Change RefPtr<DOMWrapperWorld> that causes reference cycles to DOMWrapperWorld*

Source/bindings/v8/DOMRequestState.h

Index: Source/bindings/v8/DOMRequestState.h
diff --git a/Source/bindings/v8/DOMRequestState.h b/Source/bindings/v8/DOMRequestState.h
index 32992b8340cfe349ceace8cd6867dbccf72c2402..4059a510da00377b9743b817bfd02545769154e8 100644
--- a/Source/bindings/v8/DOMRequestState.h
+++ b/Source/bindings/v8/DOMRequestState.h
@@ -47,7 +47,7 @@ public:
     void clear()
     {
         m_executionContext = 0;
-        m_world.clear();
+        m_world = 0;
     }
 
     class Scope {
@@ -65,7 +65,7 @@ public:
     v8::Local<v8::Context> context()
     {
         ASSERT(m_executionContext);
-        return toV8Context(m_executionContext, m_world.get());
+        return toV8Context(m_executionContext, m_world);
     }
 
     v8::Isolate* isolate() const
@@ -78,7 +78,7 @@ public:
 private:
     v8::Isolate* m_isolate;
     ExecutionContext* m_executionContext;
-    RefPtr<DOMWrapperWorld> m_world;
+    DOMWrapperWorld* m_world;
 };
 
 }