Cleanup some dead code in blink::ImageBuffer and friends

third_party/WebKit/Source/platform/graphics/UnacceleratedImageBufferSurface.cpp

 /*
  * Copyright (c) 2013, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 41 matching lines @@
     }
 }
 
 UnacceleratedImageBufferSurface::~UnacceleratedImageBufferSurface() { }
 
 SkCanvas* UnacceleratedImageBufferSurface::canvas()
 {
     return m_surface->getCanvas();
 }
 
-const SkBitmap& UnacceleratedImageBufferSurface::deprecatedBitmapForOverwrite()
-{
-    m_surface->notifyContentWillChange(SkSurface::kDiscard_ContentChangeMode);
-    return m_surface->getCanvas()->getDevice()->accessBitmap(false);
-}
-
 bool UnacceleratedImageBufferSurface::isValid() const
 {
     return m_surface;
 }
 
 PassRefPtr<SkImage> UnacceleratedImageBufferSurface::newImageSnapshot(AccelerationHint)
 {
     return adoptRef(m_surface->newImageSnapshot());
 }
 
 } // namespace blink