Service Worker: Make ServiceWorkerRegistration.update() return a promise. (Blink Layout 3/3)

LayoutTests/http/tests/serviceworker/update.html

Index: LayoutTests/http/tests/serviceworker/update.html
diff --git a/LayoutTests/http/tests/serviceworker/update.html b/LayoutTests/http/tests/serviceworker/update.html
index 9eb392a9898336b51f14b1d476611b9d50b2046c..cc4b88f39dda0e40cf4a8e60a74d785393813cfa 100644
--- a/LayoutTests/http/tests/serviceworker/update.html
+++ b/LayoutTests/http/tests/serviceworker/update.html
@@ -17,42 +17,43 @@ promise_test(function(t) {
         })
       .then(function() {
           assert_equals(registration.installing, null,
-                        'installing should be null in the initial state');
+                        'installing should be null in the initial state.');
           assert_equals(registration.waiting, null,
-                        'waiting should be null in the initial state');
+                        'waiting should be null in the initial state.');
           assert_equals(registration.active.scriptURL, expected_url,
-                        'active should exist in the initial state');
+                        'active should exist in the initial state.');
 
-          // A new worker should be found.
-          registration.update();
-          return wait_for_update(t, registration);
+          // A new worker (generated by update-worker.php) should be found.
+          // The returned promise should resolve when a new worker script is
+          // fetched and starts installing.
+          return registration.update();
         })
       .then(function() {
           assert_equals(registration.installing.scriptURL, expected_url,
-                        'new installing should be set after updatefound');
+                        'new installing should be set after update resolves.');
           assert_equals(registration.waiting, null,
-                        'waiting should still be null after updatefound');
+                        'waiting should still be null after update resolves.');
           assert_equals(registration.active.scriptURL, expected_url,
-                        'active should still exist after update found');
+                        'active should still exist after update found.');
           return wait_for_state(t, registration.installing, 'installed');
         })
       .then(function() {
           assert_equals(registration.installing, null,
-                        'installing should be null after installing');
+                        'installing should be null after installing.');
           assert_equals(registration.waiting.scriptURL, expected_url,
-                        'waiting should be set after installing');
+                        'waiting should be set after installing.');
           assert_equals(registration.active.scriptURL, expected_url,
-                        'active should still exist after installing');
+                        'active should still exist after installing.');
           return wait_for_state(t, registration.waiting, 'activated');
         })
       .then(function() {
           assert_equals(registration.installing, null,
-                        'installing should be null after activated');
+                        'installing should be null after activated.');
           assert_equals(registration.waiting, null,
-                        'waiting should be null after activated');
+                        'waiting should be null after activated.');
           assert_equals(registration.active.scriptURL, expected_url,
-                        'new worker should be promoted to active');
+                        'new worker should be promoted to active.');
           return service_worker_unregister_and_done(t, scope);
         })
-  }, 'Update a registration');
+  }, 'Update a registration.');
 </script>