Reason for revert:
Failing chromoting tests
Original issue's description:
> Refactor timing frame logic to work with encoders with internal sources
>
> BUG=webrtc:7594,webrtc:7893
>
> Review-Url: https://codereview.webrtc.org/2968153002
> Cr-Commit-Position: refs/heads/master@{#18955}
> Committed: a7a4535a35TBR=sprang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7594,webrtc:7893
Review-Url: https://codereview.webrtc.org/2980533002
Cr-Commit-Position: refs/heads/master@{#18957}
0b1e2f3279