Reason for revert:
due to failures on perf tests (not on perf stats, but fails running due to dcheck failures), see e.g., https://build.chromium.org/p/client.webrtc.perf/builders/Android32%20Tests%20(K%20Nexus5)
Original issue's description:
> Drop frames until specified bitrate is achieved.
>
> This CL fixes a regression introduced with the new quality scaler
> where the video would no longer start in a scaled mode. This CL adds
> code that compares incoming captured frames to the target bitrate,
> and if they are found to be too large, they are dropped and sinkWants
> set to a lower resolution. The number of dropped frames should be low
> (0-4 in most cases) and should not introduce a noticeable delay, or
> at least should be preferrable to having the first 2-4 seconds of video
> have very low quality.
>
> BUG=webrtc:6953
>
> Review-Url: https://codereview.webrtc.org/2630333002
> Cr-Commit-Position: refs/heads/master@{#16391}
> Committed: 83399caec5TBR=perkj@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,kthelgason@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6953
Review-Url: https://codereview.webrtc.org/2666303002
Cr-Commit-Position: refs/heads/master@{#16395}
35fc2aa82f