Do not block painting for in-body CSS

third_party/WebKit/Source/core/html/HTMLLinkElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 463 matching lines @@
 }
 
 LinkStyle::LinkStyle(HTMLLinkElement* owner)
     : LinkResource(owner)
     , m_disabledState(Unset)
     , m_pendingSheetType(None)
     , m_loading(false)
     , m_firedLoad(false)
     , m_loadedSheet(false)
     , m_fetchFollowingCORS(false)
+    , m_beforeBody(false)
 {
 }
 
 LinkStyle::~LinkStyle()
 {
 }
 
 Document& LinkStyle::document()
 {
     return m_owner->document();
@@ skipping 121 matching lines @@
 }
 
 void LinkStyle::addPendingSheet(PendingSheetType type)
 {
     if (type <= m_pendingSheetType)
         return;
     m_pendingSheetType = type;
 
     if (m_pendingSheetType == NonBlocking)
         return;
-    m_owner->document().styleEngine().addPendingSheet();
+    m_beforeBody = m_beforeBody || !m_owner->document().body();
+    m_owner->document().styleEngine().addPendingSheet(m_beforeBody);
 }
 
 void LinkStyle::removePendingSheet()
 {
     PendingSheetType type = m_pendingSheetType;
     m_pendingSheetType = None;
 
     if (type == None)
         return;
     if (type == NonBlocking) {
         // Tell StyleEngine to re-compute styleSheets of this m_owner's treescope.
         m_owner->document().styleEngine().modifiedStyleSheetCandidateNode(m_owner);
         return;
     }
 
-    m_owner->document().styleEngine().removePendingSheet(m_owner);
+    m_owner->document().styleEngine().removePendingSheet(m_owner, m_beforeBody);
 }
 
 void LinkStyle::setDisabledState(bool disabled)
 {
     LinkStyle::DisabledState oldDisabledState = m_disabledState;
     m_disabledState = disabled ? Disabled : EnabledViaScript;
     if (oldDisabledState != m_disabledState) {
         // If we change the disabled state while the sheet is still loading, then we have to
         // perform three checks:
         if (styleSheetIsLoading()) {
@@ skipping 127 matching lines @@
 }
 
 DEFINE_TRACE(LinkStyle)
 {
     visitor->trace(m_sheet);
     LinkResource::trace(visitor);
     ResourceOwner<StyleSheetResource>::trace(visitor);
 }
 
 } // namespace blink