Bug 1273070 P2 Execute fetch() mochitests in nested workers. r=khuey

dom/tests/mochitest/fetch/fetch_test_framework.js

@@ -36,6 +36,27 @@ function testScript(script) {
     });
   }
 
+  function nestedWorkerTest() {
+    return new Promise(function(resolve, reject) {
+      var worker = new Worker("nested_worker_wrapper.js");
+      worker.onmessage = function(event) {
+        if (event.data.context != "NestedWorker") {
+          return;
+        }
+        if (event.data.type == 'finish') {
+          resolve();
+        } else if (event.data.type == 'status') {
+          ok(event.data.status, event.data.context + ": " + event.data.msg);
+        }
+      }
+      worker.onerror = function(event) {
+        reject("Nested Worker error: " + event.message);
+      };
+
+      worker.postMessage({ "script": script });
+    });
+  }
+
   function serviceWorkerTest() {
     var isB2G = !navigator.userAgent.includes("Android") &&
                 /Mobile|Tablet/.test(navigator.userAgent);
@@ -112,6 +133,9 @@ function testScript(script) {
     .then(function() {
       return workerTest();
     })
+    .then(function() {
+      return nestedWorkerTest();
+    })
     .then(function() {
       return serviceWorkerTest();
     })

dom/tests/mochitest/fetch/mochitest.ini

@@ -10,6 +10,7 @@ support-files =
   test_request.js
   test_response.js
   utils.js
+  nested_worker_wrapper.js
   worker_wrapper.js
   message_receiver.html
   reroute.html

dom/tests/mochitest/fetch/nested_worker_wrapper.js

@@ -0,0 +1,25 @@
+addEventListener('message', function nestedWorkerWrapperOnMessage(evt) {
+  removeEventListener('message', nestedWorkerWrapperOnMessage);
+
+  var worker = new Worker('worker_wrapper.js');
+
+  worker.addEventListener('message', function(evt) {
+    self.postMessage({
+      context: 'NestedWorker',
+      type: evt.data.type,
+      status: evt.data.status,
+      msg: evt.data.msg,
+    });
+  });
+
+  worker.addEventListener('error', function(evt) {
+    self.postMessage({
+      context: 'NestedWorker',
+      type: 'status',
+      status: false,
+      msg: 'Nested worker error: ' + evt.message,
+    });
+  });
+
+  worker.postMessage(evt.data);
+});