Fix runtime JavaScript errors in chrome://options

chrome/browser/resources/options/chromeos_system_options.js

 // Copyright (c) 2010 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.
 
 ///////////////////////////////////////////////////////////////////////////////
 // SystemOptions class:
 
 /**
  * Encapsulated handling of ChromeOS system options page.
  * @constructor
@@ skipping 20 matching lines @@
   initializePage: function() {
     OptionsPage.prototype.initializePage.call(this);
     var timezone = $('timezone-select');
     if (timezone) {
       timezone.initializeValues(templateData.timezoneList);
     }
 
     $('language-button').onclick = function(event) {
       // TODO: Open ChromeOS language settings page.
     };
-    $('sync-button').onclick = function(event) {
-      OptionsPage.showPageByName('sync');
-    }
-    $('dummy-button').onclick = function(event) {
-      OptionsPage.showOverlay('dummy');
-    }
   },
 };