rem: return Components.results.NS_ERROR_NO_INTERFACE; 
add: Components.returnCode = Components.results.NS_ERROR_NO_INTERFACE; return null; 
context:     getInterface: function(iid, result){        if (iid.equals(Components.interfaces.nsIAuthPrompt)){            return this;        }        return Components.results.NS_ERROR_NO_INTERFACE;    },
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/c2dd5c4e8c1a1438effb4d12c35e70c70441a5a2/nsXmlRpcClient.js/buggy/extensions/xml-rpc/src/nsXmlRpcClient.js