Upd OWNERS for chrome/browser/chromeos/arc/policy

Change-Id: I7e3bb2e1a8a9bc848f3663e8b8edc2c2860dee16
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2320609Reviewed-by: Bartosz Fabianowski <bartfab@chromium.org>
Commit-Queue: Giovanni Pezzino <giovax@google.com>
Cr-Commit-Position: refs/heads/master@{#792173}

chrome/browser/chromeos/arc/policy/OWNERS

 bartfab@chromium.org
+phweiss@chromium.org
+pbond@chromium.org
 
 # COMPONENT: Enterprise