Pull up clearCacheExceptFrame to ImageDecoder.

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 34 matching lines @@
   ~GIFImageDecoder() override;
 
   enum GIFParseQuery { GIFSizeQuery, GIFFrameCountQuery };
 
   // ImageDecoder:
   String filenameExtension() const override { return "gif"; }
   void onSetData(SegmentReader* data) override;
   int repetitionCount() const override;
   bool frameIsCompleteAtIndex(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,
@@ skipping 22 matching lines @@
   bool initFrameBuffer(size_t frameIndex);
 
   bool m_currentBufferSawAlpha;
   mutable int m_repetitionCount;
   std::unique_ptr<GIFImageReader> m_reader;
 };
 
 }  // namespace blink
 
 #endif