Add 8bit Content-Transfer-Encoding support for reading MHTML files

Source/core/platform/network/MIMEHeader.cpp

 /*
  * Copyright (C) 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 102 matching lines @@
     return mimeHeader.release();
 }
 
 MIMEHeader::Encoding MIMEHeader::parseContentTransferEncoding(const String& text)
 {
     String encoding = text.stripWhiteSpace().lower();
     if (encoding == "base64")
         return Base64;
     if (encoding == "quoted-printable")
         return QuotedPrintable;
+    if (encoding == "8bit")
+        return EightBit;
     if (encoding == "7bit")
         return SevenBit;
     if (encoding == "binary")
         return Binary;
     LOG_ERROR("Unknown encoding '%s' found in MIME header.", text.ascii().data());
     return Unknown;
 }
 
 MIMEHeader::MIMEHeader()
     : m_contentTransferEncoding(Unknown)
 {
 }
 
 }