-equal "^3.1.1"
+    fast-json-stable-stringify "^2.0.0"
+    json-schema-traverse "^0.4.1"
+    uri-js "^4.2.2"
+
 ajv@^6.5.5:
   version "6.10.1"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.10.1.tgz#ebf8d3af22552df9dd049bfbe50cc2390e823593"
@@ -1381,6 +1455,11 @@
   dependencies:
     string-width "^3.0.0"
 
+ansi-colors@^4.1.1:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/ansi-colors/-/ansi-colors-4.1.1.tgz#cbb9ae256bf750af1eab344f229aa27fe94ba348"
+  integrity sha512-JoX0apGbHaUJBNl6yF+p6JAFYZ666/hhCGKN5t9QFjbJQKUU/g8MNbFDbvfrgKXvI1QpZplPOnwIo99lX/AAmA==
+
 ansi-escapes@^1.1.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/ansi-escapes/-/ansi-escapes-1.4.0.tgz#d3a8a83b319aa67793662b13e761c7911422306e"
@@ -1392,11 +1471,11 @@
   integrity sha512-cBhpre4ma+U0T1oM5fXg7Dy1Jw7zzwv7lt/GoCpr+hDQJoYnKVPLL4dCvSEFMmQurOQvSrwT7SL/DAlhBI97RQ==
 
 ansi-escapes@^4.2.1:
-  version "4.3.0"
-  resolved "https://registry.yarnpkg.com/ansi-escapes/-/ansi-escapes-4.3.0.tgz#a4ce2b33d6b214b7950d8595c212f12ac9cc569d"
-  integrity sha512-EiYhwo0v255HUL6eDyuLrXEkTi7WwVCLAw+SeOQ7M7qdun1z1pum4DEm/nuqIVbPvi9RPPc9k9LbyBv6H0DwVg==
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/ansi-escapes/-/ansi-escapes-4.3.1.tgz#a5c47cc43181f1f38ffd7076837700d395522a61"
+  integrity sha512-JWF7ocqNrp8u9oqpgV+wH5ftbt+cfvv+PTjOvKLT3AdYly/LmORARfEVT1iyjwN+4MqE5UmVKoAdIBqeoCHgLA==
   dependencies:
-    type-fest "^0.8.1"
+    type-fest "^0.11.0"
 
 ansi-regex@^2.0.0:
   version "2.1.1"
@@ -1423,13 +1502,20 @@
   resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-2.2.1.tgz#b432dd3358b634cf75e1e4664368240533c1ddbe"
   integrity sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4=
 
-ansi-styles@^3.2.0, ansi-styles@^3.2.1:
+ansi-styles@^3.2.1:
   version "3.2.1"
   resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-3.2.1.tgz#41fbb20243e50b12be0f04b8dedbf07520ce841d"
   integrity sha512-VT0ZI6kZRdTh8YyJw3SMbYm/u+NqfsAxEpWO0Pf9sq8/e94WxxOpPKx9FR1FlyCtOVDNOQ+8ntlqFxiRc+r5qA==
   dependencies:
     color-convert "^1.9.0"
 
+ansi-styles@^4.0.0:
+  version "4.3.0"
+  resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-4.3.0.tgz#edd803628ae71c04c85ae7a0906edad34b648937"
+  integrity sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg==
+  dependencies:
+    color-convert "^2.0.1"
+
 ansi-styles@^4.1.0:
   version "4.2.1"
   resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-4.2.1.tgz#90ae75c424d008d2624c5bf29ead3177ebfcf359"
@@ -1559,13 +1645,15 @@
   resolved "https://registry.yarnpkg.com/array-flatten/-/array-flatten-1.1.1.tgz#9a5f699051b1e7073328f2a008968b64ea2955d2"
   integrity sha1-ml9pkFGx5wczKPKgCJaLZOopVdI=
 
-array-includes@^3.0.3:
-  version "3.1.1"
-  resolved "https://registry.yarnpkg.com/array-includes/-/array-includes-3.1.1.tgz#cdd67e6852bdf9c1215460786732255ed2459348"
-  integrity sha512-c2VXaCHl7zPsvpkFsw4nxvFie4fh1ur9bpcgsVkIjqn0H/Xwdg+7fv3n2r/isyS8EBj5b06M9kHyZuIr4El6WQ==
+array-includes@^3.1.1:
+  version "3.1.2"
+  resolved "https://registry.yarnpkg.com/array-includes/-/array-includes-3.1.2.tgz#a8db03e0b88c8c6aeddc49cb132f9bcab4ebf9c8"
+  integrity sha512-w2GspexNQpx+PutG3QpT437/BenZBj0M/MZGn5mzv/MofYqo0xmRHzn4lFsoDlWJ+THYsGJmFlW68WlDFx7VRw==
   dependencies:
+    call-bind "^1.0.0"
     define-properties "^1.1.3"
-    es-abstract "^1.17.0"
+    es-abstract "^1.18.0-next.1"
+    get-intrinsic "^1.0.1"
     is-string "^1.0.5"
 
 array-union@^1.0.1:
@@ -1575,6 +1663,11 @@
   dependencies:
     array-uniq "^1.0.1"
 
+array-union@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/array-union/-/array-union-2.1.0.tgz#b798420adbeb1de828d84acd8a2e23d3efe85e8d"
+  integrity sha512-HGyxoOTYUyCM6stUe6EJgnd4EoewAI7zMdfqO+kGjnlZmBDz/cR5pf8r/cR4Wq60sL/p0IkcjUEEPwS3GFrIyw==
+
 array-uniq@^1.0.1:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/array-uniq/-/array-uniq-1.0.3.tgz#af6ac877a25cc7f74e058894753858dfdb24fdb6"
@@ -1590,13 +1683,14 @@
   resolved "https://registry.yarnpkg.com/array-unique/-/array-unique-0.3.2.tgz#a894b75d4bc4f6cd679ef3244a9fd8f46ae2d428"
   integrity sha1-qJS3XUvE9s1nnvMkSp/Y9Gri1Cg=
 
-array.prototype.flat@^1.2.1:
-  version "1.2.3"
-  resolved "https://registry.yarnpkg.com/array.prototype.flat/-/array.prototype.flat-1.2.3.tgz#0de82b426b0318dbfdb940089e38b043d37f6c7b"
-  integrity sha512-gBlRZV0VSmfPIeWfuuy56XZMvbVfbEUnOXUvt3F/eUUUSyzlgLxhEX4YAEpxNAogRGehPSnfXyPtYyKAhkzQhQ==
+array.prototype.flat@^1.2.3:
+  version "1.2.4"
+  resolved "https://registry.yarnpkg.com/array.prototype.flat/-/array.prototype.flat-1.2.4.tgz#6ef638b43312bd401b4c6199fdec7e2dc9e9a123"
+  integrity sha512-4470Xi3GAPAjZqFcljX2xzckv1qeKPizoNkiS0+O4IoPR2ZNpcjE0pkhdihlDouK+x6QOast26B4Q/O9DJnwSg==
   dependencies:
+    call-bind "^1.0.0"
     define-properties "^1.1.3"
-    es-abstract "^1.17.0-next.1"
+    es-abstract "^1.18.0-next.1"
 
 arraybuffer.slice@~0.0.7:
   version "0.0.7"
@@ -1608,11 +1702,6 @@
   resolved "https://registry.yarnpkg.com/arrify/-/arrify-1.0.1.tgz#898508da2226f380df904728456849c1501a4b0d"
   integrity sha1-iYUI2iIm84DfkEcoRWhJwVAaSw0=
 
-arrify@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/arrify/-/arrify-2.0.1.tgz#c9655e9331e0abcd588d2a7cad7e9956f66701fa"
-  integrity sha512-3duEwti880xqi4eAMN8AyR4a0ByT90zoYdLlevfrvU43vb0YZwZVfxOgxWrLXXXpyugL0hNZc9G6BiB5B3nUug==
-
 asn1@~0.2.3:
   version "0.2.4"
   resolved "https://registry.yarnpkg.com/asn1/-/asn1-0.2.4.tgz#8d2475dfab553bb33e77b54e59e880bb8ce23136"
@@ -1630,10 +1719,10 @@
   resolved "https://registry.yarnpkg.com/assign-symbols/-/assign-symbols-1.0.0.tgz#59667f41fadd4f20ccbc2bb96b8d4f7f78ec0367"
   integrity sha1-WWZ/QfrdTyDMvCu5a41Pf3jsA2c=
 
-astral-regex@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/astral-regex/-/astral-regex-1.0.0.tgz#6c8c3fb827dd43ee3918f27b82782ab7658a6fd9"
-  integrity sha512-+Ryf6g3BKoRc7jfp7ad8tM4TtMiaWvbF/1/sQcZPkkS7ag3D5nMBCe2UfOTONtAkaG0tO0ij3C5Lwmf1EiyjHg==
+astral-regex@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/astral-regex/-/astral-regex-2.0.0.tgz#483143c567aeed4785759c0865786dc77d7d2e31"
+  integrity sha512-Z7tMw1ytTXt5jqMcOP+OQteU1VuNK9Y02uuJtKQ1Sv69jXQKKg5cibLwGJow8yzZP+eAc18EmLGPal0bp36rvQ==
 
 async-each@^1.0.0:
   version "1.0.3"
@@ -2183,6 +2272,13 @@
     split-string "^3.0.2"
     to-regex "^3.0.1"
 
+braces@^3.0.1:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/braces/-/braces-3.0.2.tgz#3454e1a462ee8d599e236df336cd9ea4f8afe107"
+  integrity sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==
+  dependencies:
+    fill-range "^7.0.1"
+
 browser-capabilities@^1.0.0:
   version "1.1.4"
   resolved "https://registry.yarnpkg.com/browser-capabilities/-/browser-capabilities-1.1.4.tgz#a6bd657a07a134532ad66c722b8949904478b973"
@@ -2292,6 +2388,14 @@
     normalize-url "^4.1.0"
     responselike "^1.0.2"
 
+call-bind@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/call-bind/-/call-bind-1.0.0.tgz#24127054bb3f9bdcb4b1fb82418186072f77b8ce"
+  integrity sha512-AEXsYIyyDY3MCzbwdhzG3Jx1R0J2wetQyUynn6dYHAO+bg8l1k7jwZtRv4ryryFs7EP+NDlikJlVe59jr0cM2w==
+  dependencies:
+    function-bind "^1.1.1"
+    get-intrinsic "^1.0.0"
+
 call-me-maybe@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/call-me-maybe/-/call-me-maybe-1.0.1.tgz#26d208ea89e37b5cbde60250a15f031c16a4d66b"
@@ -2342,16 +2446,11 @@
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-4.1.0.tgz#d545635be1e33c542649c69173e5de6acfae34dd"
   integrity sha1-1UVjW+HjPFQmScaRc+Xeas+uNN0=
 
-camelcase@^5.0.0, camelcase@^5.3.1:
+camelcase@^5.3.1:
   version "5.3.1"
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-5.3.1.tgz#e3c9b31569e106811df242f715725a1f4c494320"
   integrity sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg==
 
-camelcase@^6.0.0:
-  version "6.0.0"
-  resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-6.0.0.tgz#5259f7c30e35e278f1bdc2a4d91230b37cad981e"
-  integrity sha512-8KMDF1Vz2gzOq54ONPJS65IvTUaB1cHJ2DMM7MbPmLZljDH1qpzzLsWdiN9pHh6qvkRVDTi/07+eNGch/oLU4w==
-
 cancel-token@^0.1.1:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/cancel-token/-/cancel-token-0.1.1.tgz#c18197674bb1c84c1d6933ebf15d8d5a5ce79b4f"
@@ -2369,7 +2468,7 @@
   resolved "https://registry.yarnpkg.com/caseless/-/caseless-0.12.0.tgz#1b681c21ff84033c826543090689420d187151dc"
   integrity sha1-G2gcIf+EAzyCZUMJBolCDRhxUdw=
 
-chalk@*, chalk@^2.0.0, chalk@^2.0.1, chalk@^2.1.0, chalk@^2.3.0, chalk@^2.4.1, chalk@^2.4.2:
+chalk@*, chalk@^2.0.0, chalk@^2.0.1, chalk@^2.3.0, chalk@^2.4.1, chalk@^2.4.2:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
   integrity sha512-Mti+f9lpJNcwF4tWV8/OrTTtF1gZi+f8FqlyAdouralcFWFQWF2+NgCHShjkCb+IFBLq9buZwE1xckQU4peSuQ==
@@ -2397,7 +2496,7 @@
     ansi-styles "^4.1.0"
     supports-color "^7.1.0"
 
-chalk@^4.0.0:
+chalk@^4.0.0, chalk@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-4.1.0.tgz#4e14870a618d9e2edd97dd8345fd9d9dc315646a"
   integrity sha512-qwx12AxXe2Q5xQ43Ac//I6v5aXTipYrSESdOgzrN+9XjgEpyjpKuvSGaN4qE93f7TQTlerQQ8S+EQ0EyDoVL1A==
@@ -2488,9 +2587,9 @@
   integrity sha1-T6kXw+WclKAEzWH47lCdplFocUM=
 
 cli-boxes@^2.2.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/cli-boxes/-/cli-boxes-2.2.0.tgz#538ecae8f9c6ca508e3c3c95b453fe93cb4c168d"
-  integrity sha512-gpaBrMAizVEANOpfZp/EEUixTXDyGt7DFzdK5hU+UbWt/J0lB0w20ncZj59Z9a93xHb9u12zF5BS6i9RKbtg4w==
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/cli-boxes/-/cli-boxes-2.2.1.tgz#ddd5035d25094fce220e9cab40a45840a440318f"
+  integrity sha512-y4coMcylgSCdVinjiDBuR8PCC2bLjyGTwEmPb9NHR/QaNU6EUOXcTY/s6VjGMD6ENSEaeQYHCY0GNGS5jfMwPw==
 
 cli-cursor@^1.0.1:
   version "1.0.2"
@@ -2525,6 +2624,11 @@
   resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-2.2.0.tgz#ff19ede8a9a5e579324147b0c11f0fbcbabed639"
   integrity sha1-/xnt6Kml5XkyQUewwR8PvLq+1jk=
 
+cli-width@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-3.0.0.tgz#a2f48437a2caa9a22436e794bf071ec9e61cedf6"
+  integrity sha512-FxqpkPPwu1HjuN93Omfm4h8uIanXofW0RxVEW3k5RKx+mJJYSthzNhp32Kzxxy3YAEZ/Dc/EWN1vZRY0+kOhbw==
+
 clone-buffer@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/clone-buffer/-/clone-buffer-1.0.0.tgz#e3e25b207ac4e701af721e2cb5a16792cac3dc58"
@@ -2691,10 +2795,10 @@
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.19.0.tgz#f6198aa84e5b83c46054b94ddedbfed5ee9ff12a"
   integrity sha512-6tvAOO+D6OENvRAh524Dh9jcfKTYDQAqvqezbCW82xj5X0pSrcpxtvRKHLG0yBY6SD7PSDrJaj+0AiOcKVd1Xg==
 
-comment-parser@^0.7.2:
-  version "0.7.2"
-  resolved "https://registry.yarnpkg.com/comment-parser/-/comment-parser-0.7.2.tgz#baf6d99b42038678b81096f15b630d18142f4b8a"
-  integrity sha512-4Rjb1FnxtOcv9qsfuaNuVsmmVn4ooVoBHzYfyKteiXwIU84PClyGA5jASoFMwPV93+FPh9spwueXauxFJZkGAg==
+comment-parser@^0.7.6:
+  version "0.7.6"
+  resolved "https://registry.yarnpkg.com/comment-parser/-/comment-parser-0.7.6.tgz#0e743a53c8e646c899a1323db31f6cd337b10f12"
+  integrity sha512-GKNxVA7/iuTnAqGADlTWX4tkhzxZKXp5fLJqKTlQLHkE65XDUKutZ3BHaJC5IGcper2tT3QRD1xr4o3jNpgXXg==
 
 commondir@^1.0.1:
   version "1.0.1"
@@ -2914,7 +3018,7 @@
     shebang-command "^1.2.0"
     which "^1.2.9"
 
-cross-spawn@^7.0.0:
+cross-spawn@^7.0.2, cross-spawn@^7.0.3:
   version "7.0.3"
   resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-7.0.3.tgz#f73a85b9d5d41d045551c177e2882d4ac85728a6"
   integrity sha512-iRDPJKUPVEND7dHPO8rkbOnPpyDygcDFtWjpeWNCgy8WP2rXcxXL8TskReQl6OrB2G7+UJrags1q15Fudc7G6w==
@@ -3004,6 +3108,13 @@
   dependencies:
     ms "^2.1.1"
 
