GitLab

Per the PM's request, add UMA to record how many times the hosted app
menu button are clicked.

Bug: None
Change-Id: Ib52f936ce5029bf7c23ed15f14f724db665d81f9
Reviewed-on: https://chromium-review.googlesource.com/1214084
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589739}