StyleResolver should update RuleSets lazily.

Source/core/css/RuleSet.cpp

Index: Source/core/css/RuleSet.cpp
diff --git a/Source/core/css/RuleSet.cpp b/Source/core/css/RuleSet.cpp
index cce6f4779fb6bdb97fb27e522ce5ceccf0d31c91..3740807f61dc3c1aaad4c994d3e59f122cedfbf5 100644
--- a/Source/core/css/RuleSet.cpp
+++ b/Source/core/css/RuleSet.cpp
@@ -52,11 +52,6 @@ using namespace HTMLNames;
 
 // -----------------------------------------------------------------
 
-static inline bool isDocumentScope(const ContainerNode* scope)
-{
-    return !scope || scope->isDocumentNode();
-}
-
 static inline bool isScopingNodeInShadowTree(const ContainerNode* scopingNode)
 {
     return scopingNode && scopingNode->isInShadowTree();
@@ -384,7 +379,7 @@ void RuleSet::addChildRules(const Vector<RefPtr<StyleRuleBase> >& rules, const M
             StyleRuleMedia* mediaRule = static_cast<StyleRuleMedia*>(rule);
             if ((!mediaRule->mediaQueries() || medium.eval(mediaRule->mediaQueries(), resolver->viewportDependentMediaQueryResults())))
                 addChildRules(mediaRule->childRules(), medium, resolver, scope, hasDocumentSecurityOrigin, addRuleFlags);
-        } else if (rule->isFontFaceRule() && resolver) {
+        } else if (rule->isFontFaceRule() && resolver && !(addRuleFlags & RuleSkipsFontFaceAndViewportRule)) {
             // Add this font face to our set.
             // FIXME(BUG 72461): We don't add @font-face rules of scoped style sheets for the moment.
             if (!isDocumentScope(scope))
@@ -404,7 +399,7 @@ void RuleSet::addChildRules(const Vector<RefPtr<StyleRuleBase> >& rules, const M
             resolver->setBuildScopedStyleTreeInDocumentOrder(false);
             resolver->ensureScopedStyleResolver(scope->shadowHost())->addHostRule(static_cast<StyleRuleHost*>(rule), hasDocumentSecurityOrigin, scope);
             resolver->setBuildScopedStyleTreeInDocumentOrder(enabled);
-        } else if (rule->isViewportRule()) {
+        } else if (rule->isViewportRule() && !(addRuleFlags & RuleSkipsFontFaceAndViewportRule)) {

[eseidel, 2013/11/06 01:39:10]

The double negative reads a bit odd.  But I guess your goal here was for the 0
value to mean "no special handling" where as currently skipping
font-face/viewport is special.

[tasak, 2013/11/06 05:42:26]

Yes, 0 means "no special handling". The 0 is used when creating StyleResolver.

1 means, @font-face rules and @viewport rules have been already processed, so we
don't need to process the rules now.

             // @viewport should not be scoped.
             if (!isDocumentScope(scope))
                 continue;
@@ -415,7 +410,7 @@ void RuleSet::addChildRules(const Vector<RefPtr<StyleRuleBase> >& rules, const M
     }
 }
 
-void RuleSet::addRulesFromSheet(StyleSheetContents* sheet, const MediaQueryEvaluator& medium, StyleResolver* resolver, const ContainerNode* scope)
+void RuleSet::addRulesFromSheet(StyleSheetContents* sheet, const MediaQueryEvaluator& medium, StyleResolver* resolver, const ContainerNode* scope, bool processFontFaceAndViewportRule)
 {
     ASSERT(sheet);
 
@@ -423,11 +418,11 @@ void RuleSet::addRulesFromSheet(StyleSheetContents* sheet, const MediaQueryEvalu
     for (unsigned i = 0; i < importRules.size(); ++i) {
         StyleRuleImport* importRule = importRules[i].get();
         if (importRule->styleSheet() && (!importRule->mediaQueries() || medium.eval(importRule->mediaQueries(), resolver->viewportDependentMediaQueryResults())))
-            addRulesFromSheet(importRule->styleSheet(), medium, resolver, scope);
+            addRulesFromSheet(importRule->styleSheet(), medium, resolver, scope, processFontFaceAndViewportRule);
     }
 
     bool hasDocumentSecurityOrigin = resolver && resolver->document().securityOrigin()->canRequest(sheet->baseURL());
-    AddRuleFlags addRuleFlags = static_cast<AddRuleFlags>((hasDocumentSecurityOrigin ? RuleHasDocumentSecurityOrigin : 0) | (!scope ? RuleCanUseFastCheckSelector : 0));
+    AddRuleFlags addRuleFlags = static_cast<AddRuleFlags>((hasDocumentSecurityOrigin ? RuleHasDocumentSecurityOrigin : 0) | (!scope ? RuleCanUseFastCheckSelector : 0) | (processFontFaceAndViewportRule ? 0 : RuleSkipsFontFaceAndViewportRule));
 
     addChildRules(sheet->childRules(), medium, resolver, scope, hasDocumentSecurityOrigin, addRuleFlags);
 }