GitLab

Set UNNotification not to close on default action, and handle it to
close through the bridge's Close method. Added unittest for it as well.

Bug: 1134175
Change-Id: Ia7cd5751fb5c245434f1f4877ae4988353080a8f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442970
Commit-Queue: Mohamed Adel <adelm@google.com>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Richard Knoll <knollr@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813186}