Oilpan: move WorkerGlobalScope to oilpan's heap.

Source/modules/imagebitmap/ImageBitmapFactories.h

Index: Source/modules/imagebitmap/ImageBitmapFactories.h
diff --git a/Source/modules/imagebitmap/ImageBitmapFactories.h b/Source/modules/imagebitmap/ImageBitmapFactories.h
index c5e8103cd9da611b992b4bd508c5917195ce4c15..4c6ff781416969391370b69e33fa806fe796a041 100644
--- a/Source/modules/imagebitmap/ImageBitmapFactories.h
+++ b/Source/modules/imagebitmap/ImageBitmapFactories.h
@@ -79,6 +79,8 @@ public:
 
     virtual ~ImageBitmapFactories() { }
 
+    virtual void trace(Visitor*);
+
 private:
     class ImageBitmapLoader FINAL : public RefCounted<ImageBitmapLoader>, public FileReaderLoaderClient {
     public:
@@ -120,6 +122,9 @@ private:
     HashSet<RefPtr<ImageBitmapLoader> > m_pendingLoaders;
 };
 
+template<>
+ImageBitmapFactories& ImageBitmapFactories::fromInternal(WorkerGlobalScope&);
+
 } // namespace WebCore
 
 #endif // ImageBitmapFactories_h