This is a step towards removing StreamInterface::SignalEvent. Downstream dependency will need to be updated to call FireEvent() before further changes can land in webrtc. Bug: webrtc:11943 Change-Id: Ia7d3f1c43fda52b7cf5bfa082aef3f462553cd67 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/347884 Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#42143}