Save a bitmap copy when advancing to dependent GIF and WebP animation frames

third_party/WebKit/Source/web/WebImageDecoder.cpp

 /*
  * 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 87 matching lines @@
         return false;
     return frameBuffer->getStatus() == ImageFrame::FrameComplete;
 }
 
 WebImage WebImageDecoder::getFrameAtIndex(int index = 0) const
 {
     DCHECK(m_private);
     ImageFrame* const frameBuffer = m_private->frameBufferAtIndex(index);
     if (!frameBuffer)
         return WebImage();
-    return WebImage(frameBuffer->bitmap());
+    SkBitmap bitmap = frameBuffer->bitmap();
+    if (frameBuffer->getStatus() == ImageFrame::FrameComplete)
+        bitmap.setImmutable();
+    return WebImage(bitmap);
 }
 
 } // namespace blink