The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/tlsdate/+/44b3f0249b342950f54e869bbfad67fbc132cff2

commit 44b3f0249b342950f54e869bbfad67fbc132cff2
Author: Chris Morin <cmtm@google.com>
Date: Tue Nov 27 04:31:20 2018

Adjust clock gradually when possible

Use adjtime instead of settimeofday when device time is within 30
seconds of the real time. The clock jumping backwards can make certain
logs difficult to understand, and adjtime preserves clock monotonicity.

BUG= chromium:907304 
TEST=ensure clock doesn't move backwards after boot

Change-Id: I4efd081c456cecd228037aa9f8d0b927baaf2029
Reviewed-on: https://chromium-review.googlesource.com/1344802
Commit-Ready: Christopher Morin <cmtm@google.com>
Tested-by: Christopher Morin <cmtm@google.com>
Reviewed-by: Dan Erat <derat@chromium.org>

[modify] https://crrev.com/44b3f0249b342950f54e869bbfad67fbc132cff2/src/seccomp.c
[modify] https://crrev.com/44b3f0249b342950f54e869bbfad67fbc132cff2/src/tlsdate.h
[modify] https://crrev.com/44b3f0249b342950f54e869bbfad67fbc132cff2/src/tlsdate-setter.c
[modify] https://crrev.com/44b3f0249b342950f54e869bbfad67fbc132cff2/src/events/time_set.c