diff --git a/Documentation/dev-design-doc-conclusion-template.md b/Documentation/dev-design-doc-conclusion-template.md
index 36bfa2a..0625f2b 100644
--- a/Documentation/dev-design-doc-conclusion-template.md
+++ b/Documentation/dev-design-doc-conclusion-template.md
@@ -1,3 +1,13 @@
+---
+title: "Design Doc - ${title} - Conclusion"
+sidebar: gerritdoc_sidebar
+permalink: design-doc-${folder-name}-conclusion.html
+hide_sidebar: true
+hide_navtoggle: true
+toc: false
+folder: design-docs/${folder-name}
+---
+
 # Conclusion
 
 Describe which decision was made and what were the reasons for it.
diff --git a/Documentation/dev-design-doc-index-template.md b/Documentation/dev-design-doc-index-template.md
index 604126d..10b4a81 100644
--- a/Documentation/dev-design-doc-index-template.md
+++ b/Documentation/dev-design-doc-index-template.md
@@ -1,3 +1,13 @@
+---
+title: "Design Doc - ${title}"
+sidebar: gerritdoc_sidebar
+permalink: design-doc-${folder-name}.html
+hide_sidebar: true
+hide_navtoggle: true
+toc: false
+folder: design-docs/${folder-name}
+---
+
 # Design Doc - ${title}
 
 * [Use Cases](use-cases.html)
diff --git a/Documentation/dev-design-doc-solution-template.md b/Documentation/dev-design-doc-solution-template.md
index 66b8ae7..8935902 100644
--- a/Documentation/dev-design-doc-solution-template.md
+++ b/Documentation/dev-design-doc-solution-template.md
@@ -1,3 +1,13 @@
+---
+title: "Design Doc - ${title} - Solution - ${solution-name}"
+sidebar: gerritdoc_sidebar
+permalink: design-doc-${folder-name}-solution-${solution-name}.html
+hide_sidebar: true
+hide_navtoggle: true
+toc: false
+folder: design-docs/${folder-name}
+---
+
 # Solution - ${solution-name}
 
 ## <a id="overview"> Overview
@@ -20,8 +30,13 @@
 
 ### <a id="scalability"> Scalability
 
-How does the solution scale? Consider both, data size increase (if
-applicable) and traffic increase (if applicable).
+How does the solution scale?
+
+If applicable, consider:
+
+* data size increase
+* traffic increase
+* effects on replication across sites (master-slave and master-master)
 
 ## <a id="alternatives-considered"> Alternatives Considered
 
diff --git a/Documentation/dev-design-doc-use-cases-template.md b/Documentation/dev-design-doc-use-cases-template.md
index 704ad14c..02c2fb5 100644
--- a/Documentation/dev-design-doc-use-cases-template.md
+++ b/Documentation/dev-design-doc-use-cases-template.md
@@ -1,3 +1,13 @@
+---
+title: "Design Doc - ${title} - Use Cases"
+sidebar: gerritdoc_sidebar
+permalink: design-doc-${folder-name}-use-cases.html
+hide_sidebar: true
+hide_navtoggle: true
+toc: false
+folder: design-docs/${folder-name}
+---
+
 # Use Cases
 
 In a few sentences, describe the use-cases as interactions between a
diff --git a/WORKSPACE b/WORKSPACE
index 350dba1..6a86c19 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -1251,8 +1251,8 @@
 bower_archive(
     name = "page",
     package = "visionmedia/page.js",
-    sha1 = "51a05428dd4f68fae1df5f12d0e2b61ba67f7757",
-    version = "1.7.1",
+    sha1 = "4a31889cd75cc5e7f68a4c7f256eecaf27102eee",
+    version = "1.11.4",
 )
 
