Currently we use an extra menu with two items to show download location
settings and show/hide disk space info.

This CL removes the extra menu and uses a new menu item to only show
download location setting. The icon uses a setting icon, which will be
replaced later for correct color.

Bug: 838738,792775
Change-Id: Ic2f65df05ea9a46d8d49885b15d5fa6a9273ba07
Reviewed-on: https://chromium-review.googlesource.com/1043362
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557019}