DOMDataStore should be cleared when shutting down worker threads

Source/bindings/v8/V8PerContextData.cpp

 /*
  * Copyright (C) 2012 Google Inc. 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
@@ skipping 33 matching lines @@
 {
     typename Map::iterator it = map->begin();
     for (; it != map->end(); ++it)
         it->value.dispose();
     map->clear();
 }
 
 class V8PerContextDataHolder {
     WTF_MAKE_NONCOPYABLE(V8PerContextDataHolder);
 public:
-    static void install(v8::Handle<v8::Context> context, DOMWrapperWorld* world)
+    static void install(v8::Handle<v8::Context> context, PassRefPtr<DOMWrapperWorld> world)
     {
         new V8PerContextDataHolder(context, world);
     }
 
     static V8PerContextDataHolder* from(v8::Handle<v8::Context> context)
     {
         V8PerContextDataHolder* holder = static_cast<V8PerContextDataHolder*>(context->GetAlignedPointerFromEmbedderData(v8ContextPerContextDataIndex));
         // |holder| must not be 0 because V8PerContextDataHolder is kept alive as long as the |context| is alive.
         // Here we have a handle to the |context|, which means that the V8PerContextDataHolder is alive.
         ASSERT(holder);
         return holder;
     }
 
     V8PerContextData* perContextData() const { return m_perContextData; }
     void setPerContextData(V8PerContextData* data) { m_perContextData = data; }
-    DOMWrapperWorld* world() const { return m_world; }
+    DOMWrapperWorld* world() const { return m_world.get(); }
 
 private:
-    V8PerContextDataHolder(v8::Handle<v8::Context> context, DOMWrapperWorld* world)
+    V8PerContextDataHolder(v8::Handle<v8::Context> context, PassRefPtr<DOMWrapperWorld> world)
         : m_context(v8::Isolate::GetCurrent(), context)
         , m_perContextData(0)
         , m_world(world)
     {
         m_context.setWeak(this, &V8PerContextDataHolder::weakCallback);
         context->SetAlignedPointerInEmbedderData(v8ContextPerContextDataIndex, this);
     }
 
     ~V8PerContextDataHolder() { }
 
     static void weakCallback(const v8::WeakCallbackData<v8::Context, V8PerContextDataHolder>& data)
     {
         data.GetValue()->SetAlignedPointerInEmbedderData(v8ContextPerContextDataIndex, 0);
         delete data.GetParameter();
     }
 
     ScopedPersistent<v8::Context> m_context;
     V8PerContextData* m_perContextData;
-    // This should not be a RefPtr. Otherwise, it creates a cycle:
-    // V8PerContextData => DOMWrapperWorld => DOMDataStore => global objects
-    // => Window or WorkerGlobalScope => V8PerContextData.
-    DOMWrapperWorld* m_world;
+    RefPtr<DOMWrapperWorld> m_world;
 };
 
-V8PerContextData::V8PerContextData(v8::Handle<v8::Context> context, DOMWrapperWorld* world)
+V8PerContextData::V8PerContextData(v8::Handle<v8::Context> context, PassRefPtr<DOMWrapperWorld> world)
     : m_activityLogger(0)
     , m_isolate(context->GetIsolate())
     , m_contextHolder(adoptPtr(new gin::ContextHolder(context->GetIsolate())))
     , m_context(m_isolate, context)
     , m_customElementBindings(adoptPtr(new CustomElementBindingMap()))
 {
     m_contextHolder->SetContext(context);
     V8PerContextDataHolder::install(context, world);
     V8PerContextDataHolder::from(context)->setPerContextData(this);
 
@@ skipping 150 matching lines @@
     if (!data->IsString())
         return -1;
     v8::String::Utf8Value utf8(data);
     char* comma = strnstr(*utf8, ",", utf8.length());
     if (!comma)
         return -1;
     return atoi(comma + 1);
 }
 
 } // namespace WebCore