Fix errors caused by unsafe conversions to/from size_t

third_party/WebKit/Source/platform/image-decoders/jpeg/JPEGImageDecoder.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * Portions are Copyright (C) 2001-6 mozilla.org
  *
  * Other contributors:
  *   Stuart Parmenter <stuart@mozilla.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 360 matching lines @@
     bool fillBuffer()
     {
         if (m_needsRestart) {
             m_needsRestart = false;
             m_nextReadPosition = m_restartPosition;
         } else {
             updateRestartPosition();
         }
 
         const char* segment;
-        const unsigned bytes = m_data->getSomeData(segment, m_nextReadPosition);
+        const size_t bytes = m_data->getSomeData(segment, m_nextReadPosition);
         if (bytes == 0) {
             // We had to suspend. When we resume, we will need to start from the restart position.
             m_needsRestart = true;
             clearBuffer();
             return false;
         }
 
         m_nextReadPosition += bytes;
         m_info.src->bytes_in_buffer = bytes;
         const JOCTET* nextByte = reinterpret_cast_ptr<const JOCTET*>(segment);
@@ skipping 307 matching lines @@
         m_info.src->next_input_byte = nullptr;
         m_lastSetByte = nullptr;
     }
 
     RefPtr<SharedBuffer> m_data;
     JPEGImageDecoder* m_decoder;
 
     // Input reading: True if we need to back up to m_restartPosition.
     bool m_needsRestart;
     // If libjpeg needed to restart, this is the position to restart from.
-    unsigned m_restartPosition;
+    size_t m_restartPosition;
     // This is the position where we will read from, unless there is a restart.
-    unsigned m_nextReadPosition;
+    size_t m_nextReadPosition;
     // This is how we know to update the restart position. It is the last value
     // we set to next_input_byte. libjpeg will update next_input_byte when it
     // has found the next restart position, so if it no longer matches this
     // value, we know we've reached the next restart position.
     const JOCTET* m_lastSetByte;
 
     jpeg_decompress_struct m_info;
     decoder_error_mgr m_err;
     decoder_source_mgr m_src;
     jstate m_state;
@@ skipping 348 matching lines @@
     // has failed.
     if (!m_reader->decode(onlySize) && isAllDataReceived())
         setFailed();
 
     // If decoding is done or failed, we don't need the JPEGImageReader anymore.
     if (isComplete(this, onlySize) || failed())
         m_reader.clear();
 }
 
 }