Remove PlatformEvent it is no longer used.

third_party/WebKit/Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
@@ skipping 2119 matching lines @@
     pointerEventName = EventTypeNames::pointerup;
   else
     return;
 
   PointerEventInit pointerEventInit;
 
   pointerEventInit.setPointerId(PointerEventFactory::s_mouseId);
   pointerEventInit.setPointerType("mouse");
   pointerEventInit.setIsPrimary(true);
   pointerEventInit.setButtons(
-      MouseEvent::platformModifiersToButtons(mouseEvent.modifiers()));
+      MouseEvent::webInputEventModifiersToButtons(mouseEvent.modifiers()));
 
   pointerEventInit.setBubbles(true);
   pointerEventInit.setCancelable(true);
   pointerEventInit.setComposed(true);
   pointerEventInit.setDetail(0);
 
   pointerEventInit.setScreenX(mouseEvent.globalX);
   pointerEventInit.setScreenY(mouseEvent.globalY);
 
   IntPoint locationInFrameZoomed;
@@ skipping 415 matching lines @@
   if (node) {
     std::stringstream stream;
     node->printNodePathTo(stream);
     LOG(INFO) << stream.str();
   } else {
     LOG(INFO) << "Cannot showNodePath for <null>";
   }
 }
 
 #endif