 bower_archive(
diff --git a/contrib/refresh_plugin_in_testsite.sh b/contrib/refresh_plugin_in_testsite.sh
new file mode 100755
index 0000000..bb42ce8
--- /dev/null
+++ b/contrib/refresh_plugin_in_testsite.sh
@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+# 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.
+
+# This script compiles a Gerrit plugin whose name is passed as first parameter
+# and copies it over to the plugin folder of the testsite. The path to the
+# testsite needs to be provided by the variable GERRIT_TESTSITE or as second
+# parameter.
+
+SCRIPT_DIR=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")
+GERRIT_CODE_DIR="$SCRIPT_DIR/.."
+cd "$GERRIT_CODE_DIR"
+
+if [ "$#" -lt 1 ]
+then
+  echo "No plugin name provided as first argument. Stopping."
+  exit 1
+else
+  PLUGIN_NAME="$1"
+fi
+
+
+if [ "$#" -lt 2 ]
+then
+  if [ -z ${GERRIT_TESTSITE+x} ]
+  then
+    echo "Path to local testsite is neiter set as GERRIT_TESTSITE nor passed as second argument. Stopping."
+    exit 1
+  fi
+else
+  GERRIT_TESTSITE="$2"
+fi
+
+if [ ! -d "$GERRIT_TESTSITE" ]
+then
+  echo "Testsite directory $GERRIT_TESTSITE does not exist. Stopping."
+  exit 1
+fi
+
+bazel build //plugins/"$PLUGIN_NAME"/...
+if [ $? -ne 0 ]
+then
+  echo "Building the $PLUGIN_NAME plugin failed"
+  exit 1
+fi
+
+yes | cp -f "$GERRIT_CODE_DIR/bazel-genfiles/plugins/$PLUGIN_NAME/$PLUGIN_NAME.jar" "$GERRIT_TESTSITE/plugins/"
+if [ $? -eq 0 ]
+then
+  echo "Plugin $PLUGIN_NAME copied successfully to testsite."
+fi
diff --git a/contrib/show_new_gerrit_doc_in_chrome.sh b/contrib/show_new_gerrit_doc_in_chrome.sh
new file mode 100755
index 0000000..d57bc8a
--- /dev/null
+++ b/contrib/show_new_gerrit_doc_in_chrome.sh
@@ -0,0 +1,48 @@
+#!/bin/bash
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script builds Gerrit's documentation and shows the current state in
+# Chrome. Specific pages (e.g. rest-api-changes.txt) including anchors can be
+# passed as parameter to jump directly to them.
+
+SCRIPT_DIR=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")
+GERRIT_CODE_DIR="$SCRIPT_DIR/.."
+cd "$GERRIT_CODE_DIR"
+
+bazel build Documentation:searchfree
+if [ $? -ne 0 ]
+then
+  echo "Building the documentation failed. Stopping."
+  exit 1
+fi
+
+TMP_DOCS_DIR=/tmp/gerrit_docs
+rm -rf "$TMP_DOCS_DIR"
+unzip bazel-bin/Documentation/searchfree.zip -d "$TMP_DOCS_DIR" </dev/null >/dev/null 2>&1 & disown
+if [ $? -ne 0 ]
+then
+  echo "Unzipping the documentation to $TMP_DOCS_DIR failed. Stopping."
+  exit 1
+fi
+
+if [ "$#" -lt 1 ]
+then
+  FILE_NAME="index.html"
+else
+  FILE_NAME="$1"
+fi
+DOC_FILE_NAME="${FILE_NAME/.txt/.html}"
+google-chrome "file:///$TMP_DOCS_DIR/Documentation/$DOC_FILE_NAME" </dev/null >/dev/null 2>&1 & disown
diff --git a/contrib/start_testsite.sh b/contrib/start_testsite.sh
new file mode 100755
index 0000000..014eba9
--- /dev/null
+++ b/contrib/start_testsite.sh
@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+# 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.
+
+# This script starts the local testsite in debug mode. If the flag "-u" is
+# passed, Gerrit is built from the current state of the repository and the
+# testsite is refreshed. The path to the testsite needs to be provided by
+# the variable GERRIT_TESTSITE or as parameter (after any used flags).
+# The testsite can be stopped by interrupting this script.
+
+SCRIPT_DIR=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")
+GERRIT_CODE_DIR="$SCRIPT_DIR/.."
+cd "$GERRIT_CODE_DIR"
+
+UPDATE=false
+while getopts ':u' flag; do
+  case "${flag}" in
+    u) UPDATE=true ;;
+  esac
+done
+shift $(($OPTIND-1))
+
+if [ "$#" -lt 1 ]
+then
+  if [ -z ${GERRIT_TESTSITE+x} ]
+  then
+    echo "Path to local testsite is neither set as GERRIT_TESTSITE nor passed as first argument. Stopping."
+    exit 1
+  fi
+else
+  GERRIT_TESTSITE="$1"
+fi
+
+if [ "$UPDATE" = true ]
+then
+  echo "Refreshing testsite"
+  bazel build gerrit
+  if [ $? -ne 0 ]
+  then
+    echo "Build failed. Stopping."
+    exit 1
+  fi
+  $(bazel info output_base)/external/local_jdk/bin/java -jar bazel-bin/gerrit.war init --batch -d "$GERRIT_TESTSITE"
+  if [ $? -ne 0 ]
+  then
+    echo "Patching the testsite failed. Stopping."
+    exit 1
+  fi
+fi
+
+$(bazel info output_base)/external/local_jdk/bin/java -jar -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005 bazel-bin/gerrit.war daemon -d "$GERRIT_TESTSITE" --console-log
diff --git a/java/com/google/gerrit/httpd/ProjectBasicAuthFilter.java b/java/com/google/gerrit/httpd/ProjectBasicAuthFilter.java
index e3ab70d..aa38c27 100644
--- a/java/com/google/gerrit/httpd/ProjectBasicAuthFilter.java
+++ b/java/com/google/gerrit/httpd/ProjectBasicAuthFilter.java
@@ -31,6 +31,7 @@
 import com.google.gerrit.server.account.AuthRequest;
 import com.google.gerrit.server.account.AuthResult;
 import com.google.gerrit.server.account.AuthenticationFailedException;
+import com.google.gerrit.server.account.externalids.PasswordVerifier;
 import com.google.gerrit.server.auth.NoSuchUserException;
 import com.google.gerrit.server.config.AuthConfig;
 import com.google.inject.Inject;
@@ -140,7 +141,7 @@
     GitBasicAuthPolicy gitBasicAuthPolicy = authConfig.getGitBasicAuthPolicy();
     if (gitBasicAuthPolicy == GitBasicAuthPolicy.HTTP
         || gitBasicAuthPolicy == GitBasicAuthPolicy.HTTP_LDAP) {
-      if (who.checkPassword(password, username)) {
+      if (PasswordVerifier.checkPassword(who.getExternalIds(), username, password)) {
         return succeedAuthentication(who);
       }
     }
@@ -157,7 +158,7 @@
       setUserIdentified(whoAuthResult.getAccountId());
       return true;
     } catch (NoSuchUserException e) {
-      if (who.checkPassword(password, username)) {
+      if (PasswordVerifier.checkPassword(who.getExternalIds(), username, password)) {
         return succeedAuthentication(who);
       }
       logger.atWarning().withCause(e).log(authenticationFailedMsg(username, req));
diff --git a/java/com/google/gerrit/json/EnumTypeAdapterFactory.java b/java/com/google/gerrit/json/EnumTypeAdapterFactory.java
index dc74f67..21c4891 100644
--- a/java/com/google/gerrit/json/EnumTypeAdapterFactory.java
+++ b/java/com/google/gerrit/json/EnumTypeAdapterFactory.java
@@ -34,7 +34,7 @@
 public class EnumTypeAdapterFactory implements TypeAdapterFactory {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  @SuppressWarnings({"unchecked"})
+  @SuppressWarnings({"rawtypes", "unchecked"})
   @Override
   public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
     TypeAdapter<T> defaultEnumAdapter = TypeAdapters.ENUM_FACTORY.create(gson, typeToken);
@@ -43,7 +43,7 @@
       return null;
     }
 
