
Reason for revert:
Breaks chromium.
Original issue's description:
> Add experimental simulcast screen content mode
>
> BUG=webrtc:4172
>
> Review-Url: https://codereview.webrtc.org/2636443002
> Cr-Commit-Position: refs/heads/master@{#16135}
> Committed: a28e971e3b
TBR=perkj@webrtc.org,asapersson@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:4172
Review-Url: https://codereview.webrtc.org/2643763002
Cr-Commit-Position: refs/heads/master@{#16145}