nsCOMPtr<nsIURI> url; doc->GetDocumentURL(getter_AddRefs(url));
nsIURI *url = doc->GetDocumentURL();
wallet_InitializeCurrentURL(nsIDocument * doc) {  /* get url */  nsCOMPtr<nsIURI> url;  doc->GetDocumentURL(getter_AddRefs(url));  if (wallet_lastUrl == url) {    return;  } else {    if (wallet_lastUrl) {//??      NS_RELEASE(lastUrl);    }    wallet_lastUrl = url;  }}