Cleanup: Add more conversion helpers for usage.

Source/core/events/WheelEvent.cpp

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2005, 2006, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 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
@@ skipping 130 matching lines @@
     if (!(event.deltaX() || event.deltaY()))
         return;
 
     setEvent(WheelEvent::create(FloatPoint(event.wheelTicksX(), event.wheelTicksY()), FloatPoint(event.deltaX(), event.deltaY()),
         deltaMode(event), view, event.globalPosition(), event.position(),
         event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(), event.directionInvertedFromDevice()));
 }
 
 WheelEvent* WheelEventDispatchMediator::event() const
 {
-    return static_cast<WheelEvent*>(EventDispatchMediator::event());
+    return toWheelEvent(EventDispatchMediator::event());
 }
 
 bool WheelEventDispatchMediator::dispatchEvent(EventDispatcher* dispatcher) const
 {
     ASSERT(event());
     return EventDispatchMediator::dispatchEvent(dispatcher) && !event()->defaultHandled();
 }
 
 } // namespace WebCore