Revert of Make DOMWrapperWorld::current() return a reference instead of a pointer

Source/bindings/v8/V8WindowShell.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 37 matching lines @@
 
 class DOMWindow;
 class LocalFrame;
 class HTMLDocument;
 class SecurityOrigin;
 
 // V8WindowShell represents all the per-global object state for a LocalFrame that
 // persist between navigations.
 class V8WindowShell {
 public:
-    static PassOwnPtr<V8WindowShell> create(LocalFrame*, DOMWrapperWorld&, v8::Isolate*);
+    static PassOwnPtr<V8WindowShell> create(LocalFrame*, PassRefPtr<DOMWrapperWorld>, v8::Isolate*);
 
     v8::Local<v8::Context> context() const { return m_perContextData ? m_perContextData->context() : v8::Local<v8::Context>(); }
 
     // Update document object of the frame.
     void updateDocument();
 
     void namedItemAdded(HTMLDocument*, const AtomicString&);
     void namedItemRemoved(HTMLDocument*, const AtomicString&);
 
     // Update the security origin of a document
     // (e.g., after setting docoument.domain).
     void updateSecurityOrigin(SecurityOrigin*);
 
     bool isContextInitialized() { return m_perContextData; }
     bool isGlobalInitialized() { return !m_global.isEmpty(); }
 
     bool initializeIfNeeded();
     void updateDocumentWrapper(v8::Handle<v8::Object> wrapper);
 
     void clearForNavigation();
     void clearForClose();
 
-    DOMWrapperWorld& world() { return *m_world; }
+    DOMWrapperWorld* world() { return m_world.get(); }
 
 private:
     V8WindowShell(LocalFrame*, PassRefPtr<DOMWrapperWorld>, v8::Isolate*);
     bool initialize();
 
     enum GlobalDetachmentBehavior {
         DoNotDetachGlobal,
         DetachGlobal
     };
     void disposeContext(GlobalDetachmentBehavior);
@@ skipping 16 matching lines @@
     RefPtr<DOMWrapperWorld> m_world;
     v8::Isolate* m_isolate;
     OwnPtr<V8PerContextData> m_perContextData;
     ScopedPersistent<v8::Object> m_global;
     ScopedPersistent<v8::Object> m_document;
 };
 
 } // namespace WebCore
 
 #endif // V8WindowShell_h