Early reporting of opaqueness by decoders.

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h

 /*
  * Copyright (C) 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 32 matching lines @@
     GIFImageDecoder(AlphaOption, GammaAndColorProfileOption, size_t maxDecodedBytes);
     ~GIFImageDecoder() override;
 
     enum GIFParseQuery { GIFSizeQuery, GIFFrameCountQuery };
 
     // ImageDecoder:
     String filenameExtension() const override { return "gif"; }
     void onSetData(SharedBuffer* data) override;
     int repetitionCount() const override;
     bool frameIsCompleteAtIndex(size_t) const override;
+    bool frameHasAlphaAtIndex(size_t) const override;
     float frameDurationAtIndex(size_t) const override;
     size_t clearCacheExceptFrame(size_t) override;
     // CAUTION: setFailed() deletes |m_reader|.  Be careful to avoid
     // accessing deleted memory, especially when calling this from inside
     // GIFImageReader!
     bool setFailed() override;
 
     // Callbacks from the GIF reader.
     bool haveDecodedRow(size_t frameIndex, GIFRow::const_iterator rowBegin, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels);
     bool frameComplete(size_t frameIndex);
@@ skipping 22 matching lines @@
     size_t clearCacheExceptTwoFrames(size_t, size_t);
 
     bool m_currentBufferSawAlpha;
     mutable int m_repetitionCount;
     OwnPtr<GIFImageReader> m_reader;
 };
 
 } // namespace blink
 
 #endif