Remove synchronous compositeAndReadback() from WebLayerTreeView.

public/platform/WebLayerTreeView.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 89 matching lines @@
 
     // Indicates that an animation needs to be updated.
     virtual void setNeedsAnimate() = 0;
 
     // Indicates whether a commit is pending.
     virtual bool commitRequested() const = 0;
 
     // Relays the end of a fling animation.
     virtual void didStopFlinging() { }
 
-    // Composites and attempts to read back the result into the provided
-    // buffer. If it wasn't possible, e.g. due to context lost, will return
-    // false. Pixel format is 32bit (RGBA), and the provided buffer must be
-    // large enough contain viewportSize().width() * viewportSize().height()
-    // pixels. The WebLayerTreeView does not assume ownership of the buffer.
-    // The buffer is not modified if the false is returned.
-    virtual bool compositeAndReadback(void *pixels, const WebRect&) = 0;
-
     // The caller is responsible for keeping the WebCompositeAndReadbackAsyncCallback
     // object alive until it is called.
     virtual void compositeAndReadbackAsync(WebCompositeAndReadbackAsyncCallback*) { }
 
     // Blocks until the most recently composited frame has finished rendering on the GPU.
     // This can have a significant performance impact and should be used with care.
     virtual void finishAllRendering() = 0;
 
     // Prevents updates to layer tree from becoming visible.
     virtual void setDeferCommits(bool deferCommits) { }
@@ skipping 23 matching lines @@
     // Toggles continuous painting
     virtual void setContinuousPaintingEnabled(bool) { }
 
     // Toggles scroll bottleneck rects on the HUD layer
     virtual void setShowScrollBottleneckRects(bool) { }
 };
 
 } // namespace blink
 
 #endif // WebLayerTreeView_h