ServiceWorker: Modernize postMessage tests for cleanup

third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html

Index: third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html b/third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html
index 397b41970dfb2e9d60d2c7345c3cefd46a769bc4..fadc7d2a51cdea387b23bb4bfcd14449598a26e4 100644
--- a/third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html
+++ b/third_party/WebKit/LayoutTests/http/tests/serviceworker/postmessage-to-client.html
@@ -4,38 +4,37 @@
 <script src="../resources/testharnessreport.js"></script>
 <script src="resources/test-helpers.js"></script>
 <script>
-var t = async_test('postMessage from ServiceWorker to Client');
-t.step(function() {
-    var scope = 'resources/blank.html'
-    service_worker_unregister_and_register(
-        t, 'resources/postmessage-to-client-worker.js', scope)
-      .then(function(registration) {
+
+promise_test(t => {
+    var script = 'resources/postmessage-to-client-worker.js';
+    var scope = 'resources/blank.html';
+    var w;
+
+    return service_worker_unregister_and_register(t, script, scope)
+      .then(registration => {
+          add_completion_callback(() => registration.unregister());
           return wait_for_state(t, registration.installing, 'activated');
         })
-      .then(function() { return with_iframe(scope); })
-      .then(function(frame) {
-          var w = frame.contentWindow;
-          w.navigator.serviceWorker.onmessage = t.step_func(onMessage);
-          w.navigator.serviceWorker.controller.postMessage('ping');
+      .then(() => with_iframe(scope))
+      .then(frame => {
+          return new Promise(resolve => {
+              w = frame.contentWindow;
+              w.navigator.serviceWorker.onmessage = resolve;
+              w.navigator.serviceWorker.controller.postMessage('ping');
+            });
         })
-      .catch(unreached_rejection(t));
-
-    var result = [];
-    var expected = ['Sending message via clients'];
+      .then(e => {
+          var message = e.data;
+          assert_equals(e.origin, location.origin,
+            'origin of message should be origin of Service Worker');
+          assert_equals(e.lastEventId, '',
+            'lastEventId should be an empty string');
+          assert_equals(message, 'Sending message via clients');
+          return new Promise(resolve => {
+              w.navigator.serviceWorker.onmessage = resolve;
+            });
+        })
+      .then(e => { assert_equals(e.data, 'quit'); });
+  }, 'postMessage from ServiceWorker to Client');
 
-    function onMessage(e) {
-      var message = e.data;
-      assert_equals(e.origin, location.origin,
-        'origin of message should be origin of Service Worker');
-      assert_equals(e.lastEventId, '',
-        'lastEventId should be an empty string');
-      if (message === 'quit') {
-        assert_array_equals(result, expected,
-                            'Worker should post back expected messages.');
-        service_worker_unregister_and_done(t, scope);
-      } else {
-        result.push(message);
-      }
-    }
-  });
 </script>