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

Source/platform/graphics/GraphicsLayer.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. 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
@@ skipping 214 matching lines @@
     // Return true if the animation is handled by the compositing system. If this returns
     // false, the animation will be run by AnimationController.
     // These methods handle both transitions and keyframe animations.
     bool addAnimation(PassOwnPtr<blink::WebAnimation>);
     void pauseAnimation(int animationId, double /*timeOffset*/);
     void removeAnimation(int animationId);
 
     // Layer contents
     void setContentsToImage(Image*);
     void setContentsToNinePatch(Image*, const IntRect& aperture);
-    void setContentsToSolidColor(const Color&);
     void setContentsToPlatformLayer(blink::WebLayer* layer) { setContentsTo(layer); }
     bool hasContentsLayer() const { return m_contentsLayer; }
 
     // Callback from the underlying graphics system to draw layer contents.
     void paintGraphicsLayerContents(GraphicsContext&, const IntRect& clip);
 
     // For hosting this GraphicsLayer in a native layer hierarchy.
     blink::WebLayer* platformLayer() const;
 
     enum CompositingCoordinatesOrientation { CompositingCoordinatesTopDown, CompositingCoordinatesBottomUp };
@@ skipping 129 matching lines @@
     GraphicsLayer* m_replicatedLayer; // For a replica layer, a reference to the original layer.
     FloatPoint m_replicatedLayerPosition; // For a replica layer, the position of the replica.
 
     IntRect m_contentsRect;
 
     int m_paintCount;
 
     OwnPtr<blink::WebContentLayer> m_layer;
     OwnPtr<blink::WebImageLayer> m_imageLayer;
     OwnPtr<blink::WebNinePatchLayer> m_ninePatchLayer;
-    Color m_contentsSolidColor;
-    OwnPtr<blink::WebSolidColorLayer> m_solidColorLayer;
     blink::WebLayer* m_contentsLayer;
     // We don't have ownership of m_contentsLayer, but we do want to know if a given layer is the
     // same as our current layer in setContentsTo(). Since m_contentsLayer may be deleted at this point,
     // we stash an ID away when we know m_contentsLayer is alive and use that for comparisons from that point
     // on.
     int m_contentsLayerId;
 
     Vector<LinkHighlightClient*> m_linkHighlights;
 
     OwnPtr<OpaqueRectTrackingContentLayerDelegate> m_opaqueRectTrackingContentLayerDelegate;
 
     ScrollableArea* m_scrollableArea;
     GraphicsLayerDebugInfo m_debugInfo;
     int m_3dRenderingContext;
 };
 
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void PLATFORM_EXPORT showGraphicsLayerTree(const WebCore::GraphicsLayer*);
 #endif
 
 #endif // GraphicsLayer_h