Bug 1331656 Make ServiceWorkerManager handle PBackground init failure. r=baku

dom/workers/ServiceWorkerManager.cpp

@@ -235,8 +235,6 @@ ServiceWorkerManager::ServiceWorkerManager()
   : mActor(nullptr)
   , mShuttingDown(false)
 {
-  // Register this component to PBackground.
-  MOZ_ALWAYS_TRUE(BackgroundChild::GetOrCreateForCurrentThread(this));
 }
 
 ServiceWorkerManager::~ServiceWorkerManager()
@@ -273,6 +271,12 @@ ServiceWorkerManager::Init(ServiceWorkerRegistrar* aRegistrar)
       MOZ_ASSERT(NS_SUCCEEDED(rv));
     }
   }
+
+  if (!BackgroundChild::GetOrCreateForCurrentThread(this)) {
+    // Make sure to do this last as our failure cleanup expects Init() to have
+    // executed.
+    ActorFailed();
+  }
 }
 
 void