Using random wallpaper until user select one

chrome/browser/resources/options2/chromeos/set_wallpaper_options.js

 // Copyright (c) 2012 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('options', function() {
 
   var OptionsPage = options.OptionsPage;
   var UserImagesGrid = options.UserImagesGrid;
 
   /////////////////////////////////////////////////////////////////////////////
@@ skipping 93 matching lines @@
         OptionsPage.closeOverlay();
     },
 
     /**
      * Selects user image with the given index.
      * @param {int} index index of the image to select.
      * @private
      */
     setSelectedImage_: function(index) {
       var wallpaperGrid = $('wallpaper-grid');
-      wallpaperGrid.selectionModel.selectedIndex = index;
-      wallpaperGrid.selectionModel.leadIndex = index;
+      wallpaperGrid.selectedItemIndex = index;
       $('author-name').innerText = this.wallpapers_[index].author;
       $('author-website').innerText = this.wallpapers_[index].website;
     },
 
     /**
      * Appends default images to the image grid. Should only be called once.
      * @param {Array.<{author: string, url: string, website: string}>}
      * wallpapers An array of wallpaper objects.
      * @private
      */
@@ skipping 22 matching lines @@
     };
   });
 
   // Export
   return {
     SetWallpaperOptions: SetWallpaperOptions
   };
 
 });