Clean up forward declarations in Source/core/html

Source/core/html/parser/TextResourceDecoder.h

 /*
     Copyright (C) 1999 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
     Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
@@ skipping 10 matching lines @@
 */
 
 #ifndef TextResourceDecoder_h
 #define TextResourceDecoder_h
 
 #include "wtf/RefCounted.h"
 #include "wtf/text/TextEncoding.h"
 
 namespace blink {
 
-class DocumentEncodingData;
 class HTMLMetaCharsetParser;
 
 class TextResourceDecoder {
 public:
     enum EncodingSource {
         DefaultEncoding,
         AutoDetectedEncoding,
         EncodingFromContentSniffing,
         EncodingFromXMLHeader,
         EncodingFromMetaTag,
@@ skipping 55 matching lines @@
     bool m_useLenientXMLDecoding; // Don't stop on XML decoding errors.
     bool m_sawError;
     bool m_usesEncodingDetector;
 
     OwnPtr<HTMLMetaCharsetParser> m_charsetParser;
 };
 
 }
 
 #endif