Remove the concept of user stylesheets.

Source/core/css/DocumentRuleSets.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.
  * Copyright (C) 2013 Google 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 19 matching lines @@
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class CSSStyleSheet;
 class MediaQueryEvaluator;
 class RuleFeatureSet;
 class StyleEngine;
 
+// FIXME: This class doesn't really serve a purpose anymore. Merge it into StyleResolver.
 class DocumentRuleSets {
 public:
     DocumentRuleSets();
     ~DocumentRuleSets();
-    RuleSet* userStyle() const { return m_userStyle.get(); }
 
-    void initUserStyle(StyleEngine*, const Vector<RefPtr<StyleRule> >& watchedSelectors, const MediaQueryEvaluator&, StyleResolver&);
     void resetAuthorStyle();
     void collectFeaturesTo(RuleFeatureSet&, bool isViewSource);
-
     TreeBoundaryCrossingRules& treeBoundaryCrossingRules() { return m_treeBoundaryCrossingRules; }
 
 private:
-    void collectRulesFromUserStyleSheets(const Vector<RefPtr<CSSStyleSheet> >&, RuleSet& userStyle, const MediaQueryEvaluator&, StyleResolver&);
-    void collectRulesFromWatchedSelectors(const Vector<RefPtr<StyleRule> >&, RuleSet& userStyle);
-    OwnPtr<RuleSet> m_userStyle;
     TreeBoundaryCrossingRules m_treeBoundaryCrossingRules;
 };
 
 } // namespace WebCore
 
 #endif // DocumentRuleSets_h