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

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

 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
@@ skipping 264 matching lines @@
 
     const unsigned char* localColormap(const GIFFrameContext* frame) const
     {
         return frame->isLocalColormapDefined ? data(frame->localColormapPosition) : 0;
     }
     int localColormapSize(const GIFFrameContext* frame) const
     {
         return frame->isLocalColormapDefined ? frame->localColormapSize : 0;
     }
 
-    const GIFFrameContext* frameContext() const
+    const GIFFrameContext* frameContext(size_t index) const
     {
-        return m_currentDecodingFrame < m_frames.size() ? m_frames[m_currentDecodingFrame].get() : 0;
+        return index < m_frames.size() ? m_frames[index].get() : 0;
     }
 
+    bool parseCompleted() const { return m_parseCompleted; }
+
 private:
     bool parse(size_t dataPosition, size_t len, bool parseSizeOnly);
     void setRemainingBytes(size_t);
 
     const unsigned char* data(size_t dataPosition) const
     {
         return reinterpret_cast<const unsigned char*>(m_data->data()) + dataPosition;
     }
 
     void addFrameIfNecessary();
@@ skipping 20 matching lines @@
     int m_loopCount; // Netscape specific extension block to control the number of animation loops a GIF renders.
     
     Vector<OwnPtr<GIFFrameContext> > m_frames;
     size_t m_currentDecodingFrame;
 
     RefPtr<WebCore::SharedBuffer> m_data;
     bool m_parseCompleted;
 };
 
 #endif