GitLab

In preparation for removing the overview's shield widget,
this CL extracts the DesksBarView into its own widget.

BUG=866622, 942759
TEST=Manual, DesksTests still pass.

Change-Id: Ic378e113dae4b7abdc1ce856655b74cfcd3337d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1542664
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#645351}