rem: var p = this.update.selectedPatch; if (p) p.QueryInterface(Components.interfaces.nsIWritablePropertyBag); 
context:   setUpdate: function(update) {    this.update = update;    this.update.QueryInterface(Components.interfaces.nsIWritablePropertyBag);    var p = this.update.selectedPatch;    if (p)      p.QueryInterface(Components.interfaces.nsIWritablePropertyBag);  },
meta: 7628	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/7628/ac6e0d82b442792623335e20d6840bf77bb3d9de/updates.js/buggy/content/updates.js