-    return (TypeAdapter<T>) new EnumTypeAdapter(defaultEnumAdapter, typeToken);
+    return new EnumTypeAdapter(defaultEnumAdapter, typeToken);
   }
 
   private static class EnumTypeAdapter<T extends Enum<T>> extends TypeAdapter<T> {
diff --git a/java/com/google/gerrit/server/account/AccountState.java b/java/com/google/gerrit/server/account/AccountState.java
index 8555166..6eb6ca1 100644
--- a/java/com/google/gerrit/server/account/AccountState.java
+++ b/java/com/google/gerrit/server/account/AccountState.java
@@ -14,13 +14,9 @@
 
 package com.google.gerrit.server.account;
 
-import static com.google.gerrit.server.account.externalids.ExternalId.SCHEME_USERNAME;
-
 import com.google.common.base.MoreObjects;
-import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.client.DiffPreferencesInfo;
 import com.google.gerrit.extensions.client.EditPreferencesInfo;
@@ -34,7 +30,6 @@
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Optional;
-import org.apache.commons.codec.DecoderException;
 import org.eclipse.jgit.lib.ObjectId;
 
 /**
@@ -45,8 +40,6 @@
  * account cache (see {@link AccountCache#get(Account.Id)}).
  */
 public class AccountState {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
   /**
    * Creates an AccountState from the given account config.
    *
@@ -175,29 +168,6 @@
     return userName;
   }
 
-  public boolean checkPassword(@Nullable String password, String username) {
-    if (password == null) {
-      return false;
-    }
-    for (ExternalId id : getExternalIds()) {
-      // Only process the "username:$USER" entry, which is unique.
-      if (!id.isScheme(SCHEME_USERNAME) || !username.equals(id.key().id())) {
-        continue;
-      }
-
-      String hashedStr = id.password();
-      if (!Strings.isNullOrEmpty(hashedStr)) {
-        try {
-          return HashedPassword.decode(hashedStr).checkPassword(password);
-        } catch (DecoderException e) {
-          logger.atSevere().log("DecoderException for user %s: %s ", username, e.getMessage());
-          return false;
-        }
-      }
-    }
-    return false;
-  }
-
   /** The external identities that identify the account holder. */
   public ImmutableSet<ExternalId> getExternalIds() {
     return externalIds;
diff --git a/java/com/google/gerrit/server/account/externalids/PasswordVerifier.java b/java/com/google/gerrit/server/account/externalids/PasswordVerifier.java
new file mode 100644
index 0000000..e4bf27b
--- /dev/null
+++ b/java/com/google/gerrit/server/account/externalids/PasswordVerifier.java
@@ -0,0 +1,54 @@
+// 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.account.externalids;
+
+import static com.google.gerrit.server.account.externalids.ExternalId.SCHEME_USERNAME;
+
+import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.server.account.HashedPassword;
+import java.util.Collection;
+import org.apache.commons.codec.DecoderException;
+
+/** Checks if a given username and password match a user's external IDs. */
+public class PasswordVerifier {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  /** Returns {@code true} if there is an external ID matching both the username and password. */
+  public static boolean checkPassword(
+      Collection<ExternalId> externalIds, String username, @Nullable String password) {
+    if (password == null) {
+      return false;
+    }
+    for (ExternalId id : externalIds) {
+      // Only process the "username:$USER" entry, which is unique.
+      if (!id.isScheme(SCHEME_USERNAME) || !username.equals(id.key().id())) {
+        continue;
+      }
+
+      String hashedStr = id.password();
+      if (!Strings.isNullOrEmpty(hashedStr)) {
+        try {
+          return HashedPassword.decode(hashedStr).checkPassword(password);
+        } catch (DecoderException e) {
+          logger.atSevere().log("DecoderException for user %s: %s ", username, e.getMessage());
+          return false;
+        }
+      }
+    }
+    return false;
+  }
+}
diff --git a/java/com/google/gerrit/server/auth/InternalAuthBackend.java b/java/com/google/gerrit/server/auth/InternalAuthBackend.java
index c06c66b..2821bf6 100644
--- a/java/com/google/gerrit/server/auth/InternalAuthBackend.java
+++ b/java/com/google/gerrit/server/auth/InternalAuthBackend.java
@@ -16,6 +16,7 @@
 
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.account.externalids.PasswordVerifier;
 import com.google.gerrit.server.config.AuthConfig;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
@@ -62,7 +63,7 @@
               + ": account inactive or not provisioned in Gerrit");
     }
 
-    if (!who.checkPassword(req.getPassword().get(), username)) {
+    if (!PasswordVerifier.checkPassword(who.getExternalIds(), username, req.getPassword().get())) {
       throw new InvalidCredentialsException();
     }
     return new AuthUser(AuthUser.UUID.create(username), username);
diff --git a/javatests/com/google/gerrit/json/JsonEnumMappingTest.java b/javatests/com/google/gerrit/json/JsonEnumMappingTest.java
index 6e57b01..dd710f9 100644
--- a/javatests/com/google/gerrit/json/JsonEnumMappingTest.java
+++ b/javatests/com/google/gerrit/json/JsonEnumMappingTest.java
@@ -71,10 +71,6 @@
 
   private static class TestData {
     TestEnum value;
-
-    public TestData(TestEnum value) {
-      this.value = value;
-    }
   }
 
   private enum TestEnum {
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
index 077af1f..8500e3b 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
@@ -159,6 +159,11 @@
     },
 
     _computePreferences(account, preferences) {
+      // Polymer 2: check for undefined
+      if ([account, preferences].some(arg => arg === undefined)) {
+        return;
+      }
+
       this.changeTableColumns = this.columnNames;
 
       if (account) {
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
index 90641df..54e2edd 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
@@ -590,6 +590,15 @@
 
     _actionsChanged(actionsChangeRecord, revisionActionsChangeRecord,
         additionalActionsChangeRecord) {
+      // Polymer 2: check for undefined
+      if ([
+        actionsChangeRecord,
+        revisionActionsChangeRecord,
+        additionalActionsChangeRecord,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       const additionalActions = (additionalActionsChangeRecord &&
           additionalActionsChangeRecord.base) || [];
       this.hidden = this._keyCount(actionsChangeRecord) === 0 &&
@@ -620,6 +629,15 @@
 
