StyleResolver should update RuleSets lazily.

Source/core/dom/DocumentStyleSheetCollection.cpp

Index: Source/core/dom/DocumentStyleSheetCollection.cpp
diff --git a/Source/core/dom/DocumentStyleSheetCollection.cpp b/Source/core/dom/DocumentStyleSheetCollection.cpp
index 95d2c79cb2c7a7a657e51db889583fbaf088d254..67fbeda1149246448818a8fcaacb6919a0e419d6 100644
--- a/Source/core/dom/DocumentStyleSheetCollection.cpp
+++ b/Source/core/dom/DocumentStyleSheetCollection.cpp
@@ -170,10 +170,11 @@ bool DocumentStyleSheetCollection::updateActiveStyleSheets(StyleEngine* collecti
         styleResolver->setBuildScopedStyleTreeInDocumentOrder(false);
         if (styleResolverUpdateType == Reset) {
             resetAllRuleSetsInTreeScope(styleResolver);
-            styleResolver->appendAuthorStyleSheets(0, activeCSSStyleSheets);
+            styleResolver->removePendingAuthorStyleSheets(m_activeAuthorStyleSheets);
+            styleResolver->lazyAppendAuthorStyleSheets(0, activeCSSStyleSheets);
         } else {
             ASSERT(styleResolverUpdateType == Additive);
-            styleResolver->appendAuthorStyleSheets(m_activeAuthorStyleSheets.size(), activeCSSStyleSheets);
+            styleResolver->lazyAppendAuthorStyleSheets(m_activeAuthorStyleSheets.size(), activeCSSStyleSheets);
         }
     }
     m_scopingNodesForStyleScoped.didRemoveScopingNodes();