Implement "replacement" text encoding.

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 25 matching lines @@
 #include "core/dom/ExceptionCode.h"
 #include "wtf/text/TextEncodingRegistry.h"
 
 namespace WebCore {
 
 PassRefPtrWillBeRawPtr<TextDecoder> TextDecoder::create(const String& label, const Dictionary& options, ExceptionState& exceptionState)
 {
     const String& encodingLabel = label.isNull() ? String("utf-8") : label;
 
     WTF::TextEncoding encoding(encodingLabel);
-    if (!encoding.isValid()) {
+    if (!encoding.isValid() || !strcmp(encoding.name(), "replacement")) {
         exceptionState.throwTypeError("The encoding label provided ('" + encodingLabel + "') is invalid.");
         return nullptr;
     }
 
     bool fatal = false;
     options.get("fatal", fatal);
 
-    return adoptRefWillBeNoop(new TextDecoder(encoding.name(), fatal));
+    return adoptRefWillBeNoop(new TextDecoder(encodingLabel, encoding.name(), fatal));
 }
 
-
-TextDecoder::TextDecoder(const String& encoding, bool fatal)
-    : m_encoding(encoding)
-    , m_codec(newTextCodec(m_encoding))
+TextDecoder::TextDecoder(const String& label, const String& name, bool fatal)
+    : m_encoding(name)
+    , m_codec(newTextCodec(label))
     , m_fatal(fatal)
     , m_bomSeen(false)
 {
 }
 
 TextDecoder::~TextDecoder()
 {
 }
 
 String TextDecoder::encoding() const
 {
-    String name = String(m_encoding.name()).lower();
+    String name = m_encoding.lower();
     // Where possible, encoding aliases should be handled by changes to Chromium's ICU or Blink's WTF.
     // The same codec is used, but WTF maintains a different name/identity for these.
     if (name == "iso-8859-1" || name == "us-ascii")
         return "windows-1252";
     return name;
 }
 
 String TextDecoder::decode(ArrayBufferView* input, const Dictionary& options, ExceptionState& exceptionState)
 {
     bool stream = false;
     options.get("stream", stream);
 
     const char* start = input ? static_cast<const char*>(input->baseAddress()) : 0;
     size_t length = input ? input->byteLength() : 0;
 
     WTF::FlushBehavior flush = stream ? WTF::DoNotFlush : WTF::DataEOF;
 
     bool sawError = false;
     String s = m_codec->decode(start, length, flush, m_fatal, sawError);
 
     if (m_fatal && sawError) {
         exceptionState.throwDOMException(EncodingError, "The encoded data was not valid.");
         return String();
     }
 
     if (!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 ((m_encoding == "UTF-8" || m_encoding == "UTF-16LE" || m_encoding == "UTF-16BE") && s[0] == 0xFEFF)
             s.remove(0);
     }
 
     if (flush)
         m_bomSeen = false;
 
     return s;
 }
 
 } // namespace WebCore