     _editStatusChanged(editMode, editPatchsetLoaded,
         editBasedOnCurrentPatchSet, disableEdit) {
+      // Polymer 2: check for undefined
+      if ([
+        editMode,
+        editBasedOnCurrentPatchSet,
+        disableEdit,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (disableEdit) {
         this._deleteAndNotify('publishEdit');
         this._deleteAndNotify('rebaseEdit');
@@ -1344,6 +1362,17 @@
      */
     _computeAllActions(changeActionsRecord, revisionActionsRecord,
         primariesRecord, additionalActionsRecord, change) {
+      // Polymer 2: check for undefined
+      if ([
+        changeActionsRecord,
+        revisionActionsRecord,
+        primariesRecord,
+        additionalActionsRecord,
+        change,
+      ].some(arg => arg === undefined)) {
+        return [];
+      }
+
       const revisionActionValues = this._getActionValues(revisionActionsRecord,
           primariesRecord, additionalActionsRecord, ActionType.REVISION);
       const changeActionValues = this._getActionValues(changeActionsRecord,
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
index 154fc36..2b6528a 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.js
@@ -438,7 +438,7 @@
     },
 
     _computeParents(change) {
-      if (!change.current_revision ||
+      if (!change || !change.current_revision ||
           !change.revisions[change.current_revision] ||
           !change.revisions[change.current_revision].commit) {
         return undefined;
@@ -447,13 +447,13 @@
     },
 
     _computeParentsLabel(parents) {
-      return parents.length > 1 ? 'Parents' : 'Parent';
+      return parents && parents.length > 1 ? 'Parents' : 'Parent';
     },
 
     _computeParentListClass(parents, parentIsCurrent) {
       return [
         'parentList',
-        parents.length > 1 ? 'merge' : 'nonMerge',
+        parents && parents.length > 1 ? 'merge' : 'nonMerge',
         parentIsCurrent ? 'current' : 'notCurrent',
       ].join(' ');
     },
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index 3a5f326..05bbb5b 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -60,6 +60,7 @@
   };
 
   const CHANGE_DATA_TIMING_LABEL = 'ChangeDataLoaded';
+  const CHANGE_RELOAD_TIMING_LABEL = 'ChangeReloaded';
   const SEND_REPLY_TIMING_LABEL = 'SendReply';
 
   Polymer({
@@ -303,6 +304,7 @@
       '_labelsChanged(_change.labels.*)',
       '_paramsAndChangeChanged(params, _change)',
       '_patchNumChanged(_patchRange.patchNum)',
+      '_loadDynamicTabHeaderAndContent(_change, _selectedRevision)',
     ],
 
     keyboardShortcuts() {
@@ -337,17 +339,6 @@
         this._setDiffViewMode();
       });
 
-      Gerrit.awaitPluginsLoaded().then(() => {
-        this._dynamicTabHeaderEndpoints =
-            Gerrit._endpoints.getDynamicEndpoints('change-view-tab-header');
-        this._dynamicTabContentEndpoints =
-            Gerrit._endpoints.getDynamicEndpoints('change-view-tab-content');
-        if (this._dynamicTabContentEndpoints.length
-            !== this._dynamicTabHeaderEndpoints.length) {
-          console.warn('Different number of tab headers and tab content.');
-        }
-      });
-
       this.addEventListener('comment-save', this._handleCommentSave.bind(this));
       this.addEventListener('comment-refresh', this._reloadDrafts.bind(this));
       this.addEventListener('comment-discard',
@@ -770,7 +761,47 @@
       });
     },
 
-    _paramsAndChangeChanged(value) {
+    /**
+     * We use an observer to observe 'change' and 'selectedRevision'
+     * variables. This fixes an issue under Polymer 2 so that the dynamic
+     * plugins loads when these variables load.
+     */
+    _loadDynamicTabHeaderAndContent(change, selectedRevision) {
+      // These vars are unused, but because primaryTabs extension point
+      // uses it, we makes sure we doin't load the plugin until these vars
+      // exist.
+      if (!change || !selectedRevision) return;
+
+      // We cache the _dynamicTabHeaderEndpoints and _dynamicTabContentEndpoints
+      // var so that we doin't keep loading the same dynamic plugin
+      // over and over when 'change' or 'selectedRevision' change.
+      if (this._dynamicTabHeaderEndpoints || this._dynamicTabContentEndpoints) {
+        return;
+      }
+
+      Gerrit.awaitPluginsLoaded().then(() => {
+        this._dynamicTabHeaderEndpoints =
+            Gerrit._endpoints.getDynamicEndpoints('change-view-tab-header');
+        this._dynamicTabContentEndpoints =
+            Gerrit._endpoints.getDynamicEndpoints('change-view-tab-content');
+        if (this._dynamicTabContentEndpoints.length
+            !== this._dynamicTabHeaderEndpoints.length) {
+          console.warn('Different number of tab headers and tab content.');
+        }
+      }).then(() => {
+        // We need a second then(..) to ensure that the dynamic endpoints
+        // are created before we call _performPostLoadTasks(). This ensures it has
+        // enough time before the primary tab gets selected.
+        this._performPostLoadTasks();
+      });
+    },
+
+    _paramsAndChangeChanged(value, change) {
+      // Polymer 2: check for undefined
+      if ([value, change].some(arg => arg === undefined)) {
+        return;
+      }
+
       // If the change number or patch range is different, then reset the
       // selected file index.
       const patchRangeState = this.viewState.patchRange;
@@ -909,8 +940,8 @@
       return 'PARENT';
     },
 
-    _computeShowPrimaryTabs(dynamicTabContentEndpoints) {
-      return dynamicTabContentEndpoints.length > 0;
+    _computeShowPrimaryTabs(dynamicTabHeaderEndpoints) {
+      return dynamicTabHeaderEndpoints && dynamicTabHeaderEndpoints.length > 0;
     },
 
