StyleResolver should update RuleSets lazily.

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,
@@ skipping 20 matching lines @@
 #include "wtf/HashMap.h"
 #include "wtf/LinkedStack.h"
 
 namespace WebCore {
 
 enum AddRuleFlags {
     RuleHasNoSpecialState         = 0,
     RuleHasDocumentSecurityOrigin = 1,
     RuleCanUseFastCheckSelector   = 1 << 1,
     RuleIsInRegionRule            = 1 << 2,
+    ViewportRuleIsProcessed       = 1 << 3
 };
 
 enum PropertyWhitelistType {
     PropertyWhitelistNone   = 0,
     PropertyWhitelistRegion,
     PropertyWhitelistCue
 };
 
 class CSSSelector;
 class MediaQueryEvaluator;
@@ skipping 64 matching lines @@
     unsigned d[4];
 };
 
 COMPILE_ASSERT(sizeof(RuleData) == sizeof(SameSizeAsRuleData), RuleData_should_stay_small);
 
 class RuleSet {
     WTF_MAKE_NONCOPYABLE(RuleSet); WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<RuleSet> create() { return adoptPtr(new RuleSet); }
 
-    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, bool hasDocumentSecurityOrigin = false);
+    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, AddRuleFlags = RuleHasNoSpecialState);
     void addStyleRule(StyleRule*, AddRuleFlags);
     void addRule(StyleRule*, unsigned selectorIndex, AddRuleFlags);
+    void addViewportRule(StyleRuleViewport*);
 
     const RuleFeatureSet& features() const { return m_features; }
 
     const RuleData* idRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
     const RuleData* classRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
     const RuleData* tagRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
     const RuleData* shadowPseudoElementRules(StringImpl* key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }
     const Vector<RuleData>* linkPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_linkPseudoClassRules; }
     const Vector<RuleData>* cuePseudoRules() const { ASSERT(!m_pendingRules); return &m_cuePseudoRules; }
     const Vector<RuleData>* focusPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_focusPseudoClassRules; }
@@ skipping 30 matching lines @@
     typedef HashMap<StringImpl*, OwnPtr<LinkedStack<RuleData> > > PendingRuleMap;
     typedef HashMap<StringImpl*, OwnPtr<RuleData> > CompactRuleMap;
 
     RuleSet()
         : m_ruleCount(0)
     {
     }
 
     void addToRuleSet(StringImpl* key, PendingRuleMap&, const RuleData&);
     void addPageRule(StyleRulePage*);
-    void addViewportRule(StyleRuleViewport*);
     void addFontFaceRule(StyleRuleFontFace*);
     void addKeyframesRule(StyleRuleKeyframes*);
     void addHostRule(StyleRuleHost*);
     void addRegionRule(StyleRuleRegion*, bool hasDocumentSecurityOrigin);
 
-    void addChildRules(const Vector<RefPtr<StyleRuleBase> >&, const MediaQueryEvaluator& medium, bool hasDocumentSecurityOrigin, AddRuleFlags);
+    void addChildRules(const Vector<RefPtr<StyleRuleBase> >&, const MediaQueryEvaluator& medium, AddRuleFlags);
     bool findBestRuleSetAndAdd(const CSSSelector*, RuleData&);
 
     void compactRules();
     static void compactPendingRules(PendingRuleMap&, CompactRuleMap&);
 
     struct PendingRuleMaps {
         PendingRuleMap idRules;
         PendingRuleMap classRules;
         PendingRuleMap tagRules;
         PendingRuleMap shadowPseudoElementRules;
@@ skipping 25 matching lines @@
 
     MediaQueryResultList m_viewportDependentMediaQueryResults;
 
     unsigned m_ruleCount;
     OwnPtr<PendingRuleMaps> m_pendingRules;
 };
 
 } // namespace WebCore
 
 #endif // RuleSet_h