synchronize three props for tab-dragging for Mash

Those three boolean window properties are used both in ash (split
screens, overview mode, and tablet mode) and browser / tab-dragging.
They need to be synchronized.

ash::kTabDraggingSourceWindowKey also needs to be addressed for
the same reason, though the aura::Window* type requires some
additional complications. Another CL should deal with it.

Bug: 867074
Test: none
Change-Id: I3f71b13322724cf20fbe103826532074c21c3c38
Reviewed-on: https://chromium-review.googlesource.com/1180094
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584167}
2 files changed