Add OWNERS file for content/app_shim_remote_cocoa

Bug: None
Change-Id: I3a1e8849a9fe97c44f0fa537124bdca29c4d4ddc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2001178Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: Leonard Grey <lgrey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732428}

content/app_shim_remote_cocoa/OWNERS

+ccameron@chromium.org
+lgrey@chromium.org
+
+# COMPONENT: UI
\ No newline at end of file