Don't store a RuleFeatureSet on ScopedStyleResolver.

sky/engine/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 77 matching lines @@
     updateActiveStyleSheets();
 }
 
 void StyleEngine::updateDocumentFonts()
 {
     // TODO(esprehn): We should really support @font-face in ShadowRoot too.
 
     const auto& sheets = m_document->scopedStyleResolver().authorStyleSheets();
 
     for (const auto& sheet : sheets) {
-        RuleSet& ruleSet = sheet->contents()->ruleSet();
+        RuleSet& ruleSet = sheet->contents()->ensureRuleSet();
         for (const auto& rule : ruleSet.fontFaceRules()) {
             if (RefPtr<FontFace> fontFace = FontFace::create(m_document, rule))
                 m_fontSelector->fontFaceCache()->add(m_fontSelector.get(), rule, fontFace);
         }
         if (!ruleSet.fontFaceRules().isEmpty())
             m_resolver->invalidateMatchedPropertiesCache();
     }
 
     m_document->renderView()->style()->font().update(m_fontSelector.get());
 }
@@ skipping 47 matching lines @@
     m_sheetToTextCache.remove(contents);
 }
 
 void StyleEngine::fontsNeedUpdate(CSSFontSelector*)
 {
     m_resolver->invalidateMatchedPropertiesCache();
     m_document->setNeedsStyleRecalc(SubtreeStyleChange);
 }
 
 }