Move WebMouseEvent into its own header file.

third_party/WebKit/Source/core/events/MouseEvent.h

 /*
  * 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, 2004, 2005, 2006, 2008 Apple Inc. 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 11 matching lines @@
  */
 
 #ifndef MouseEvent_h
 #define MouseEvent_h
 
 #include "core/CoreExport.h"
 #include "core/events/EventDispatchMediator.h"
 #include "core/events/MouseEventInit.h"
 #include "core/events/UIEventWithKeyState.h"
 #include "platform/PlatformMouseEvent.h"
+#include "public/platform/WebMouseEvent.h"
 
 namespace blink {
 class DataTransfer;
 class EventDispatcher;
 
 class CORE_EXPORT MouseEvent : public UIEventWithKeyState {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   static MouseEvent* create() { return new MouseEvent; }
@@ skipping 238 matching lines @@
   MouseEvent& event() const;
 
   DispatchEventResult dispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(MouseEvent);
 
 }  // namespace blink
 
 #endif  // MouseEvent_h