StyleResolver should update RuleSets lazily.

Source/core/css/RuleSet.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 33 matching lines @@
 #include "core/css/resolver/StyleResolver.h"
 #include "core/html/track/TextTrackCue.h"
 #include "weborigin/SecurityOrigin.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 // -----------------------------------------------------------------
 
-static inline bool isDocumentScope(const ContainerNode* scope)
-{
-    return !scope || scope->isDocumentNode();
-}
-
 static inline bool isSelectorMatchingHTMLBasedOnRuleHash(const CSSSelector* selector)
 {
     ASSERT(selector);
     if (selector->m_match == CSSSelector::Tag) {
         const AtomicString& selectorNamespace = selector->tagQName().namespaceURI();
         if (selectorNamespace != starAtom && selectorNamespace != xhtmlNamespaceURI)
             return false;
         if (selector->relation() == CSSSelector::SubSelector)
             return isSelectorMatchingHTMLBasedOnRuleHash(selector->tagHistory());
         return true;
@@ skipping 328 matching lines @@
             if ((!mediaRule->mediaQueries() || medium.eval(mediaRule->mediaQueries(), resolver->viewportDependentMediaQueryResults())))
                 addChildRules(mediaRule->childRules(), medium, resolver, scope, hasDocumentSecurityOrigin, addRuleFlags);
         } else if (rule->isFontFaceRule()) {
             addFontFaceRule(static_cast<StyleRuleFontFace*>(rule));
         } else if (rule->isKeyframesRule()) {
             addKeyframesRule(static_cast<StyleRuleKeyframes*>(rule));
         } else if (rule->isRegionRule()) {
             addRegionRule(static_cast<StyleRuleRegion*>(rule), hasDocumentSecurityOrigin);
         } else if (rule->isHostRule()) {
             addHostRule(static_cast<StyleRuleHost*>(rule));
-        } else if (rule->isViewportRule()) {
+        } else if (rule->isViewportRule() && !(addRuleFlags & ViewportRuleIsProcessed)) {
             addViewportRule(static_cast<StyleRuleViewport*>(rule));
         } else if (rule->isSupportsRule() && static_cast<StyleRuleSupports*>(rule)->conditionIsSupported()) {
             addChildRules(static_cast<StyleRuleSupports*>(rule)->childRules(), medium, resolver, scope, hasDocumentSecurityOrigin, addRuleFlags);
         }
     }
 }
 
-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 viewportRuleIsProcessed)
 {
     ASSERT(sheet);
 
     const Vector<RefPtr<StyleRuleImport> >& importRules = sheet->importRules();
     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, viewportRuleIsProcessed);
     }
 
     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) | (viewportRuleIsProcessed ? ViewportRuleIsProcessed : 0));
 
     addChildRules(sheet->childRules(), medium, resolver, scope, hasDocumentSecurityOrigin, addRuleFlags);
 }
 
 void RuleSet::addStyleRule(StyleRule* rule, AddRuleFlags addRuleFlags)
 {
     for (size_t selectorIndex = 0; selectorIndex != kNotFound; selectorIndex = rule->selectorList().indexOfNextSelectorAfter(selectorIndex))
         addRule(rule, selectorIndex, addRuleFlags);
 }
 
@@ skipping 26 matching lines @@
     m_linkPseudoClassRules.shrinkToFit();
     m_cuePseudoRules.shrinkToFit();
     m_focusPseudoClassRules.shrinkToFit();
     m_universalRules.shrinkToFit();
     m_pageRules.shrinkToFit();
     m_viewportRules.shrinkToFit();
     m_fontFaceRules.shrinkToFit();
 }
 
 } // namespace WebCore