Remove external BitmapImage lazy decoding tracking

Source/platform/graphics/BitmapImage.h

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008-2009 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.
@@ skipping 100 matching lines @@
 
     size_t currentFrame() const { return m_currentFrame; }
     size_t frameCount();
 
     PassRefPtr<SkImage> frameAtIndex(size_t);
 
     bool frameIsCompleteAtIndex(size_t);
     float frameDurationAtIndex(size_t);
     bool frameHasAlphaAtIndex(size_t);
     ImageOrientation frameOrientationAtIndex(size_t);
-    bool frameIsLazyDecodedAtIndex(size_t) const;
 
     // Decodes and caches a frame. Never accessed except internally.
     void cacheFrame(size_t index);
 
     // Called before accessing m_frames[index]. Returns false on index out of bounds.
     bool ensureFrameIsCached(size_t index);
 
     // Returns the total number of bytes allocated for all framebuffers, i.e.
     // the sum of m_source.frameBytesAtIndex(...) for all frames.  This is
     // returned as an int for caller convenience, to allow safely subtracting
@@ skipping 57 matching lines @@
     bool m_sizeAvailable : 1; // Whether or not we can obtain the size of the first image frame yet from ImageIO.
     mutable bool m_hasUniformFrameSize : 1;
     mutable bool m_haveFrameCount : 1;
 };
 
 DEFINE_IMAGE_TYPE_CASTS(BitmapImage);
 
 } // namespace blink
 
 #endif