Reland again "Decode GIF image frames on demand".

Source/core/platform/graphics/Image.h

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, 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 76 matching lines @@
     IntRect rect() const { return IntRect(IntPoint(), size()); }
     int width() const { return size().width(); }
     int height() const { return size().height(); }
     virtual bool getHotSpot(IntPoint&) const { return false; }
 
     bool setData(PassRefPtr<SharedBuffer> data, bool allDataReceived);
     virtual bool dataChanged(bool /*allDataReceived*/) { return false; }
     
     virtual String filenameExtension() const { return String(); } // null string if unknown
 
-    virtual void destroyDecodedData(bool destroyAll = true) = 0;
+    virtual void destroyDecodedData() = 0;
     virtual unsigned decodedSize() const = 0;
 
     SharedBuffer* data() { return m_encodedImageData.get(); }
 
     // Animation begins whenever someone draws the image, so startAnimation() is not normally called.
     // It will automatically pause once all observers no longer want to render the image anywhere.
     virtual void startAnimation(bool /*catchUpIfNecessary*/ = true) { }
     virtual void stopAnimation() {}
     virtual void resetAnimation() {}
     
@@ skipping 35 matching lines @@
     virtual Color solidColor() const { return Color(); }
     
 private:
     RefPtr<SharedBuffer> m_encodedImageData;
     ImageObserver* m_imageObserver;
 };
 
 }
 
 #endif