Implement "replacement" text encoding.

Source/wtf/text/TextCodecReplacement.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TextCodecReplacement_h
+#define TextCodecReplacement_h
+
+#include "wtf/text/TextCodec.h"
+#include "wtf/text/TextCodecUTF8.h"
+
+namespace WTF {
+
+class TextCodecReplacement FINAL : public TextCodecUTF8 {
+public:
+    static void registerEncodingNames(EncodingNameRegistrar);
+    static void registerCodecs(TextCodecRegistrar);
+
+private:
+    virtual String decode(const char*, size_t length, bool flush, bool stopOnError, bool& sawError) OVERRIDE;
+};
+
+} // namespace WTF
+
+#endif // TextCodecReplacement_h