MD Settings: Lazy load the contents of the "advanced" settings.

chrome/test/data/webui/settings/advanced_page_browsertest.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 Suite of tests for the Settings advanced page. */
 
 GEN_INCLUDE(['settings_page_browsertest.js']);
 
 /**
  * @constructor
@@ skipping 23 matching lines @@
   suite('SettingsPage', function() {
     suiteSetup(function() {
       self.toggleAdvanced();
     });
 
     test('load page', function() {
       // This will fail if there are any asserts or errors in the Settings page.
     });
 
     test('advanced pages', function() {
-      var page = self.getPage('basic');
+      var page = self.basicPage;
       var sections = ['privacy', 'passwordsAndForms', 'languages', 'downloads',
           'reset'];
       if (cr.isChromeOS)
         sections = sections.concat(['dateTime', 'a11y']);
 
       for (var i = 0; i < sections.length; i++) {
         var section = self.getSection(page, sections[i]);
-        expectTrue(!!section);
+        assertTrue(!!section);
         self.verifySubpagesHidden(section);
       }
     });
   });
 
   // Run all registered tests.
   mocha.run();
 });