Update tests for chrome, as MediaStream label, ended attributes and stop() method will be removed

chrome/test/data/extensions/api_test/tab_capture/active_tab_chrome_pages.js

 // Copyright 2014 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.
 
 var afterTabOpened = function() {
   chrome.tabCapture.capture({audio: true, video: true}, function(stream) {
     chrome.test.assertTrue(!!stream);
-    stream.stop();
+    stream.getVideoTracks()[0].stop();
+    stream.getAudioTracks()[0].stop();
     chrome.test.succeed();
   });
 };
 
 chrome.test.notifyPass();
 chrome.test.sendMessage('ready1', afterTabOpened);