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: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/5b9489e9046633a4e8287838684d61e69a791c65/updates.js/buggy/toolkit/mozapps/update/content/updates.js