StyleResolver should update RuleSets lazily.

Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 441 matching lines @@
 
     StyleResolver* styleResolverIfExists() const { return m_styleResolver.get(); }
 
     bool isViewSource() const { return m_isViewSource; }
     void setIsViewSource(bool);
 
     bool sawElementsInKnownNamespaces() const { return m_sawElementsInKnownNamespaces; }
 
     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();
     }
 
     void notifyRemovePendingSheetIfNeeded();
 
     bool haveStylesheetsLoaded() const;
     bool haveStylesheetsAndImportsLoaded() const { return haveImportsLoaded() && haveStylesheetsLoaded(); }
 
     // This is a DOM function.
     StyleSheetList* styleSheets();
@@ skipping 644 matching lines @@
     virtual void addMessage(MessageSource, MessageLevel, const String& message, const String& sourceURL, unsigned lineNumber, ScriptState*);
     void internalAddMessage(MessageSource, MessageLevel, const String& message, const String& sourceURL, unsigned lineNumber, PassRefPtr<ScriptCallStack>, ScriptState*);
 
     virtual double timerAlignmentInterval() const;
 
     void updateTitle(const String&);
     void updateFocusAppearanceTimerFired(Timer<Document>*);
     void updateBaseURL();
 
     void createStyleResolver();
+    void appendPendingAuthorStyleSheets();
 
     void executeScriptsWaitingForResourcesIfNeeded();
 
     void seamlessParentUpdatedStylesheets();
 
     void recalcStyleForLayoutIgnoringPendingStylesheets();
 
     PassRefPtr<NodeList> handleZeroPadding(const HitTestRequest&, HitTestResult&) const;
 
     void loadEventDelayTimerFired(Timer<Document>*);
@@ skipping 309 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == documentInternal();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h