The Tor Browser / file revision

 // This test must be run with debugging already enabled

 function run_test() {

     const Cc = Components.classes;

     const Ci = Components.interfaces;

     const DebuggerService = Cc["@mozilla.org/js/jsd/debugger-service;1"];

     const jsdIDebuggerService = Ci.jsdIDebuggerService;

     var jsd = DebuggerService.getService(jsdIDebuggerService);

     do_check_true(jsd.isOn);

     jsd.scriptHook = {

         onScriptCreated: function(script) {

             // Just the presence of this will trigger the script to be handed

             // to JSD and trigger the crash

         },

         onScriptDestroyed: function(script) {

         }

     }

     eval("4+4");

     eval("4+4"); // Will be found in the eval cache

 }