Revert of Never consolidate data in ICO decoder

Source/platform/image-decoders/png/PNGImageDecoder.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
  *
  * Portions are Copyright (C) 2001 mozilla.org
  *
  * Other contributors:
  *   Stuart Parmenter <stuart@mozilla.com>
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 71 matching lines @@
     longjmp(JMPBUF(png), 1);
 }
 
 } // anonymous
 
 namespace blink {
 
 class PNGImageReader {
     WTF_MAKE_FAST_ALLOCATED(PNGImageReader);
 public:
-    PNGImageReader(PNGImageDecoder* decoder, unsigned readOffset)
+    PNGImageReader(PNGImageDecoder* decoder)
         : m_decoder(decoder)
-        , m_readOffset(readOffset)
+        , m_readOffset(0)
         , m_currentBufferSize(0)
         , m_decodingSizeOnly(false)
         , m_hasAlpha(false)
 #if USE(QCMSLIB)
         , m_transform(0)
         , m_rowBuffer()
 #endif
     {
         m_png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, pngFailed, 0);
         m_info = png_create_info_struct(m_png);
@@ skipping 92 matching lines @@
     unsigned m_currentBufferSize;
     bool m_decodingSizeOnly;
     bool m_hasAlpha;
     OwnPtr<png_byte[]> m_interlaceBuffer;
 #if USE(QCMSLIB)
     qcms_transform* m_transform;
     OwnPtr<png_byte[]> m_rowBuffer;
 #endif
 };
 
-PNGImageDecoder::PNGImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes, unsigned offset)
+PNGImageDecoder::PNGImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes)
     : ImageDecoder(alphaOption, colorOptions, maxDecodedBytes)
     , m_hasColorProfile(false)
-    , m_offset(offset)
 {
 }
 
 PNGImageDecoder::~PNGImageDecoder()
 {
 }
 
 #if USE(QCMSLIB)
 static void getColorProfile(png_structp png, png_infop info, ColorProfile& colorProfile, bool& sRGB)
 {
@@ skipping 268 matching lines @@
 {
     return decoder->frameIsCompleteAtIndex(0);
 }
 
 void PNGImageDecoder::decode(bool onlySize)
 {
     if (failed())
         return;
 
     if (!m_reader)
-        m_reader = adoptPtr(new PNGImageReader(this, m_offset));
+        m_reader = adoptPtr(new PNGImageReader(this));
 
     // If we couldn't decode the image but have received all the data, decoding
     // has failed.
     if (!m_reader->decode(*m_data, onlySize) && isAllDataReceived())
         setFailed();
 
     // If decoding is done or failed, we don't need the PNGImageReader anymore.
     if (isComplete(this) || failed())
         m_reader.clear();
 }
 
 } // namespace blink