Merge 102310 - WebPImageDecoder should not do a full image decode if progressive decoding is active

Source/WebCore/platform/image-decoders/webp/WEBPImageDecoder.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * 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 93 matching lines @@
         ASSERT(height == size().height());
         if (!buffer.setSize(width, height))
             return setFailed();
         buffer.setStatus(allDataReceived ? ImageFrame::FrameComplete : ImageFrame::FramePartial);
         // FIXME: We currently hard code false below because libwebp doesn't support alpha yet.
         buffer.setHasAlpha(false);
         buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
         m_rgbOutput.resize(height * stride);
     }
     int newLastVisibleRow = 0; // Last completed row.
-    if (allDataReceived) {
+    if (allDataReceived && !m_decoder) {
         if (!WebPDecodeRGBInto(dataBytes, dataSize, m_rgbOutput.data(), m_rgbOutput.size(), stride))
             return setFailed();
         newLastVisibleRow = height;
     } else {
         if (!m_decoder) {
             m_decoder = WebPINewRGB(MODE_RGB, m_rgbOutput.data(), m_rgbOutput.size(), stride);
             if (!m_decoder)
                 return setFailed();
         }
         const VP8StatusCode status = WebPIUpdate(m_decoder, dataBytes, dataSize);
@@ skipping 12 matching lines @@
     }
     m_lastVisibleRow = newLastVisibleRow;
     if (m_lastVisibleRow == height)
          buffer.setStatus(ImageFrame::FrameComplete);
     return m_lastVisibleRow == height;
 }
 
 }
 
 #endif