Remove PlatformEvent it is no longer used.

third_party/WebKit/Source/core/page/EventWithHitTestResults.h

 /*
    Copyright (C) 2000 Simon Hausmann <hausmann@kde.org>
    Copyright (C) 2006 Apple Computer, Inc.
 
    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.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
 */
 
 #ifndef EventWithHitTestResults_h
 #define EventWithHitTestResults_h
 
 #include "core/layout/HitTestResult.h"
-#include "platform/PlatformEvent.h"
 #include "public/platform/WebGestureEvent.h"
 #include "public/platform/WebMouseEvent.h"
 
 namespace blink {
 
 class Scrollbar;
 
 template <typename EventType>
 class EventWithHitTestResults {
   STACK_ALLOCATED();
@@ skipping 19 matching lines @@
   HitTestResult m_hitTestResult;
 };
 
 using MouseEventWithHitTestResults = EventWithHitTestResults<WebMouseEvent>;
 
 using GestureEventWithHitTestResults = EventWithHitTestResults<WebGestureEvent>;
 
 }  // namespace blink
 
 #endif  // EventWithHitTestResults_h