Remove unused includes from core/platform .cpp files

Source/core/platform/DragData.cpp

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 16 matching lines @@
 #include "config.h"
 #include "core/platform/DragData.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/DocumentFragment.h"
 #include "core/dom/Range.h"
 #include "core/editing/markup.h"
 #include "core/page/Frame.h"
 #include "core/platform/FileSystem.h"
 #include "core/platform/KURL.h"
-#include "core/platform/PlatformEvent.h"
-#include "core/platform/PlatformKeyboardEvent.h"
 #include "core/platform/chromium/ChromiumDataObject.h"
 #include "core/platform/chromium/ClipboardMimeTypes.h"
 #include "modules/filesystem/DraggedIsolatedFileSystem.h"
 #include "wtf/text/WTFString.h"
 
 #include <public/Platform.h>
 #include <public/WebFileUtilities.h>
 
 namespace WebCore {
 
@@ skipping 118 matching lines @@
 
 String DragData::droppedFileSystemId() const
 {
     DraggedIsolatedFileSystem* filesystem = DraggedIsolatedFileSystem::from(m_platformDragData);
     if (!filesystem)
         return String();
     return filesystem->filesystemId();
 }
 
 } // namespace WebCore