Don't cache any SkBitmaps in DeferredImageDecoder

Source/platform/image-decoders/ImageDecoder.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) Research In Motion Limited 2009-2010. 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 29 matching lines @@
 #include "wtf/text/WTFString.h"
 
 #if USE(QCMSLIB)
 #include "qcms.h"
 #endif
 
 typedef Vector<char> ColorProfile;
 
 namespace blink {
 
+// GIF and WebP support animation. The explanation below is in terms of GIF,
+// but the same constants are used for WebP, too.
+// GIFs have an optional 16-bit unsigned loop count that describes how an
+// animated GIF should be cycled.  If the loop count is absent, the animation
+// cycles once; if it is 0, the animation cycles infinitely; otherwise the
+// animation plays n + 1 cycles (where n is the specified loop count).  If the
+// GIF decoder defaults to cAnimationLoopOnce in the absence of any loop count
+// and translates an explicit "0" loop count to cAnimationLoopInfinite, then we
+// get a couple of nice side effects:
+//   * By making cAnimationLoopOnce be 0, we allow the animation cycling code in
+//     BitmapImage.cpp to avoid special-casing it, and simply treat all
+//     non-negative loop counts identically.
+//   * By making the other two constants negative, we avoid conflicts with any
+//     real loop count values.
+const int cAnimationLoopOnce = 0;
+const int cAnimationLoopInfinite = -1;
+const int cAnimationNone = -2;
+
 // ImagePlanes can be used to decode color components into provided buffers instead of using an ImageFrame.
 class PLATFORM_EXPORT ImagePlanes {
 public:
     ImagePlanes();
     ImagePlanes(void* planes[3], size_t rowBytes[3]);
 
     void* plane(int);
     size_t rowBytes(int) const;
 
 private:
@@ skipping 262 matching lines @@
 
     IntSize m_size;
     bool m_sizeAvailable;
     bool m_isAllDataReceived;
     bool m_failed;
 };
 
 } // namespace blink
 
 #endif