Reland "Split MainPageBehavior between browser and OS settings."

This is a reland of e1e445e8
with fixes for a compile error on chromeos_linux when building
with the optimize_webui flag enabled.

Original change's description:
> Split MainPageBehavior between browser and OS settings.
>
> This is a prerequisite to implement lazy loading for Polymer 3.
>
> Bug: 1045266
> Change-Id: I92c428cd2c18d6f4096ee5fbdd26ae77efb831ec
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2321954
> Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
> Reviewed-by: dpapad <dpapad@chromium.org>
> Commit-Queue: Jon Mann <jonmann@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#792491}

Bug: 1045266
Change-Id: Ie3e50ceb5cf23dc8e2eedf69cc7b169a790b0f31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2327312Reviewed-by: dpapad <dpapad@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Jon Mann <jonmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792950}

chrome/browser/resources/settings/chromeos/BUILD.gn

@@ -275,7 +275,8 @@ group("closure_compile_module") {
     #"os_search_page:closure_compile_module",
     #"os_settings_main:closure_compile_module",
     #"os_settings_menu:closure_compile_module",
-    #"os_settings_page:closure_compile_module",
+    "os_settings_page:closure_compile_module",
+
     #"os_settings_search_box:closure_compile_module",
     #"os_settings_ui:closure_compile_module",
     #"os_toolbar:closure_compile_module",

chrome/browser/resources/settings/chromeos/os_about_page/os_about_page.html

@@ -8,7 +8,7 @@
 <link rel="import" href="../../prefs/prefs.html">
 <link rel="import" href="../os_route.html">
 <link rel="import" href="../../router.html">
-<link rel="import" href="../../settings_page/main_page_behavior.html">
+<link rel="import" href="../os_settings_page/main_page_behavior.html">
 <link rel="import" href="../../settings_page/settings_animated_pages.html">
 <link rel="import" href="../../settings_page/settings_section.html">
 <link rel="import" href="../../settings_page/settings_subpage.html">

chrome/browser/resources/settings/chromeos/os_settings_main/BUILD.gn

@@ -13,7 +13,7 @@ js_library("os_settings_main") {
     "..:os_page_visibility",
     "../..:router",
     "../..:search_settings",
-    "../../settings_page:main_page_behavior",
+    "../os_settings_page:main_page_behavior",
     "../os_settings_page:os_settings_page",
     "//third_party/polymer/v1_0/components-chromium/iron-a11y-announcer:iron-a11y-announcer-extracted",
     "//ui/webui/resources/js:assert",

chrome/browser/resources/settings/chromeos/os_settings_page/BUILD.gn

@@ -3,18 +3,23 @@
 # found in the LICENSE file.
 
 import("//third_party/closure_compiler/compile_js.gni")
+import("//ui/webui/resources/tools/js_modulizer.gni")
+import("../os_settings.gni")
 
 js_type_check("closure_compile") {
-  deps = [ ":os_settings_page" ]
+  deps = [
+    ":main_page_behavior",
+    ":os_settings_page",
+  ]
 }
 
 js_library("os_settings_page") {
   deps = [
+    ":main_page_behavior",
     "..:os_page_visibility",
     "..:os_route",
     "../..:router",
     "../..:search_settings",
-    "../../settings_page:main_page_behavior",
     "../os_apps_page:android_apps_browser_proxy",
     "//ui/webui/resources/js:load_time_data",
     "//ui/webui/resources/js:web_ui_listener_behavior",
@@ -22,13 +27,24 @@ js_library("os_settings_page") {
   externs_list = [ "$externs_path/pending.js" ]
 }
 
+js_library("main_page_behavior") {
+  deps = [
+    "../..:router",
+    "../../settings_page:settings_section",
+    "//ui/webui/resources/js:assert",
+    "//ui/webui/resources/js:util",
+  ]
+  externs_list = [ "$externs_path/pending.js" ]
+}
+
 # TODO: Uncomment as the Polymer3 migration makes progress.
-#js_type_check("closure_compile_module") {
-#  is_polymer3 = true
-#  deps = [
-#    ":os_settings_page.m"
-#  ]
-#}
+js_type_check("closure_compile_module") {
+  is_polymer3 = true
+  deps = [
+    #    ":os_settings_page.m",
+    ":main_page_behavior.m",
+  ]
+}
 
 js_library("os_settings_page.m") {
   sources = [ "$root_gen_dir/chrome/browser/resources/settings/chromeos/os_settings_page/os_settings_page.m.js" ]
@@ -38,10 +54,25 @@ js_library("os_settings_page.m") {
   extra_deps = [ ":os_settings_page_module" ]
 }
 
