Reason for revert:
Multiple definitions of TestEstimator
Original issue's description:
> Avoid precision loss in TrendlineEstimator by passing the arrival time as an int64_t instead of a double.
>
> BUG=webrtc:6884
>
> Committed: https://crrev.com/c12cbaf9dd0729dd45f3fc45a1938d1b3455e40a
> Cr-Commit-Position: refs/heads/master@{#15631}
TBR=stefan@webrtc.org,brandtr@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6884
Review-Url: https://codereview.webrtc.org/2582513002
Cr-Commit-Position: refs/heads/master@{#15636}
43c382111d