ServiceWorker: Enable ServiceWorkerRegistration and update layout tests

LayoutTests/http/tests/serviceworker/unregister-controller.html

Index: LayoutTests/http/tests/serviceworker/unregister-controller.html
diff --git a/LayoutTests/http/tests/serviceworker/unregister-controller.html b/LayoutTests/http/tests/serviceworker/unregister-controller.html
index c3394fe059341e3f8120071e6e35ecebff9773c7..59920c222414a5b97fefb1f6be88c70afee6e1c9 100644
--- a/LayoutTests/http/tests/serviceworker/unregister-controller.html
+++ b/LayoutTests/http/tests/serviceworker/unregister-controller.html
@@ -13,6 +13,9 @@ async_test(function(t) {
   var controller;
 
   service_worker_unregister_and_register(t, worker_url, scope)
+    .then(function(registration) {
+        return wait_for_update(t, registration);
+      })
     .then(function(registered_worker) {
         worker = registered_worker;
         return wait_for_state(t, worker, 'activated');
@@ -46,6 +49,9 @@ async_test(function(t) {
       'resources/unregister-controller-page.html?load-after-unregister';
 
   service_worker_unregister_and_register(t, worker_url, scope)
+    .then(function(registration) {
+        return wait_for_update(t, registration);
+      })
     .then(function(worker) {
         return wait_for_state(t, worker, 'activated');
       })
@@ -74,6 +80,9 @@ async_test(function(t) {
         'scope/no-new-controllee-even-if-registration-is-still-used';
 
     service_worker_unregister_and_register(t, worker_url, scope)
+      .then(function(registration) {
+          return wait_for_update(t, registration);
+        })
       .then(function(registered_worker) {
           return wait_for_state(t, registered_worker, 'activated');
         })