Merge 72924

WebCore/css/StyleSheet.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006 Apple Computer, Inc.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 38 matching lines @@
     , m_originalURL(originalURL)
     , m_finalURL(finalURL)
     , m_disabled(false)
 {
 }
 
 StyleSheet::~StyleSheet()
 {
     if (m_media)
         m_media->setParent(0);
+
+    // For style rules outside the document, .parentStyleSheet can become null even if the style rule
+    // is still observable from JavaScript. This matches the behavior of .parentNode for nodes, but
+    // it's not ideal because it makes the CSSOM's behavior depend on the timing of garbage collection.
+    for (unsigned i = 0; i < length(); ++i) {
+        ASSERT(item(i)->parent() == this);
+        item(i)->setParent(0);
+    }
 }
 
 StyleSheet* StyleSheet::parentStyleSheet() const
 {
     return (parent() && parent()->isStyleSheet()) ? static_cast<StyleSheet*>(parent()) : 0;
 }
 
 void StyleSheet::setMedia(PassRefPtr<MediaList> media)
 {
     if (m_media)
         m_media->setParent(0);
 
     m_media = media;
     m_media->setParent(this);
 }
 
 KURL StyleSheet::completeURL(const String& url) const
 {
     // Always return a null URL when passed a null string.
     // FIXME: Should we change the KURL constructor to have this behavior?
     // See also Document::completeURL(const String&)
     if (url.isNull())
         return KURL();
     return KURL(baseURL(), url);
 }
 
 }