Remove all members in ScopedStyleTree for preparing class removal

Source/core/css/resolver/ScopedStyleResolver.cpp

 /*
  * 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) 2012 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.
@@ skipping 62 matching lines @@
 {
     m_authorStyleSheets.append(cssSheet);
     StyleSheetContents* sheet = cssSheet->contents();
 
     AddRuleFlags addRuleFlags = resolver->document().securityOrigin()->canRequest(sheet->baseURL()) ? RuleHasDocumentSecurityOrigin : RuleHasNoSpecialState;
     const RuleSet& ruleSet = sheet->ensureRuleSet(medium, addRuleFlags);
     resolver->addMediaQueryResults(ruleSet.viewportDependentMediaQueryResults());
     resolver->processScopedRules(ruleSet, cssSheet, treeScope().rootNode());
 }
 
-void ScopedStyleResolver::collectFeaturesTo(RuleFeatureSet& features, HashSet<const StyleSheetContents*>& visitedSharedStyleSheetContents)
+void ScopedStyleResolver::collectFeaturesTo(RuleFeatureSet& features, HashSet<const StyleSheetContents*>& visitedSharedStyleSheetContents) const
 {
     for (size_t i = 0; i < m_authorStyleSheets.size(); ++i) {
         StyleSheetContents* contents = m_authorStyleSheets[i]->contents();
         if (contents->hasOneClient() || visitedSharedStyleSheetContents.add(contents).isNewEntry)
             features.add(contents->ruleSet().features());
     }
 }
 
 void ScopedStyleResolver::resetAuthorStyle()
 {
@@ skipping 60 matching lines @@
 void ScopedStyleResolver::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_scope);
     visitor->trace(m_authorStyleSheets);
     visitor->trace(m_keyframesRuleMap);
 #endif
 }
 
 } // namespace blink