Document* XSLStyleSheet::ownerDocument()
{
    for (XSLStyleSheet* styleSheet = this; styleSheet; styleSheet = styleSheet->parentStyleSheet()) {
        Node* node = styleSheet->ownerNode();
        if (node)
            return &node->document();
    }
    return 0;
}
Document* XSLStyleSheet::ownerDocument()
{
    for (XSLStyleSheet* styleSheet = this; styleSheet; styleSheet = styleSheet->parentStyleSheet()) {
        if (styleSheet->m_ownerDocument)
            return styleSheet->m_ownerDocument.get();
        Node* node = styleSheet->ownerNode();
        if (node)
            return &node->document();
    }
    return nullptr;
}