Share a single blob URL between all workers (#3239)

js/util/browser/web_worker.js

@@ -1,6 +1,9 @@
 'use strict';
+
 var WebWorkify = require('webworkify');
+var window = require('../window');
+var workerURL = window.URL.createObjectURL(new WebWorkify(require('../../source/worker'), {bare: true}));
 
 module.exports = function () {
-    return new WebWorkify(require('../../source/worker'));
+    return new window.Worker(workerURL);
 };

js/util/worker_pool.js

@@ -2,7 +2,6 @@
 
 var assert = require('assert');
 var WebWorker = require('./web_worker');
-var URL = require('./window').URL;
 
 module.exports = WorkerPool;
 
@@ -37,7 +36,6 @@ WorkerPool.prototype = {
         delete this.active[mapId];
         if (Object.keys(this.active).length === 0) {
             this.workers.forEach(function (w) {
-                URL.revokeObjectURL(w.objectURL);
                 w.terminate();
             });
             this.workers = null;

test/js/util/worker_pool.test.js

@@ -24,22 +24,15 @@ test('WorkerPool', function (t) {
 
     t.test('#release', function (t) {
         var workersTerminated = 0;
-        var objectUrlsRevoked = {};
         var WorkerPool = proxyquire('../../../js/util/worker_pool', {
-            '../mapbox-gl': { workerCount: 4 },
-            './window': {
-                URL: {
-                    revokeObjectURL: function (url) { objectUrlsRevoked[url] = true; }
-                }
-            }
+            '../mapbox-gl': { workerCount: 4 }
         });
 
         var pool = new WorkerPool();
         pool.acquire('map-1');
         var workers = pool.acquire('map-2');
-        workers.forEach(function (w, i) {
+        workers.forEach(function (w) {
             w.terminate = function () { workersTerminated += 1; };
-            w.objectURL = 'blob:worker-' + i;
         });
 
         pool.release('map-2');
@@ -50,7 +43,6 @@ test('WorkerPool', function (t) {
         t.comment('terminates workers if no dispatchers are active');
         pool.release('map-1');
         t.equal(workersTerminated, 4);
-        t.equal(Object.keys(objectUrlsRevoked).length, 4);
         t.notOk(pool.workers);
 
         t.end();