Enable a11y audit for chrome://settings

chrome/browser/ui/webui/options/chromeos/accounts_options_browsertest.js

 // Copyright 2013 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.
 
+GEN_INCLUDE(['chrome/browser/ui/webui/options/options_browsertest_base.js']);
+
 function AccountsOptionsWebUITest() {}
 
 AccountsOptionsWebUITest.prototype = {
-  __proto__: testing.Test.prototype,
+  __proto__: OptionsBrowsertestBase.prototype,
 
   /**
    * Browse to accounts options.
    */
   browsePreload: 'chrome://settings-frame/accounts',
 };
 
 function createEnterKeyboardEvent(type) {
   return new KeyboardEvent(type, {
     'bubbles': true,
@@ skipping 12 matching lines @@
   assertTrue(accountsOptionsPage.visible);
 
   // Simulate pressing the enter key in the edit field.
   inputField.dispatchEvent(createEnterKeyboardEvent('keydown'));
   inputField.dispatchEvent(createEnterKeyboardEvent('keypress'));
   inputField.dispatchEvent(createEnterKeyboardEvent('keyup'));
 
   // Verify the overlay is still visible.
   assertTrue(accountsOptionsPage.visible);
 });