StyleResolver should update RuleSets lazily.

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index faab9b14cd442d8f4a0532b68aba0cc7e16d7047..88d37181ebaad8caeb06af0d6a11aac1e43d9f9e 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -459,8 +459,11 @@ public:
 
     StyleResolver* styleResolver()
     {
-        if (!m_styleResolver)
+        if (!m_styleResolver) {
             createStyleResolver();
+        } else {
+            appendPendingAuthorStyleSheets();

[esprehn, 2013/10/25 02:37:58]

You can't put a function call in here. This is really hot, we call
styleResolver() all over the place.

[tasak, 2013/10/25 10:10:10]

I see.
I moved appendPendingAuthorStyleSheets to callers if callers need.

+        }
         return m_styleResolver.get();
     }
 
@@ -1125,6 +1128,7 @@ private:
     void updateBaseURL();
 
     void createStyleResolver();
+    void appendPendingAuthorStyleSheets();
 
     void executeScriptsWaitingForResourcesIfNeeded();