Fix the pref binding by binding to the object rather than the element

chrome/browser/resources/settings/downloads_page/downloads_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
  * 'cr-settings-downloads-page' is the settings page containing downloads
  * settings.
  *
  * Example:
  *
  *    <iron-animated-pages>
  *      <cr-settings-downloads-page prefs="{{prefs}}">
  *      </cr-settings-downloads-page>
  *      ... other pages ...
  *    </iron-animated-pages>
  *
  * @group Chrome Settings Elements
  * @element cr-settings-downloads-page
  */
 Polymer({
   is: 'cr-settings-downloads-page',
 
   properties: {
     /**
      * Preferences state.
-     * @type {?CrSettingsPrefsElement}
      */
     prefs: {
       type: Object,
       notify: true,
     },
 
     /**
      * Route for the page.
      */
     route: String,
@@ skipping 36 matching lines @@
     },
   },
 
   /** @private */
   selectDownloadLocation_: function() {
     // TODO(orenb): Communicate with the C++ to actually display a folder
     // picker.
     this.$.downloadsPath.value = '/Downloads';
   },
 });