Remove PlatformWheelEvent and use WebMouseWheelEvent instead

third_party/WebKit/Source/platform/PlatformEvent.h

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 25 matching lines @@
  public:
   enum EventType {
     NoType = 0,
 
     // PlatformMouseEvent
     MouseMoved,
     MousePressed,
     MouseReleased,
     MouseScroll,
 
-    // PlatformWheelEvent
-    Wheel,
-
     // PlatformTouchEvent
     TouchStart,
     TouchMove,
     TouchEnd,
     TouchCancel,
     TouchScrollStarted,
   };
 
   // These values are direct mappings of the values in WebInputEvent so the
   // values can be cast between the enumerations. static_asserts checking this
@@ skipping 78 matching lines @@
   ~PlatformEvent() {}
 
   unsigned m_type;
   unsigned m_modifiers;
   TimeTicks m_timestamp;
 };
 
 }  // namespace blink
 
 #endif  // PlatformEvent_h