Merge 147178 "[Chromium] Don't create SolidColorLayer for full t..."

Source/WebCore/platform/graphics/chromium/GraphicsLayerChromium.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 506 matching lines @@
 
 void GraphicsLayerChromium::setContentsToSolidColor(const Color& color)
 {
     if (color == m_contentsSolidColor)
         return;
 
     bool childrenChanged = false;
 
     m_contentsSolidColor = color;
 
-    if (color.isValid()) {
+    if (color.isValid() && color.alpha()) {
         if (!m_contentsSolidColorLayer) {
             m_contentsSolidColorLayer = adoptPtr(Platform::current()->compositorSupport()->createSolidColorLayer());
             registerContentsLayer(m_contentsSolidColorLayer->layer());
 
             setupContentsLayer(m_contentsSolidColorLayer->layer());
             childrenChanged = true;
         }
 
         m_contentsSolidColorLayer->setBackgroundColor(color.rgb());
         updateContentsRect();
@@ skipping 371 matching lines @@
     info.addMember(m_contentsLayer, "contentsLayer");
     info.addMember(m_linkHighlight, "linkHighlight");
     info.addMember(m_opaqueRectTrackingContentLayerDelegate, "opaqueRectTrackingContentLayerDelegate");
     info.addMember(m_animationIdMap, "animationIdMap");
     info.addMember(m_scrollableArea, "scrollableArea");
 }
 
 } // namespace WebCore
 
 #endif // USE(ACCELERATED_COMPOSITING)