     _computeChangeUrl(change) {
@@ -1358,15 +1389,17 @@
 
     /**
      * Reload the change.
-     * @param {boolean=} opt_reloadRelatedChanges Reloads the related chanegs
-     *     when true.
+     * @param {boolean=} opt_isLocationChange Reloads the related changes
+     *     when true and ends reporting events that started on location change.
      * @return {Promise} A promise that resolves when the core data has loaded.
      *     Some non-core data loading may still be in-flight when the core data
      *     promise resolves.
      */
-    _reload(opt_reloadRelatedChanges) {
+    _reload(opt_isLocationChange) {
       this._loading = true;
       this._relatedChangesCollapsed = true;
+      this.$.reporting.time(CHANGE_RELOAD_TIMING_LABEL);
+      this.$.reporting.time(CHANGE_DATA_TIMING_LABEL);
 
       // Array to house all promises related to data requests.
       const allDataPromises = [];
@@ -1380,7 +1413,12 @@
       // change content may start appearing.
       const loadingFlagSet = detailCompletes
           .then(() => { this._loading = false; })
-          .then(() => { this.$.reporting.changeDisplayed(); });
+          .then(() => {
+            this.$.reporting.timeEnd(CHANGE_RELOAD_TIMING_LABEL);
+            if (opt_isLocationChange) {
+              this.$.reporting.changeDisplayed();
+            }
+          });
 
       // Resolves when the project config has loaded.
       const projectConfigLoaded = detailCompletes
@@ -1440,16 +1478,17 @@
         coreDataPromise = mergeabilityLoaded;
       }
 
-      if (opt_reloadRelatedChanges) {
+      if (opt_isLocationChange) {
         const relatedChangesLoaded = coreDataPromise
             .then(() => this.$.relatedChanges.reload());
         allDataPromises.push(relatedChangesLoaded);
       }
 
-      this.$.reporting.time(CHANGE_DATA_TIMING_LABEL);
       Promise.all(allDataPromises).then(() => {
         this.$.reporting.timeEnd(CHANGE_DATA_TIMING_LABEL);
-        this.$.reporting.changeFullyLoaded();
+        if (opt_isLocationChange) {
+          this.$.reporting.changeFullyLoaded();
+        }
       });
 
       return coreDataPromise;
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index e8de93b..79d8d93 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -1844,5 +1844,50 @@
       MockInteractions.tap(element.$.changeStar.$$('button'));
       assert.isTrue(stub.called);
     });
+
+    suite('gr-reporting tests', () => {
+      setup(() => {
+        element._patchRange = {
+          basePatchNum: 'PARENT',
+          patchNum: 1,
+        };
+        sandbox.stub(element, '_getChangeDetail').returns(Promise.resolve());
+        sandbox.stub(element, '_getProjectConfig').returns(Promise.resolve());
+        sandbox.stub(element, '_reloadComments').returns(Promise.resolve());
+        sandbox.stub(element, '_getMergeability').returns(Promise.resolve());
+        sandbox.stub(element, '_getLatestCommitMessage')
+            .returns(Promise.resolve());
+      });
+
+      test('don\'t report changedDisplayed on reply', done => {
+        const changeDisplayStub =
+          sandbox.stub(element.$.reporting, 'changeDisplayed');
+        const changeFullyLoadedStub =
+          sandbox.stub(element.$.reporting, 'changeFullyLoaded');
+        element._handleReplySent();
+        flush(() => {
+          assert.isFalse(changeDisplayStub.called);
+          assert.isFalse(changeFullyLoadedStub.called);
+          done();
+        });
+      });
+
+      test('report changedDisplayed on _paramsChanged', done => {
+        const changeDisplayStub =
+          sandbox.stub(element.$.reporting, 'changeDisplayed');
+        const changeFullyLoadedStub =
+          sandbox.stub(element.$.reporting, 'changeFullyLoaded');
+        element._paramsChanged({
+          view: Gerrit.Nav.View.CHANGE,
+          changeNum: 101,
+          project: 'test-project',
+        });
+        flush(() => {
+          assert.isTrue(changeDisplayStub.called);
+          assert.isTrue(changeFullyLoadedStub.called);
+          done();
+        });
+      });
+    });
   });
 </script>
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.js b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.js
index f4523cf..2f098de 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.js
@@ -60,6 +60,15 @@
     ],
 
     _computeMessage(changeStatus, commitNum, commitMessage) {
+      // Polymer 2: check for undefined
+      if ([
+        changeStatus,
+        commitNum,
+        commitMessage,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       let newMessage = commitMessage;
 
       if (changeStatus === 'MERGED') {
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.js b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.js
index 1c3bcfb..22ce27e 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.js
@@ -144,6 +144,11 @@
      * the corresponding value to be submitted.
      */
     _updateSelectedOption(rebaseOnCurrent, hasParent) {
+      // Polymer 2: check for undefined
+      if ([rebaseOnCurrent, hasParent].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (this._displayParentOption(rebaseOnCurrent, hasParent)) {
         this.$.rebaseOnParentInput.checked = true;
       } else if (this._displayTipOption(rebaseOnCurrent, hasParent)) {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
index a802fb9..aff1e0a 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
@@ -137,6 +137,11 @@
     },
 
     _computePatchSetDescription(change, patchNum) {
+      // Polymer 2: check for undefined
+      if ([change, patchNum].some(arg => arg === undefined)) {
+        return;
+      }
+
       const rev = this.getRevisionByPatchNum(change.revisions, patchNum);
       this._patchsetDescription = (rev && rev.description) ?
           rev.description.substring(0, PATCH_DESC_MAX_LENGTH) : '';
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
index 4f160e4..1620610 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
@@ -817,6 +817,17 @@
     },
 
     _computeFiles(filesByPath, changeComments, patchRange, reviewed, loading) {
+      // Polymer 2: check for undefined
+      if ([
+        filesByPath,
+        changeComments,
+        patchRange,
+        reviewed,
+        loading,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       // Await all promises resolving from reload. @See Issue 9057
       if (loading || !changeComments) { return; }
 
@@ -904,6 +915,11 @@
     },
 
     _computePatchSetDescription(revisions, patchNum) {
+      // Polymer 2: check for undefined
+      if ([revisions, patchNum].some(arg => arg === undefined)) {
+        return '';
+      }
+
       const rev = this.getRevisionByPatchNum(revisions, patchNum);
       return (rev && rev.description) ?
           rev.description.substring(0, PATCH_DESC_MAX_LENGTH) : '';
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
index eeec437..4166511 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
@@ -292,6 +292,17 @@
 
