Pass implementation object to supplemental classes by reference

Source/core/dom/WheelController.h

Index: Source/core/dom/WheelController.h
diff --git a/Source/core/dom/WheelController.h b/Source/core/dom/WheelController.h
index 5f25f9831f25f0d517f89e327008bcc5d5513e7d..49879f4f0045652d012bd63b9ea1bd7ad446039d 100644
--- a/Source/core/dom/WheelController.h
+++ b/Source/core/dom/WheelController.h
@@ -41,19 +41,19 @@ public:
     virtual ~WheelController();
 
     static const char* supplementName();
-    static WheelController* from(Document*);
+    static WheelController* from(Document&);
 
     unsigned wheelEventHandlerCount() { return m_wheelEventHandlerCount; }
 
-    void didAddWheelEventHandler(Document*);
-    void didRemoveWheelEventHandler(Document*);
+    void didAddWheelEventHandler(Document&);
+    void didRemoveWheelEventHandler(Document&);
 
     // Inherited from DOMWindowLifecycleObserver
     virtual void didAddEventListener(DOMWindow*, const AtomicString&) OVERRIDE;
     virtual void didRemoveEventListener(DOMWindow*, const AtomicString&) OVERRIDE;
 
 private:
-    explicit WheelController(Document*);
+    explicit WheelController(Document&);
 
     unsigned m_wheelEventHandlerCount;
 };