P2PSocketDispatcherHost (p2p/socket_dispatcher_host.cc) subscribes to network change events (through net::NetworkChangeNotifier::NetworkChangeObserver). On network change, it queries the list of network interfaces (through net::GetNetworkList).

With network service, we will need to support these features.
For listening to network change events, we have services/network/public/mojom/network_change_manager.mojom, but still need a way to get the list of network interfaces.