Reland "[upgrade_detector] Avoid the macOS Catalina file consent dialog."

This reverts commit 84ad51ea57c904571bcc6cb1372f67eb988100a2.

Reason for revert: This is not the right fix

Original change's description:
> Revert "[upgrade_detector] Avoid the macOS Catalina file consent dialog."
>
> This reverts commit df9d1d0c056736fced587d48487694d68e87f2ef.
>
> This revert switches from a "trivial" watch on macOS back to a
> non-recursive watch. This means that parent directories will also be
> monitored. It is this monitoring of parent dirs that may trigger the
> consent dialog.
>
> This revert is yet another attempt to address a crash in
> base::FilePathWatcherKQueue::OnKQueueReadable that appears to correlate
> with the landing of https://crrev.com/830353.
>
> TBR=grt@chromium.org
>
> Bug: 1147071,1156603
> Change-Id: I09f15fa1d668c18578e63cb011faa7047a07f102
> Fixed: 88
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2642159
> Auto-Submit: Greg Thompson <grt@chromium.org>
> Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
> Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
> Cr-Original-Original-Commit-Position: refs/heads/master@{#846666}
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2652896
> Reviewed-by: Greg Thompson <grt@chromium.org>
> Commit-Queue: Greg Thompson <grt@chromium.org>
> Cr-Commit-Position: refs/branch-heads/4324@{#2059}
> Cr-Branched-From: c73b5a651d37a6c4d0b8e3262cc4015a5579c6c8-refs/heads/master@{#827102}

TBR=grt@chromium.org,jdoerrie@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com

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

Bug: 1147071
Bug: 1156603
Change-Id: Ib251ad229f70bbaf94e0d156cb6fa3bcf2e0310d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2665346
Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/branch-heads/4324@{#2085}
Cr-Branched-From: c73b5a651d37a6c4d0b8e3262cc4015a5579c6c8-refs/heads/master@{#827102}

• chrome/browser/upgrade_detector/directory_monitor.cc[diff]