Add listeners for the creation and destruction of virtual displays.
This will be used later by VibrationSettings to keep record of active
virtual displays.

Test: VirtualDeviceManagerServiceTest

bug:189474679

Change-Id: I8d39dccc194cac7aab08446fbdeea2ded7e1030f
(cherry picked from commit c17a6a127deea8119d592115e875a9c7067968b8)
3 files changed