DOMDataStore should be cleared when shutting down worker threads

Source/bindings/v8/V8PerContextData.h

Index: Source/bindings/v8/V8PerContextData.h
diff --git a/Source/bindings/v8/V8PerContextData.h b/Source/bindings/v8/V8PerContextData.h
index 04c255690737b107db900c46c49503b04ebfedcd..ad46ce540c16620e696f9914f5287ae920f16ad5 100644
--- a/Source/bindings/v8/V8PerContextData.h
+++ b/Source/bindings/v8/V8PerContextData.h
@@ -61,7 +61,7 @@ enum V8ContextEmbedderDataField {
 
 class V8PerContextData {
 public:
-    static PassOwnPtr<V8PerContextData> create(v8::Handle<v8::Context> context, DOMWrapperWorld* world)
+    static PassOwnPtr<V8PerContextData> create(v8::Handle<v8::Context> context, PassRefPtr<DOMWrapperWorld> world)
     {
         return adoptPtr(new V8PerContextData(context, world));
     }
@@ -101,7 +101,7 @@ public:
     CustomElementBinding* customElementBinding(CustomElementDefinition*);
 
 private:
-    V8PerContextData(v8::Handle<v8::Context>, DOMWrapperWorld*);
+    V8PerContextData(v8::Handle<v8::Context>, PassRefPtr<DOMWrapperWorld>);
 
     v8::Local<v8::Object> createWrapperFromCacheSlowCase(const WrapperTypeInfo*);
     v8::Local<v8::Function> constructorForTypeSlowCase(const WrapperTypeInfo*);