void ImageDocumentElement::willMoveToNewOwnerDocument()
{
    if (m_imageDocument) {
        m_imageDocument->disconnectImageElement();
        m_imageDocument = 0;
    }
    HTMLImageElement::willMoveToNewOwnerDocument();
}
void ImageDocumentElement::didMoveToNewDocument(Document* oldDocument)
{
    if (m_imageDocument) {
        m_imageDocument->disconnectImageElement();
        m_imageDocument = nullptr;
    }
    HTMLImageElement::didMoveToNewDocument(oldDocument);
}