Don't leak contexts in Object.observe

src/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // Overview:
 //
 // This file contains all of the routing and accounting for Object.observe.
 // User code will interact with these mechanisms via the Object.observe APIs
@@ skipping 38 matching lines @@
 
   return observationState;
 }
 
 function GetWeakMapWrapper() {
   function MapWrapper(map) {
     this.map_ = map;
   };
 
   MapWrapper.prototype = {
+    __proto__: null,
     get: function(key) {
       return %WeakCollectionGet(this.map_, key);
     },
     set: function(key, value) {
       %WeakCollectionSet(this.map_, key, value);
     },
     has: function(key) {
       return !IS_UNDEFINED(this.get(key));
     }
   };
@@ skipping 288 matching lines @@
     throw MakeTypeError("observe_non_object", ["observe"]);
   if (%IsJSGlobalProxy(object))
     throw MakeTypeError("observe_global_proxy", ["observe"]);
   if (!IS_SPEC_FUNCTION(callback))
     throw MakeTypeError("observe_non_function", ["observe"]);
   if (ObjectIsFrozen(callback))
     throw MakeTypeError("observe_callback_frozen");
   if (!AcceptArgIsValid(acceptList))
     throw MakeTypeError("observe_accept_invalid");
 
+  return %NativeObjectObserve(object, callback, acceptList);
+}
+
+function NativeObjectObserve(object, callback, acceptList) {
   var objectInfo = ObjectInfoGetOrCreate(object);
   ObjectInfoAddObserver(objectInfo, callback, acceptList);
   return object;
 }
 
 function ObjectUnobserve(object, callback) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["unobserve"]);
   if (%IsJSGlobalProxy(object))
     throw MakeTypeError("observe_global_proxy", ["unobserve"]);
@@ skipping 143 matching lines @@
     throw MakeTypeError("observe_type_non_string");
 
   ObjectInfoEnqueueExternalChangeRecord(objectInfo, changeRecord);
 }
 
 function ObjectNotifierPerformChange(changeType, changeFn) {
   if (!IS_SPEC_OBJECT(this))
     throw MakeTypeError("called_on_non_object", ["performChange"]);
 
   var objectInfo = ObjectInfoGetFromNotifier(this);
-
   if (IS_UNDEFINED(objectInfo))
     throw MakeTypeError("observe_notify_non_notifier");
   if (!IS_STRING(changeType))
     throw MakeTypeError("observe_perform_non_string");
   if (!IS_SPEC_FUNCTION(changeFn))
     throw MakeTypeError("observe_perform_non_function");
 
+  return %NativeObjectNotifierPerformChange(objectInfo, changeType, changeFn)
+}
+
+function NativeObjectNotifierPerformChange(objectInfo, changeType, changeFn) {
   ObjectInfoAddPerformingType(objectInfo, changeType);
 
   var changeRecord;
   try {
     changeRecord = %_CallFunction(UNDEFINED, changeFn);
   } finally {
     ObjectInfoRemovePerformingType(objectInfo, changeType);
   }
 
   if (IS_SPEC_OBJECT(changeRecord))
     ObjectInfoEnqueueExternalChangeRecord(objectInfo, changeRecord, changeType);
 }
 
 function ObjectGetNotifier(object) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["getNotifier"]);
   if (%IsJSGlobalProxy(object))
     throw MakeTypeError("observe_global_proxy", ["getNotifier"]);
 
   if (ObjectIsFrozen(object)) return null;
 
   if (!%ObjectWasCreatedInCurrentOrigin(object)) return null;
 
+  return %NativeObjectGetNotifier(object);
+}
+
+function NativeObjectGetNotifier(object) {
   var objectInfo = ObjectInfoGetOrCreate(object);
   return ObjectInfoGetNotifier(objectInfo);
 }
 
 function CallbackDeliverPending(callback) {
   var callbackInfo = GetCallbackInfoMap().get(callback);
   if (IS_UNDEFINED(callbackInfo) || IS_NUMBER(callbackInfo))
     return false;
 
   // Clear the pending change records from callback and return it to its
@@ skipping 42 matching lines @@
     "observe", ArrayObserve,
     "unobserve", ArrayUnobserve
   ));
   InstallFunctions(notifierPrototype, DONT_ENUM, $Array(
     "notify", ObjectNotifierNotify,
     "performChange", ObjectNotifierPerformChange
   ));
 }
 
 SetupObjectObserve();