RuntimeParticipantsAdding covers the described behaviour: "EXPECT_EQ(frames_in_flight_sizes.back().value, 0)" Bug: webrtc:12247 Change-Id: I296c607d3b7fb9f337b887347e60ccfc0e042143 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/203524 Commit-Queue: Andrey Logvin <landrey@webrtc.org> Reviewed-by: Artem Titov <titovartem@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33563}