Re-land "Drop background color optimization for composited layers"

Source/web/tests/GraphicsLayerTest.cpp

 /*
  * Copyright (C) 2012 Google 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 147 matching lines @@
     FakeScrollableArea scrollableArea;
     m_graphicsLayer->setScrollableArea(&scrollableArea, false);
 
     WebPoint scrollPosition(7, 9);
     m_platformLayer->setScrollPosition(scrollPosition);
     m_graphicsLayer->didScroll();
 
     EXPECT_EQ(scrollPosition, WebPoint(scrollableArea.scrollPosition()));
 }
 
-TEST_F(GraphicsLayerTest, DISABLED_setContentsToSolidColor)
-{
-    m_graphicsLayer->setContentsToSolidColor(Color::transparent);
-    EXPECT_FALSE(m_graphicsLayer->contentsLayer());
-
-    m_graphicsLayer->setContentsToSolidColor(Color::white);
-    EXPECT_TRUE(m_graphicsLayer->contentsLayer());
-
-    m_graphicsLayer->setContentsToSolidColor(Color());
-    EXPECT_FALSE(m_graphicsLayer->contentsLayer());
-}
-
 } // namespace