Remove PlatformMouseEvent::m_modifierFlags member.

Source/web/WebInputEventConversion.cpp

 /*
  * Copyright (C) 2009 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 87 matching lines @@
     m_modifiers = 0;
     if (e.modifiers & WebInputEvent::ShiftKey)
         m_modifiers |= PlatformEvent::ShiftKey;
     if (e.modifiers & WebInputEvent::ControlKey)
         m_modifiers |= PlatformEvent::CtrlKey;
     if (e.modifiers & WebInputEvent::AltKey)
         m_modifiers |= PlatformEvent::AltKey;
     if (e.modifiers & WebInputEvent::MetaKey)
         m_modifiers |= PlatformEvent::MetaKey;
 
-    m_modifierFlags = e.modifiers;
     m_timestamp = e.timeStampSeconds;
     m_clickCount = e.clickCount;
 
     switch (e.type) {
     case WebInputEvent::MouseMove:
     case WebInputEvent::MouseLeave:  // synthesize a move event
         m_type = PlatformEvent::MouseMoved;
         break;
 
     case WebInputEvent::MouseDown:
@@ skipping 697 matching lines @@
     modifiers = getWebInputModifiers(event);
 
     globalX = event.screenX();
     globalY = event.screenY();
     IntPoint localPoint = convertAbsoluteLocationForRenderObject(event.absoluteLocation(), *renderObject);
     x = localPoint.x();
     y = localPoint.y();
 }
 
 } // namespace blink