Revert of Separate repaint and layout requirements of StyleDifference (Step 1)

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 133 matching lines @@
     setInline(false);
 }
 
 void RenderScrollbarPart::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
 {
     RenderBlock::styleDidChange(diff, oldStyle);
     setInline(false);
     clearPositionedState();
     setFloating(false);
     setHasOverflowClip(false);
-    if (oldStyle && m_scrollbar && m_part != NoPart && (diff.needsRepaint() || diff.needsLayout()))
+    if (oldStyle && m_scrollbar && m_part != NoPart && diff >= StyleDifferenceRepaint)
         m_scrollbar->theme()->invalidatePart(m_scrollbar, m_part);
 }
 
 void RenderScrollbarPart::imageChanged(WrappedImagePtr image, const IntRect* rect)
 {
     if (m_scrollbar && m_part != NoPart)
         m_scrollbar->theme()->invalidatePart(m_scrollbar, m_part);
     else {
         if (FrameView* frameView = view()->frameView()) {
             if (frameView->isFrameViewScrollCorner(this)) {
@@ skipping 30 matching lines @@
 }
 
 RenderObject* RenderScrollbarPart::rendererOwningScrollbar() const
 {
     if (!m_scrollbar)
         return 0;
     return m_scrollbar->owningRenderer();
 }
 
 }