blink: Cleanup class forward declarations

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.h

 /*
  * Copyright (c) 2010, 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 44 matching lines @@
 class GLES2Interface;
 }
 }
 
 namespace WTF {
 class ArrayBufferContents;
 }
 
 namespace blink {
 class Extensions3DUtil;
-class ImageBuffer;
 class StaticBitmapImage;
-class WebExternalBitmap;
 class WebExternalTextureLayer;
 class WebGraphicsContext3DProvider;
 class WebLayer;
 
 // Manages a rendering target (framebuffer + attachment) for a canvas.  Can
 // publish its rendering results to a WebLayer for compositing.
 class PLATFORM_EXPORT DrawingBuffer
     : public NON_EXPORTED_BASE(cc::TextureLayerClient),
       public RefCounted<DrawingBuffer> {
   WTF_MAKE_NONCOPYABLE(DrawingBuffer);
@@ skipping 435 matching lines @@
   // RuntimeEnabledFeatures::webGLImageChromiumEnabled() call with
   // shouldUseChromiumImage() calls, and set m_chromiumImageUsage to
   // DisallowChromiumImage in the case of OffscreenCanvas.
   ChromiumImageUsage m_chromiumImageUsage;
   bool shouldUseChromiumImage();
 };
 
 }  // namespace blink
 
 #endif  // DrawingBuffer_h