Improve GIF decoding performance

Source/core/platform/image-decoders/gif/GIFImageDecoder.h

Index: Source/core/platform/image-decoders/gif/GIFImageDecoder.h
diff --git a/Source/core/platform/image-decoders/gif/GIFImageDecoder.h b/Source/core/platform/image-decoders/gif/GIFImageDecoder.h
index 3159b7bedbce1961c0d067d466ea672369d7eacd..23309a40ced312f05cb094e0edd3c36c5d1e7bb5 100644
--- a/Source/core/platform/image-decoders/gif/GIFImageDecoder.h
+++ b/Source/core/platform/image-decoders/gif/GIFImageDecoder.h
@@ -57,7 +57,7 @@ namespace WebCore {
         virtual bool setFailed() OVERRIDE;
 
         // Callbacks from the GIF reader.
-        bool haveDecodedRow(size_t frameIndex, const Vector<unsigned char>& rowBuffer, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels);
+        bool haveDecodedRow(size_t frameIndex, Vector<unsigned char>::const_iterator rowBegin, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels);
         bool frameComplete(size_t frameIndex);
 
         // For testing.