Previously this functionality only worked correctly with a single
Transport instance, meaning a single video track.
This CL moves the transport pointer from being a member in
FakeNetworkPipe to being set on each packet, so that e.g. audio packets
point to the audio transport and video packet to the video transport.
This means we need a separate adapter per stream in DegradedCall.
Additionally, since Transport instances can potentially be destroyed
before it's time to forward the message to it, we need to keep track
of which instance that are live and ignore packets we can't forward.
Bug: None
Change-Id: I314d431c04ff81c3859cf661e2722c99342f785e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/148586
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28831}
eea605deeb