Update comment on ServiceWorkerSubresourceLoaderFactory::Create()

In production, the loader factory runs on a background thread.

Change-Id: If5261b012d96b714135118a2157092cb7fa983f2
Bug: N/A
Reviewed-on: https://chromium-review.googlesource.com/c/1256396
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596132}

content/renderer/service_worker/service_worker_subresource_loader.h

@@ -182,9 +182,8 @@ class CONTENT_EXPORT ServiceWorkerSubresourceLoaderFactory
   // default URLLoaderFactory for network fallback. This should be the
   // URLLoaderFactory that directly goes to network without going through
   // any custom URLLoader factories.
-  // |task_runner| is the runner where this loader runs. (We need to pass
-  // this around because calling base::SequencedTaskRunnerHandle is
-  // prohibited in the renderer :()
+  // |task_runner| is the runner where this loader runs. In production it runs,
+  // on a background thread.
   static void Create(
       scoped_refptr<ControllerServiceWorkerConnector> controller_connector,
       scoped_refptr<network::SharedURLLoaderFactory> fallback_factory,