GIF Animations "clear from cache related glitch" fix

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

Index: third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
index 3ce2da9d3bbc71324c81ccc2e0559ece8a61b519..f9aa02c42e4c4174ef5844a4f2e57371150e9849 100644
--- a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
+++ b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
@@ -81,6 +81,9 @@ private:
     // failure, this will mark the image as failed.
     bool initFrameBuffer(size_t frameIndex);
 
+    // Like clearCacheExceptFrame(), but preserves two frames instead of one.
+    size_t clearCacheExceptTwoFrames(size_t, size_t);
+
     bool m_currentBufferSawAlpha;
     mutable int m_repetitionCount;
     OwnPtr<GIFImageReader> m_reader;