ServiceWorker cleanup: remove wait_for_activated(); just use wait_for_state()

LayoutTests/http/tests/serviceworker/chromium/memory-cache.html

Index: LayoutTests/http/tests/serviceworker/chromium/memory-cache.html
diff --git a/LayoutTests/http/tests/serviceworker/chromium/memory-cache.html b/LayoutTests/http/tests/serviceworker/chromium/memory-cache.html
index a2d2a9b691d43c52e33ef898701b1d5a2ca363bd..9c6a81e5b9cb4c90f94106a6e7368a963e40ca9d 100644
--- a/LayoutTests/http/tests/serviceworker/chromium/memory-cache.html
+++ b/LayoutTests/http/tests/serviceworker/chromium/memory-cache.html
@@ -28,7 +28,7 @@ async_test(function(t) {
   service_worker_unregister_and_register(t, worker, scope)
     .then(function(r) {
         registration = r;
-        return wait_for_activated(t, registration);
+        return wait_for_state(t, r.installing, 'activated');
       })
     .then(function() { return with_iframe(scope); })
     .then(function(f) {