NavigationURLLoaderImpl::OnComplete has code to handle a status of net::OK.  The NetworkService itself will never call URLLoader::OnComplete with net::OK without calling OnReceiveResponse.

I think we should remove the net::OK logic from that function, and DCHECK instead (And possibly do something reasonable, just from a security standpoint, like show an error page, instead of treating it as a success).  If some other URLLoaderFactory implementations can send net::OK without calling OnReceiveResponse first, we should fix them.