Chrome::client() should return a ChromeClient reference.

Source/core/page/Chrome.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012, Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 40 matching lines @@
 struct DateTimeChooserParameters;
 struct ViewportArguments;
 struct WindowFeatures;
 
 class Chrome : public HostWindow {
 public:
     ~Chrome();
 
     static PassOwnPtr<Chrome> create(Page*, ChromeClient*);
 
-    ChromeClient* client() { return m_client; }
+    ChromeClient& client() { return *m_client; }
 
     // HostWindow methods.
     virtual void invalidateContentsAndRootView(const IntRect&) OVERRIDE;
     virtual void invalidateContentsForSlowScroll(const IntRect&) OVERRIDE;
     virtual void scroll(const IntSize&, const IntRect&, const IntRect&) OVERRIDE;
     virtual IntPoint screenToRootView(const IntPoint&) const OVERRIDE;
     virtual IntRect rootViewToScreen(const IntRect&) const OVERRIDE;
     virtual WebKit::WebScreenInfo screenInfo() const OVERRIDE;
     virtual void setCursor(const Cursor&) OVERRIDE;
 
@@ skipping 65 matching lines @@
     void notifyPopupOpeningObservers() const;
 
     Page* m_page;
     ChromeClient* m_client;
     Vector<PopupOpeningObserver*> m_popupOpeningObservers;
 };
 
 }
 
 #endif // Chrome_h