So that applications don't need to construct it from the exposed
network_thread.
The EmulatedNetworkManagerInterface::network_thread() accessor is currently
used as a way to get to emulation's SocketServer, and should be deleted
when applications of the emulation framework have migrated away from
that usage.
Bug: webrtc:13145
Change-Id: I3efa55d117cad8ac601c48a9d2d2aa62a121f9c9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231649
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34964}