Clean up forward declarations in Source/core/html

Source/core/html/parser/BackgroundHTMLParser.h

 /*
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 #include "core/html/parser/HTMLSourceTracker.h"
 #include "core/html/parser/HTMLTreeBuilderSimulator.h"
 #include "core/html/parser/TextResourceDecoder.h"
 #include "core/html/parser/XSSAuditorDelegate.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/WeakPtr.h"
 
 namespace blink {
 
 class HTMLDocumentParser;
-class SharedBuffer;
 class XSSAuditor;
 
 class BackgroundHTMLParser {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     struct Configuration {
         HTMLParserOptions options;
         WeakPtr<HTMLDocumentParser> parser;
         OwnPtr<XSSAuditor> xssAuditor;
         OwnPtr<TokenPreloadScanner> preloadScanner;
@@ skipping 49 matching lines @@
 
     OwnPtr<XSSAuditor> m_xssAuditor;
     OwnPtr<TokenPreloadScanner> m_preloadScanner;
     OwnPtr<TextResourceDecoder> m_decoder;
     DocumentEncodingData m_lastSeenEncodingData;
 };
 
 }
 
 #endif