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)