OWNERS file for ios/chrome/browser/download.

Bug: None
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I9d4b146bc1bb8f37d248df49f77452da67108866
Reviewed-on: https://chromium-review.googlesource.com/811424Reviewed-by: Gregory Chatzinoff <gchatz@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522130}

ios/chrome/browser/download/OWNERS

+eugenebut@chromium.org
+gchatz@chromium.org
+
+# TEAM: ios-directory-owners@chromium.org
+# OS: iOS