     _resultsChanged(related, submittedTogether, conflicts,
         cherryPicks, sameTopic) {
+      // Polymer 2: check for undefined
+      if ([
+        related,
+        submittedTogether,
+        conflicts,
+        cherryPicks,
+        sameTopic,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       const results = [
         related && related.changes,
         submittedTogether && submittedTogether.changes,
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
index cd42606..640cbc8 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
@@ -623,6 +623,11 @@
     },
 
     _changeUpdated(changeRecord, owner) {
+      // Polymer 2: check for undefined
+      if ([changeRecord, owner].some(arg => arg === undefined)) {
+        return;
+      }
+
       this._rebuildReviewerArrays(changeRecord.base, owner);
     },
 
diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
index 43ea7f0..63e0647 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
@@ -165,6 +165,11 @@
     },
 
     _reviewersChanged(changeRecord, owner) {
+      // Polymer 2: check for undefined
+      if ([changeRecord, owner].some(arg => arg === undefined)) {
+        return;
+      }
+
       let result = [];
       const reviewers = changeRecord.base;
       for (const key in reviewers) {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
index 2c14609..bce3d07 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
@@ -742,6 +742,15 @@
     _whitespaceChanged(
         preferredWhitespaceLevel, loadedWhitespaceLevel,
         noRenderOnPrefsChange) {
+      // Polymer 2: check for undefined
+      if ([
+        preferredWhitespaceLevel,
+        loadedWhitespaceLevel,
+        noRenderOnPrefsChange,
+      ].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (preferredWhitespaceLevel !== loadedWhitespaceLevel &&
           !noRenderOnPrefsChange) {
         this.reload();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
index d604df2..0c1facd 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
@@ -260,6 +260,11 @@
     },
 
     _getFiles(changeNum, patchRangeRecord) {
+      // Polymer 2: check for undefined
+      if ([changeNum, patchRangeRecord].some(arg => arg === undefined)) {
+        return;
+      }
+
       const patchRange = patchRangeRecord.base;
       return this.$.restAPI.getChangeFilePathsAsSpeciallySortedArray(
           changeNum, patchRange).then(files => {
@@ -680,6 +685,11 @@
     },
 
     _setReviewedObserver(_loggedIn, paramsRecord, _prefs) {
+      // Polymer 2: check for undefined
+      if ([_loggedIn, paramsRecord, _prefs].some(arg => arg === undefined)) {
+        return;
+      }
+
       const params = paramsRecord.base || {};
       if (!_loggedIn) { return; }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index 1bafe48..c69b313 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -297,6 +297,11 @@
     },
 
     _enableSelectionObserver(loggedIn, isAttached) {
+      // Polymer 2: check for undefined
+      if ([loggedIn, isAttached].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (loggedIn && isAttached) {
         this.listen(document, 'selectionchange', '_handleSelectionChange');
         this.listen(document, 'mouseup', '_handleMouseUp');
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
index 5603391..7f0a754 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
@@ -159,6 +159,9 @@
     ],
 
     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.fire('title-change', {title: 'Settings'});
 
       this._isDark = !!window.localStorage.getItem('dark-theme');
@@ -215,9 +218,28 @@
 
       this._loadingPromise = Promise.all(promises).then(() => {
         this._loading = false;
+
+        // Handle anchor tag for initial load
+        this._handleLocationChange();
       });
     },
 
+    detached() {
+      this.unlisten(window, 'location-change', '_handleLocationChange');
+    },
+
+    _handleLocationChange() {
+      // Handle anchor tag after dom attached
+      const urlHash = window.location.hash;
+      if (urlHash) {
+        // Use shadowRoot for Polymer 2
+        const elem = (this.shadowRoot || document).querySelector(urlHash);
+        if (elem) {
+          elem.scrollIntoView();
+        }
+      }
+    },
+
     reloadAccountDetail() {
       Promise.all([
         this.$.accountInfo.loadData(),
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.html b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.html
index 7f71c89..2f2c7ba 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.html
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.html
@@ -40,14 +40,8 @@
       :host([show-avatar]) .container {
         padding-left: 0;
       }
-      gr-button.remove:hover,
-      gr-button.remove:focus {
-        --gr-button: {
-          color: #333;
-        }
-      }
       gr-button.remove {
-        --gr-button: {
+        --gr-remove-button-style: {
           border: 0;
           color: var(--deemphasized-text-color);
           font-size: 1.7rem;
@@ -59,6 +53,19 @@
           text-decoration: none;
         }
       }
+
+      gr-button.remove:hover,
+      gr-button.remove:focus {
+        --gr-button: {
+          @apply --gr-remove-button-style
+          color: #333;
+        }
+      }
+      gr-button.remove {
+        --gr-button: {
+          @apply --gr-remove-button-style
+        }
+      }
       :host:focus {
         border-color: transparent;
         box-shadow: none;
diff --git a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.html b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.html
index 2b043c4..cc6453c 100644
--- a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.html
+++ b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert.html
@@ -35,7 +35,6 @@
         box-shadow: 0 1px 3px rgba(0, 0, 0, .3);
         color: var(--view-background-color);
         left: 1.25rem;
-        padding: 1em 1.5em;
         position: fixed;
         transform: translateY(5rem);
         transition: transform var(--gr-alert-transition-duration, 80ms) ease-out;
@@ -44,6 +43,17 @@
       :host([shown]) {
         transform: translateY(0);
       }
+      /**
+       * NOTE: To avoid style being overwritten by outside of the shadow DOM
+       * (as outside styles always win), .content-wrapper is introduced as a
+       * wrapper around main content to have better encapsulation, styles that
+       * may be affected by outside should be defined on it.
+       * In this case, `padding:0px` is defined in main.css for all elements
+       * with the universal selector: *.
+       */
+      .content-wrapper {
+        padding: 1em 1.5em;
+      }
       .text {
         color: var(--tooltip-text-color);
         display: inline-block;
@@ -62,12 +72,14 @@
         }
       }
     </style>
-    <span class="text">[[text]]</span>
-    <gr-button
-        link
-        class="action"
-        hidden$="[[_hideActionButton]]"
-        on-tap="_handleActionTap">[[actionText]]</gr-button>
+    <div class="content-wrapper">
+      <span class="text">[[text]]</span>
+      <gr-button
+          link
+          class="action"
+          hidden$="[[_hideActionButton]]"
+          on-tap="_handleActionTap">[[actionText]]</gr-button>
+    </div>
   </template>
   <script src="gr-alert.js"></script>
 </dom-module>
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.html b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.html
index b74e48c..46877d7 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.html
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.html
@@ -76,14 +76,31 @@
         on-focus="_onInputFocus"
         on-blur="_onInputBlur"
         autocomplete="off">
-      <!-- slot is for future use (2.x) while prefix attribute is for 1.x
-        (current) -->
-      <iron-icon
-          icon="gr-icons:search"
-          slot="prefix"
+
+      <template is="dom-if" if="[[_isPolymer2()]]">
+        <!-- Content uses vertical-align:baseline. If iron-icon is placed
+          directly in the slot and is not visible,  vertical-align doesn't
+          work, because display:none convert it from inline-block element to
+          block element. To fix this problem, iron-icon is wrapped in div
+          which never changes display type.
+          The problem doesn't exist in Polymer1 because DOM is different.
+          Applying the same fix to Polymer1 breaks vertical-align.
+        -->
+        <div slot="prefix">
+          <iron-icon
+            icon="gr-icons:search"
+            class$="searchIcon [[_computeShowSearchIconClass(showSearchIcon)]]">
+          </iron-icon>
+        </div>
+      </template>
+      <template is="dom-if" if="[[!_isPolymer2()]]">
+        <iron-icon
           prefix
+          icon="gr-icons:search"
           class$="searchIcon [[_computeShowSearchIconClass(showSearchIcon)]]">
-      </iron-icon>
+        </iron-icon>
+      </template>
+
     </paper-input>
     <gr-autocomplete-dropdown
         vertical-align="top"
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
index c36ec21..af31473 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete.js
@@ -242,8 +242,13 @@
     },
 
