The Tor Browser / file revision

 const Cc = SpecialPowers.Cc;

 const Ci = SpecialPowers.Ci;

 const RETURN_CONTINUE = Ci.jsdIExecutionHook.RETURN_CONTINUE;

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

 var jsd = Cc['@mozilla.org/js/jsd/debugger-service;1']

           .getService(Ci.jsdIDebuggerService);

 var jsdOnAtStart = false;

 function setupJSD(test) {

   netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");

   jsdOnAtStart = jsd.isOn;

   if (jsdOnAtStart) {

       runTest();

   } else {

       jsd.asyncOn({ onDebuggerActivated: function() { runTest(); } });

   }

 }

 // Ugly workaround: when you turn the debugger on, it will only see scripts

 // compiled after that point. And it may be turned on asynchronously. So

 // we put the debugged code into a separate script that gets loaded after

 // the debugger is on.

 function loadScript(url, element) {

     var script = document.createElement('script');

     script.type = 'text/javascript';

     script.src = url;

     script.defer = false;

     element.appendChild(script);

 }

 function findScriptByFunction(name) {

     var script;

     jsd.enumerateScripts({ enumerateScript:

                            function(script_) {

                                if (script_.functionName === name) {

                                    script = script_;

                                }

                            }

                          });

     if (typeof(script) === "undefined") {

         throw("Cannot find function named '" + name + "'");

     }

     return script;

 }

 // Pass in a JSD script

 function breakOnAllLines(script) {

     // Map each line to a PC, and collect that set of PCs (removing

     // duplicates.)

     var pcs = {};

     for (i = 0; i < script.lineExtent; i++) {

         var jsdLine = script.baseLineNumber + i;

         var pc = script.lineToPc(jsdLine, Ci.jsdIScript.PCMAP_SOURCETEXT);

         pcs[pc] = 1;

     }

     // Set a breakpoint on each of those PCs.

     for (pc in pcs) {

         try {

             script.setBreakpoint(pc);

         } catch(e) {

             alert("Error setting breakpoint: " + e);

         }

     }

 }

 // Set a breakpoint on a script, where lineno is relative to the beginning

 // of the script (NOT the absolute line number within the file).

 function breakOnLine(script, lineno) {

     breakOnAbsoluteLine(script, script.baseLineNumber + lineno);

 }

 function breakOnAbsoluteLine(script, lineno) {

     var pc = script.lineToPc(lineno, Ci.jsdIScript.PCMAP_SOURCETEXT);

     script.setBreakpoint(pc);

 }

 function loadPage(page) {

     var url;

     if (page.match(/^\w+:/)) {

         // Full URI, so just use it

         url = page;

     } else {

         // Treat as relative to previous page

         url = document.location.href.replace(/\/[^\/]*$/, "/" + page);

     }

     dump("Switching to URL " + url + "\n");

     gURLBar.value = url;

     gURLBar.handleCommand();

 }

 function breakpointObserver(lines, interesting, callback) {

     jsd.breakpointHook = { onExecute: function(frame, type, rv) {

         breakpoints_hit.push(frame.line);

         if (frame.line in interesting) {

             return callback(frame, type, breakpoints_hit);

         } else {

             return RETURN_CONTINUE;

         }

     } };

 }

 function dumpStack(frame, msg) {

     dump(msg + ":\n");

     while(frame) {

         var callee = frame.callee;

         if (callee !== null)

           callee = callee.jsClassName;

         dump("  " + frame.script.fileName + ":" + frame.line + " func=" + frame.script.functionName + " ffunc=" + frame.functionName + " callee=" + callee + " pc=" + frame.pc + "\n");

         frame = frame.callingFrame;

     }

 }