Replaced UglifyJS2 with Traceur for fair comparison of ES6-enabled parsers.

test/bench.html

@@ -4,7 +4,7 @@
   <title>Acorn benchmark</title>
   <script src="../acorn.js"></script>
   <script src="compare/esprima.js"></script>
-  <script src="compare/uglifyjs2.js"></script>
+  <script src="compare/traceur.js"></script>
   <script src="jquery-string.js"></script>
   <script src="codemirror-string.js"></script>
   <style>
@@ -15,11 +15,11 @@
   </style>
 </head>
 
-<h1>Acorn/Esprima/UglifyJS2 speed comparison</h1>
+<h1>Acorn/Esprima/Traceur speed comparison</h1>
 
-<p>This will run each of the three parsers on the source code of
+<p>This will run each of the three ES6 parsers on the source code of
 jQuery 1.6.4 and CodeMirror 3.0b1 for two seconds, and show a table
-indicating the number of lines parsed per second. Note that UglifyJS
+indicating the number of lines parsed per second. Note that Traceur
 always stores location data, and is thus not fairly compared by the
 benchmark <em>without</em> location data.<p>
 
@@ -35,28 +35,34 @@ numbers.</p>
 <span id="running"></span>
 
 <script>
+  var sourceFileName = 'source.js';
+
   function runAcorn(code, locations) {
-    acorn.parse(code, {ecmaVersion: 6, locations: locations});
+    acorn.parse(code, {ecmaVersion: 6, locations: locations, sourceFile: sourceFileName});
   }
   function runEsprima(code, locations) {
-    esprima.parse(code, {loc: locations});
+    esprima.parse(code, {loc: locations, source: sourceFileName});
   }
-  function runUglifyJS(code) {
-    uglifyjs.parse(code);
+  function runTraceur(code) {
+    var file = new traceur.syntax.SourceFile(sourceFileName, code);
+    var parser = new traceur.syntax.Parser(file);
+    parser.parseScript();
   }
 
   var totalLines = codemirror30.split("\n").length + jquery164.split("\n").length;
 
+  var nowHost = (typeof performance === 'object' && 'now' in performance) ? performance : Date;
+
   function benchmark(runner, locations) {
     // Give it a chance to warm up (first runs are usually outliers)
     runner(jquery164, locations);
     runner(codemirror30, locations);
-    var t0 = +new Date, t1, lines = 0;
+    var t0 = nowHost.now(), t1, lines = 0;
     for (;;) {
       runner(jquery164, locations);
       runner(codemirror30, locations);
       lines += totalLines;
-      t1 = +new Date;
+      t1 = nowHost.now();
       if (t1 - t0 > 2000) break;
     }
     return lines / ((t1 - t0) / 1000);
@@ -75,7 +81,7 @@ numbers.</p>
     running.innerHTML = "Running benchmark...";
     var data = [{name: "Acorn", runner: runAcorn},
                 {name: "Esprima", runner: runEsprima},
-                {name: "UglifyJS2", runner: runUglifyJS}];
+                {name: "Traceur", runner: runTraceur}];
     if (acornOnly) data.length = 1;
     var pos = 0;
     function next() {