+debug@^4.3.1:
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/debug/-/debug-4.3.1.tgz#f0d229c505e0c6d8c49ac553d1b13dc183f6b2ee"
+  integrity sha512-doEwdvm4PCeK4K3RQN2ZC2BYUBaxwLARCqZmMjtF8a51J2Rb0xpVloFRnCODwqjpwnAoao4pelN8l3RJdv3gRQ==
+  dependencies:
+    ms "2.1.2"
+
 debug@~3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/debug/-/debug-3.1.0.tgz#5bb5a0672628b64149566ba16819e61518c67261"
@@ -3019,7 +3130,7 @@
     decamelize "^1.1.0"
     map-obj "^1.0.0"
 
-decamelize@^1.1.0, decamelize@^1.1.2, decamelize@^1.2.0:
+decamelize@^1.1.0, decamelize@^1.1.2:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"
   integrity sha1-9lNNFRSCabIDUue+4m9QH5oZEpA=
@@ -3046,7 +3157,7 @@
   resolved "https://registry.yarnpkg.com/deep-extend/-/deep-extend-0.6.0.tgz#c4fa7c95404a17a9c3e8ca7e1537312b736330ac"
   integrity sha512-LOHxIOaPYdHlJRtCQfDIVZtfw/ufM8+rVj649RIHzcm/vGwQRXFt6OPqIFWsm2XEMrNIEtWR64sY1LEKD2vAOA==
 
-deep-is@~0.1.3:
+deep-is@^0.1.3:
   version "0.1.3"
   resolved "https://registry.yarnpkg.com/deep-is/-/deep-is-0.1.3.tgz#b369d6fb5dbc13eecf524f91b070feedc357cf34"
   integrity sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ=
@@ -3196,6 +3307,13 @@
     arrify "^1.0.1"
     path-type "^3.0.0"
 
+dir-glob@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/dir-glob/-/dir-glob-3.0.1.tgz#56dbf73d992a4a93ba1584f4534063fd2e41717f"
+  integrity sha512-WkrWp9GR4KXfKGYzOLmTuGVi1UWFfws377n9cc55/tb6DuqyF6pcQ5AbiHEshaDpY9v6oaSr2XCDidGmMwdzIA==
+  dependencies:
+    path-type "^4.0.0"
+
 doctrine@1.5.0:
   version "1.5.0"
   resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-1.5.0.tgz#379dce730f6166f76cefa4e6707a159b02c5a6fa"
@@ -3218,12 +3336,13 @@
   dependencies:
     esutils "^2.0.2"
 
-dom-serializer@0:
-  version "0.2.2"
-  resolved "https://registry.yarnpkg.com/dom-serializer/-/dom-serializer-0.2.2.tgz#1afb81f533717175d478655debc5e332d9f9bb51"
-  integrity sha512-2/xPb3ORsQ42nHYiSunXkDjPLBaEj/xTwUO4B7XCZQTRk7EBtTOPaygh10YAAh2OI1Qrp6NWfpAhzswj0ydt9g==
+dom-serializer@^1.0.1:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/dom-serializer/-/dom-serializer-1.2.0.tgz#3433d9136aeb3c627981daa385fc7f32d27c48f1"
+  integrity sha512-n6kZFH/KlCrqs/1GHMOd5i2fd/beQHuehKdWvNNffbGHTr/almdhuVvTVFb3V7fglz+nC50fFusu3lY33h12pA==
   dependencies:
     domelementtype "^2.0.1"
+    domhandler "^4.0.0"
     entities "^2.0.0"
 
 dom-urls@^1.1.0:
@@ -3242,30 +3361,33 @@
     clone "^2.1.0"
     parse5 "^4.0.0"
 
-domelementtype@1, domelementtype@^1.3.1:
-  version "1.3.1"
-  resolved "https://registry.yarnpkg.com/domelementtype/-/domelementtype-1.3.1.tgz#d048c44b37b0d10a7f2a3d5fee3f4333d790481f"
-  integrity sha512-BSKB+TSpMpFI/HOxCNr1O8aMOTZ8hT3pM3GQ0w/mWRmkhEDSFJkkyzz4XQsBV44BChwGkrDfMyjVD0eA2aFV3w==
+domelementtype@^2.0.1, domelementtype@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/domelementtype/-/domelementtype-2.1.0.tgz#a851c080a6d1c3d94344aed151d99f669edf585e"
+  integrity sha512-LsTgx/L5VpD+Q8lmsXSHW2WpA+eBlZ9HPf3erD1IoPF00/3JKHZ3BknUVA2QGDNu69ZNmyFmCWBSO45XjYKC5w==
 
-domelementtype@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/domelementtype/-/domelementtype-2.0.1.tgz#1f8bdfe91f5a78063274e803b4bdcedf6e94f94d"
-  integrity sha512-5HOHUDsYZWV8FGWN0Njbr/Rn7f/eWSQi1v7+HsUVwXgn8nWWlL64zKDkS0n8ZmQ3mlWOMuXOnR+7Nx/5tMO5AQ==
-
-domhandler@^2.3.0:
-  version "2.4.2"
-  resolved "https://registry.yarnpkg.com/domhandler/-/domhandler-2.4.2.tgz#8805097e933d65e85546f726d60f5eb88b44f803"
-  integrity sha512-JiK04h0Ht5u/80fdLMCEmV4zkNh2BcoMFBmZ/91WtYZ8qVXSKjiw7fXMgFPnHcSZgOo3XdinHvmnDUeMf5R4wA==
+domhandler@^3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/domhandler/-/domhandler-3.3.0.tgz#6db7ea46e4617eb15cf875df68b2b8524ce0037a"
+  integrity sha512-J1C5rIANUbuYK+FuFL98650rihynUOEzRLxW+90bKZRWB6A1X1Tf82GxR1qAWLyfNPRvjqfip3Q5tdYlmAa9lA==
   dependencies:
-    domelementtype "1"
+    domelementtype "^2.0.1"
 
-domutils@^1.5.1:
-  version "1.7.0"
-  resolved "https://registry.yarnpkg.com/domutils/-/domutils-1.7.0.tgz#56ea341e834e06e6748af7a1cb25da67ea9f8c2a"
-  integrity sha512-Lgd2XcJ/NjEw+7tFvfKxOzCYKZsdct5lczQ2ZaQY8Djz7pfAD3Gbp8ySJWtreII/vDlMVmxwa6pHmdxIYgttDg==
+domhandler@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/domhandler/-/domhandler-4.0.0.tgz#01ea7821de996d85f69029e81fa873c21833098e"
+  integrity sha512-KPTbnGQ1JeEMQyO1iYXoagsI6so/C96HZiFyByU3T6iAzpXn8EGEvct6unm1ZGoed8ByO2oirxgwxBmqKF9haA==
   dependencies:
-    dom-serializer "0"
-    domelementtype "1"
+    domelementtype "^2.1.0"
+
+domutils@^2.4.2:
+  version "2.4.4"
+  resolved "https://registry.yarnpkg.com/domutils/-/domutils-2.4.4.tgz#282739c4b150d022d34699797369aad8d19bbbd3"
+  integrity sha512-jBC0vOsECI4OMdD0GC9mGn7NXPLb+Qt6KW1YDQzeQYRUFKmNG8lh7mO5HiELfr+lLQE7loDVI4QcAxV80HS+RA==
+  dependencies:
+    dom-serializer "^1.0.1"
+    domelementtype "^2.0.1"
+    domhandler "^4.0.0"
 
 dot-prop@^3.0.0:
   version "3.0.0"
@@ -3282,9 +3404,9 @@
     is-obj "^1.0.0"
 
 dot-prop@^5.2.0:
-  version "5.2.0"
-  resolved "https://registry.yarnpkg.com/dot-prop/-/dot-prop-5.2.0.tgz#c34ecc29556dc45f1f4c22697b6f4904e0cc4fcb"
-  integrity sha512-uEUyaDKoSQ1M4Oq8l45hSE26SnTxL6snNnqvK/VWx5wJhmff5z0FUVJDKDanor/6w3kzE3i7XZOk+7wC0EXr1A==
+  version "5.3.0"
+  resolved "https://registry.yarnpkg.com/dot-prop/-/dot-prop-5.3.0.tgz#90ccce708cd9cd82cc4dc8c3ddd9abdd55b20e88"
+  integrity sha512-QM8q3zDe58hqUqjraQOmzZ1LIH9SWQJTlEKCH4kJ2oQvLZk7RbQXvtDM2XEq3fwkV9CCvvH4LA0AV+ogFsBM2Q==
   dependencies:
     is-obj "^2.0.0"
 
@@ -3422,15 +3544,17 @@
     engine.io-parser "~2.2.0"
     ws "^7.1.2"
 
-entities@^1.1.1:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/entities/-/entities-1.1.2.tgz#bdfa735299664dfafd34529ed4f8522a275fea56"
-  integrity sha512-f2LZMYl1Fzu7YSBKg+RoROelpOaNrcGmE9AZubeDfrCEia483oW4MI4VyFd5VNHIgQ/7qm1I0wUHK1eJnn2y2w==
+enquirer@^2.3.5:
+  version "2.3.6"
+  resolved "https://registry.yarnpkg.com/enquirer/-/enquirer-2.3.6.tgz#2a7fe5dd634a1e4125a975ec994ff5456dc3734d"
+  integrity sha512-yjNnPr315/FjS4zIsUxYguYUPP2e1NK4d7E7ZOLiyYCcbFBiTMyID+2wvm2w6+pZ/odMA7cRkjhsPbltwBOrLg==
+  dependencies:
+    ansi-colors "^4.1.1"
 
 entities@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/entities/-/entities-2.0.0.tgz#68d6084cab1b079767540d80e56a39b423e4abf4"
-  integrity sha512-D9f7V0JSRwIxlRI2mjMqufDrRDnx8p+eEOz7aUM9SuvF8gsBzra0/6tbjl1m8eQHrZlYj6PxqE00hZ1SAIKPLw==
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/entities/-/entities-2.1.0.tgz#992d3129cf7df6870b96c57858c249a120f8b8b5"
+  integrity sha512-hCx1oky9PFrJ611mf0ifBLBRW8lUUVRlFolb5gWRfIELabBlbp9xZvrqZLZAs+NxFnbfQoeGd8wDkygjg7U85w==
 
 env-variable@0.0.x:
   version "0.0.5"
@@ -3459,22 +3583,23 @@
     string-template "~0.2.1"
     xtend "~4.0.0"
 
-es-abstract@^1.17.0, es-abstract@^1.17.0-next.1:
-  version "1.17.5"
-  resolved "https://registry.yarnpkg.com/es-abstract/-/es-abstract-1.17.5.tgz#d8c9d1d66c8981fb9200e2251d799eee92774ae9"
-  integrity sha512-BR9auzDbySxOcfog0tLECW8l28eRGpDpU3Dm3Hp4q/N+VtLTmyj4EUN088XZWQDW/hzj6sYRDXeOFsaAODKvpg==
+es-abstract@^1.18.0-next.1:
+  version "1.18.0-next.1"
+  resolved "https://registry.yarnpkg.com/es-abstract/-/es-abstract-1.18.0-next.1.tgz#6e3a0a4bda717e5023ab3b8e90bec36108d22c68"
+  integrity sha512-I4UGspA0wpZXWENrdA0uHbnhte683t3qT/1VFH9aX2dA5PPSf6QW5HHXf5HImaqPmjXaVeVk4RGWnaylmV7uAA==
   dependencies:
     es-to-primitive "^1.2.1"
     function-bind "^1.1.1"
     has "^1.0.3"
     has-symbols "^1.0.1"
-    is-callable "^1.1.5"
-    is-regex "^1.0.5"
-    object-inspect "^1.7.0"
+    is-callable "^1.2.2"
+    is-negative-zero "^2.0.0"
+    is-regex "^1.1.1"
+    object-inspect "^1.8.0"
     object-keys "^1.1.1"
-    object.assign "^4.1.0"
-    string.prototype.trimleft "^2.1.1"
-    string.prototype.trimright "^2.1.1"
+    object.assign "^4.1.1"
+    string.prototype.trimend "^1.0.1"
+    string.prototype.trimstart "^1.0.1"
 
 es-to-primitive@^1.2.1:
   version "1.2.1"
@@ -3517,30 +3642,30 @@
   resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
   integrity sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=
 
-eslint-config-google@^0.13.0:
-  version "0.13.0"
-  resolved "https://registry.yarnpkg.com/eslint-config-google/-/eslint-config-google-0.13.0.tgz#e277d16d2cb25c1ffd3fd13fb0035ad7421382fe"
-  integrity sha512-ELgMdOIpn0CFdsQS+FuxO+Ttu4p+aLaXHv9wA9yVnzqlUGV7oN/eRRnJekk7TCur6Cu2FXX0fqfIXRBaM14lpQ==
+eslint-config-google@^0.14.0:
+  version "0.14.0"
+  resolved "https://registry.yarnpkg.com/eslint-config-google/-/eslint-config-google-0.14.0.tgz#4f5f8759ba6e11b424294a219dbfa18c508bcc1a"
+  integrity sha512-WsbX4WbjuMvTdeVL6+J3rK1RGhCTqjsFjX7UMSMgZiyxxaNLkoJENbrGExzERFeoTpGw3F3FypTiWAP9ZXzkEw==
 
-eslint-config-prettier@^6.10.1:
-  version "6.11.0"
-  resolved "https://registry.yarnpkg.com/eslint-config-prettier/-/eslint-config-prettier-6.11.0.tgz#f6d2238c1290d01c859a8b5c1f7d352a0b0da8b1"
-  integrity sha512-oB8cpLWSAjOVFEJhhyMZh6NOEOtBVziaqdDQ86+qhDHFbZXoRTM7pNSvFRfW/W/L/LrQ38C99J5CGuRBBzBsdA==
+eslint-config-prettier@^6.12.0:
+  version "6.15.0"
+  resolved "https://registry.yarnpkg.com/eslint-config-prettier/-/eslint-config-prettier-6.15.0.tgz#7f93f6cb7d45a92f1537a70ecc06366e1ac6fed9"
+  integrity sha512-a1+kOYLR8wMGustcgAjdydMsQ2A/2ipRPwRKUmfYaSxc9ZPcrku080Ctl6zrZzZNs/U82MjSv+qKREkoq3bJaw==
   dependencies:
     get-stdin "^6.0.0"
 
-eslint-import-resolver-node@^0.3.2:
-  version "0.3.3"
-  resolved "https://registry.yarnpkg.com/eslint-import-resolver-node/-/eslint-import-resolver-node-0.3.3.tgz#dbaa52b6b2816b50bc6711af75422de808e98404"
-  integrity sha512-b8crLDo0M5RSe5YG8Pu2DYBj71tSB6OvXkfzwbJU2w7y8P4/yo0MyF8jU26IEuEuHF2K5/gcAJE3LhQGqBBbVg==
+eslint-import-resolver-node@^0.3.4:
+  version "0.3.4"
+  resolved "https://registry.yarnpkg.com/eslint-import-resolver-node/-/eslint-import-resolver-node-0.3.4.tgz#85ffa81942c25012d8231096ddf679c03042c717"
+  integrity sha512-ogtf+5AB/O+nM6DIeBUNr2fuT7ot9Qg/1harBfBtaP13ekEWFQEEMP94BCB7zaNW3gyY+8SHYF00rnqYwXKWOA==
   dependencies:
     debug "^2.6.9"
     resolve "^1.13.1"
 
-eslint-module-utils@^2.4.1:
-  version "2.5.2"
-  resolved "https://registry.yarnpkg.com/eslint-module-utils/-/eslint-module-utils-2.5.2.tgz#7878f7504824e1b857dd2505b59a8e5eda26a708"
-  integrity sha512-LGScZ/JSlqGKiT8OC+cYRxseMjyqt6QO54nl281CK93unD89ijSeRV6An8Ci/2nvWVKe8K/Tqdm75RQoIOCr+Q==
+eslint-module-utils@^2.6.0:
+  version "2.6.0"
+  resolved "https://registry.yarnpkg.com/eslint-module-utils/-/eslint-module-utils-2.6.0.tgz#579ebd094f56af7797d19c9866c9c9486629bfa6"
+  integrity sha512-6j9xxegbqe8/kZY8cYpcp0xhbK0EgJlg3g9mib3/miLaExuuwc3n5UEfSnU6hWMbT0FAYVvDbL9RrRgpUeQIvA==
   dependencies:
     debug "^2.6.9"
     pkg-dir "^2.0.0"
@@ -3553,44 +3678,44 @@
     eslint-utils "^2.0.0"
     regexpp "^3.0.0"
 
