The Tor Browser / file revision

 if (typeof Cc === "undefined")

   Cc = Components.classes;

 if (typeof Ci === "undefined")

   Ci = Components.interfaces;

 function destroy_transient_docshell() {

   var docshell = Cc["@mozilla.org/docshell;1"].createInstance(Ci.nsIDocShell);

   docshell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = true;

   do_test_pending();

   do_timeout(0, Components.utils.forceGC);

 }

 function run_test() {

   var obs = {

     observe: function(aSubject, aTopic, aData) {

       do_check_eq(aTopic, "last-pb-context-exited");

       do_test_finished();

     }

   };

   var os = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);

   os.addObserver(obs, "last-pb-context-exited", false);

   destroy_transient_docshell();

 }