This field-trial allows us to provide multipliers for the opus target
bitrate.
Bug: webrtc:11055
Change-Id: I79c4c6389c6908daadda355e5ce0668413d0aaa1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158530
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29634}