Make StructRtMsg constructor visible for testing.

Refactor IpClientTest by parsing the netlink message directly instead
of netd callbacks, so we have to initialize a StructRtMsg instance to
fill in the RtNetlinkRouteMessage constructor.

Bug: 318764217
Test: atest NetworkStackTests
Change-Id: I1481cb8fab29ae94d48fa342ecf2b303a9701a31
1 file changed