+js_library("main_page_behavior.m") {
+  sources = [ "$root_gen_dir/chrome/browser/resources/settings/chromeos/os_settings_page/main_page_behavior.m.js" ]
+  deps = [
+    "../..:router.m",
+    "../../settings_page:settings_section.m",
+    "//third_party/polymer/v3_0/components-chromium/polymer:polymer_bundled",
+    "//ui/webui/resources/js:assert.m",
+    "//ui/webui/resources/js:util.m",
+  ]
+  extra_deps = [ ":modulize" ]
+}
+
 import("//tools/polymer/polymer.gni")
 
 group("polymer3_elements") {
-  public_deps = [ ":os_settings_page_module" ]
+  public_deps = [
+    ":modulize",
+    ":os_settings_page_module",
+  ]
 }
 
 polymer_modulizer("os_settings_page") {
@@ -49,3 +80,8 @@ polymer_modulizer("os_settings_page") {
   html_file = "os_settings_page.html"
   html_type = "dom-module"
 }
+
+js_modulizer("modulize") {
+  input_files = [ "main_page_behavior.js" ]
+  namespace_rewrites = os_settings_namespace_rewrites
+}

chrome/browser/resources/settings/chromeos/os_settings_page/main_page_behavior.html

+<link rel="import" href="chrome://resources/html/polymer.html">
+
+<link rel="import" href="chrome://resources/html/assert.html">
+<link rel="import" href="../../router.html">
+
+<script src="main_page_behavior.js"></script>

chrome/browser/resources/settings/chromeos/os_settings_page/os_settings_page.html

@@ -4,6 +4,7 @@
 <link rel="import" href="chrome://resources/cr_elements/hidden_style_css.html">
 <link rel="import" href="chrome://resources/cr_elements/shared_vars_css.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
+<link rel="import" href="main_page_behavior.html">
 <link rel="import" href="../os_a11y_page/os_a11y_page.html">
 <link rel="import" href="../os_apps_page/android_apps_browser_proxy.html">
 <link rel="import" href="../os_apps_page/os_apps_page.html">
@@ -11,7 +12,6 @@
 <link rel="import" href="../os_search_page/os_search_page.html">
 <link rel="import" href="../personalization_page/personalization_page.html">
 <link rel="import" href="../../controls/settings_idle_load.html">
-<link rel="import" href="../../settings_page/main_page_behavior.html">
 <link rel="import" href="../../settings_page/settings_section.html">
 <link rel="import" href="../../settings_page_css.html">
 <link rel="import" href="../bluetooth_page/bluetooth_page.html">

chrome/browser/resources/settings/os_settings_resources.grd

@@ -418,10 +418,10 @@
                  file="settings_page_css.html"
                  compress="false" type="chrome_html" />
       <structure name="IDR_OS_SETTINGS_MAIN_PAGE_BEHAVIOR_HTML"
-                 file="settings_page/main_page_behavior.html"
+                 file="chromeos/os_settings_page/main_page_behavior.html"
                  compress="false" type="chrome_html" />
       <structure name="IDR_OS_SETTINGS_MAIN_PAGE_BEHAVIOR_JS"
-                 file="settings_page/main_page_behavior.js"
+                 file="chromeos/os_settings_page/main_page_behavior.js"
                  compress="false" type="chrome_html"
                  preprocess="true" />
       <structure name="IDR_OS_SETTINGS_SETTINGS_VARS_CSS_HTML"

chrome/browser/resources/settings/settings_page/main_page_behavior.js

@@ -9,6 +9,7 @@
 // #import {Route, Router, MinimumRoutes} from '../router.m.js';
 // clang-format on
 
+// TODO(dpapad): Fully migrate this file to polymer 3.
 cr.define('settings', function() {
   /**
    * @enum {string}
@@ -147,12 +148,7 @@ cr.define('settings', function() {
     shouldExpandAdvanced_(route) {
       const routes = /** @type {!settings.MinimumRoutes} */ (
           settings.Router.getInstance().getRoutes());
-      return (
-                 this.tagName === 'SETTINGS-BASIC-PAGE'
-                 // <if expr="chromeos">
-                 || this.tagName === 'OS-SETTINGS-PAGE'
-                 // </if>
-                 ) &&
+      return this.tagName === 'SETTINGS-BASIC-PAGE' &&
           routes.ADVANCED && routes.ADVANCED.contains(route);
     },
 
@@ -203,16 +199,8 @@ cr.define('settings', function() {
 
       // Explicitly load the lazy_load.html module, since all subpages reside in
       // the lazy loaded module.
-      // TODO(dpapad): On chrome://os-settings the lazy_load.html file resides
-      // at a different path. Remove conditional logic once this file is not
-      // shared between chrome://settings and chrome://os-settings.
       // Polymer 2 codepath
-      /* #ignore */ const lazyLoadPathPrefix =
-          /* #ignore */ window.location.origin === 'chrome://settings' ?
-          /* #ignore */ '' :
-          /* #ignore */ '/chromeos';
-      /* #ignore */ Polymer.importHref(
-          /* #ignore */ `${lazyLoadPathPrefix}/lazy_load.html`, () => {});
+      /* #ignore */ Polymer.importHref('/lazy_load.html', () => {});
 
       // Polymer 3 codepath, do not delete next line comment.
       // #polymer3 ensureLazyLoaded();

chrome/browser/resources/settings/settings_page_css.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 
-<link rel="import" href="settings_page/main_page_behavior.html">
-
 <dom-module id="settings-page-styles">
   <template>
     <style>