-eslint-plugin-html@^6.0.0:
-  version "6.0.0"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-html/-/eslint-plugin-html-6.0.0.tgz#28e5c3e71e6f612e07e73d7c215e469766628c13"
-  integrity sha512-PQcGippOHS+HTbQCStmH5MY1BF2MaU8qW/+Mvo/8xTa/ioeMXdSP+IiaBw2+nh0KEMfYQKuTz1Zo+vHynjwhbg==
+eslint-plugin-html@^6.1.1:
+  version "6.1.1"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-html/-/eslint-plugin-html-6.1.1.tgz#95aee151900b9bb2da5fa017b45cc64456a0a74e"
+  integrity sha512-JSe3ZDb7feKMnQM27XWGeoIjvP4oWQMJD9GZ6wW67J7/plVL87NK72RBwlvfc3tTZiYUchHhxAwtgEd1GdofDA==
   dependencies:
-    htmlparser2 "^3.10.1"
+    htmlparser2 "^5.0.1"
 
-eslint-plugin-import@^2.20.1:
-  version "2.20.1"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.20.1.tgz#802423196dcb11d9ce8435a5fc02a6d3b46939b3"
-  integrity sha512-qQHgFOTjguR+LnYRoToeZWT62XM55MBVXObHM6SKFd1VzDcX/vqT1kAz8ssqigh5eMj8qXcRoXXGZpPP6RfdCw==
+eslint-plugin-import@^2.22.1:
+  version "2.22.1"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.22.1.tgz#0896c7e6a0cf44109a2d97b95903c2bb689d7702"
+  integrity sha512-8K7JjINHOpH64ozkAhpT3sd+FswIZTfMZTjdx052pnWrgRCVfp8op9tbjpAk3DdUeI/Ba4C8OjdC0r90erHEOw==
   dependencies:
-    array-includes "^3.0.3"
-    array.prototype.flat "^1.2.1"
+    array-includes "^3.1.1"
+    array.prototype.flat "^1.2.3"
     contains-path "^0.1.0"
     debug "^2.6.9"
     doctrine "1.5.0"
-    eslint-import-resolver-node "^0.3.2"
-    eslint-module-utils "^2.4.1"
+    eslint-import-resolver-node "^0.3.4"
+    eslint-module-utils "^2.6.0"
     has "^1.0.3"
     minimatch "^3.0.4"
-    object.values "^1.1.0"
+    object.values "^1.1.1"
     read-pkg-up "^2.0.0"
-    resolve "^1.12.0"
+    resolve "^1.17.0"
+    tsconfig-paths "^3.9.0"
 
-eslint-plugin-jsdoc@^19.2.0:
-  version "19.2.0"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-jsdoc/-/eslint-plugin-jsdoc-19.2.0.tgz#f522b970878ae402b28ce62187305b33dfe2c834"
-  integrity sha512-QdNifBFLXCDGdy+26RXxcrqzEZarFWNybCZQVqJQYEYPlxd6lm+LPkrs6mCOhaGc2wqC6zqpedBQFX8nQJuKSw==
+eslint-plugin-jsdoc@^30.7.9:
+  version "30.7.9"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-jsdoc/-/eslint-plugin-jsdoc-30.7.9.tgz#b0a9881990edc1bc8a635467bad9edfae9ecbaaf"
+  integrity sha512-qMM0fNx7/6OCnIh3jRpIrEBAhTG1THNXXbr3yfJ8yqLrDbzJR98xsstX25xt9GCPlrjNc/bBpTHfJQOvn7nVMA==
   dependencies:
-    comment-parser "^0.7.2"
-    debug "^4.1.1"
-    jsdoctypeparser "^6.1.0"
-    lodash "^4.17.15"
-    object.entries-ponyfill "^1.0.1"
-    regextras "^0.7.0"
-    semver "^6.3.0"
-    spdx-expression-parse "^3.0.0"
+    comment-parser "^0.7.6"
+    debug "^4.3.1"
+    jsdoctypeparser "^9.0.0"
+    lodash "^4.17.20"
+    regextras "^0.7.1"
+    semver "^7.3.4"
+    spdx-expression-parse "^3.0.1"
 
 eslint-plugin-node@^11.1.0:
   version "11.1.0"
@@ -3604,17 +3729,10 @@
     resolve "^1.10.1"
     semver "^6.1.0"
 
-eslint-plugin-prettier@^3.1.2:
-  version "3.1.4"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-prettier/-/eslint-plugin-prettier-3.1.4.tgz#168ab43154e2ea57db992a2cd097c828171f75c2"
-  integrity sha512-jZDa8z76klRqo+TdGDTFJSavwbnWK2ZpqGKNZ+VvweMW516pDUMmQ2koXvxEE4JhzNvTv+radye/bWGBmA6jmg==
-  dependencies:
-    prettier-linter-helpers "^1.0.0"
-
-eslint-plugin-prettier@^3.1.3:
-  version "3.1.3"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-prettier/-/eslint-plugin-prettier-3.1.3.tgz#ae116a0fc0e598fdae48743a4430903de5b4e6ca"
-  integrity sha512-+HG5jmu/dN3ZV3T6eCD7a4BlAySdN7mLIbJYo0z1cFQuI+r2DiTJEFeF68ots93PsnrMxbzIZ2S/ieX+mkrBeQ==
+eslint-plugin-prettier@^3.1.4, eslint-plugin-prettier@^3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-prettier/-/eslint-plugin-prettier-3.3.0.tgz#61e295349a65688ffac0b7808ef0a8244bdd8d40"
+  integrity sha512-tMTwO8iUWlSRZIwS9k7/E4vrTsfvsrcM5p1eftyuqWH25nKsz/o6/54I7jwQ/3zobISyC7wMy9ZsFwgTxOcOpQ==
   dependencies:
     prettier-linter-helpers "^1.0.0"
 
@@ -3626,14 +3744,15 @@
     esrecurse "^4.1.0"
     estraverse "^4.1.1"
 
-eslint-utils@^1.4.3:
-  version "1.4.3"
-  resolved "https://registry.yarnpkg.com/eslint-utils/-/eslint-utils-1.4.3.tgz#74fec7c54d0776b6f67e0251040b5806564e981f"
-  integrity sha512-fbBN5W2xdY45KulGXmLHZ3c3FHfVYmKg0IrAKGOkT/464PQsx2UeIzfz1RmEci+KLm1bBaAzZAh8+/E+XAeZ8Q==
+eslint-scope@^5.1.1:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/eslint-scope/-/eslint-scope-5.1.1.tgz#e786e59a66cb92b3f6c1fb0d508aab174848f48c"
+  integrity sha512-2NxwbF/hZ0KpepYN0cNbo+FN6XoK7GaHlQhgx/hIZl6Va0bF45RQOOwhLIy8lQDbuCiadSLCBnH2CFYquit5bw==
   dependencies:
-    eslint-visitor-keys "^1.1.0"
+    esrecurse "^4.3.0"
+    estraverse "^4.1.1"
 
-eslint-utils@^2.0.0:
+eslint-utils@^2.0.0, eslint-utils@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/eslint-utils/-/eslint-utils-2.1.0.tgz#d2de5e03424e707dc10c74068ddedae708741b27"
   integrity sha512-w94dQYoauyvlDc43XnGB8lU3Zt713vNChgt4EWwhXAP2XkBvndfxF0AgIqKOOasjPIPzj9JqgwkwbCYD0/V3Zg==
@@ -3645,46 +3764,56 @@
   resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-1.1.0.tgz#e2a82cea84ff246ad6fb57f9bde5b46621459ec2"
   integrity sha512-8y9YjtM1JBJU/A9Kc+SbaOV4y29sSWckBwMHa+FGtVj5gN/sbnKDf6xJUl+8g7FAij9LVaP8C24DUiH/f/2Z9A==
 
-eslint@^6.6.0, eslint@^6.8.0:
-  version "6.8.0"
-  resolved "https://registry.yarnpkg.com/eslint/-/eslint-6.8.0.tgz#62262d6729739f9275723824302fb227c8c93ffb"
-  integrity sha512-K+Iayyo2LtyYhDSYwz5D5QdWw0hCacNzyq1Y821Xna2xSJj7cijoLLYmLxTQgcgZ9mC61nryMy9S7GRbYpI5Ig==
+eslint-visitor-keys@^1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-1.3.0.tgz#30ebd1ef7c2fdff01c3a4f151044af25fab0523e"
+  integrity sha512-6J72N8UNa462wa/KFODt/PJ3IU60SDpC3QXC1Hjc1BXXpfL2C9R5+AU7jhe0F6GREqVMh4Juu+NY7xn+6dipUQ==
+
+eslint-visitor-keys@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-2.0.0.tgz#21fdc8fbcd9c795cc0321f0563702095751511a8"
+  integrity sha512-QudtT6av5WXels9WjIM7qz1XD1cWGvX4gGXvp/zBn9nXG02D0utdU3Em2m/QjTnrsk6bBjmCygl3rmj118msQQ==
+
+eslint@^7.10.0, eslint@^7.16.0:
+  version "7.16.0"
+  resolved "https://registry.yarnpkg.com/eslint/-/eslint-7.16.0.tgz#a761605bf9a7b32d24bb7cde59aeb0fd76f06092"
+  integrity sha512-iVWPS785RuDA4dWuhhgXTNrGxHHK3a8HLSMBgbbU59ruJDubUraXN8N5rn7kb8tG6sjg74eE0RA3YWT51eusEw==
   dependencies:
     "@babel/code-frame" "^7.0.0"
+    "@eslint/eslintrc" "^0.2.2"
     ajv "^6.10.0"
-    chalk "^2.1.0"
-    cross-spawn "^6.0.5"
+    chalk "^4.0.0"
+    cross-spawn "^7.0.2"
     debug "^4.0.1"
     doctrine "^3.0.0"
-    eslint-scope "^5.0.0"
-    eslint-utils "^1.4.3"
-    eslint-visitor-keys "^1.1.0"
-    espree "^6.1.2"
-    esquery "^1.0.1"
+    enquirer "^2.3.5"
+    eslint-scope "^5.1.1"
+    eslint-utils "^2.1.0"
+    eslint-visitor-keys "^2.0.0"
+    espree "^7.3.1"
+    esquery "^1.2.0"
     esutils "^2.0.2"
-    file-entry-cache "^5.0.1"
+    file-entry-cache "^6.0.0"
     functional-red-black-tree "^1.0.1"
     glob-parent "^5.0.0"
     globals "^12.1.0"
     ignore "^4.0.6"
     import-fresh "^3.0.0"
     imurmurhash "^0.1.4"
-    inquirer "^7.0.0"
     is-glob "^4.0.0"
     js-yaml "^3.13.1"
     json-stable-stringify-without-jsonify "^1.0.1"
-    levn "^0.3.0"
-    lodash "^4.17.14"
+    levn "^0.4.1"
+    lodash "^4.17.19"
     minimatch "^3.0.4"
-    mkdirp "^0.5.1"
     natural-compare "^1.4.0"
-    optionator "^0.8.3"
+    optionator "^0.9.1"
     progress "^2.0.0"
-    regexpp "^2.0.1"
-    semver "^6.1.2"
-    strip-ansi "^5.2.0"
-    strip-json-comments "^3.0.1"
-    table "^5.2.3"
+    regexpp "^3.1.0"
+    semver "^7.2.1"
+    strip-ansi "^6.0.0"
+    strip-json-comments "^3.1.0"
+    table "^6.0.4"
     text-table "^0.2.0"
     v8-compile-cache "^2.0.3"
 
@@ -3696,26 +3825,26 @@
     acorn "^5.5.0"
     acorn-jsx "^3.0.0"
 
-espree@^6.1.2:
-  version "6.1.2"
-  resolved "https://registry.yarnpkg.com/espree/-/espree-6.1.2.tgz#6c272650932b4f91c3714e5e7b5f5e2ecf47262d"
-  integrity sha512-2iUPuuPP+yW1PZaMSDM9eyVf8D5P0Hi8h83YtZ5bPc/zHYjII5khoixIUTMO794NOY8F/ThF1Bo8ncZILarUTA==
+espree@^7.3.0, espree@^7.3.1:
+  version "7.3.1"
+  resolved "https://registry.yarnpkg.com/espree/-/espree-7.3.1.tgz#f2df330b752c6f55019f8bd89b7660039c1bbbb6"
+  integrity sha512-v3JCNCE64umkFpmkFGqzVKsOT0tN1Zr+ueqLZfpV1Ob8e+CEgPWa+OxCoGH3tnhimMKIaBm4m/vaRpJ/krRz2g==
   dependencies:
-    acorn "^7.1.0"
-    acorn-jsx "^5.1.0"
-    eslint-visitor-keys "^1.1.0"
+    acorn "^7.4.0"
+    acorn-jsx "^5.3.1"
+    eslint-visitor-keys "^1.3.0"
 
 esprima@^4.0.0:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.1.tgz#13b04cdb3e6c5d19df91ab6987a8695619b0aa71"
   integrity sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A==
 
-esquery@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.yarnpkg.com/esquery/-/esquery-1.0.1.tgz#406c51658b1f5991a5f9b62b1dc25b00e3e5c708"
-  integrity sha512-SmiyZ5zIWH9VM+SRUReLS5Q8a7GxtRdxEBVZpm98rJM7Sb+A9DVCndXfkeFUd3byderg+EbDkfnevfCwynWaNA==
+esquery@^1.2.0:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/esquery/-/esquery-1.3.1.tgz#b78b5828aa8e214e29fb74c4d5b752e1c033da57"
+  integrity sha512-olpvt9QG0vniUBZspVRN6lwB7hOZoTRtT+jzR+tS4ffYx2mzbw+z0XCOk44aaLYKApNX5nMm+E+P6o25ip/DHQ==
   dependencies:
-    estraverse "^4.0.0"
+    estraverse "^5.1.0"
 
 esrecurse@^4.1.0:
   version "4.2.1"
@@ -3724,11 +3853,23 @@
   dependencies:
     estraverse "^4.1.0"
 
-estraverse@^4.0.0, estraverse@^4.1.0, estraverse@^4.1.1:
+esrecurse@^4.3.0:
+  version "4.3.0"
+  resolved "https://registry.yarnpkg.com/esrecurse/-/esrecurse-4.3.0.tgz#7ad7964d679abb28bee72cec63758b1c5d2c9921"
+  integrity sha512-KmfKL3b6G+RXvP8N1vr3Tq1kL/oCFgn2NYXEtqP8/L3pKapUA4G8cFVaoF3SU323CD4XypR/ffioHmkti6/Tag==
+  dependencies:
+    estraverse "^5.2.0"
+
+estraverse@^4.1.0, estraverse@^4.1.1:
   version "4.3.0"
   resolved "https://registry.yarnpkg.com/estraverse/-/estraverse-4.3.0.tgz#398ad3f3c5a24948be7725e83d11a7de28cdbd1d"
   integrity sha512-39nnKffWz8xN1BU/2c79n9nB9HDzo0niYUqx6xyqUnyoAnQyyWpOTdZEeiCch8BBu515t4wp9ZmgVfVhn9EBpw==
 
+estraverse@^5.1.0, estraverse@^5.2.0:
+  version "5.2.0"
+  resolved "https://registry.yarnpkg.com/estraverse/-/estraverse-5.2.0.tgz#307df42547e6cc7324d3cf03c155d5cdb8c53880"
+  integrity sha512-BxbNGGNm0RyRYvUdHpIwv9IWzeM9XClbOxwoATuFdOE7ZE6wHL+HQ5T8hoPM+zHvmKzzsEqhgy0GrQ5X13afiQ==
+
 esutils@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/esutils/-/esutils-2.0.2.tgz#0abf4f1caa5bcb1f7a9d8acc6dea4faaa04bac9b"
@@ -3770,19 +3911,19 @@
     signal-exit "^3.0.0"
     strip-eof "^1.0.0"
 
-execa@^4.0.0:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/execa/-/execa-4.0.2.tgz#ad87fb7b2d9d564f70d2b62d511bee41d5cbb240"
-  integrity sha512-QI2zLa6CjGWdiQsmSkZoGtDx2N+cQIGb3yNolGTdjSQzydzLgYYf8LRuagp7S7fPimjcrzUDSUFd/MgzELMi4Q==
+execa@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/execa/-/execa-5.0.0.tgz#4029b0007998a841fbd1032e5f4de86a3c1e3376"
+  integrity sha512-ov6w/2LCiuyO4RLYGdpFGjkcs0wMTgGE8PrkTHikeUy5iJekXyPIKUjifk5CsE0pt7sMCrMZ3YNqoCj6idQOnQ==
   dependencies:
-    cross-spawn "^7.0.0"
-    get-stream "^5.0.0"
-    human-signals "^1.1.1"
+    cross-spawn "^7.0.3"
+    get-stream "^6.0.0"
+    human-signals "^2.1.0"
     is-stream "^2.0.0"
     merge-stream "^2.0.0"
-    npm-run-path "^4.0.0"
-    onetime "^5.1.0"
-    signal-exit "^3.0.2"
+    npm-run-path "^4.0.1"
+    onetime "^5.1.2"
+    signal-exit "^3.0.3"
     strip-final-newline "^2.0.0"
 
 exit-hook@^1.0.0:
@@ -3953,6 +4094,11 @@
   resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-2.0.1.tgz#7b05218ddf9667bf7f370bf7fdb2cb15fdd0aa49"
   integrity sha1-ewUhjd+WZ79/Nwv3/bLLFf3Qqkk=
 
