MD Settings: Add mechanism to restore focus after subpage exiting.

chrome/test/data/webui/settings/cr_settings_interactive_ui_tests.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** @fileoverview Runs the Polymer Settings interactive UI tests. */
 
 /** @const {string} Path to source root. */
 var ROOT_PATH = '../../../../../';
 
 // Polymer BrowserTest fixture.
@@ skipping 46 matching lines @@
 
   /** @override */
   extraLibraries: CrSettingsInteractiveUITest.prototype.extraLibraries.concat([
     'focus_row_behavior_test.js',
   ]),
 };
 
 TEST_F('CrSettingsFocusRowBehavior', 'FocusTest', function() {
   mocha.run();
 });
+
+
+/**
+ * @constructor
+ * @extends {CrSettingsInteractiveUITest}
+ */
+function CrSettingsAnimatedPagesTest() {}
+
+CrSettingsAnimatedPagesTest.prototype = {
+  __proto__: CrSettingsInteractiveUITest.prototype,
+
+  /** @override */
+  browsePreload:
+      'chrome://md-settings/settings_page/settings_animated_pages.html',
+
+  extraLibraries: CrSettingsInteractiveUITest.prototype.extraLibraries.concat([
+    'settings_animated_pages_test.js',
+  ]),
+};
+
+TEST_F('CrSettingsAnimatedPagesTest', 'All', function() {
+  mocha.run()
+});