This class will be used in upcoming VideoQualiyObserver. Bug: none Change-Id: I7d79a6caf3040a3f707ed8700842dea1de81e0a6 Reviewed-on: https://webrtc-review.googlesource.com/77724 Reviewed-by: Erik Språng <sprang@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23343}