+fast-deep-equal@^3.1.1:
+  version "3.1.3"
+  resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz#3a7d56b559d6cbc3eb512325244e619a65c6c525"
+  integrity sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==
+
 fast-diff@^1.1.2:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/fast-diff/-/fast-diff-1.2.0.tgz#73ee11982d86caaf7959828d519cfe927fac5f03"
@@ -3970,12 +4116,24 @@
     merge2 "^1.2.3"
     micromatch "^3.1.10"
 
+fast-glob@^3.1.1:
+  version "3.2.4"
+  resolved "https://registry.yarnpkg.com/fast-glob/-/fast-glob-3.2.4.tgz#d20aefbf99579383e7f3cc66529158c9b98554d3"
+  integrity sha512-kr/Oo6PX51265qeuCYsyGypiO5uJFgBS0jksyG7FUeCyQzNwYnzrNIMR1NXfkZXsMYXYLRAHgISHBz8gQcxKHQ==
+  dependencies:
+    "@nodelib/fs.stat" "^2.0.2"
+    "@nodelib/fs.walk" "^1.2.3"
+    glob-parent "^5.1.0"
+    merge2 "^1.3.0"
+    micromatch "^4.0.2"
+    picomatch "^2.2.1"
+
 fast-json-stable-stringify@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/fast-json-stable-stringify/-/fast-json-stable-stringify-2.0.0.tgz#d5142c0caee6b1189f87d3a76111064f86c8bbf2"
   integrity sha1-1RQsDK7msRifh9OnYREGT4bIu/I=
 
-fast-levenshtein@^2.0.6, fast-levenshtein@~2.0.6:
+fast-levenshtein@^2.0.6:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/fast-levenshtein/-/fast-levenshtein-2.0.6.tgz#3d8a5c66883a16a30ca8643e851f19baa7797917"
   integrity sha1-PYpcZog6FqMMqGQ+hR8Zuqd5eRc=
@@ -3985,6 +4143,13 @@
   resolved "https://registry.yarnpkg.com/fast-safe-stringify/-/fast-safe-stringify-2.0.6.tgz#04b26106cc56681f51a044cfc0d76cf0008ac2c2"
   integrity sha512-q8BZ89jjc+mz08rSxROs8VsrBBcn1SIw1kq9NjolL509tkABRk9io01RAjSaEv1Xb2uFLt8VtRiZbGp5H8iDtg==
 
+fastq@^1.6.0:
+  version "1.10.0"
+  resolved "https://registry.yarnpkg.com/fastq/-/fastq-1.10.0.tgz#74dbefccade964932cdf500473ef302719c652bb"
+  integrity sha512-NL2Qc5L3iQEsyYzweq7qfgy5OtXCmGzGvhElGEd/SoFWEMOEczNh5s5ocaF01HDetxz+p8ecjNPA6cZxxIHmzA==
+  dependencies:
+    reusify "^1.0.4"
+
 fd-slicer@~1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/fd-slicer/-/fd-slicer-1.1.0.tgz#25c7c89cb1f9077f8891bbe61d8f390eae256f1e"
@@ -4013,18 +4178,18 @@
     escape-string-regexp "^1.0.5"
 
 figures@^3.0.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/figures/-/figures-3.1.0.tgz#4b198dd07d8d71530642864af2d45dd9e459c4ec"
-  integrity sha512-ravh8VRXqHuMvZt/d8GblBeqDMkdJMBdv/2KntFH+ra5MXkO7nxNKpzQ3n6QD/2da1kH0aWmNISdvhM7gl2gVg==
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/figures/-/figures-3.2.0.tgz#625c18bd293c604dc4a8ddb2febf0c88341746af"
+  integrity sha512-yaduQFRKLXYOGgEn6AZau90j3ggSOyiqXU0F9JZfeXYhNa+Jk4X+s45A2zg5jns87GAFa34BBm2kXw4XpNcbdg==
   dependencies:
     escape-string-regexp "^1.0.5"
 
-file-entry-cache@^5.0.1:
-  version "5.0.1"
-  resolved "https://registry.yarnpkg.com/file-entry-cache/-/file-entry-cache-5.0.1.tgz#ca0f6efa6dd3d561333fb14515065c2fafdf439c"
-  integrity sha512-bCg29ictuBaKUwwArK4ouCaqDgLZcysCFLmM/Yn/FDoqndh/9vNuQfXRDvTuXKLxfD/JtZQGKFT8MGcJBK644g==
+file-entry-cache@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/file-entry-cache/-/file-entry-cache-6.0.0.tgz#7921a89c391c6d93efec2169ac6bf300c527ea0a"
+  integrity sha512-fqoO76jZ3ZnYrXLDRxBR1YvOvc0k844kcOg40bgsPrE25LAb/PDqTY+ho64Xh2c8ZXgIKldchCFHczG2UVRcWA==
   dependencies:
-    flat-cache "^2.0.1"
+    flat-cache "^3.0.4"
 
 filename-regex@^2.0.0:
   version "2.0.1"
@@ -4052,6 +4217,13 @@
     repeat-string "^1.6.1"
     to-regex-range "^2.1.0"
 
+fill-range@^7.0.1:
+  version "7.0.1"
+  resolved "https://registry.yarnpkg.com/fill-range/-/fill-range-7.0.1.tgz#1919a6a7c75fe38b2c7c77e5198535da9acdda40"
+  integrity sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==
+  dependencies:
+    to-regex-range "^5.0.1"
+
 filled-array@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/filled-array/-/filled-array-1.1.0.tgz#c3c4f6c663b923459a9aa29912d2d031f1507f84"
@@ -4146,19 +4318,18 @@
   dependencies:
     readable-stream "^2.0.2"
 
-flat-cache@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/flat-cache/-/flat-cache-2.0.1.tgz#5d296d6f04bda44a4630a301413bdbc2ec085ec0"
-  integrity sha512-LoQe6yDuUMDzQAEH8sgmh4Md6oZnc/7PjtwjNFSzveXqSHt6ka9fPBuso7IGf9Rz4uqnSnWiFH2B/zj24a5ReA==
+flat-cache@^3.0.4:
+  version "3.0.4"
+  resolved "https://registry.yarnpkg.com/flat-cache/-/flat-cache-3.0.4.tgz#61b0338302b2fe9f957dcc32fc2a87f1c3048b11"
+  integrity sha512-dm9s5Pw7Jc0GvMYbshN6zchCA9RgQlzzEZX3vylR9IqFfS8XciblUXOKfW6SiuJ0e13eDYZoZV5wdrev7P3Nwg==
   dependencies:
-    flatted "^2.0.0"
-    rimraf "2.6.3"
-    write "1.0.3"
+    flatted "^3.1.0"
+    rimraf "^3.0.2"
 
-flatted@^2.0.0:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/flatted/-/flatted-2.0.1.tgz#69e57caa8f0eacbc281d2e2cb458d46fdb449e08"
-  integrity sha512-a1hQMktqW9Nmqr5aktAux3JMNqaucxGcjtjWnZLHX7yyPCmlSV3M54nGYbqT8K+0GhF3NBgmJCc3ma+WOgX8Jg==
+flatted@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.1.0.tgz#a5d06b4a8b01e3a63771daa5cb7a1903e2e57067"
+  integrity sha512-tW+UkmtNg/jv9CSofAKvgVcO7c2URjhTdW1ZTkcAritblu8tajiYy7YisnIflEwtKssCtOxpnBRoCB7iap0/TA==
 
 follow-redirects@^1.0.0:
   version "1.9.0"
@@ -4257,6 +4428,11 @@
     nan "^2.12.1"
     node-pre-gyp "^0.12.0"
 
+fsevents@~2.1.2:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.1.3.tgz#fb738703ae8d2f9fe900c33836ddebee8b97f23e"
+  integrity sha512-Auw9a4AxqWpa9GUfj370BMPzzyncfBABW8Mab7BGWBYDj4Isgq+cDKtx0i6u9jcX9pQDnswsaaOTgTmA5pEjuQ==
+
 function-bind@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
@@ -4281,6 +4457,15 @@
     strip-ansi "^3.0.1"
     wide-align "^1.1.0"
 
+get-intrinsic@^1.0.0, get-intrinsic@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/get-intrinsic/-/get-intrinsic-1.0.2.tgz#6820da226e50b24894e08859469dc68361545d49"
+  integrity sha512-aeX0vrFm21ILl3+JpFFRNe9aUvp6VFZb2/CTbgLb8j75kOhvoNYjt9d8KA/tJG4gSo8nzEDedRl0h7vDmBYRVg==
+  dependencies:
+    function-bind "^1.1.1"
+    has "^1.0.3"
+    has-symbols "^1.0.1"
+
 get-stdin@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/get-stdin/-/get-stdin-4.0.1.tgz#b968c6b0a04384324902e8bf1a5df32579a450fe"
@@ -4303,13 +4488,18 @@
   dependencies:
     pump "^3.0.0"
 
-get-stream@^5.0.0, get-stream@^5.1.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-5.1.0.tgz#01203cdc92597f9b909067c3e656cc1f4d3c4dc9"
-  integrity sha512-EXr1FOzrzTfGeL0gQdeFEvOMm2mzMOglyiOXSTpPC+iAjAKftbr3jpCMWynogwYnM+eSj9sHGc6wjIcDvYiygw==
+get-stream@^5.1.0:
+  version "5.2.0"
+  resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-5.2.0.tgz#4966a1795ee5ace65e706c4b7beb71257d6e22d3"
+  integrity sha512-nBF+F1rAZVCu/p7rjzgA+Yb4lfYXrpl7a6VmJrU8wF9I1CKvP/QwPNZHnOlwbTkY6dvtFIzFMSyQXbLoTQPRpA==
   dependencies:
     pump "^3.0.0"
 
+get-stream@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-6.0.0.tgz#3e0012cb6827319da2706e601a1583e8629a6718"
+  integrity sha512-A1B3Bh1UmL0bidM/YX2NsCOTnGJePL9rO/M+Mw3m9f2gUpfokS0hi5Eah0WSUEWZdZhIZtMjkIYS7mDfOqNHbg==
+
 get-value@^2.0.3, get-value@^2.0.6:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/get-value/-/get-value-2.0.6.tgz#dc15ca1c672387ca76bd37ac0a395ba2042a2c28"
@@ -4367,6 +4557,13 @@
   dependencies:
     is-glob "^4.0.1"
 
+glob-parent@^5.1.0:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.1.1.tgz#b6c1ef417c4e5663ea498f1c45afac6916bbc229"
+  integrity sha512-FnI+VGOpnlGHWZxthPGR+QhR78fuiK0sNLkHQv+bL9fQi57lNNdquIbna/WrfROrolq8GK5Ek6BiMwqL/voRYQ==
+  dependencies:
+    is-glob "^4.0.1"
+
 glob-stream@^5.3.2:
   version "5.3.5"
   resolved "https://registry.yarnpkg.com/glob-stream/-/glob-stream-5.3.5.tgz#a55665a9a8ccdc41915a87c701e32d4e016fad22"
@@ -4420,7 +4617,7 @@
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
-glob@^7.1.3, glob@^7.1.4, glob@^7.1.6:
+glob@^7.1.3, glob@^7.1.4:
   version "7.1.6"
   resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.6.tgz#141f33b81a7c2492e125594307480c46679278a6"
   integrity sha512-LwaxwyZ72Lk7vZINtNNrywX0ZuLyStrdDtabefZKAY5ZGJhVtgdznluResxNmPitE0SAO+O26sWTHeKSI2wMBA==
@@ -4440,11 +4637,11 @@
     ini "^1.3.4"
 
 global-dirs@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/global-dirs/-/global-dirs-2.0.1.tgz#acdf3bb6685bcd55cb35e8a052266569e9469201"
-  integrity sha512-5HqUqdhkEovj2Of/ms3IeS/EekcO54ytHRLV4PEY2rhRwrHXLQjeVEES0Lhka0xwNDtGYn58wyC4s5+MHsOO6A==
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/global-dirs/-/global-dirs-2.1.0.tgz#e9046a49c806ff04d6c1825e196c8f0091e8df4d"
+  integrity sha512-MG6kdOUh/xBnyo9cJFeIKkLEc1AyFq42QTU4XiX51i2NEdxLxLWXIjEjmqKeSuKR7pAZjTqUVoT2b2huxVLgYQ==
   dependencies:
-    ini "^1.3.5"
+    ini "1.3.7"
 
 global-modules@^0.2.3:
   version "0.2.3"
@@ -4501,6 +4698,18 @@
   resolved "https://registry.yarnpkg.com/globals/-/globals-9.18.0.tgz#aa3896b3e69b487f17e31ed2143d69a8e30c2d8a"
   integrity sha512-S0nG3CLEQiY/ILxqtztTWH/3iRRdyBLw6KMDxnKMchrtbj2OFmehVh0WUCfW3DUrIgx/qFrJPICrq4Z4sTR9UQ==
 
+globby@^11.0.1:
+  version "11.0.1"
+  resolved "https://registry.yarnpkg.com/globby/-/globby-11.0.1.tgz#9a2bf107a068f3ffeabc49ad702c79ede8cfd357"
+  integrity sha512-iH9RmgwCmUJHi2z5o2l3eTtGBtXek1OYlHrbcxOYugyHLmAsZrPj43OtHThd62Buh/Vv6VyCBD2bdyWcGNQqoQ==
+  dependencies:
+    array-union "^2.1.0"
+    dir-glob "^3.0.1"
+    fast-glob "^3.1.1"
+    ignore "^5.1.4"
+    merge2 "^1.3.0"
+    slash "^3.0.0"
+
 globby@^4.0.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/globby/-/globby-4.1.0.tgz#080f54549ec1b82a6c60e631fc82e1211dbe95f8"
@@ -4629,25 +4838,25 @@
   dependencies:
     lodash "^4.17.2"
 
-gts@^2.0.2:
-  version "2.0.2"
-  resolved "https://registry.yarnpkg.com/gts/-/gts-2.0.2.tgz#b8b28de99361b5c5c24db30a375a0f546bbc04a4"
-  integrity sha512-SLytzl2IqKXf6kGULwr07XQ9lVsvjrzFD3OAA7DEfIQYuD+lKBPt/cZ/RYGxaWerY4PTfmnXT7KdxEr9Ec8uHQ==
+gts@^3.0.3:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/gts/-/gts-3.0.3.tgz#36716d87680c2d1a0e02867c91bb7169cede9369"
+  integrity sha512-XHFGhDzoyaHDVHlhNfz369erxuSEIyVMtJoRAz8Dt2NpidG5pOJzI/44lWhsLVigph64TgAWPWBsBTQFCQ1mTw==
   dependencies:
-    "@typescript-eslint/eslint-plugin" "2.31.0"
-    "@typescript-eslint/parser" "2.31.0"
-    chalk "^4.0.0"
-    eslint "^6.8.0"
-    eslint-config-prettier "^6.10.1"
+    "@typescript-eslint/eslint-plugin" "^4.2.0"
+    "@typescript-eslint/parser" "^4.2.0"
+    chalk "^4.1.0"
+    eslint "^7.10.0"
+    eslint-config-prettier "^6.12.0"
     eslint-plugin-node "^11.1.0"
-    eslint-plugin-prettier "^3.1.2"
-    execa "^4.0.0"
-    inquirer "^7.1.0"
-    meow "^7.0.0"
+    eslint-plugin-prettier "^3.1.4"
+    execa "^5.0.0"
+    inquirer "^7.3.3"
+    meow "^8.0.0"
     ncp "^2.0.0"
-    prettier "^2.0.4"
+    prettier "^2.1.2"
     rimraf "^3.0.2"
-    update-notifier "^4.1.0"
+    update-notifier "^5.0.0"
     write-file-atomic "^3.0.3"
 
 gulp-if@^2.0.2:
@@ -4833,6 +5042,13 @@
   resolved "https://registry.yarnpkg.com/hosted-git-info/-/hosted-git-info-2.7.1.tgz#97f236977bd6e125408930ff6de3eec6281ec047"
   integrity sha512-7T/BxH19zbcCTa8XkMlbK5lTo1WtgkFi3GvdWEyNuc4Vex7/9Dqbnpsf4JMydcfj9HCg4zUWFTL3Za6lapg5/w==
 
