Don't call OnRegistrationDeleted when the unregistration failed.

content/browser/service_worker/service_worker_context_core.cc

Index: content/browser/service_worker/service_worker_context_core.cc
diff --git a/content/browser/service_worker/service_worker_context_core.cc b/content/browser/service_worker/service_worker_context_core.cc
index 1cc9387adfce4de9033d13bce069f9f87863d014..376db13a90dd0354695fce9fc649a87515fccb47 100644
--- a/content/browser/service_worker/service_worker_context_core.cc
+++ b/content/browser/service_worker/service_worker_context_core.cc
@@ -356,7 +356,7 @@ void ServiceWorkerContextCore::UnregistrationComplete(
     int64 registration_id,
     ServiceWorkerStatusCode status) {
   callback.Run(status);
-  if (observer_list_.get()) {
+  if (status == SERVICE_WORKER_OK && observer_list_.get()) {
     observer_list_->Notify(FROM_HERE,
                            &ServiceWorkerContextObserver::OnRegistrationDeleted,
                            registration_id, pattern);