vp9 encoder wrapper rely on that behavioue when generates vp9-specific temporal references Bug: webrtc:11999 Change-Id: Ie1b4cb60adf290992cc3307b56397a88eda78be4 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/211661 Reviewed-by: Philip Eliasson <philipel@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33446}