Remove unused includes from core/accessibility, core/css and core/dom

Source/core/css/RuleSet.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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 RuleSet_h
 #define RuleSet_h
 
 #include "core/css/RuleFeature.h"
 #include "core/css/StyleRule.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
-#include "wtf/HashSet.h"
 #include "wtf/LinkedStack.h"
-#include "wtf/text/AtomicString.h"
 
 namespace WebCore {
 
 enum AddRuleFlags {
     RuleHasNoSpecialState         = 0,
     RuleHasDocumentSecurityOrigin = 1,
     RuleCanUseFastCheckSelector   = 1 << 1,
     RuleIsInRegionRule            = 1 << 2,
 };
     
@@ skipping 147 matching lines @@
     RuleFeatureSet m_features;
     Vector<StyleRulePage*> m_pageRules;
 
     unsigned m_ruleCount;
     OwnPtr<PendingRuleMaps> m_pendingRules;
 };
 
 } // namespace WebCore
 
 #endif // RuleSet_h