Upstream commit: https://webrtc.googlesource.com/src/+/b2887131ee7872b53724e7b9e7d67aab7b18d9b5 Adds rust version of webrtc::RateTracker This includes some updates to how units FFI is exposed and removes the previous bridge tests as now we have real tests for cxx bridges. Bug: webrtc:416446214 Change-Id: I027e68b4521e14d5a1687dd0f0d03ed16a6a6964 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/470180 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Auto-Submit: Evan Shrubsole <eshr@webrtc.org> Commit-Queue: Evan Shrubsole <eshr@webrtc.org> Reviewed-by: Victor Boivie <boivie@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/main@{#47663}