Checking if frame is complete and access duration doesn't need a decode

Source/core/platform/graphics/ImageSource.h

 /*
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2007-2008 Torch Mobile, Inc.
  *
  * 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 109 matching lines @@
     size_t bytesDecodedToDetermineProperties() const;
 
     int repetitionCount();
 
     size_t frameCount() const;
 
     // Callers should not call this after calling clear() with a higher index;
     // see comments on clear() above.
     PassNativeImagePtr createFrameAtIndex(size_t);
 
-    float frameDurationAtIndex(size_t);
-    bool frameHasAlphaAtIndex(size_t); // Whether or not the frame actually used any alpha.
-    bool frameIsCompleteAtIndex(size_t); // Whether or not the frame is completely decoded.
+    float frameDurationAtIndex(size_t) const;
+    bool frameHasAlphaAtIndex(size_t) const; // Whether or not the frame actually used any alpha.
+    bool frameIsCompleteAtIndex(size_t) const; // Whether or not the frame is fully received.
     ImageOrientation orientationAtIndex(size_t) const; // EXIF image orientation
 
     // Return the number of bytes in the decoded frame. If the frame is not yet
     // decoded then return 0.
     unsigned frameBytesAtIndex(size_t) const;
 
 #if ENABLE(IMAGE_DECODER_DOWN_SAMPLING)
     static unsigned maxPixelsPerDecodedImage() { return s_maxPixelsPerDecodedImage; }
     static void setMaxPixelsPerDecodedImage(unsigned maxPixels) { s_maxPixelsPerDecodedImage = maxPixels; }
 #endif
 
     void reportMemoryUsage(MemoryObjectInfo*) const;
 
 private:
     OwnPtr<NativeImageDecoderPtr> m_decoder;
 
     AlphaOption m_alphaOption;
     GammaAndColorProfileOption m_gammaAndColorProfileOption;
 #if ENABLE(IMAGE_DECODER_DOWN_SAMPLING)
     static unsigned s_maxPixelsPerDecodedImage;
 #endif
 };
 
 }
 
 #endif