Create pre-frozen change records for Object.observe

src/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 112 matching lines @@
     observationState.pendingObservers[observerInfo.priority] = observer;
     %SetObserverDeliveryPending();
     if (IS_NULL(observerInfo.pendingChangeRecords)) {
       observerInfo.pendingChangeRecords = new InternalArray(changeRecord);
     } else {
       observerInfo.pendingChangeRecords.push(changeRecord);
     }
   }
 }
 
-function NotifyChange(type, object, name, oldValue) {
-  var objectInfo = objectInfoMap.get(object);
-  var changeRecord = (arguments.length < 4) ?
-      { type: type, object: object, name: name } :
-      { type: type, object: object, name: name, oldValue: oldValue };
-  ObjectFreeze(changeRecord);
+function NotifyChange(changeRecord) {
+  var objectInfo = objectInfoMap.get(changeRecord.object);
   EnqueueChangeRecord(changeRecord, objectInfo.changeObservers);
 }
 
 var notifierPrototype = {};
 
 function ObjectNotifierNotify(changeRecord) {
   if (!IS_SPEC_OBJECT(this))
     throw MakeTypeError("called_on_non_object", ["notify"]);
 
   var target = notifierTargetMap.get(this);
@@ skipping 77 matching lines @@
     "getNotifier", ObjectGetNotifier,
     "observe", ObjectObserve,
     "unobserve", ObjectUnobserve
   ));
   InstallFunctions(notifierPrototype, DONT_ENUM, $Array(
     "notify", ObjectNotifierNotify
   ));
 }
 
 SetupObjectObserve();