Implement dumb URLLoader{Factory} for ServiceWorker script loading (for try)

content/common/service_worker/service_worker.mojom

Index: content/common/service_worker/service_worker.mojom
diff --git a/content/common/service_worker/service_worker.mojom b/content/common/service_worker/service_worker.mojom
index 7e8f5c8cd3ef4e4ba5d6b84b639a88d08e6d9d64..b9834324e19301a12e65a63f59ce1e4535fede3f 100644
--- a/content/common/service_worker/service_worker.mojom
+++ b/content/common/service_worker/service_worker.mojom
@@ -16,12 +16,4 @@ interface ServiceWorkerDispatcherHost {
   // ServiceWorkerProviderHost will be tied to the
   // mojom::ServiceWorkerProviderHost interface.
   OnProviderCreated(ServiceWorkerProviderHostInfo provider_info);
-
-  // Informs the browser that a service worker is starting up. |provider_id|
-  // identifies the ServiceWorkerProviderHost hosting the service
-  // worker. |version_id| identifies the ServiceWorkerVersion and
-  // |embedded_worker_id| identifies the EmbeddedWorkerInstance.  
-  OnSetHostedVersionId(int32 provider_id,
-                       int64 version_id,
-                       int32 embedded_worker_id);
 };