Oilpan: move WorkerGlobalScope to oilpan's heap.

Source/platform/RefCountedSupplement.h

 /*
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 42 matching lines @@
         RefPtr<ThisType> m_wrapped;
     };
 
     static void provideTo(Supplementable<T>& host, const char* key, PassRefPtr<ThisType> supplement)
     {
         host.provideSupplement(key, adoptPtr(new Wrapper(supplement)));
     }
 
     static ThisType* from(Supplementable<T>& host, const char* key)
     {
-        Supplement<T>* found = host.requireSupplement(key);
+        Supplement<T>* found = static_cast<Supplement<T>*>(host.requireSupplement(key));
         if (!found)
             return 0;
         ASSERT_WITH_SECURITY_IMPLICATION(found->isRefCountedWrapper());
         return static_cast<Wrapper*>(found)->wrapped();
     }
 };
 
 } // namespace WebCore
 
 #endif // RefCountedSupplement_h