Pass implementation object to supplemental classes by reference

Source/modules/screen_orientation/ScreenOrientationController.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScreenOrientationController_h
 #define ScreenOrientationController_h
 
 #include "core/dom/DocumentSupplementable.h"
 #include "public/platform/WebScreenOrientation.h"
 
 namespace WebCore {
 
 class ScreenOrientationController FINAL : public DocumentSupplement {
 public:
     virtual ~ScreenOrientationController();
 
     void didChangeScreenOrientation(blink::WebScreenOrientation);
 
     blink::WebScreenOrientation orientation() const { return m_orientation; }
 
     // DocumentSupplement API.
-    static ScreenOrientationController* from(Document*);
+    static ScreenOrientationController& from(Document&);
     static const char* supplementName();
 
 private:
     explicit ScreenOrientationController(Document&);
 
     void dispatchOrientationChangeEvent();
 
     Document& m_document;
     blink::WebScreenOrientation m_orientation;
 };
 
 } // namespace WebCore
 
 #endif // ScreenOrientationController_h