Remove PlatformEvent it is no longer used.

third_party/WebKit/Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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
@@ skipping 1877 matching lines @@
   // keyboard.  This is required for web compatibility.
   WebInputEvent::Type eventType = WebInputEvent::MouseDown;
   if (m_frame->settings() && m_frame->settings()->getShowContextMenuOnMouseUp())
     eventType = WebInputEvent::MouseUp;
 
   WebMouseEvent mouseEvent(
       eventType,
       WebFloatPoint(locationInRootFrame.x(), locationInRootFrame.y()),
       WebFloatPoint(globalPosition.x(), globalPosition.y()),
       WebPointerProperties::Button::NoButton, /* clickCount */ 0,
-      PlatformEvent::NoModifiers, TimeTicks::Now().InSeconds());
+      WebInputEvent::NoModifiers, TimeTicks::Now().InSeconds());
 
   // TODO(dtapuska): Transition the mouseEvent to be created really in viewport
   // coordinates instead of root frame coordinates.
   mouseEvent.setFrameScale(1);
 
   return sendContextMenuEvent(mouseEvent, overrideTargetElement);
 }
 
 void EventHandler::scheduleHoverStateUpdate() {
   // TODO(https://crbug.com/668758): Use a normal BeginFrame update for this.
@@ skipping 223 matching lines @@
 }
 
 FrameHost* EventHandler::frameHost() const {
   if (!m_frame->page())
     return nullptr;
 
   return &m_frame->page()->frameHost();
 }
 
 }  // namespace blink