     _updateSuggestions(text, threshold, noDebounce) {
+      // Polymer 2: check for undefined
+      if ([text, threshold, noDebounce].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (this._disableSuggestions) { return; }
-      if (text === undefined || text.length < threshold) {
+      if (text.length < threshold) {
         this._suggestions = [];
         this.value = '';
         return;
@@ -420,5 +425,9 @@
     _computeShowSearchIconClass(showSearchIcon) {
       return showSearchIcon ? 'showSearchIcon' : '';
     },
+
+    _isPolymer2() {
+      return window.POLYMER2;
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete_test.html b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete_test.html
index 217321f..cff35b4 100644
--- a/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-autocomplete/gr-autocomplete_test.html
@@ -320,12 +320,15 @@
       });
     });
 
-    test('search icon shows with showSearchIcon property', () => {
-      assert.equal(getComputedStyle(element.$$('iron-icon')).display,
-          'none');
-      element.showSearchIcon = true;
-      assert.notEqual(getComputedStyle(element.$$('iron-icon')).display,
-          'none');
+    test('search icon shows with showSearchIcon property', done => {
+      flush(() => {
+        assert.equal(getComputedStyle(element.$$('iron-icon')).display,
+            'none');
+        element.showSearchIcon = true;
+        assert.notEqual(getComputedStyle(element.$$('iron-icon')).display,
+            'none');
+        done();
+      });
     });
 
     test('vertical offset overridden by param if it exists', () => {
diff --git a/polygerrit-ui/app/elements/shared/gr-button/gr-button.html b/polygerrit-ui/app/elements/shared/gr-button/gr-button.html
index 754c3c0..340297f 100644
--- a/polygerrit-ui/app/elements/shared/gr-button/gr-button.html
+++ b/polygerrit-ui/app/elements/shared/gr-button/gr-button.html
@@ -39,6 +39,37 @@
         text-transform: none;
       }
       paper-button {
+        /* The next lines contains a copy of paper-button style.
+          Without a copy, the @apply works incorrectly with Polymer 2.
+          @apply is deprecated and is not recommended to use. It is expected
+          that @apply will be replaced with the ::part CSS pseudo-element.
+          After replacecment copied lines can be removed.
+        */
+        @apply --layout-inline;
+        @apply --layout-center-center;
+        position: relative;
+        box-sizing: border-box;
+        min-width: 5.14em;
+        margin: 0 0.29em;
+        background: transparent;
+        -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
+        -webkit-tap-highlight-color: transparent;
+        font: inherit;
+        text-transform: uppercase;
+        outline-width: 0;
+        border-radius: 3px;
+        -moz-user-select: none;
+        -ms-user-select: none;
+        -webkit-user-select: none;
+        user-select: none;
+        cursor: pointer;
+        z-index: 0;
+        padding: 0.7em 0.57em;
+
+        @apply --paper-font-common-base;
+        @apply --paper-button;
+        /* End of copy*/
+
         /* paper-button sets this to anti-aliased, which appears different than
           bold font elsewhere on macOS. */
         -webkit-font-smoothing: initial;
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
index 57835a3..cf2f57d 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.js
@@ -211,6 +211,11 @@
     },
 
     _calculateActionstoShow(showActions, isRobotComment) {
+      // Polymer 2: check for undefined
+      if ([showActions, isRobotComment].some(arg => arg === undefined)) {
+        return;
+      }
+
       this._showHumanActions = showActions && !isRobotComment;
       this._showRobotActions = showActions && isRobotComment;
     },
@@ -601,6 +606,11 @@
     },
 
     _loadLocalDraft(changeNum, patchNum, comment) {
+      // Polymer 2: check for undefined
+      if ([changeNum, patchNum, comment].some(arg => arg === undefined)) {
+        return;
+      }
+
       // Only apply local drafts to comments that haven't been saved
       // remotely, and haven't been given a default message already.
       //
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
index bcf3729..b6d909d 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.js
@@ -104,6 +104,11 @@
     },
 
