Removing getBackingTextureImage from ImageBufferSurface

Source/platform/graphics/gpu/AcceleratedImageBufferSurface.h

 /*
  * 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 29 matching lines @@
 
 class PLATFORM_EXPORT AcceleratedImageBufferSurface : public ImageBufferSurface {
     WTF_MAKE_NONCOPYABLE(AcceleratedImageBufferSurface); WTF_MAKE_FAST_ALLOCATED(AcceleratedImageBufferSurface);
 public:
     AcceleratedImageBufferSurface(const IntSize&, OpacityMode = NonOpaque);
     ~AcceleratedImageBufferSurface() override { }
 
     SkCanvas* canvas() const override { return m_surface ? m_surface->getCanvas() : 0; }
     bool isValid() const override { return m_surface; }
     bool isAccelerated() const override { return true; }
-    PassRefPtr<SkImage> getBackingTextureImage() const override;
     void didModifyBackingTexture() override;
     PassRefPtr<SkImage> newImageSnapshot() const override;
 
 private:
     OwnPtr<SkSurface> m_surface;
     OwnPtr<WebGraphicsContext3DProvider> m_contextProvider;
 };
 
 
 } // namespace blink
 
 #endif