Use PageManager in About page

chrome/browser/resources/options/browser_options.js

 // Copyright (c) 2012 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.
 
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
   var ArrayDataModel = cr.ui.ArrayDataModel;
   var RepeatingButton = cr.ui.RepeatingButton;
@@ skipping 61 matching lines @@
      * @type {?number}
      * @private
      */
     sectionHeightChangeTimeout_: null,
 
     /** @override */
     initializePage: function() {
       Page.prototype.initializePage.call(this);
       var self = this;
 
+      if (window.top != window) {
+        // The options page is not in its own window.
+        document.body.classList.add('uber-frame');
+        PageManager.horizontalOffset = 155;
+      }
+
       // Ensure that navigation events are unblocked on uber page. A reload of
       // the settings page while an overlay is open would otherwise leave uber
       // page in a blocked state, where tab switching is not possible.
       uber.invokeMethodOnParent('stopInterceptingEvents');
 
       window.addEventListener('message', this.handleWindowMessage_.bind(this));
 
       if (loadTimeData.getBoolean('allowAdvancedSettings')) {
         $('advanced-settings-expander').onclick = function() {
           var showAdvanced =
@@ skipping 1817 matching lines @@
     BrowserOptions.getLoggedInUsername = function() {
       return BrowserOptions.getInstance().username_;
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });