Add map load benchmark

bench/benchmarks/map_load.js

@@ -0,0 +1,40 @@
+'use strict';
+
+var Evented = require('../../js/util/evented');
+var util = require('../../js/util/util');
+var formatNumber = require('../lib/format_number');
+
+module.exports = function(options) {
+    var evented = util.extend({}, Evented);
+
+    var mapsOnPage = 6;
+
+    evented.fire('log', { message: 'Creating ' + mapsOnPage + ' maps' });
+
+    var loaded = 0;
+    var start = Date.now();
+    for (var i = 0; i < mapsOnPage; i++) {
+        var map = options.createMap({});
+        map.on('load', onload.bind(null, map));
+        map.on('error', function (err) {
+            evented.fire('error', err);
+        });
+    }
+
+    function onload () {
+        if (++loaded >= mapsOnPage) {
+            var duration = Date.now() - start;
+            evented.fire('end', {
+                message: formatNumber(duration) + ' ms, loaded ' + mapsOnPage + ' maps.',
+                score: duration
+            });
+            done();
+        }
+    }
+
+    function done () {
+    }
+
+    return evented;
+};
+

bench/index.js

@@ -198,6 +198,7 @@ var BenchmarksView = React.createClass({
 });
 
 var benchmarks = {
+    'load-multiple-maps': require('./benchmarks/map_load'),
     buffer: require('./benchmarks/buffer'),
     fps: require('./benchmarks/fps'),
     'frame-duration': require('./benchmarks/frame_duration'),