Revert 168245 "Drop background color optimization for composited..."

trunk/Source/platform/graphics/GraphicsLayer.h

Index: trunk/Source/platform/graphics/GraphicsLayer.h
===================================================================
--- trunk/Source/platform/graphics/GraphicsLayer.h	(revision 168316)
+++ trunk/Source/platform/graphics/GraphicsLayer.h	(working copy)
@@ -232,6 +232,7 @@
     // 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; }
 
@@ -381,6 +382,8 @@
     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,