Thanks, revert incoming, diagnosis @ https://bugs.chromium.org/p/chromium/issues/detail?id=854237#c9

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/050feaa75927b7216306c6a12084cb64920f9e78

commit 050feaa75927b7216306c6a12084cb64920f9e78
Author: Gabriel Charette <gab@chromium.org>
Date: Wed Jul 18 19:16:12 2018

Revert "[MessageLoop] Disable hi-res timers when not sleeping"

This reverts commit 62973d1b3f85cbc12f3f6e255e8d5dd1f91225b4.

Reason for revert: results in more churn in
base::Time::ActivateHighResolutionTimer()
without much benefits (decreased 97th and 98th percentile of
Windows.HighResolutionTimerUsage from 100% to 97% and 99%
respectively). See  crbug.com/863938 

Original change's description:
> [MessageLoop] Disable hi-res timers when not sleeping
> 
> Time::ActivateHighResolutionTimer(bool activating) is a per-thread vote
> for a system-wide side-effect. For a given thread, hi-res timers are
> only useful when going to sleep (if it has pending hi-res tasks).
> 
> Deactivating a thread's vote while it's active will prevent other
> threads on the system which do not have hi-res requirements from
> being forced to use hi-res timers in that period.
> 
> Bug:  854237 
> Change-Id: I1393e184cac6c9321d13b92b6077a38c62b1f590
> Reviewed-on: https://chromium-review.googlesource.com/1107110
> Reviewed-by: danakj <danakj@chromium.org>
> Reviewed-by: kylechar <kylechar@chromium.org>
> Commit-Queue: Gabriel Charette <gab@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#574259}

TBR=danakj@chromium.org,gab@chromium.org,kylechar@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  854237 ,  863938 
Change-Id: I7c26646cac8548ae7b02c90e045bc857ae890ce7
Reviewed-on: https://chromium-review.googlesource.com/1140753
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576157}
[modify] https://crrev.com/050feaa75927b7216306c6a12084cb64920f9e78/base/message_loop/message_loop.cc
[modify] https://crrev.com/050feaa75927b7216306c6a12084cb64920f9e78/base/message_loop/message_loop.h
[modify] https://crrev.com/050feaa75927b7216306c6a12084cb64920f9e78/base/message_loop/message_loop_unittest.cc

Should be fixed by revert.