[CrOS MultiDevice] Proactively sync after FindEligibleDevices() call.

When a host verification is forced via the "Verify" button in settings,
HostVerifierImpl makes a call to FindEligibleDevices(), which should end
up resulting in a sync tickle being sent to the Chromebook. In practice,
we've found that this tickle is often missed by the device.

This CL ensures that a sync occurs by forcing a sync after a successful
FindEligibleDevices() call. The sync is scheduled for 5 seconds after
the FindEligibleDevices() call completes to ensure that the server has
had enough time to update its database before the sync.

TBR=khorimoto@chromium.org

(cherry picked from commit 790b6a7867682cdf632c1ac679894014301d7359)

Bug: 913816
Change-Id: Iaf8686ce4ac34e0e48a0613108949ba1b9a06cff
Reviewed-on: https://chromium-review.googlesource.com/c/1444053
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Jeremy Klein <jlklein@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#627240}
Reviewed-on: https://chromium-review.googlesource.com/c/1447256
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/branch-heads/3683@{#79}
Cr-Branched-From: e51029943e0a38dd794b73caaf6373d5496ae783-refs/heads/master@{#625896}
4 files changed