Oilpan: move WorkerGlobalScope to oilpan's heap.

Source/core/loader/WorkerThreadableLoader.h

Index: Source/core/loader/WorkerThreadableLoader.h
diff --git a/Source/core/loader/WorkerThreadableLoader.h b/Source/core/loader/WorkerThreadableLoader.h
index ec69fec9a99b1d74b604f6eee02cc2d3066c802d..f1a747232f07cb5740cbc66d3bd1569fcd2e2a57 100644
--- a/Source/core/loader/WorkerThreadableLoader.h
+++ b/Source/core/loader/WorkerThreadableLoader.h
@@ -34,6 +34,7 @@
 #include "core/loader/ThreadableLoader.h"
 #include "core/loader/ThreadableLoaderClient.h"
 #include "core/loader/ThreadableLoaderClientWrapper.h"
+#include "heap/Handle.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
@@ -133,7 +134,7 @@ namespace WebCore {
 
         WorkerThreadableLoader(WorkerGlobalScope*, PassRefPtr<ThreadableLoaderClientWrapper>, PassOwnPtr<ThreadableLoaderClient>, const ResourceRequest&, const ThreadableLoaderOptions&);
 
-        RefPtr<WorkerGlobalScope> m_workerGlobalScope;
+        RefPtrWillBePersistent<WorkerGlobalScope> m_workerGlobalScope;
         RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
         MainThreadBridge& m_bridge;
     };