+hosted-git-info@^3.0.6:
+  version "3.0.7"
+  resolved "https://registry.yarnpkg.com/hosted-git-info/-/hosted-git-info-3.0.7.tgz#a30727385ea85acfcee94e0aad9e368c792e036c"
+  integrity sha512-fWqc0IcuXs+BmE9orLDyVykAG9GJtGLGuZAAqgcckPgv5xad4AcXGIv8galtQvlwutxSlaMcdw7BUtq2EIvqCQ==
+  dependencies:
+    lru-cache "^6.0.0"
+
 hpack.js@^2.1.6:
   version "2.1.6"
   resolved "https://registry.yarnpkg.com/hpack.js/-/hpack.js-2.1.6.tgz#87774c0949e513f42e84575b3c45681fade2a0b2"
@@ -4856,17 +5072,15 @@
     relateurl "0.2.x"
     uglify-js "3.4.x"
 
-htmlparser2@^3.10.1:
-  version "3.10.1"
-  resolved "https://registry.yarnpkg.com/htmlparser2/-/htmlparser2-3.10.1.tgz#bd679dc3f59897b6a34bb10749c855bb53a9392f"
-  integrity sha512-IgieNijUMbkDovyoKObU1DUhm1iwNYE/fuifEoEHfd1oZKZDaONBSkal7Y01shxsM49R4XaMdGez3WnF9UfiCQ==
+htmlparser2@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/htmlparser2/-/htmlparser2-5.0.1.tgz#7daa6fc3e35d6107ac95a4fc08781f091664f6e7"
+  integrity sha512-vKZZra6CSe9qsJzh0BjBGXo8dvzNsq/oGvsjfRdOrrryfeD9UOBEEQdeoqCRmKZchF5h2zOBMQ6YuQ0uRUmdbQ==
   dependencies:
-    domelementtype "^1.3.1"
-    domhandler "^2.3.0"
-    domutils "^1.5.1"
-    entities "^1.1.1"
-    inherits "^2.0.1"
-    readable-stream "^3.1.1"
+    domelementtype "^2.0.1"
+    domhandler "^3.3.0"
+    domutils "^2.4.2"
+    entities "^2.0.0"
 
 http-cache-semantics@^4.0.0:
   version "4.1.0"
@@ -4943,10 +5157,10 @@
     agent-base "^4.3.0"
     debug "^3.1.0"
 
-human-signals@^1.1.1:
-  version "1.1.1"
-  resolved "https://registry.yarnpkg.com/human-signals/-/human-signals-1.1.1.tgz#c5b1cd14f50aeae09ab6c59fe63ba3395fe4dfa3"
-  integrity sha512-SEQu7vl8KjNL2eoGBLF3+wAjpsNfA9XMlXAYj/3EdaNfAlxKthD1xjEQfGOUhllCGGJVNY34bRr6lPINhNjyZw==
+human-signals@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/human-signals/-/human-signals-2.1.0.tgz#dc91fcba42e4d06e4abaed33b3e7a3c02f514ea0"
+  integrity sha512-B4FFZ6q/T2jhhksgkbEW3HBvWIfDW85snkQgawt07S7J5QXTk6BkNV+0yAeZrM5QpMAdYlocGoljn0sJ/WQkFw==
 
 iconv-lite@0.4.24, iconv-lite@^0.4.24, iconv-lite@^0.4.4:
   version "0.4.24"
@@ -4977,7 +5191,7 @@
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-4.0.6.tgz#750e3db5862087b4737ebac8207ffd1ef27b25fc"
   integrity sha512-cyFDKrqc/YdcWFniJhzI42+AzS+gNwmUzOSFcRCQYwySuBBBy/KjuxWLZ/FHEH6Moq1NizMOBWyTcv8O4OZIMg==
 
-ignore@^5.1.1:
+ignore@^5.1.1, ignore@^5.1.4:
   version "5.1.8"
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-5.1.8.tgz#f150a8b50a34289b33e22f5889abd4d8016f0e57"
   integrity sha512-BMpfD7PpiETpBl/A6S498BaIJ6Y/ABT93ETbby2fP00v4EbvPBXWEoaR1UBPKs3iR53pJY7EtZk5KACI57i1Uw==
@@ -4990,6 +5204,14 @@
     parent-module "^1.0.0"
     resolve-from "^4.0.0"
 
+import-fresh@^3.2.1:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/import-fresh/-/import-fresh-3.3.0.tgz#37162c25fcb9ebaa2e6e53d5b4d88ce17d9e0c2b"
+  integrity sha512-veYYhQa+D1QBKznvhUHxb8faxlrwUnxseDAbAp457E0wLNio2bOSKnjYDhMj+YiAq61xrMGhQk9iXVk5FzgQMw==
+  dependencies:
+    parent-module "^1.0.0"
+    resolve-from "^4.0.0"
+
 import-lazy@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/import-lazy/-/import-lazy-2.1.0.tgz#05698e3d45c88e8d7e9d92cb0584e77f096f3e43"
@@ -5040,7 +5262,12 @@
   resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.3.tgz#633c2c83e3da42a502f52466022480f4208261de"
   integrity sha1-Yzwsg+PaQqUC9SRmAiSA9CCCYd4=
 
-ini@^1.3.4, ini@^1.3.5, ini@~1.3.0:
+ini@1.3.7:
+  version "1.3.7"
+  resolved "https://registry.yarnpkg.com/ini/-/ini-1.3.7.tgz#a09363e1911972ea16d7a8851005d84cf09a9a84"
+  integrity sha512-iKpRpXP+CrP2jyrxvg1kMUpXDyRUFDWurxbnVT1vQPx+Wz9uCYsMIqYuSBLV+PAaZG/d7kRLKRFc9oDMsH+mFQ==
+
+ini@^1.3.4, ini@~1.3.0:
   version "1.3.5"
   resolved "https://registry.yarnpkg.com/ini/-/ini-1.3.5.tgz#eee25f56db1c9ec6085e0c22778083f596abf927"
   integrity sha512-RZY5huIKCMRWDUqZlEi72f/lmXKMvuszcMBduliQ3nnWbx9X/ZBQO7DijMEYS9EhHBb2qacRUMtC7svLwe0lcw==
@@ -5084,40 +5311,21 @@
     strip-ansi "^5.1.0"
     through "^2.3.6"
 
-inquirer@^7.0.0:
-  version "7.0.3"
-  resolved "https://registry.yarnpkg.com/inquirer/-/inquirer-7.0.3.tgz#f9b4cd2dff58b9f73e8d43759436ace15bed4567"
-  integrity sha512-+OiOVeVydu4hnCGLCSX+wedovR/Yzskv9BFqUNNKq9uU2qg7LCcCo3R86S2E7WLo0y/x2pnEZfZe1CoYnORUAw==
+inquirer@^7.3.3:
+  version "7.3.3"
+  resolved "https://registry.yarnpkg.com/inquirer/-/inquirer-7.3.3.tgz#04d176b2af04afc157a83fd7c100e98ee0aad003"
+  integrity sha512-JG3eIAj5V9CwcGvuOmoo6LB9kbAYT8HXffUl6memuszlwDC/qvFAJw49XJ5NROSFNPxp3iQg1GqkFhaY/CR0IA==
   dependencies:
     ansi-escapes "^4.2.1"
-    chalk "^2.4.2"
+    chalk "^4.1.0"
     cli-cursor "^3.1.0"
-    cli-width "^2.0.0"
+    cli-width "^3.0.0"
     external-editor "^3.0.3"
     figures "^3.0.0"
-    lodash "^4.17.15"
-    mute-stream "0.0.8"
-    run-async "^2.2.0"
-    rxjs "^6.5.3"
-    string-width "^4.1.0"
-    strip-ansi "^5.1.0"
-    through "^2.3.6"
-
-inquirer@^7.1.0:
-  version "7.2.0"
-  resolved "https://registry.yarnpkg.com/inquirer/-/inquirer-7.2.0.tgz#63ce99d823090de7eb420e4bb05e6f3449aa389a"
-  integrity sha512-E0c4rPwr9ByePfNlTIB8z51kK1s2n6jrHuJeEHENl/sbq2G/S1auvibgEwNR4uSyiU+PiYHqSwsgGiXjG8p5ZQ==
-  dependencies:
-    ansi-escapes "^4.2.1"
-    chalk "^3.0.0"
-    cli-cursor "^3.1.0"
-    cli-width "^2.0.0"
-    external-editor "^3.0.3"
-    figures "^3.0.0"
-    lodash "^4.17.15"
+    lodash "^4.17.19"
     mute-stream "0.0.8"
     run-async "^2.4.0"
-    rxjs "^6.5.3"
+    rxjs "^6.6.0"
     string-width "^4.1.0"
     strip-ansi "^6.0.0"
     through "^2.3.6"
@@ -5180,10 +5388,10 @@
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.6.tgz#efaa2ea9daa0d7ab2ea13a97b2b8ad51fefbe8be"
   integrity sha512-NcdALwpXkTm5Zvvbk7owOUSvVvBKDgKP5/ewfXEznmQFfs4ZRmanOeKBTjRVjka3QFoN6XJ+9F3USqfHqTaU5w==
 
-is-callable@^1.1.4, is-callable@^1.1.5:
-  version "1.1.5"
-  resolved "https://registry.yarnpkg.com/is-callable/-/is-callable-1.1.5.tgz#f7e46b596890456db74e7f6e976cb3273d06faab"
-  integrity sha512-ESKv5sMCJB2jnHTWZ3O5itG+O128Hsus4K4Qh1h2/cgn2vbgnLSVqfV46AeJA9D5EeeLa9w81KUXMtn34zhX+Q==
+is-callable@^1.1.4, is-callable@^1.2.2:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/is-callable/-/is-callable-1.2.2.tgz#c7c6715cd22d4ddb48d3e19970223aceabb080d9"
+  integrity sha512-dnMqspv5nU3LoewK2N/y7KLtxtakvTuaCsU9FU50/QDmdbHNy/4/JuRtMHqRU22o3q+W89YQndQEeCVwK+3qrA==
 
 is-ci@^1.0.10:
   version "1.2.1"
@@ -5199,6 +5407,13 @@
   dependencies:
     ci-info "^2.0.0"
 
+is-core-module@^2.1.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/is-core-module/-/is-core-module-2.2.0.tgz#97037ef3d52224d85163f5597b2b63d9afed981a"
+  integrity sha512-XRAfAdyyY5F5cOXn7hYQDqh2Xmii+DEfIcQGxK/uNwMHhIkPWO0g8msXcbzLe+MpGoR951MlqM/2iIlU4vKDdQ==
+  dependencies:
+    has "^1.0.3"
+
 is-data-descriptor@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/is-data-descriptor/-/is-data-descriptor-0.1.4.tgz#0b5ee648388e2c860282e793f1856fec3f301b56"
@@ -5333,7 +5548,7 @@
     global-dirs "^0.1.0"
     is-path-inside "^1.0.0"
 
-is-installed-globally@^0.3.1:
+is-installed-globally@^0.3.2:
   version "0.3.2"
   resolved "https://registry.yarnpkg.com/is-installed-globally/-/is-installed-globally-0.3.2.tgz#fd3efa79ee670d1187233182d5b0a1dd00313141"
   integrity sha512-wZ8x1js7Ia0kecP/CHM/3ABkAmujX7WPvQk6uu3Fly/Mk44pySulQpnHG46OMjHGXApINnV4QhY3SWnECO2z5g==
@@ -5341,15 +5556,20 @@
     global-dirs "^2.0.1"
     is-path-inside "^3.0.1"
 
+is-negative-zero@^2.0.0:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/is-negative-zero/-/is-negative-zero-2.0.1.tgz#3de746c18dda2319241a53675908d8f766f11c24"
+  integrity sha512-2z6JzQvZRa9A2Y7xC6dQQm4FSTSTNWjKIYYTt4246eMTJmIo0Q+ZyOsU66X8lxK1AbB92dFeglPLrhwpeRKO6w==
+
 is-npm@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/is-npm/-/is-npm-1.0.0.tgz#f2fb63a65e4905b406c86072765a1a4dc793b9f4"
   integrity sha1-8vtjpl5JBbQGyGBydloaTceTufQ=
 
-is-npm@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/is-npm/-/is-npm-4.0.0.tgz#c90dd8380696df87a7a6d823c20d0b12bbe3c84d"
-  integrity sha512-96ECIfh9xtDDlPylNPXhzjsykHsMJZ18ASpaWzQyBr4YRTcVjUvzaHayDAES2oU/3KpljhHUjtSRNiDwi0F0ig==
+is-npm@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/is-npm/-/is-npm-5.0.0.tgz#43e8d65cc56e1b67f8d47262cf667099193f45a8"
+  integrity sha512-WW/rQLOazUq+ST/bCAVBp/2oMERWLsR7OrKyt052dNDk4DHcDE0/7QSXITlmi+VBcV13DfIbysG3tZJm5RfdBA==
 
 is-number@^2.1.0:
   version "2.1.0"
@@ -5370,6 +5590,11 @@
   resolved "https://registry.yarnpkg.com/is-number/-/is-number-4.0.0.tgz#0026e37f5454d73e356dfe6564699867c6a7f0ff"
   integrity sha512-rSklcAIlf1OmFdyAqbnWTLVelsQ58uvZ66S/ZyawjWqIviTWCjg2PzVGw8WUA+nNuPTqb4wgA+NszrJ+08LlgQ==
 
+is-number@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
+  integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
+
 is-obj@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/is-obj/-/is-obj-1.0.1.tgz#3e4729ac1f5fde025cd7d83a896dab9f4f67db0f"
@@ -5453,12 +5678,12 @@
   resolved "https://registry.yarnpkg.com/is-redirect/-/is-redirect-1.0.0.tgz#1d03dded53bd8db0f30c26e4f95d36fc7c87dc24"
   integrity sha1-HQPd7VO9jbDzDCbk+V02/HyH3CQ=
 
-is-regex@^1.0.5:
-  version "1.0.5"
-  resolved "https://registry.yarnpkg.com/is-regex/-/is-regex-1.0.5.tgz#39d589a358bf18967f726967120b8fc1aed74eae"
-  integrity sha512-vlKW17SNq44owv5AQR3Cq0bQPEb8+kF3UKZ2fiZNOWtztYE5i0CzCZxFDwO58qAOWtxdBRVO/V5Qin1wjCqFYQ==
+is-regex@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/is-regex/-/is-regex-1.1.1.tgz#c6f98aacc546f6cec5468a07b7b153ab564a57b9"
+  integrity sha512-1+QkEcxiLlB7VEyFtyBg94e08OAsvq7FUBgApTq/w2ymCLyKJgDPsybBENVtA7XCQEgEXxKPonG+mvYRxh/LIg==
   dependencies:
-    has "^1.0.3"
+    has-symbols "^1.0.1"
 
 is-retry-allowed@^1.0.0:
   version "1.1.0"
@@ -5613,10 +5838,10 @@
   resolved "https://registry.yarnpkg.com/jsbn/-/jsbn-0.1.1.tgz#a5e654c2e5a2deb5f201d96cefbca80c0ef2f513"
   integrity sha1-peZUwuWi3rXyAdls77yoDA7y9RM=
 
-jsdoctypeparser@^6.1.0:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/jsdoctypeparser/-/jsdoctypeparser-6.1.0.tgz#acfb936c26300d98f1405cb03e20b06748e512a8"
-  integrity sha512-UCQBZ3xCUBv/PLfwKAJhp6jmGOSLFNKzrotXGNgbKhWvz27wPsCsVeP7gIcHPElQw2agBmynAitXqhxR58XAmA==
+jsdoctypeparser@^9.0.0:
+  version "9.0.0"
+  resolved "https://registry.yarnpkg.com/jsdoctypeparser/-/jsdoctypeparser-9.0.0.tgz#8c97e2fb69315eb274b0f01377eaa5c940bd7b26"
+  integrity sha512-jrTA2jJIL6/DAEILBEh2/w9QxCuwmvNXIry39Ay/HVfhE3o2yVV0U44blYkqdHA/OKloJEqvJy0xU+GSdE2SIw==
 
 jsesc@^1.3.0:
   version "1.3.0"
@@ -5643,6 +5868,11 @@
   resolved "https://registry.yarnpkg.com/json-parse-better-errors/-/json-parse-better-errors-1.0.2.tgz#bb867cfb3450e69107c131d1c514bab3dc8bcaa9"
   integrity sha512-mrqyZKfX5EhL7hvqcV6WG1yYjnjeuYDzDhhcAAUrq8Po85NBQBJP+ZDUT75qZQ98IkUoBqdkExkukOU7Ts2wrw==
 
+json-parse-even-better-errors@^2.3.0:
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/json-parse-even-better-errors/-/json-parse-even-better-errors-2.3.1.tgz#7c47805a94319928e05777405dc12e1f7a4ee02d"
+  integrity sha512-xyFwyhro/JEof6Ghe2iz2NcXoj2sloNsWr/XsERDK/oiPCfaNhl5ONfp+jQdAZRQQ0IJWNzH9zIZF7li91kh2w==
+
 json-schema-traverse@^0.4.1:
   version "0.4.1"
   resolved "https://registry.yarnpkg.com/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz#69f6a87d9513ab8bb8fe63bdb0979c448e684660"
@@ -5663,6 +5893,13 @@
   resolved "https://registry.yarnpkg.com/json-stringify-safe/-/json-stringify-safe-5.0.1.tgz#1296a2d58fd45f19a0f6ce01d65701e2c735b6eb"
   integrity sha1-Epai1Y/UXxmg9s4B1lcB4sc1tus=
 
