Allow API users to access the NetworkControllerInterface instance that a
given PC ended up with, to allow integrators who have provided a
PeerConnectionFactoryDependencies.network_controller_factory to
associate a created instance of their custom network controller with the
PC using it.
Eg for the RTCRtpTransport Chromium implementation as in crrev.com/c/5607744.
Bug: chromium:345101934
Change-Id: Ia712ca4f45b90d5078f4e8e5977622d3e9f9aa6f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/353980
Commit-Queue: Tony Herre <herre@google.com>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42506}
418bcf2acb