Move PlatformScreen, PlatformScreenChromium, and Widget to Source/platform

Source/core/rendering/RenderWidget.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2009, 2010 Apple Inc. All rights reserved.
  *
  * 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 RenderWidget_h
 #define RenderWidget_h
 
-#include "core/platform/Widget.h"
 #include "core/rendering/RenderReplaced.h"
+#include "platform/Widget.h"
 
 namespace WebCore {
 
 class RenderWidget : public RenderReplaced {
 public:
     virtual ~RenderWidget();
 
     Widget* widget() const { return m_widget.get(); }
     virtual void setWidget(PassRefPtr<Widget>);
 
@@ skipping 53 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isWidget());
     return static_cast<const RenderWidget*>(object);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toRenderWidget(const RenderWidget*);
 
 } // namespace WebCore
 
 #endif // RenderWidget_h