This better reflects the ownership passing of AddTrack, and is more consistent for RemoveTrack. Bug: webrtc:13980 Change-Id: Ide5baccf15fc687a4e092f8831ce8c0fea46604e Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/259740 Reviewed-by: Niels Moller <nisse@webrtc.org> Commit-Queue: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#36603}