Use window.URL instead of window.webkitURL.

chrome/test/data/extensions/platform_apps/iframes/main.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.
 
 chrome.test.getConfig(function(config) {
   var LOCAL_URL = 'local-iframe.html';
   var DATA_URL = 'data:text/plain,This frame should be displayed.';
   var REMOTE_URL = 'http://localhost:' + config.testServer.port
       '/extensions/platform_apps/iframes/remote-iframe.html';
 
@@ skipping 42 matching lines @@
                                            {type: 'text/html'});
                       fileWriter.write(blob);
                     });
                 });
           });
     },
 
     function blobUrlIframe() {
       var blob = new Blob(['This frame should be displayed'],
                           {type: 'text/html'});
-      var blobUrl = window.webkitURL.createObjectURL(blob);
+      var blobUrl = window.URL.createObjectURL(blob);
       var iframe = document.createElement('iframe');
       iframe.onload = chrome.test.callbackPass(function() {
         console.log('blob: URL iframe loaded');
       });
       iframe.src = blobUrl;
       document.body.appendChild(iframe);
     },
 
     function remoteIframe() {
       var iframe = document.createElement('iframe');
       iframe.onload = function() {
         chrome.test.notifyFail('Remote iframe should not have loaded');
       };
       iframe.src = REMOTE_URL;
       document.body.appendChild(iframe);
 
       // Load failure should happen synchronously, but wait a bit before
       // declaring success.
       setTimeout(chrome.test.succeed, 500);
     }
   ]);
 });