Revert of Oilpan: fix build after r201639.

Source/core/css/ElementRuleCollector.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,
@@ skipping 40 matching lines @@
         static const unsigned BitsForPositionInRuleData = 18;
         m_position = ((uint64_t)styleSheetIndex << BitsForPositionInRuleData) + m_ruleData->position();
     }
 
     const RuleData* ruleData() const { return m_ruleData; }
     uint64_t position() const { return m_position; }
     unsigned specificity() const { return ruleData()->specificity() + m_specificity; }
     const CSSStyleSheet* parentStyleSheet() const { return m_parentStyleSheet; }
     DEFINE_INLINE_TRACE()
     {
-        visitor->trace(m_ruleData);
         visitor->trace(m_parentStyleSheet);
     }
 
 private:
     RawPtrWillBeMember<const RuleData> m_ruleData;
     unsigned m_specificity;
     uint64_t m_position;
     RawPtrWillBeMember<const CSSStyleSheet> m_parentStyleSheet;
 };
 
@@ skipping 82 matching lines @@
 
     // Output.
     RefPtrWillBeMember<StaticCSSRuleList> m_cssRuleList;
     RefPtrWillBeMember<StyleRuleList> m_styleRuleList;
     MatchResult m_result;
 };
 
 } // namespace blink
 
 #endif // ElementRuleCollector_h