[MD settings] idle load basic and advanced pages

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

 // Copyright 2016 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('settings_main_page', function() {
   /**
    * Extending TestBrowserProxy even though SearchManager is not a browser proxy
    * itself. Essentially TestBrowserProxy can act as a "proxy" for any external
    * dependency, not just "browser proxies" (and maybe should be renamed to
    * TestProxy).
@@ skipping 158 matching lines @@
        * Asserts the visibility of the basic and advanced pages.
        * @param {string} Expected 'display' value for the basic page.
        * @param {string} Expected 'display' value for the advanced page.
        */
       function assertPageVisibility(expectedBasic, expectedAdvanced) {
         Polymer.dom.flush();
         var page = settingsMain.$$('settings-basic-page');
         assertEquals(
             expectedBasic, page.$$('#basicPage').style.display);
         assertEquals(
-            expectedAdvanced, page.$$('#advancedPage').style.display);
+            expectedAdvanced, page.$.advancedPageTemplate.get().style.display);
       }
 
       // TODO(michaelpg): It would be better not to drill into
       // settings-basic-page. If search should indeed only work in Settings
       // (as opposed to Advanced), perhaps some of this logic should be
       // delegated to settings-basic-page now instead of settings-main.
 
       /**
        * Asserts the visibility of the basic and advanced pages after exiting
        * search mode.
@@ skipping 74 matching lines @@
 
         assertPageVisibility('', '');
       });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });