Prevent image downscaling on HiDPI devices with impl-side painting.

Source/Platform/chromium/public/WebContentLayerClient.h

 /*
  * Copyright (C) 2011 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
@@ skipping 23 matching lines @@
 
 class WebContentLayerClient {
 public:
     // Paints the content area for the layer, typically dirty rects submitted
     // through WebContentLayer::setNeedsDisplay, submitting drawing commands
     // through the WebCanvas.
     // The canvas is already clipped to the |clip| rect.
     // Optionally, the implementation may set |opaque| to a rect covering pixels that
     // the implementation knows are opaque. This information can be used for various
     // optimizations.
-    virtual void paintContents(WebCanvas*, const WebRect& clip, bool canPaintLCDText, WebFloatRect& opaque) = 0;
+    virtual void paintContents(WebCanvas*, const WebRect& clip, bool canPaintLCDText, WebFloatRect& opaque, bool deferred = false) = 0;
 
 protected:
     virtual ~WebContentLayerClient() { }
 };
 
 } // namespace WebKit
 
 #endif // WebContentLayerClient_h