Clean up forward declarations in Source/core/css

Source/core/css/CSSCharsetRule.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2006, 2008, 2012 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef CSSCharsetRule_h
 #define CSSCharsetRule_h
 
 #include "core/css/CSSRule.h"
 
 namespace blink {
 
-class ExceptionState;
-
 class CSSCharsetRule FINAL : public CSSRule {
 public:
     static PassRefPtrWillBeRawPtr<CSSCharsetRule> create(CSSStyleSheet* parent, const String& encoding)
     {
         return adoptRefWillBeNoop(new CSSCharsetRule(parent, encoding));
     }
 
     virtual ~CSSCharsetRule() { }
 
     virtual CSSRule::Type type() const OVERRIDE { return CHARSET_RULE; }
     virtual String cssText() const OVERRIDE;
     virtual void reattach(StyleRuleBase* rule) OVERRIDE { ASSERT_UNUSED(rule, !rule); }
 
     const String& encoding() const { return m_encoding; }
     void setEncoding(const String& encoding) { m_encoding = encoding; }
 
     virtual void trace(Visitor* visitor) OVERRIDE { CSSRule::trace(visitor); }
 
 private:
     CSSCharsetRule(CSSStyleSheet* parent, const String& encoding);
 
     String m_encoding;
 };
 
 DEFINE_CSS_RULE_TYPE_CASTS(CSSCharsetRule, CHARSET_RULE);
 
 } // namespace blink
 
 #endif // CSSCharsetRule_h