MD Settings: implement support for extension-controlled startup URLs

chrome/browser/resources/settings/on_startup_page/startup_urls_page.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 'settings-startup-urls-page' is the settings page
  * containing the urls that will be opened when chrome is started.
  */
 
 Polymer({
   is: 'settings-startup-urls-page',
 
   behaviors: [CrScrollableBehavior, WebUIListenerBehavior],
 
   properties: {
+    prefs: Object,
+
     /** @type {settings.StartupUrlsPageBrowserProxy} */
     browserProxy_: Object,
 
     /**
      * Pages to load upon browser startup.
      * @private {!Array<!StartupPageInfo>}
      */
     startupPages_: Array,
 
     /** @private */
@@ skipping 32 matching lines @@
   destroyUrlDialog_: function() {
     this.showStartupUrlDialog_ = false;
     this.startupUrlDialogModel_ = null;
   },
 
   /** @private */
   onUseCurrentPagesTap_: function() {
     this.browserProxy_.useCurrentPages();
   },
 });