+json5@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/json5/-/json5-1.0.1.tgz#779fb0018604fa854eacbf6252180d83543e3dbe"
+  integrity sha512-aKS4WQjPenRxiQsC93MNfjx+nbF4PAdYzmd/1JIj8HYzqfbu86beTuNgXDzPknWk0n0uARlyewZo4s++ES36Ow==
+  dependencies:
+    minimist "^1.2.0"
+
 json5@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/json5/-/json5-2.1.0.tgz#e7a0c62c48285c628d20a10b85c89bb807c32850"
@@ -5742,7 +5979,7 @@
   dependencies:
     package-json "^4.0.0"
 
-latest-version@^5.0.0:
+latest-version@^5.1.0:
   version "5.1.0"
   resolved "https://registry.yarnpkg.com/latest-version/-/latest-version-5.1.0.tgz#119dfe908fe38d15dfa43ecd13fa12ec8832face"
   integrity sha512-weT+r0kTkRQdCdYCNtkMwWXQTMEswKrFBkm4ckQOMVhhqhIMI1UT2hMj+1iigIhgSZm5gTmrRXBNoGUgaTY1xA==
@@ -5775,13 +6012,13 @@
   dependencies:
     readable-stream "^2.0.5"
 
-levn@^0.3.0, levn@~0.3.0:
-  version "0.3.0"
-  resolved "https://registry.yarnpkg.com/levn/-/levn-0.3.0.tgz#3b09924edf9f083c0490fdd4c0bc4421e04764ee"
-  integrity sha1-OwmSTt+fCDwEkP3UwLxEIeBHZO4=
+levn@^0.4.1:
+  version "0.4.1"
+  resolved "https://registry.yarnpkg.com/levn/-/levn-0.4.1.tgz#ae4562c007473b932a6200d403268dd2fffc6ade"
+  integrity sha512-+bT2uH4E5LGE7h/n3evcS/sQlJXCpIp6ym8OWJ5eV6+67Dsql/LaaT7qJBAt2rzfoa/5QBGBhxDix1dMt2kQKQ==
   dependencies:
-    prelude-ls "~1.1.2"
-    type-check "~0.3.2"
+    prelude-ls "^1.2.1"
+    type-check "~0.4.0"
 
 lines-and-columns@^1.1.6:
   version "1.1.6"
@@ -5942,6 +6179,11 @@
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.12.tgz#a712c74fdc31f7ecb20fe44f157d802d208097ef"
   integrity sha512-+CiwtLnsJhX03p20mwXuvhoebatoh5B3tt+VvYlrPgZC1g36y+RRbkufX95Xa+X4I59aWEacDFYwnJZiyBh9gA==
 
+lodash@^4.17.19, lodash@^4.17.20:
+  version "4.17.20"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.20.tgz#b44a9b6297bcb698f1c51a3545a2b3b368d59c52"
+  integrity sha512-PlhdFcillOINfeV7Ni6oF1TAEayyZBoZ8bcshTHqOYJYlrqzRK5hagpagky5o4HfCzzd1TRkXPMFq6cKk9rGmA==
+
 log-symbols@^1.0.0, log-symbols@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-1.0.2.tgz#376ff7b58ea3086a0f09facc74617eca501e1a18"
@@ -6026,6 +6268,13 @@
     pseudomap "^1.0.2"
     yallist "^2.1.2"
 
+lru-cache@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-6.0.0.tgz#6d6fe6570ebd96aaf90fcad1dafa3b2566db3a94"
+  integrity sha512-Jo6dJ04CmSjuznwJSS3pUeWmd/H0ffTlkXXgwZi+eq1UCmqQwCh+eLsYOYCwY991i2Fah4h1BEMCx4qThGbsiA==
+  dependencies:
+    yallist "^4.0.0"
+
 macos-release@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/macos-release/-/macos-release-2.3.0.tgz#eb1930b036c0800adebccd5f17bc4c12de8bb71f"
@@ -6142,24 +6391,22 @@
     redent "^1.0.0"
     trim-newlines "^1.0.0"
 
-meow@^7.0.0:
-  version "7.0.1"
-  resolved "https://registry.yarnpkg.com/meow/-/meow-7.0.1.tgz#1ed4a0a50b3844b451369c48362eb0515f04c1dc"
-  integrity sha512-tBKIQqVrAHqwit0vfuFPY3LlzJYkEOFyKa3bPgxzNl6q/RtN8KQ+ALYEASYuFayzSAsjlhXj/JZ10rH85Q6TUw==
+meow@^8.0.0:
+  version "8.0.0"
+  resolved "https://registry.yarnpkg.com/meow/-/meow-8.0.0.tgz#1aa10ee61046719e334ffdc038bb5069250ec99a"
+  integrity sha512-nbsTRz2fwniJBFgUkcdISq8y/q9n9VbiHYbfwklFh5V4V2uAcxtKQkDc0yCLPM/kP0d+inZBewn3zJqewHE7kg==
   dependencies:
     "@types/minimist" "^1.2.0"
-    arrify "^2.0.1"
-    camelcase "^6.0.0"
     camelcase-keys "^6.2.2"
     decamelize-keys "^1.1.0"
     hard-rejection "^2.1.0"
-    minimist-options "^4.0.2"
-    normalize-package-data "^2.5.0"
+    minimist-options "4.1.0"
+    normalize-package-data "^3.0.0"
     read-pkg-up "^7.0.1"
     redent "^3.0.0"
     trim-newlines "^3.0.0"
-    type-fest "^0.13.1"
-    yargs-parser "^18.1.3"
+    type-fest "^0.18.0"
+    yargs-parser "^20.2.3"
 
 merge-descriptors@1.0.1:
   version "1.0.1"
@@ -6183,6 +6430,11 @@
   resolved "https://registry.yarnpkg.com/merge2/-/merge2-1.2.3.tgz#7ee99dbd69bb6481689253f018488a1b902b0ed5"
   integrity sha512-gdUU1Fwj5ep4kplwcmftruWofEFt6lfpkkr3h860CXbAB9c3hGb55EOL2ali0Td5oebvW0E1+3Sr+Ur7XfKpRA==
 
+merge2@^1.3.0:
+  version "1.4.1"
+  resolved "https://registry.yarnpkg.com/merge2/-/merge2-1.4.1.tgz#4368892f885e907455a6fd7dc55c0c9d404990ae"
+  integrity sha512-8q7VEgMJW4J8tcfVPy8g09NcQwZdbwFEqhe/WZkoIzjn/3TGDwtOCYtXGxA3O8tPzpczCCDgv+P2P5y00ZJOOg==
+
 methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
@@ -6226,6 +6478,14 @@
     snapdragon "^0.8.1"
     to-regex "^3.0.2"
 
+micromatch@^4.0.2:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/micromatch/-/micromatch-4.0.2.tgz#4fcb0999bf9fbc2fcbdd212f6d629b9a56c39259"
+  integrity sha512-y7FpHSbMUMoyPbYUSzO6PaZ6FyRnQOpHuKwbo1G+Knck95XVU4QAiKdGEnj5wwoS7PlOgthX/09u5iFJ+aYf5Q==
+  dependencies:
+    braces "^3.0.1"
+    picomatch "^2.0.5"
+
 mime-db@1.40.0, mime-db@^1.28.0:
   version "1.40.0"
   resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.40.0.tgz#a65057e998db090f732a68f6c276d387d4126c32"
@@ -6304,7 +6564,7 @@
   dependencies:
     brace-expansion "^1.1.7"
 
-minimist-options@^4.0.2:
+minimist-options@4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/minimist-options/-/minimist-options-4.1.0.tgz#c0655713c53a8a2ebd77ffa247d342c40f010619"
   integrity sha512-Q4r8ghd80yhO/0j1O3B2BjweX3fiHg9cdOwjJd2J76Q135c+NDxGCqdYKQ1SKBuFfgWbAUzBfvYjPUEeNgqN1A==
@@ -6368,7 +6628,7 @@
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.1.tgz#30a5864eb3ebb0a66f2ebe6d727af06a09d86e0a"
   integrity sha512-tgp+dl5cGk28utYktBsrFqA7HKgrhgPsg6Z/EfhWI4gl1Hwq8B/GmY/0oXZ6nF8hDVesS/FpnYaD/kOWhYQvyg==
 
-ms@^2.1.1:
+ms@2.1.2, ms@^2.1.1:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.2.tgz#d09d1f357b443f493382a8eb3ccd183872ae6009"
   integrity sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==
@@ -6544,6 +6804,16 @@
     semver "2 || 3 || 4 || 5"
     validate-npm-package-license "^3.0.1"
 
+normalize-package-data@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/normalize-package-data/-/normalize-package-data-3.0.0.tgz#1f8a7c423b3d2e85eb36985eaf81de381d01301a"
+  integrity sha512-6lUjEI0d3v6kFrtgA/lOx4zHCWULXsFNIjHolnZCKCTLA6m/G625cdn3O7eNmT0iD3jfo6HZ9cdImGZwf21prw==
+  dependencies:
+    hosted-git-info "^3.0.6"
+    resolve "^1.17.0"
+    semver "^7.3.2"
+    validate-npm-package-license "^3.0.1"
+
 normalize-path@^2.0.0, normalize-path@^2.0.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/normalize-path/-/normalize-path-2.1.1.tgz#1ab28b556e198363a8c1a6f7e6fa20137fe6aed9"
@@ -6581,7 +6851,7 @@
   dependencies:
     path-key "^2.0.0"
 
-npm-run-path@^4.0.0:
+npm-run-path@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/npm-run-path/-/npm-run-path-4.0.1.tgz#b7ecd1e5ed53da8e37a55e1c2269e0b97ed748ea"
   integrity sha512-S48WzZW777zhNIrn7gxOlISNAqi9ZC/uQFnRdbeIHhZhCA6UqpkOT8T1G7BvfdgP4Er8gF4sUbaS0i7QvIfCWw==
@@ -6627,10 +6897,10 @@
     define-property "^0.2.5"
     kind-of "^3.0.3"
 
-object-inspect@^1.7.0:
-  version "1.7.0"
-  resolved "https://registry.yarnpkg.com/object-inspect/-/object-inspect-1.7.0.tgz#f4f6bd181ad77f006b5ece60bd0b6f398ff74a67"
-  integrity sha512-a7pEHdh1xKIAgTySUGgLMx/xwDZskN1Ud6egYYN3EdRW4ZMPNEDUTF+hwy2LUC+Bl+SyLXANnwz/jyh/qutKUw==
+object-inspect@^1.8.0:
+  version "1.9.0"
+  resolved "https://registry.yarnpkg.com/object-inspect/-/object-inspect-1.9.0.tgz#c90521d74e1127b67266ded3394ad6116986533a"
+  integrity sha512-i3Bp9iTqwhaLZBxGkRfo5ZbE07BQRT7MGu8+nNgwW9ItGp1TzCTw2DLEoWwjClxBjOFI/hWljTAmYGCEwmtnOw==
 
 object-keys@^1.0.11, object-keys@^1.0.12, object-keys@^1.1.1:
   version "1.1.1"
@@ -6654,10 +6924,15 @@
     has-symbols "^1.0.0"
     object-keys "^1.0.11"
 
-object.entries-ponyfill@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.yarnpkg.com/object.entries-ponyfill/-/object.entries-ponyfill-1.0.1.tgz#29abdf77cbfbd26566dd1aa24e9d88f65433d256"
-  integrity sha1-Kavfd8v70mVm3RqiTp2I9lQz0lY=
+object.assign@^4.1.1:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/object.assign/-/object.assign-4.1.2.tgz#0ed54a342eceb37b38ff76eb831a0e788cb63940"
+  integrity sha512-ixT2L5THXsApyiUPYKmW+2EHpXXe5Ii3M+f4e+aJFAHao5amFRW6J0OO6c/LU8Be47utCx2GL89hxGB6XSmKuQ==
+  dependencies:
+    call-bind "^1.0.0"
+    define-properties "^1.1.3"
+    has-symbols "^1.0.1"
+    object-keys "^1.1.1"
 
 object.omit@^2.0.0:
   version "2.0.1"
@@ -6674,14 +6949,14 @@
   dependencies:
     isobject "^3.0.1"
 
-object.values@^1.1.0:
-  version "1.1.1"
-  resolved "https://registry.yarnpkg.com/object.values/-/object.values-1.1.1.tgz#68a99ecde356b7e9295a3c5e0ce31dc8c953de5e"
-  integrity sha512-WTa54g2K8iu0kmS/us18jEmdv1a4Wi//BZ/DTVYEcH0XhLM5NYdpDHja3gt57VrZLcNAO2WGA+KpWsDBaHt6eA==
+object.values@^1.1.1:
+  version "1.1.2"
+  resolved "https://registry.yarnpkg.com/object.values/-/object.values-1.1.2.tgz#7a2015e06fcb0f546bd652486ce8583a4731c731"
+  integrity sha512-MYC0jvJopr8EK6dPBiO8Nb9mvjdypOachO5REGk6MXzujbBrAisKo3HmdEI6kZDL6fC31Mwee/5YbtMebixeag==
   dependencies:
+    call-bind "^1.0.0"
     define-properties "^1.1.3"
-    es-abstract "^1.17.0-next.1"
-    function-bind "^1.1.1"
+    es-abstract "^1.18.0-next.1"
     has "^1.0.3"
 
 obuf@^1.0.0, obuf@^1.1.1:
@@ -6730,10 +7005,10 @@
   dependencies:
     mimic-fn "^1.0.0"
 
-onetime@^5.1.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/onetime/-/onetime-5.1.0.tgz#fff0f3c91617fe62bb50189636e99ac8a6df7be5"
-  integrity sha512-5NcSkPHhwTVFIQN+TUqXoS5+dlElHXdpAWu9I0HP20YOtIi+aZ0Ct82jdlILDxjLEAWwvm+qj1m6aEtsDVmm6Q==
+onetime@^5.1.0, onetime@^5.1.2:
+  version "5.1.2"
+  resolved "https://registry.yarnpkg.com/onetime/-/onetime-5.1.2.tgz#d0e96ebb56b07476df1dd9c4806e5237985ca45e"
+  integrity sha512-kbpaSSGJTWdAY5KPVeMOKXSrPtr8C8C7wodJbcsd51jRnmD+GZu8Y0VoU6Dm5Z4vWr0Ig/1NKuWRKf7j5aaYSg==
   dependencies:
     mimic-fn "^2.1.0"
 
@@ -6752,17 +7027,17 @@
     minimist "~0.0.1"
     wordwrap "~0.0.2"
 
-optionator@^0.8.3:
-  version "0.8.3"
-  resolved "https://registry.yarnpkg.com/optionator/-/optionator-0.8.3.tgz#84fa1d036fe9d3c7e21d99884b601167ec8fb495"
-  integrity sha512-+IW9pACdk3XWmmTXG8m3upGUJst5XRGzxMRjXzAuJ1XnIFNvfhjjIuYkDvysnPQ7qzqVzLt78BCruntqRhWQbA==
+optionator@^0.9.1:
+  version "0.9.1"
+  resolved "https://registry.yarnpkg.com/optionator/-/optionator-0.9.1.tgz#4f236a6373dae0566a6d43e1326674f50c291499"
+  integrity sha512-74RlY5FCnhq4jRxVUPKDaRwrVNXMqsGsiW6AJw4XK8hmtm10wC0ypZBLw5IIp85NZMr91+qd1RvvENwg7jjRFw==
   dependencies:
-    deep-is "~0.1.3"
-    fast-levenshtein "~2.0.6"
-    levn "~0.3.0"
-    prelude-ls "~1.1.2"
-    type-check "~0.3.2"
-    word-wrap "~1.2.3"
+    deep-is "^0.1.3"
+    fast-levenshtein "^2.0.6"
+    levn "^0.4.1"
+    prelude-ls "^1.2.1"
+    type-check "^0.4.0"
+    word-wrap "^1.2.3"
 
 ordered-read-streams@^0.3.0:
   version "0.3.0"
@@ -6957,13 +7232,13 @@
     json-parse-better-errors "^1.0.1"
 
 parse-json@^5.0.0:
-  version "5.0.0"
-  resolved "https://registry.yarnpkg.com/parse-json/-/parse-json-5.0.0.tgz#73e5114c986d143efa3712d4ea24db9a4266f60f"
-  integrity sha512-OOY5b7PAEFV0E2Fir1KOkxchnZNCdowAJgQ5NuxjpBKTRP3pQhwkrkxqQjeoKJ+fO7bCpmIZaogI4eZGDMEGOw==
+  version "5.1.0"
+  resolved "https://registry.yarnpkg.com/parse-json/-/parse-json-5.1.0.tgz#f96088cdf24a8faa9aea9a009f2d9d942c999646"
+  integrity sha512-+mi/lmVVNKFNVyLXV31ERiy2CY5E1/F6QtJFEzoChPRwwngMNXRDQ9GJ5WdE2Z2P4AujsOi0/+2qHID68KwfIQ==
   dependencies:
     "@babel/code-frame" "^7.0.0"
     error-ex "^1.3.1"
-    json-parse-better-errors "^1.0.1"
+    json-parse-even-better-errors "^2.3.0"
     lines-and-columns "^1.1.6"
 
 parse-passwd@^1.0.0:
@@ -7089,6 +7364,11 @@
   dependencies:
     pify "^3.0.0"
 
