The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc

commit dad88f97d6b272bc9ba751e89bcd50dac3a6abfc
Author: Findit <findit-for-me@appspot.gserviceaccount.com>
Date: Fri Sep 28 02:07:52 2018

Revert "Use accurate X11 event timestamp computation."

This reverts commit 3225e1d5ea4626a770d835dd03a25b6c095b58b5.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 594844 as the
culprit for flakes in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vMzIyNWUxZDVlYTQ2MjZhNzcwZDgzNWRkMDNhMjViNmMwOTViNThiNQw

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.linux/Linux%20Tests/72634

Sample Failed Step: events_unittests

Sample Flaky Test: X11EventTest.AutoRepeat

Original change's description:
> Use accurate X11 event timestamp computation.
> 
> X events have a timestamp which is only well defined relative to the X11 Server
> time. The previous computation for timestamp for X11 events was making the
> assumption that Server time and Chrome time were the same. This assumption is
> not always true -- this is likely the root cause of "bad" timestamps observed in
> https://bugs.chromium.org/p/chromium/issues/detail?id=650338#c1
> 
> This CL changes event timestamp computation to make a roundtrip to the X11
> Server to get an accurate base::TimeTicks. This logic was lifted out of the
> responsiveness calculator, which was already doing this computation. The latter
> will subsequently be changed to use the computation in this CL.
> 
> Change-Id: I963019cd8bfb8ce14e06b3743a159c9c85f2cb82
> Bug:  859155 
> Reviewed-on: https://chromium-review.googlesource.com/1249383
> Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#594844}

Change-Id: I911f8bd268739b5e91c550e3f6a6186ae4dfbecb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  859155 ,  890121 
Reviewed-on: https://chromium-review.googlesource.com/1250210
Cr-Commit-Position: refs/heads/master@{#594958}
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/event_unittest.cc
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/platform/x11/x11_event_source.cc
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/platform/x11/x11_event_source.h
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/x/events_x.cc
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/x/events_x_unittest.cc
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/x/events_x_utils.cc
[modify] https://crrev.com/dad88f97d6b272bc9ba751e89bcd50dac3a6abfc/ui/events/x/events_x_utils.h

Removing the sheriff label for now as looks like the culprit has been reverted, erikchen@ - PTAL. If it's wrong, please readd the sheriff label.

CL was relanded with no issues: https://chromium-review.googlesource.com/c/chromium/src/+/1252685