Remove gr-app.html and all its reference

Use gr-app.js as the entry and shell.
https://polymer-library.polymer-project.org/3.0/docs/tools/polymer-json

Change-Id: Iacd7a433157355f89d7f8e6c782abfe43ba725ea
diff --git a/polygerrit-ui/app/BUILD b/polygerrit-ui/app/BUILD
index 096c665..bab00b0 100644
--- a/polygerrit-ui/app/BUILD
+++ b/polygerrit-ui/app/BUILD
@@ -18,7 +18,7 @@
         ],
     ),
     outs = ["polygerrit_ui.zip"],
-    entry_point = "elements/gr-app.html",
+    entry_point = "elements/gr-app.js",
 )
 
 filegroup(
diff --git a/polygerrit-ui/app/elements/gr-app.html b/polygerrit-ui/app/elements/gr-app.html
deleted file mode 100644
index 1483f7a..0000000
--- a/polygerrit-ui/app/elements/gr-app.html
+++ /dev/null
@@ -1 +0,0 @@
-<script src='./gr-app.js' type='module'></script>
diff --git a/polygerrit-ui/app/polymer.json b/polygerrit-ui/app/polymer.json
index 411c969..affa7f2 100644
--- a/polygerrit-ui/app/polymer.json
+++ b/polygerrit-ui/app/polymer.json
@@ -1,5 +1,5 @@
 {
-  "entrypoint": "elements/gr-app.html",
+  "shell": "elements/gr-app.js",
   "sources": [
     "behaviors/**/*",
     "elements/**/*",
diff --git a/polygerrit-ui/app/rules.bzl b/polygerrit-ui/app/rules.bzl
index 5ccf92d..83860d5 100644
--- a/polygerrit-ui/app/rules.bzl
+++ b/polygerrit-ui/app/rules.bzl
@@ -8,10 +8,10 @@
         name: rule name
         srcs: source files
         outs: array with a single item - the output file name
-        entry_point: application entry-point
+        entry_point: application js entry-point
     """
 
-    app_name = entry_point.split(".html")[0].split("/").pop()  # eg: gr-app
+    app_name = entry_point.split(".js")[0].split("/").pop()  # eg: gr-app
 
     native.filegroup(
         name = app_name + "-full-src",
@@ -24,7 +24,7 @@
         name = app_name + "-bundle-js",
         srcs = [app_name + "-full-src"],
         config_file = ":rollup.config.js",
-        entry_point = "elements/" + app_name + ".js",
+        entry_point = entry_point,
         rollup_bin = "//tools/node_tools:rollup-bin",
         sourcemap = "hidden",
         deps = [
@@ -36,7 +36,6 @@
         name = name + "_app_sources",
         srcs = [
             app_name + "-bundle-js.js",
-            entry_point,
         ],
     )
 
diff --git a/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy b/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
index d162714..32ba0bc 100644
--- a/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
+++ b/resources/com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy
@@ -139,7 +139,7 @@
   // Content between webcomponents-lite and the load of the main app element
   // run before polymer-resin is installed so may have security consequences.
   // Contact your local security engineer if you have any questions, and
-  // CC them on any changes that load content before gr-app.html.
+  // CC them on any changes that load content before gr-app.js.
   //
   // github.com/Polymer/polymer-resin/blob/master/getting-started.md#integrating
   {if $assetsPath and $assetsBundle}