[Sync] Move some code into new class JsMutationEventObserver

chrome/browser/resources/sync_internals/chrome_sync.js

 // Copyright (c) 2011 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 chrome = chrome || {};
 // TODO(akalin): Add mocking code for e.g. chrome.send() so that we
 // can test this without rebuilding chrome.
 chrome.sync = chrome.sync || {};
 (function () {
 
@@ skipping 73 matching lines @@
     'onInitializationComplete',
     'onStopSyncingPermanently',
     'onClearServerDataSucceeded',
     'onClearServerDataFailed',
     'onEncryptionComplete',
     'onActionableError'
   ],
 
   'transaction': [
     'onTransactionStart',
-    'onTransactionMutate',
+    'onTransactionWrite',
     'onTransactionEnd'
   ]
 };
 
 for (var eventType in chrome.sync.events) {
   var events = chrome.sync.events[eventType];
   for (var i = 0; i < events.length; ++i) {
     var event = events[i];
     chrome.sync[event] = new Event();
   }
@@ skipping 57 matching lines @@
      * @return {number} The number of seconds since the timer was
      * created.
      */
     get elapsedSeconds() {
       return ((new Date()).getTime() - start.getTime()) / 1000.0;
     }
   };
 };
 
 })();