     _handleValueChange(value, items) {
+      // Polymer 2: check for undefined
+      if ([value, items].some(arg => arg === undefined)) {
+        return;
+      }
+
       if (!value) { return; }
       const selectedObj = items.find(item => {
         return item.value + '' === value + '';
diff --git a/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js b/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
index 44a8791..479dd1e 100644
--- a/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
+++ b/polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js
@@ -66,6 +66,11 @@
      * enabled.
      */
     _updateTitle(text, limit, tooltipLimit) {
+      // Polymer 2: check for undefined
+      if ([text, limit, tooltipLimit].some(arg => arg === undefined)) {
+        return;
+      }
+
       this.hasTooltip = !!limit && !!text && text.length > limit;
       if (this.hasTooltip) {
         this.setAttribute('title', text.substr(0, tooltipLimit));
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.html b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.html
index f6332f4..939d582 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.html
+++ b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.html
@@ -37,14 +37,8 @@
         display: inline-flex;
         padding: 0 .5em;
       }
-      gr-button.remove:hover,
-      gr-button.remove:focus {
-        --gr-button: {
-          color: #333;
-        }
-      }
       gr-button.remove {
-        --gr-button: {
+        --gr-remove-button-style: {
           border: 0;
           color: var(--deemphasized-text-color);
           font-size: 1.7rem;
@@ -56,6 +50,19 @@
           text-decoration: none;
         }
       }
+
+      gr-button.remove:hover,
+      gr-button.remove:focus {
+        --gr-button: {
+          @apply --gr-remove-button-style
+          color: #333;
+        }
+      }
+      gr-button.remove {
+        --gr-button: {
+          @apply --gr-remove-button-style
+        }
+      }
       .transparentBackground,
       gr-button.transparentBackground {
         background-color: transparent;
diff --git a/polygerrit-ui/app/styles/gr-voting-styles.html b/polygerrit-ui/app/styles/gr-voting-styles.html
index 3b1ee64..eec79be 100644
--- a/polygerrit-ui/app/styles/gr-voting-styles.html
+++ b/polygerrit-ui/app/styles/gr-voting-styles.html
@@ -23,6 +23,7 @@
           border: 1px solid rgba(0,0,0,.12);
           border-radius: 1em;
           box-shadow: none;
+          box-sizing: border-box;
           min-width: 3em;
         }
       }
diff --git a/polygerrit-ui/server.go b/polygerrit-ui/server.go
index e849469..305a6b8 100644
--- a/polygerrit-ui/server.go
+++ b/polygerrit-ui/server.go
@@ -103,7 +103,7 @@
 func handleIndex(writer http.ResponseWriter, originalRequest *http.Request) {
 	fakeRequest := &http.Request{
 		URL: &url.URL{
-			Path: "/",
+			Path:     "/",
 			RawQuery: originalRequest.URL.RawQuery,
 		},
 	}
@@ -170,7 +170,7 @@
 func patchResponse(req *http.Request, res *http.Response) io.Reader {
 	switch req.URL.EscapedPath() {
 	case "/":
-		return replaceCdn(res.Body)
+		return rewriteHostPage(res.Body)
 	case "/config/server/info":
 		return injectLocalPlugins(res.Body)
 	default:
@@ -178,13 +178,39 @@
 	}
 }
 
-func replaceCdn(reader io.Reader) io.Reader {
+func rewriteHostPage(reader io.Reader) io.Reader {
 	buf := new(bytes.Buffer)
 	buf.ReadFrom(reader)
 	original := buf.String()
 
+	// Simply remove all CDN references, so files are loaded from the local file system  or the proxy
+	// server instead.
 	replaced := cdnPattern.ReplaceAllString(original, "")
 
+	// Modify window.INITIAL_DATA so that it has the same effect as injectLocalPlugins. To achieve
+	// this let's add JavaScript lines at the end of the <script>...</script> snippet that also
+	// contains window.INITIAL_DATA=...
+	// Here we rely on the fact that the <script> snippet that we want to append to is the first one.
+	if len(*plugins) > 0 {
+		insertionPoint := strings.Index(replaced, "</script>")
+		builder := new(strings.Builder)
+		builder.WriteString(
+			"window.INITIAL_DATA['/config/server/info'].plugin.html_resource_paths = []; ")
+		builder.WriteString(
+			"window.INITIAL_DATA['/config/server/info'].plugin.js_resource_paths = []; ")
+		for _, p := range strings.Split(*plugins, ",") {
+			if filepath.Ext(p) == ".html" {
+				builder.WriteString(
+					"window.INITIAL_DATA['/config/server/info'].plugin.html_resource_paths.push('" + p + "'); ")
+			}
+			if filepath.Ext(p) == ".js" {
+				builder.WriteString(
+					"window.INITIAL_DATA['/config/server/info'].plugin.js_resource_paths.push('" + p + "'); ")
+			}
+		}
+		replaced = replaced[:insertionPoint] + builder.String() + replaced[insertionPoint:]
+	}
+
 	return strings.NewReader(replaced)
 }
 
@@ -209,11 +235,11 @@
 	jsResources := getJsonPropByPath(response, jsPluginsPath).([]interface{})
 
 	for _, p := range strings.Split(*plugins, ",") {
-		if strings.HasSuffix(p, ".html") {
+		if filepath.Ext(p) == ".html" {
 			htmlResources = append(htmlResources, p)
 		}
 
-		if strings.HasSuffix(p, ".js") {
+		if filepath.Ext(p) == ".js" {
 			jsResources = append(jsResources, p)
 		}
 	}
@@ -263,7 +289,7 @@
 
 // Any path prefixes that should resolve to index.html.
 var (
-	fePaths    = []string{"/q/", "/c/", "/p/", "/x/", "/dashboard/", "/admin/"}
+	fePaths    = []string{"/q/", "/c/", "/p/", "/x/", "/dashboard/", "/admin/", "/settings/"}
 	issueNumRE = regexp.MustCompile(`^\/\d+\/?$`)
 )