+path-type@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/path-type/-/path-type-4.0.0.tgz#84ed01c0a7ba380afe09d90a8c180dcd9d03043b"
+  integrity sha512-gDKb8aZMDeD/tZWs9P6+q0J9Mwkdl6xMV8TjnGP3qJVJ06bdMgkbBlLU8IdfOsIsFz2BW1rNVT3XuNEl8zPAvw==
+
 peek-stream@^1.1.0:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/peek-stream/-/peek-stream-1.1.3.tgz#3b35d84b7ccbbd262fff31dc10da56856ead6d67"
@@ -7118,6 +7398,11 @@
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-2.1.0.tgz#6309f4e0e5fa913ec1c69307ae364b4b377c9e7b"
   integrity sha1-Ywn04OX6kT7BxpMHrjZLSzd8nns=
 
+picomatch@^2.0.5, picomatch@^2.2.1:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.2.tgz#21f333e9b6b8eaff02468f5146ea406d345f4dad"
+  integrity sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==
+
 pify@^2.0.0, pify@^2.3.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"
@@ -7441,10 +7726,10 @@
   resolved "https://registry.yarnpkg.com/posix-character-classes/-/posix-character-classes-0.1.1.tgz#01eac0fe3b5af71a2a6c02feabb8c1fef7e00eab"
   integrity sha1-AerA/jta9xoqbAL+q7jB/vfgDqs=
 
-prelude-ls@~1.1.2:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
-  integrity sha1-IZMqVJ9eUv/ZqCf1cOBL5iqX2lQ=
+prelude-ls@^1.2.1:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.2.1.tgz#debc6489d7a6e6b0e7611888cec880337d316396"
+  integrity sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==
 
 prepend-http@^1.0.1:
   version "1.0.4"
@@ -7468,11 +7753,16 @@
   dependencies:
     fast-diff "^1.1.2"
 
-prettier@2.0.5, prettier@^2.0.4:
+prettier@2.0.5:
   version "2.0.5"
   resolved "https://registry.yarnpkg.com/prettier/-/prettier-2.0.5.tgz#d6d56282455243f2f92cc1716692c08aa31522d4"
   integrity sha512-7PtVymN48hGcO4fGjybyBSIWDsLU4H4XlvOHfq91pz9kkGlonzwTfYkaIEwiRg/dAJF9YlbsduBAgtYLi+8cFg==
 
+prettier@^2.1.2:
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-2.2.1.tgz#795a1a78dd52f073da0cd42b21f9c91381923ff5"
+  integrity sha512-PqyhM2yCjg/oKkFPtTGUojv7gnZAoG80ttl45O6x2Ug/rMJw4wcc9k6aaf2hibP7BGVCCM33gZoGjyvt9mm16Q==
+
 pretty-bytes@^4.0.2:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/pretty-bytes/-/pretty-bytes-4.0.2.tgz#b2bf82e7350d65c6c33aa95aaa5a4f6327f61cd9"
@@ -7578,10 +7868,10 @@
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"
   integrity sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==
 
-pupa@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/pupa/-/pupa-2.0.1.tgz#dbdc9ff48ffbea4a26a069b6f9f7abb051008726"
-  integrity sha512-hEJH0s8PXLY/cdXh66tNEQGndDrIKNqNC5xmrysZy3i5C3oEoLna7YAOad+7u125+zH1HNXUmGEkrhb3c2VriA==
+pupa@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/pupa/-/pupa-2.1.1.tgz#f5e8fd4afc2c5d97828faa523549ed8744a20d62"
+  integrity sha512-l1jNAspIBSFqbT+y+5FosojNpVpF94nlI+wDUpqP9enwOTfHx9f0gh5nB96vl+6yTpsJsypeNrwfzPrKuHB41A==
   dependencies:
     escape-goat "^2.0.0"
 
@@ -7856,12 +8146,7 @@
     extend-shallow "^3.0.2"
     safe-regex "^1.1.0"
 
-regexpp@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/regexpp/-/regexpp-2.0.1.tgz#8d19d31cf632482b589049f8281f93dbcba4d07f"
-  integrity sha512-lv0M6+TkDVniA3aD1Eg0DVpfU/booSu7Eev3TDO/mZKHBfVjgCGTV4t4buppESEYDtkArYFOxTJWv6S5C+iaNw==
-
-regexpp@^3.0.0:
+regexpp@^3.0.0, regexpp@^3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/regexpp/-/regexpp-3.1.0.tgz#206d0ad0a5648cffbdb8ae46438f3dc51c9f78e2"
   integrity sha512-ZOIzd8yVsQQA7j8GCSlPGXwg5PfmA1mrq0JP4nGhh54LaKN3xdai/vHUDu74pKwV8OxseMS65u2NImosQcSD0Q==
@@ -7878,10 +8163,10 @@
     unicode-match-property-ecmascript "^1.0.4"
     unicode-match-property-value-ecmascript "^1.1.0"
 
-regextras@^0.7.0:
-  version "0.7.0"
-  resolved "https://registry.yarnpkg.com/regextras/-/regextras-0.7.0.tgz#2298bef8cfb92b1b7e3b9b12aa8f69547b7d71e4"
-  integrity sha512-ds+fL+Vhl918gbAUb0k2gVKbTZLsg84Re3DI6p85Et0U0tYME3hyW4nMK8Px4dtDaBA2qNjvG5uWyW7eK5gfmw==
+regextras@^0.7.1:
+  version "0.7.1"
+  resolved "https://registry.yarnpkg.com/regextras/-/regextras-0.7.1.tgz#be95719d5f43f9ef0b9fa07ad89b7c606995a3b2"
+  integrity sha512-9YXf6xtW+qzQ+hcMQXx95MOvfqXFgsKDZodX3qZB0x2n5Z94ioetIITsBtvJbiOyxa/6s9AtyweBLCdPmPko/w==
 
 registry-auth-token@^3.0.1:
   version "3.4.0"
@@ -7892,9 +8177,9 @@
     safe-buffer "^5.0.1"
 
 registry-auth-token@^4.0.0:
-  version "4.1.1"
-  resolved "https://registry.yarnpkg.com/registry-auth-token/-/registry-auth-token-4.1.1.tgz#40a33be1e82539460f94328b0f7f0f84c16d9479"
-  integrity sha512-9bKS7nTl9+/A1s7tnPeGrUpRcVY+LUh7bfFgzpndALdPfXQBfQV77rQVtqgUV3ti4vc/Ik81Ex8UJDWDQ12zQA==
+  version "4.2.1"
+  resolved "https://registry.yarnpkg.com/registry-auth-token/-/registry-auth-token-4.2.1.tgz#6d7b4006441918972ccd5fedcd41dc322c79b250"
+  integrity sha512-6gkSb4U6aWJB4SF2ZvLb76yCBjcvufXBqvvEx1HbmKPkutswjW1xNVRY0+daljIYRbogN7O0etYSlbiaEQyMyw==
   dependencies:
     rc "^1.2.8"
 
@@ -8037,11 +8322,12 @@
   dependencies:
     path-parse "^1.0.6"
 
-resolve@^1.12.0, resolve@^1.13.1:
-  version "1.15.1"
-  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.15.1.tgz#27bdcdeffeaf2d6244b95bb0f9f4b4653451f3e8"
-  integrity sha512-84oo6ZTtoTUpjgNEr5SJyzQhzL72gaRodsSfyxC/AXRvwu0Yse9H8eF9IpGo7b8YetZhlI6v7ZQ6bKBFV/6S7w==
+resolve@^1.13.1, resolve@^1.17.0:
+  version "1.19.0"
+  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.19.0.tgz#1af5bf630409734a067cae29318aac7fa29a267c"
+  integrity sha512-rArEXAgsBG4UgRGcynxWIWKFvh/XZCcS8UJdHhwy91zwAvCZIbcs+vAbflgBnNjYMs/i/i+/Ux6IZhML1yPvxg==
   dependencies:
+    is-core-module "^2.1.0"
     path-parse "^1.0.6"
 
 resolve@^1.5.0:
@@ -8087,7 +8373,12 @@
   resolved "https://registry.yarnpkg.com/ret/-/ret-0.1.15.tgz#b8a4825d5bdb1fc3f6f53c2bc33f81388681c7bc"
   integrity sha512-TTlYpa+OL+vMMNG24xSlQGEJ3B/RzEfUlLct7b5G/ytav+wPrplCpVMFuwzXbkecJrb6IYo1iFb0S9v37754mg==
 
-rimraf@2.6.3, rimraf@^2.2.8, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.6.2, rimraf@~2.6.2:
+reusify@^1.0.4:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/reusify/-/reusify-1.0.4.tgz#90da382b1e126efc02146e90845a88db12925d76"
+  integrity sha512-U9nH88a3fc/ekCF1l0/UP1IosiuIjyTh7hBvXVMHYgVcfGvt897Xguj2UOLDeI5BG2m7/uwyaLVT6fbtCwTyzw==
+
+rimraf@^2.2.8, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.6.2, rimraf@~2.6.2:
   version "2.6.3"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.3.tgz#b2d104fe0d8fb27cf9e0a1cda8262dd3833c6cab"
   integrity sha512-mwqeW5XsA2qAejG46gYdENaxXjx9onRNCfn7L0duuP4hCuTIi/QO7PDK07KJfp1d+izWPrzEJDcSqBa0OZQriA==
@@ -8122,6 +8413,13 @@
     "@types/node" "^12.0.10"
     acorn "^6.1.1"
 
+rollup@^2.3.4:
+  version "2.35.1"
+  resolved "https://registry.yarnpkg.com/rollup/-/rollup-2.35.1.tgz#e6bc8d10893556a638066f89e8c97f422d03968c"
+  integrity sha512-q5KxEyWpprAIcainhVy6HfRttD9kutQpHbeqDTWnqAFNJotiojetK6uqmcydNMymBEtC4I8bCYR+J3mTMqeaUA==
+  optionalDependencies:
+    fsevents "~2.1.2"
+
 run-async@^2.0.0, run-async@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/run-async/-/run-async-2.3.0.tgz#0371ab4ae0bdd720d4166d7dfda64ff7a445a6c0"
@@ -8134,6 +8432,11 @@
   resolved "https://registry.yarnpkg.com/run-async/-/run-async-2.4.1.tgz#8440eccf99ea3e70bd409d49aab88e10c189a455"
   integrity sha512-tvVnVv01b8c1RrA6Ep7JkStj85Guv/YrMcwqYQnwjsAS2cTmmPGBBjAjpCW7RrSodNSoE2/qg9O4bceNvUuDgQ==
 
+run-parallel@^1.1.9:
+  version "1.1.10"
+  resolved "https://registry.yarnpkg.com/run-parallel/-/run-parallel-1.1.10.tgz#60a51b2ae836636c81377df16cb107351bcd13ef"
+  integrity sha512-zb/1OuZ6flOlH6tQyMPUrE3x3Ulxjlo9WIVXR4yVYi4H9UXQaeIsPbLn2R3O3vQCnDKkAl2qHiuocKKX4Tz/Sw==
+
 rx@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/rx/-/rx-4.1.0.tgz#a5f13ff79ef3b740fe30aa803fb09f98805d4782"
@@ -8146,10 +8449,10 @@
   dependencies:
     tslib "^1.9.0"
 
-rxjs@^6.5.3:
-  version "6.5.4"
-  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.5.4.tgz#e0777fe0d184cec7872df147f303572d414e211c"
-  integrity sha512-naMQXcgEo3csAEGvw/NydRA0fuS2nDZJiw1YUWFKU7aPPAPGZEsD4Iimit96qwCieH6y614MCLYwdkrWx7z/7Q==
+rxjs@^6.6.0:
+  version "6.6.3"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.3.tgz#8ca84635c4daa900c0d3967a6ee7ac60271ee552"
+  integrity sha512-trsQc+xYYXZ3urjOiJOuCOa5N3jAZ3eiSpQB5hIT8zGlL2QfnHLJ2r7GMkBGuIausdJN1OneaI6gQlsqNHHmZQ==
   dependencies:
     tslib "^1.9.0"
 
@@ -8249,11 +8552,18 @@
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.6.0.tgz#7e74256fbaa49c75aa7c7a205cc22799cac80004"
   integrity sha512-RS9R6R35NYgQn++fkDWaOmqGoj4Ek9gGs+DPxNUZKuwE183xjJroKvyo1IzVFeXvUrvmALy6FWD5xrdJT25gMg==
 
-semver@^6.0.0, semver@^6.1.0, semver@^6.1.2, semver@^6.2.0, semver@^6.3.0:
+semver@^6.0.0, semver@^6.1.0, semver@^6.2.0, semver@^6.3.0:
   version "6.3.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-6.3.0.tgz#ee0a64c8af5e8ceea67687b133761e1becbd1d3d"
   integrity sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==
 
+semver@^7.2.1, semver@^7.3.2, semver@^7.3.4:
+  version "7.3.4"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-7.3.4.tgz#27aaa7d2e4ca76452f98d3add093a72c943edc97"
+  integrity sha512-tCfb2WLjqFAtXn4KEdxIhalnRtoKFN7nAwj0B3ZXCbQloV2tq5eDbcTmT68JJD3nRJq24/XgxtQKFIpQdtvmVw==
+  dependencies:
+    lru-cache "^6.0.0"
+
 send@0.17.1:
   version "0.17.1"
   resolved "https://registry.yarnpkg.com/send/-/send-0.17.1.tgz#c1d8b059f7900f7466dd4938bdc44e11ddb376c8"
@@ -8380,6 +8690,11 @@
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
   integrity sha1-tf3AjxKH6hF4Yo5BXiUTK3NkbG0=
 
+signal-exit@^3.0.3:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.3.tgz#a1410c2edd8f077b08b4e253c8eacfcaf057461c"
+  integrity sha512-VUJ49FC8U1OxwZLxIbTTrDvLnf/6TDgxZcK8wxR8zs13xpx7xbG60ndBlhNrFi2EMuFRoeDoJO7wthSLq42EjA==
+
 simple-swizzle@^0.2.2:
   version "0.2.2"
   resolved "https://registry.yarnpkg.com/simple-swizzle/-/simple-swizzle-0.2.2.tgz#a4da6b635ffcccca33f70d17cb92592de95e557a"
@@ -8411,14 +8726,19 @@
   resolved "https://registry.yarnpkg.com/slash/-/slash-1.0.0.tgz#c41f2f6c39fc16d1cd17ad4b5d896114ae470d55"
   integrity sha1-xB8vbDn8FtHNF61LXYlhFK5HDVU=
 
-slice-ansi@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/slice-ansi/-/slice-ansi-2.1.0.tgz#cacd7693461a637a5788d92a7dd4fba068e81636"
-  integrity sha512-Qu+VC3EwYLldKa1fCxuuvULvSJOKEgk9pi8dZeCVK7TqBfUNTH4sFkk4joj8afVSfAYgJoSOetjx9QWOJ5mYoQ==
+slash@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/slash/-/slash-3.0.0.tgz#6539be870c165adbd5240220dbe361f1bc4d4634"
+  integrity sha512-g9Q1haeby36OSStwb4ntCGGGaKsaVSjQ68fBxoQcutl5fS1vuY18H3wSt3jFyFtrkx+Kz0V1G85A4MyAdDMi2Q==
+
+slice-ansi@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/slice-ansi/-/slice-ansi-4.0.0.tgz#500e8dd0fd55b05815086255b3195adf2a45fe6b"
+  integrity sha512-qMCMfhY040cVHT43K9BFygqYbUPFZKHOg7K73mtTWJRb8pyP3fzf4Ixd5SzdEJQ6MRUg/WBnOLxghZtKKurENQ==
   dependencies:
-    ansi-styles "^3.2.0"
-    astral-regex "^1.0.0"
-    is-fullwidth-code-point "^2.0.0"
+    ansi-styles "^4.0.0"
+    astral-regex "^2.0.0"
+    is-fullwidth-code-point "^3.0.0"
 
 slide@^1.1.5:
   version "1.1.6"
@@ -8595,6 +8915,14 @@
     spdx-exceptions "^2.1.0"
     spdx-license-ids "^3.0.0"
 
