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

third_party/WebKit/Source/platform/image-decoders/ImageFrame.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 75 matching lines @@
     // These do not touch other metadata, only the raw pixel data.
     void clearPixelData();
     void zeroFillPixelData();
     void zeroFillFrameRect(const IntRect&);
 
     // Makes this frame have an independent copy of the provided image's
     // pixel data, so that modifications in one frame are not reflected in
     // the other.  Returns whether the copy succeeded.
     bool copyBitmapData(const ImageFrame&);
 
+    // Takes over other's frame pixel data. Other becomes empty after this call.

[Peter Kasting, 2016/07/19 03:04:17]

Nit: To match declaration above as closely as possible:

    // Moves the bitmap data from the provided frame to this one, leaving the
    // provided frame empty.
    void moveBitmapData(ImageFrame*);

This also fixes a violation of
http://google.github.io/styleguide/cppguide.html#Reference_Arguments .

[aleksandar.stojiljkovic, 2016/07/19 11:10:40]

Done.

+    void takeBitmapData(ImageFrame& other);
+
     // Copies the pixel data at [(startX, startY), (endX, startY)) to the
     // same X-coordinates on each subsequent row up to but not including
     // endY.
     void copyRowNTimes(int startX, int endX, int startY, int endY)
     {
         ASSERT(startX < width());
         ASSERT(endX <= width());
         ASSERT(startY < height());
         ASSERT(endY <= height());
         const int rowBytes = (endX - startX) * sizeof(PixelData);
@@ skipping 107 matching lines @@
     // The frame that must be decoded before this frame can be decoded.
     // WTF::kNotFound if this frame doesn't require any previous frame.
     // This is used by ImageDecoder::clearCacheExceptFrame(), and will never
     // be read for image formats that do not have multiple frames.
     size_t m_requiredPreviousFrameIndex;
 };
 
 } // namespace blink
 
 #endif