This patch adds translation from ConnectivityMetricsEvent to
IpConnectivityEvent of recently added fields:
- top-level network id
- top-level ifname
- transports
Also adds inference of link layer from transports or ifname.
At the moment these new fields are not populated in
ConnectivityMetricsEvent. Follow-up patches will fill this gap for
the events of the android.net.metrics package.
Test: new unit tests, $ runtest frameworks-net passes
Bug: 34901696
Change-Id: I563a6a3183470bdfaabb7c781a1beaf6b1058bf0
45f6ef836d