Implement "replacement" text encoding.

Source/wtf/text/TextCodecReplacement.h

Index: Source/wtf/text/TextCodecReplacement.h
diff --git a/Source/wtf/text/TextCodecReplacement.h b/Source/wtf/text/TextCodecReplacement.h
new file mode 100644
index 0000000000000000000000000000000000000000..9e37e3e364308759c7efe32aab1fda4e4b02c06a
--- /dev/null
+++ b/Source/wtf/text/TextCodecReplacement.h
@@ -0,0 +1,28 @@
+// 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:
+    TextCodecReplacement();
+
+    static void registerEncodingNames(EncodingNameRegistrar);
+    static void registerCodecs(TextCodecRegistrar);
+
+private:
+    virtual String decode(const char*, size_t length, FlushBehavior, bool stopOnError, bool& sawError) OVERRIDE;
+
+    bool m_sentEOF;
+};
+
+} // namespace WTF
+
+#endif // TextCodecReplacement_h