Add chrome/browser/chromeos/arc/pip/OWNERS

BUG=b:116761000
TEST=None

Change-Id: I183b22eaa8c1bebad3f2797604bf7a98712c958d
Reviewed-on: https://chromium-review.googlesource.com/c/1252385Reviewed-by: Eliot Courtney <edcourtney@chromium.org>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596339}

chrome/browser/chromeos/arc/pip/OWNERS

+edcourtney@chromium.org