StyleResolver should update RuleSets lazily.

Source/core/css/resolver/ScopedStyleResolver.h

Index: Source/core/css/resolver/ScopedStyleResolver.h
diff --git a/Source/core/css/resolver/ScopedStyleResolver.h b/Source/core/css/resolver/ScopedStyleResolver.h
index 3e9c995049f4e49e3102af7ceb95b8ca4b6d8326..2310d61bf7e8e5b68d291725232002802623a417 100644
--- a/Source/core/css/resolver/ScopedStyleResolver.h
+++ b/Source/core/css/resolver/ScopedStyleResolver.h
@@ -71,8 +71,9 @@ public:
     void matchAuthorRules(ElementRuleCollector&, bool includeEmptyRules, bool applyAuthorStyles);
     void collectMatchingAuthorRules(ElementRuleCollector&, bool includeEmptyRules, bool applyAuthorStyles, CascadeScope, CascadeOrder = ignoreCascadeOrder);
     void matchPageRules(PageRuleCollector&);
-    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, StyleResolver*);
+    void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, StyleResolver*, bool viewportRuleIsProcessed);
     void addHostRule(StyleRuleHost*, bool hasDocumentSecurityOrigin, const ContainerNode* scopingNode);
+    void addViewportRule(StyleRuleViewport*);
     void collectFeaturesTo(RuleFeatureSet&);
     void resetAuthorStyle();
     void resetAtHostRules(const ShadowRoot*);
@@ -83,6 +84,7 @@ private:
 
     RuleSet* ensureAtHostRuleSetFor(const ShadowRoot*);
     RuleSet* atHostRuleSetFor(const ShadowRoot*) const;
+    RuleSet* ensureAuthorStyle();
 
     const ContainerNode& m_scopingNode;
     ScopedStyleResolver* m_parent;