rem: } throw Components.results.NS_ERROR_NO_INTERFACE; 
add:  Components.returnCode = Components.results.NS_ERROR_NO_INTERFACE; return null; 
context:     QueryInterface: function (iid) {        if (iid.equals(Components.interfaces.nsISupportsWeakReference) ||            iid.equals(Components.interfaces.nsISupports)) {            return this;        }        throw Components.results.NS_ERROR_NO_INTERFACE;    }
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/7b5970dc1f631c4a1ed682420229b370547edc65/xpctest_observer.js/clean/js/src/xpconnect/tests/js/old/xpctest_observer.js