Remove dedicated TextCodecUTF16

Source/modules/encoding/TextDecoder.cpp

 /*
  * Copyright (C) 2013 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 88 matching lines @@
     String s = m_codec->decode(start, length, flush, m_fatal, sawError);
 
     if (m_fatal && sawError) {
         exceptionState.throwTypeError("The encoded data was not valid.");
         return String();
     }
 
     if (!m_ignoreBOM && !m_bomSeen && !s.isEmpty()) {
         m_bomSeen = true;
         String name(m_encoding.name());
-        if ((name == "UTF-8" || name == "UTF-16LE" || name == "UTF-16BE") && s[0] == 0xFEFF)
+        if ((name == "UTF-8" || name == "utf-16le" || name == "utf-16be") && s[0] == 0xFEFF)
             s.remove(0);
     }
 
     if (flush)
         m_bomSeen = false;
 
     return s;
 }
 
 String TextDecoder::decode(ExceptionState& exceptionState)
 {
     TextDecodeOptions options;
     return decode(nullptr, 0, options, exceptionState);
 }
 
 } // namespace blink