Re-enable solid background color optimization for composited layers.

Source/core/rendering/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 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 1250 matching lines @@
         m_graphicsLayer->setBackgroundColor(Color());
     } else {
         // An unset (invalid) color will remove the solid color.
         m_graphicsLayer->setContentsToSolidColor(Color());
         m_graphicsLayer->setBackgroundColor(backgroundColor);
     }
 }
 
 static bool supportsDirectBoxDecorationsComposition(const RenderObject* renderer)
 {
-    if (!GraphicsLayer::supportsBackgroundColorContent())
-        return false;
-
     if (renderer->hasClip())
         return false;
 
     if (hasBoxDecorationsOrBackgroundImage(renderer->style()))
         return false;
 
     // FIXME: we should be able to allow backgroundComposite; However since this is not a common use case it has been deferred for now.
     if (renderer->style()->backgroundComposite() != CompositeSourceOver)
         return false;
 
@@ skipping 719 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore