Move rendering/RenderObject to layout/LayoutObject.

Source/core/rendering/RenderScrollbarPart.cpp

 /*
  * Copyright (C) 2008 Apple 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 181 matching lines @@
             if (frameView->isFrameViewScrollCorner(this)) {
                 frameView->invalidateScrollCorner(frameView->scrollCornerRect());
                 return;
             }
         }
 
         RenderBlock::imageChanged(image, rect);
     }
 }
 
-RenderObject* RenderScrollbarPart::rendererOwningScrollbar() const
+LayoutObject* RenderScrollbarPart::rendererOwningScrollbar() const
 {
     if (!m_scrollbar)
         return 0;
     return m_scrollbar->owningRenderer();
 }
 
 }