Object.observe: Use [[DefineOwnProperty]] to create properties of changeRecord

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
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 "use strict";
 
-var InternalObjectIsFrozen = $Object.isFrozen;
-var InternalObjectFreeze = $Object.freeze;
-
 var observationState = %GetObservationState();
 if (IS_UNDEFINED(observationState.observerInfoMap)) {
   observationState.observerInfoMap = %CreateObjectHashTable();
   observationState.objectInfoMap = %CreateObjectHashTable();
   observationState.notifierTargetMap = %CreateObjectHashTable();
   observationState.pendingObservers = new InternalArray;
   observationState.observerPriority = 0;
 }
 
 function InternalObjectHashTable(tableName) {
@@ skipping 24 matching lines @@
   };
   objectInfoMap.set(object, info);
   return info;
 }
 
 function ObjectObserve(object, callback) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["observe"]);
   if (!IS_SPEC_FUNCTION(callback))
     throw MakeTypeError("observe_non_function", ["observe"]);
-  if (InternalObjectIsFrozen(callback))
+  if (ObjectIsFrozen(callback))
     throw MakeTypeError("observe_callback_frozen");
 
   if (!observerInfoMap.has(callback)) {
     observerInfoMap.set(callback, {
       pendingChangeRecords: null,
       priority: observationState.observerPriority++,
     });
   }
 
   var objectInfo = objectInfoMap.get(object);
@@ skipping 39 matching lines @@
       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 };
-  InternalObjectFreeze(changeRecord);
+  ObjectFreeze(changeRecord);
   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);
   if (IS_UNDEFINED(target))
     throw MakeTypeError("observe_notify_non_notifier");
 
   if (!IS_STRING(changeRecord.type))
     throw MakeTypeError("observe_type_non_string");
 
   var objectInfo = objectInfoMap.get(target);
   if (IS_UNDEFINED(objectInfo))
     return;
 
   if (!objectInfo.changeObservers.length)
     return;
 
   var newRecord = {
     object: target
   };
   for (var prop in changeRecord) {
     if (prop === 'object')
       continue;
-    newRecord[prop] = changeRecord[prop];
+
+    %DefineOrRedefineDataProperty(newRecord, prop, changeRecord[prop],
+        READ_ONLY + DONT_DELETE);
   }
-  InternalObjectFreeze(newRecord);
+  ObjectFreeze(newRecord);
 
   EnqueueChangeRecord(newRecord, objectInfo.changeObservers);
 }
 
 function ObjectGetNotifier(object) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["getNotifier"]);
 
-  if (InternalObjectIsFrozen(object))
+  if (ObjectIsFrozen(object))
     return null;
 
   var objectInfo = objectInfoMap.get(object);
   if (IS_UNDEFINED(objectInfo))
     objectInfo = CreateObjectInfo(object);
 
   if (IS_NULL(objectInfo.notifier)) {
     objectInfo.notifier = {
       __proto__: notifierPrototype
     };
@@ skipping 45 matching lines @@
     "getNotifier", ObjectGetNotifier,
     "observe", ObjectObserve,
     "unobserve", ObjectUnobserve
   ));
   InstallFunctions(notifierPrototype, DONT_ENUM, $Array(
     "notify", ObjectNotifierNotify
   ));
 }
 
 SetupObjectObserve();