Ignored title in shadow should cause StyleSheet.title = null.

third_party/WebKit/Source/core/html/HTMLStyleElement.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, 2010 Apple Inc. All rights reserved.
  *           (C) 2007 Rob Buis (buis@kde.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 42 matching lines @@
 {
 }
 
 HTMLStyleElement* HTMLStyleElement::create(Document& document, bool createdByParser)
 {
     return new HTMLStyleElement(document, createdByParser);
 }
 
 void HTMLStyleElement::parseAttribute(const QualifiedName& name, const AtomicString& oldValue, const AtomicString& value)
 {
-    if (name == titleAttr && m_sheet) {
+    if (name == titleAttr && m_sheet && isInDocumentTree()) {
         m_sheet->setTitle(value);
     } else if (name == mediaAttr && isConnected() && document().isActive() && m_sheet) {
         m_sheet->setMediaQueries(MediaQuerySet::create(value));
         document().styleEngine().setNeedsActiveStyleUpdate(m_sheet.get(), FullStyleUpdate);
     } else {
         HTMLElement::parseAttribute(name, oldValue, value);
     }
 }
 
 void HTMLStyleElement::finishParsingChildren()
@@ skipping 75 matching lines @@
         styleSheet->setDisabled(setDisabled);
 }
 
 DEFINE_TRACE(HTMLStyleElement)
 {
     StyleElement::trace(visitor);
     HTMLElement::trace(visitor);
 }
 
 } // namespace blink