GitLab

1) The screensaver app should be hidden because it doesn't make sense
   to let a user launch the screensaver.

2) The Web store and the Get Help app should be hidden per UI review.

Bug: 883034, 885364
Change-Id: Ic4c481cb0cea0b535efde16997f0c4ad74c11b33
Reviewed-on: https://chromium-review.googlesource.com/1222347Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592569}