NS_IMETHOD ContentRemoved(nsIDocument *aDocument, nsIContent* aContainer, nsIContent* aChild, PRInt32 aIndexInContainer) { return NS_OK; }
NS_IMPL_NSIDOCUMENTOBSERVER_CONTENT(HTMLContentSink)
  NS_IMETHOD ContentRemoved(nsIDocument *aDocument, nsIContent* aContainer,                            nsIContent* aChild, PRInt32 aIndexInContainer)  {    return NS_OK;  }