Currently there are two NavigationURLLoader implementations: one that uses ResourceDispatcherHost (NavigationURLLoaderImpl) and one that uses network service (NavigationURLLoaderNetworkService).

As we've discussed, in order to migrate many features' networking glue to be compatible with the network service, we need to use the URLLoader interface whether the network service is in use or not. That way, for example service worker or download code can use the same interface to talk to the provider of network requests. We could ship the new code independent of the network service launch.

It shouldn't be much work to wrap the plznavigate use of RDH through a URLLoader interface. We need to wait for MojoLoading and PlzNavigate to launch first though.