StyleResolver should update RuleSets lazily.

Source/core/css/resolver/StyleResolver.h

Index: Source/core/css/resolver/StyleResolver.h
diff --git a/Source/core/css/resolver/StyleResolver.h b/Source/core/css/resolver/StyleResolver.h
index 5431346533c6e5eb4decfe3fe12cafcf3cd3da7d..5de019d31d4a4948aabd358bc5568f62a493d20d 100644
--- a/Source/core/css/resolver/StyleResolver.h
+++ b/Source/core/css/resolver/StyleResolver.h
@@ -40,6 +40,7 @@
 #include "wtf/Deque.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashSet.h"
+#include "wtf/ListHashSet.h"
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 
@@ -145,6 +146,11 @@ public:
     TreeBoundaryCrossingRules& treeBoundaryCrossingRules() { return m_treeBoundaryCrossingRules; }
     void processScopedRules(const RuleSet& authorRules, const KURL&, const ContainerNode* scope = 0);
 
+    void lazyAppendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >&);
+    void removePendingAuthorStyleSheets(const Vector<RefPtr<CSSStyleSheet> >&);
+    void appendPendingAuthorStyleSheets();
+    bool hasPendingAuthorStyleSheets() const { return m_pendingStyleSheets.size() > 0 || m_needCollectFeatures; }
+
     SelectorFilter& selectorFilter() { return m_selectorFilter; }
 
     void setBuildScopedStyleTreeInDocumentOrder(bool enabled) { m_styleTree.setBuildInDocumentOrder(enabled); }
@@ -198,7 +204,12 @@ public:
     // FIXME: StyleResolver should not have this member or method.
     InspectorCSSOMWrappers& inspectorCSSOMWrappers() { return m_inspectorCSSOMWrappers; }
 
-    const RuleFeatureSet& ruleFeatureSet() const { return m_features; }
+    const RuleFeatureSet& ensureRuleFeatureSet()
+    {
+        if (hasPendingAuthorStyleSheets())
+            appendPendingAuthorStyleSheets();
+        return m_features;
+    }
 
     StyleSharingList& styleSharingList() { return m_styleSharingList; }
 
@@ -224,6 +235,10 @@ private:
     // FIXME: This should probably go away, folded into FontBuilder.
     void updateFont(StyleResolverState&);
 
+    void filterViewportRules(const Vector<RefPtr<StyleRuleBase> >& rules, bool& needsResolveViewport);
+    void filterViewportRulesFromSheet(StyleSheetContents*, bool& needsResolveViewport);
+    bool filterViewportRulesFromAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >& styleSheets);
+
     void collectPseudoRulesForElement(Element*, ElementRuleCollector&, PseudoId, unsigned rulesToInclude);
     void matchUARules(ElementRuleCollector&, RuleSet*);
     void matchAuthorRules(Element*, ElementRuleCollector&, bool includeEmptyRules);
@@ -235,6 +250,7 @@ private:
     void matchWatchSelectorRules(ElementRuleCollector&);
     void collectFeatures();
     void collectTreeBoundaryCrossingRules(Element*, ElementRuleCollector&, bool includeEmptyRules);
+    void resetRuleFeatures();
 
     bool fastRejectSelector(const RuleData&) const;
 
@@ -286,6 +302,8 @@ private:
 
     RefPtr<ViewportStyleResolver> m_viewportStyleResolver;
 
+    ListHashSet<CSSStyleSheet*, 16> m_pendingStyleSheets;
+
     ScopedStyleTree m_styleTree;
 
     // FIXME: The entire logic of collecting features on StyleResolver, as well astransferring them
@@ -293,10 +311,13 @@ private:
     RuleFeatureSet m_features;
     OwnPtr<RuleSet> m_siblingRuleSet;
     OwnPtr<RuleSet> m_uncommonAttributeRuleSet;
+
     // FIXME: watched selectors should be implemented using injected author stylesheets: http://crbug.com/316960
     OwnPtr<RuleSet> m_watchedSelectorsRules;
     TreeBoundaryCrossingRules m_treeBoundaryCrossingRules;
 
+    bool m_needCollectFeatures;
+
     InspectorCSSOMWrappers m_inspectorCSSOMWrappers;
 
     StyleResourceLoader m_styleResourceLoader;
@@ -323,6 +344,18 @@ inline bool checkRegionSelector(const CSSSelector* regionSelector, Element* regi
     return false;
 }
 
+inline bool isDocumentScope(const ContainerNode* scope)
+{
+    return !scope || scope->isDocumentNode();
+}
+
+inline void appendPendingStyleSheetsIfNeeded(StyleResolver* styleResolver)
+{
+    if (!styleResolver || !styleResolver->hasPendingAuthorStyleSheets())
+        return;
+    styleResolver->appendPendingAuthorStyleSheets();
+}
+
 } // namespace WebCore
 
 #endif // StyleResolver_h