The max bitrate is already constrained to the bitrate specified by
ScreenshareLayerConfig, it should not be boosted past that.
Bug: webrtc:8785
Change-Id: If400e829b6bf209e3052e908fcabd65ba2c9457e
Reviewed-on: https://webrtc-review.googlesource.com/53320
Reviewed-by: Seth Hampson <shampson@webrtc.org>
Reviewed-by: Peter Thatcher <pthatcher@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22027}