+spdx-expression-parse@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/spdx-expression-parse/-/spdx-expression-parse-3.0.1.tgz#cf70f50482eefdc98e3ce0a6833e4a53ceeba679"
+  integrity sha512-cbqHunsQWnJNE6KhVSMsMeH5H/L9EpymbzqTQ3uLwNCLZ1Q481oWaofqH7nO6V07xlXwY6PhQdQ2IedWx/ZK4Q==
+  dependencies:
+    spdx-exceptions "^2.1.0"
+    spdx-license-ids "^3.0.0"
+
 spdx-license-ids@^3.0.0:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/spdx-license-ids/-/spdx-license-ids-3.0.4.tgz#75ecd1a88de8c184ef015eafb51b5b48bfd11bb1"
@@ -8736,7 +9064,7 @@
     is-fullwidth-code-point "^2.0.0"
     strip-ansi "^5.1.0"
 
-string-width@^4.0.0, string-width@^4.1.0:
+string-width@^4.0.0, string-width@^4.1.0, string-width@^4.2.0:
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-4.2.0.tgz#952182c46cc7b2c313d1596e623992bd163b72b5"
   integrity sha512-zUz5JD+tgqtuDjMhwIg5uFVV3dtqZ9yQJlZVfq4I01/K5Paj5UHj7VyrQOJvzawSVlKpObApbfD0Ed6yJc+1eg==
@@ -8745,21 +9073,21 @@
     is-fullwidth-code-point "^3.0.0"
     strip-ansi "^6.0.0"
 
-string.prototype.trimleft@^2.1.1:
-  version "2.1.1"
-  resolved "https://registry.yarnpkg.com/string.prototype.trimleft/-/string.prototype.trimleft-2.1.1.tgz#9bdb8ac6abd6d602b17a4ed321870d2f8dcefc74"
-  integrity sha512-iu2AGd3PuP5Rp7x2kEZCrB2Nf41ehzh+goo8TV7z8/XDBbsvc6HQIlUl9RjkZ4oyrW1XM5UwlGl1oVEaDjg6Ag==
+string.prototype.trimend@^1.0.1:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/string.prototype.trimend/-/string.prototype.trimend-1.0.3.tgz#a22bd53cca5c7cf44d7c9d5c732118873d6cd18b"
+  integrity sha512-ayH0pB+uf0U28CtjlLvL7NaohvR1amUvVZk+y3DYb0Ey2PUV5zPkkKy9+U1ndVEIXO8hNg18eIv9Jntbii+dKw==
   dependencies:
+    call-bind "^1.0.0"
     define-properties "^1.1.3"
-    function-bind "^1.1.1"
 
-string.prototype.trimright@^2.1.1:
-  version "2.1.1"
-  resolved "https://registry.yarnpkg.com/string.prototype.trimright/-/string.prototype.trimright-2.1.1.tgz#440314b15996c866ce8a0341894d45186200c5d9"
-  integrity sha512-qFvWL3/+QIgZXVmJBfpHmxLB7xsUXz6HsUmP8+5dRaC3Q7oKUv9Vo6aMCRZC1smrtyECFsIT30PqBJ1gTjAs+g==
+string.prototype.trimstart@^1.0.1:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/string.prototype.trimstart/-/string.prototype.trimstart-1.0.3.tgz#9b4cb590e123bb36564401d59824298de50fd5aa"
+  integrity sha512-oBIBUy5lea5tt0ovtOFiEQaBkoBBkyJhZXzJYrSmDo5IUUqbOPvVezuRs/agBIdZ2p2Eo1FD6bD9USyBLfl3xg==
   dependencies:
+    call-bind "^1.0.0"
     define-properties "^1.1.3"
-    function-bind "^1.1.1"
 
 string_decoder@^1.1.1:
   version "1.3.0"
@@ -8794,7 +9122,7 @@
   dependencies:
     ansi-regex "^3.0.0"
 
-strip-ansi@^5.1.0, strip-ansi@^5.2.0:
+strip-ansi@^5.1.0:
   version "5.2.0"
   resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-5.2.0.tgz#8c9a536feb6afc962bdfa5b104a5091c1ad9c0ae"
   integrity sha512-DuRs1gKbBqsMKIZlrffwlug8MHkcnpjs5VPmL1PAh+mA30U0DTotfDZ0d2UUsXpPmPmMMJ6W773MaA3J+lbiWA==
@@ -8870,10 +9198,10 @@
   dependencies:
     min-indent "^1.0.0"
 
-strip-json-comments@^3.0.1:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-3.0.1.tgz#85713975a91fb87bf1b305cca77395e40d2a64a7"
-  integrity sha512-VTyMAUfdm047mwKl+u79WIdrZxtFtn+nBxHeb844XBQ9uMNTuTHdx2hc5RiAJYqwTj3wc/xe5HLSdJSkJ+WfZw==
+strip-json-comments@^3.1.0, strip-json-comments@^3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-3.1.1.tgz#31f1281b3832630434831c310c01cccda8cbe006"
+  integrity sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==
 
 strip-json-comments@~2.0.1:
   version "2.0.1"
@@ -8934,15 +9262,15 @@
     typical "^2.6.1"
     wordwrapjs "^3.0.0"
 
-table@^5.2.3:
-  version "5.4.6"
-  resolved "https://registry.yarnpkg.com/table/-/table-5.4.6.tgz#1292d19500ce3f86053b05f0e8e7e4a3bb21079e"
-  integrity sha512-wmEc8m4fjnob4gt5riFRtTu/6+4rSe12TpAELNSqHMfF3IqnA+CH37USM6/YR3qRZv7e56kAEAtd6nKZaxe0Ug==
+table@^6.0.4:
+  version "6.0.4"
+  resolved "https://registry.yarnpkg.com/table/-/table-6.0.4.tgz#c523dd182177e926c723eb20e1b341238188aa0d"
+  integrity sha512-sBT4xRLdALd+NFBvwOz8bw4b15htyythha+q+DVZqy2RS08PPC8O2sZFgJYEY7bJvbCFKccs+WIZ/cd+xxTWCw==
   dependencies:
-    ajv "^6.10.2"
-    lodash "^4.17.14"
-    slice-ansi "^2.1.0"
-    string-width "^3.0.0"
+    ajv "^6.12.4"
+    lodash "^4.17.20"
+    slice-ansi "^4.0.0"
+    string-width "^4.2.0"
 
 tar-fs@^1.12.0:
   version "1.16.3"
@@ -9025,9 +9353,9 @@
     execa "^0.7.0"
 
 term-size@^2.1.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/term-size/-/term-size-2.2.0.tgz#1f16adedfe9bdc18800e1776821734086fcc6753"
-  integrity sha512-a6sumDlzyHVJWb8+YofY4TW112G6p2FCPEAFk+59gIYHv3XHRhm9ltVQ9kli4hNWeQBwSpe8cRN25x0ROunMOw==
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/term-size/-/term-size-2.2.1.tgz#2a6a54840432c2fb6320fea0f415531e90189f54"
+  integrity sha512-wK0Ri4fOGjv/XPy8SBHZChl8CM7uMc5VML7SqiQ0zG7+J5Vr+RMQDoHa2CNT6KHUnTGIXH34UDMkPzAUyapBZg==
 
 ternary-stream@^2.0.1:
   version "2.0.1"
@@ -9197,6 +9525,13 @@
     is-number "^3.0.0"
     repeat-string "^1.6.1"
 
+to-regex-range@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/to-regex-range/-/to-regex-range-5.0.1.tgz#1648c44aae7c8d988a326018ed72f5b4dd0392e4"
+  integrity sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==
+  dependencies:
+    is-number "^7.0.0"
+
 to-regex@^3.0.1, to-regex@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/to-regex/-/to-regex-3.0.2.tgz#13cfdd9b336552f30b51f33a8ae1b42a7a7599ce"
@@ -9247,6 +9582,16 @@
   resolved "https://registry.yarnpkg.com/triple-beam/-/triple-beam-1.3.0.tgz#a595214c7298db8339eeeee083e4d10bd8cb8dd9"
   integrity sha512-XrHUvV5HpdLmIj4uVMxHggLbFSZYIn7HEWsqePZcI50pco+MPqJ50wMGY794X7AOOhxOBAjbkqfAbEe/QMp2Lw==
 
+tsconfig-paths@^3.9.0:
+  version "3.9.0"
+  resolved "https://registry.yarnpkg.com/tsconfig-paths/-/tsconfig-paths-3.9.0.tgz#098547a6c4448807e8fcb8eae081064ee9a3c90b"
+  integrity sha512-dRcuzokWhajtZWkQsDVKbWyY+jgcLC5sqJhg2PSgf4ZkH2aHPvaOY8YWGhmjb68b5qqTfasSsDO9k7RUiEmZAw==
+  dependencies:
+    "@types/json5" "^0.0.29"
+    json5 "^1.0.1"
+    minimist "^1.2.0"
+    strip-bom "^3.0.0"
+
 tslib@^1.8.1:
   version "1.13.0"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.13.0.tgz#c881e13cc7015894ed914862d276436fa9a47043"
@@ -9283,22 +9628,27 @@
   resolved "https://registry.yarnpkg.com/tweetnacl/-/tweetnacl-0.14.5.tgz#5ae68177f192d4456269d108afa93ff8743f4f64"
   integrity sha1-WuaBd/GS1EViadEIr6k/+HQ/T2Q=
 
-type-check@~0.3.2:
-  version "0.3.2"
-  resolved "https://registry.yarnpkg.com/type-check/-/type-check-0.3.2.tgz#5884cab512cf1d355e3fb784f30804b2b520db72"
-  integrity sha1-WITKtRLPHTVeP7eE8wgEsrUg23I=
+type-check@^0.4.0, type-check@~0.4.0:
+  version "0.4.0"
+  resolved "https://registry.yarnpkg.com/type-check/-/type-check-0.4.0.tgz#07b8203bfa7056c0657050e3ccd2c37730bab8f1"
+  integrity sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==
   dependencies:
-    prelude-ls "~1.1.2"
+    prelude-ls "^1.2.1"
 
 type-detect@^4.0.0:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
   integrity sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==
 
-type-fest@^0.13.1:
-  version "0.13.1"
-  resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.13.1.tgz#0172cb5bce80b0bd542ea348db50c7e21834d934"
-  integrity sha512-34R7HTnG0XIJcBSn5XhDd7nNFPRcXYRZrBB2O2jdKqYODldSzBAqzsWoZYYvduky73toYS/ESqxPvkDf/F0XMg==
+type-fest@^0.11.0:
+  version "0.11.0"
+  resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.11.0.tgz#97abf0872310fed88a5c466b25681576145e33f1"
+  integrity sha512-OdjXJxnCN1AvyLSzeKIgXTXxV+99ZuXl3Hpo9XpJAv9MBcHrrJOQ5kV7ypXOuQie+AmWG25hLbiKdwYTifzcfQ==
+
+type-fest@^0.18.0:
+  version "0.18.1"
+  resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.18.1.tgz#db4bc151a4a2cf4eebf9add5db75508db6cc841f"
+  integrity sha512-OIAYXk8+ISY+qTOwkHtKqzAuxchoMiD9Udx+FSGQDuiRR+PJKJHc2NJAXlbhkGwTt/4/nKZxELY1w3ReWOL8mw==
 
 type-fest@^0.6.0:
   version "0.6.0"
@@ -9330,10 +9680,10 @@
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@3.9.5:
-  version "3.9.5"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.5.tgz#586f0dba300cde8be52dd1ac4f7e1009c1b13f36"
-  integrity sha512-hSAifV3k+i6lEoCJ2k6R2Z/rp/H3+8sdmcn5NrS3/3kE7+RyZXm9aqvxWqjEXHAd8b0pShatpcdMTvEdvAJltQ==
+typescript@4.0.5:
+  version "4.0.5"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.5.tgz#ae9dddfd1069f1cb5beb3ef3b2170dd7c1332389"
+  integrity sha512-ywmr/VrTVCmNTJ6iV2LwIrfG1P+lv6luD8sUJs+2eI9NLGigaN+nUQc13iHqisq7bra9lnmUSYqbJvegraBOPQ==
 
 typical@^2.6.1:
   version "2.6.1"
@@ -9495,22 +9845,23 @@
     semver-diff "^2.0.0"
     xdg-basedir "^3.0.0"
 
-update-notifier@^4.1.0:
-  version "4.1.0"
-  resolved "https://registry.yarnpkg.com/update-notifier/-/update-notifier-4.1.0.tgz#4866b98c3bc5b5473c020b1250583628f9a328f3"
-  integrity sha512-w3doE1qtI0/ZmgeoDoARmI5fjDoT93IfKgEGqm26dGUOh8oNpaSTsGNdYRN/SjOuo10jcJGwkEL3mroKzktkew==
+update-notifier@^5.0.0:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/update-notifier/-/update-notifier-5.0.1.tgz#1f92d45fb1f70b9e33880a72dd262bc12d22c20d"
+  integrity sha512-BuVpRdlwxeIOvmc32AGYvO1KVdPlsmqSh8KDDBxS6kDE5VR7R8OMP1d8MdhaVBvxl4H3551k9akXr0Y1iIB2Wg==
   dependencies:
     boxen "^4.2.0"
-    chalk "^3.0.0"
+    chalk "^4.1.0"
     configstore "^5.0.1"
     has-yarn "^2.1.0"
     import-lazy "^2.1.0"
     is-ci "^2.0.0"
-    is-installed-globally "^0.3.1"
-    is-npm "^4.0.0"
+    is-installed-globally "^0.3.2"
+    is-npm "^5.0.0"
     is-yarn-global "^0.3.0"
-    latest-version "^5.0.0"
-    pupa "^2.0.1"
+    latest-version "^5.1.0"
+    pupa "^2.1.1"
+    semver "^7.3.2"
     semver-diff "^3.1.1"
     xdg-basedir "^4.0.0"
 
@@ -9881,7 +10232,7 @@
     p-try "^2.1.0"
     pify "^4.0.1"
 
-word-wrap@~1.2.3:
+word-wrap@^1.2.3:
   version "1.2.3"
   resolved "https://registry.yarnpkg.com/word-wrap/-/word-wrap-1.2.3.tgz#610636f6b1f703891bd34771ccb17fb93b47079c"
   integrity sha512-Hz/mrNwitNRh/HUAtM/VT/5VH+ygD6DV7mYKZAtHOrbs8U7lvPS6xf7EJKMF0uW1KJCl0H701g3ZGus+muE5vQ==
@@ -9932,13 +10283,6 @@
     signal-exit "^3.0.2"
     typedarray-to-buffer "^3.1.5"
 
-write@1.0.3:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/write/-/write-1.0.3.tgz#0800e14523b923a387e415123c865616aae0f5c3"
-  integrity sha512-/lg70HAjtkUgWPVZhZcm+T4hkL8Zbtp1nFNOn3lRrxnlv50SRBv7cR7RqR+GMsd3hUXy9hWBo4CHTbFTcOYwig==
-  dependencies:
-    mkdirp "^0.5.1"
-
 ws@^7.1.2:
   version "7.2.1"
   resolved "https://registry.yarnpkg.com/ws/-/ws-7.2.1.tgz#03ed52423cd744084b2cf42ed197c8b65a936b8e"
@@ -9998,13 +10342,15 @@
   resolved "https://registry.yarnpkg.com/yallist/-/yallist-3.0.3.tgz#b4b049e314be545e3ce802236d6cd22cd91c3de9"
   integrity sha512-S+Zk8DEWE6oKpV+vI3qWkaK+jSbIK86pCwe2IF/xwIpQ8jEuxpw9NyaGjmp9+BoJv5FV2piqCDcoCtStppiq2A==
 
-yargs-parser@^18.1.3:
-  version "18.1.3"
-  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-18.1.3.tgz#be68c4975c6b2abf469236b0c870362fab09a7b0"
-  integrity sha512-o50j0JeToy/4K6OZcaQmW6lyXXKhq7csREXcDwk2omFPJEwUNOVtJKvmDr9EI1fAJZUyZcRF7kxGBWmRXudrCQ==
-  dependencies:
-    camelcase "^5.0.0"
-    decamelize "^1.2.0"
+yallist@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/yallist/-/yallist-4.0.0.tgz#9bb92790d9c0effec63be73519e11a35019a3a72"
+  integrity sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A==
+
+yargs-parser@^20.2.3:
+  version "20.2.4"
+  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-20.2.4.tgz#b42890f14566796f85ae8e3a25290d205f154a54"
+  integrity sha512-WOkpgNhPTlE73h4VFAFsOnomJVaovO8VqLDzy5saChRBFQFBoMYirowyW+Q9HB4HFF4Z7VZTiG3iSzJJA29yRA==
 
 yauzl@^2.10.0:
   version "2.10.0"