Find next focus id from inside-out.

Bug: 5165543

This change fixes some problems when the view hierarchy contains
duplicate ids, such as when ListViews contain nested custom views.
If the custom views contain next focused id hints, then the system
should prefer the other views within the ListView item over any
other views outside of the ListView item.

Change-Id: I5653ff6bac0bf9f08bd6ecbe5a3bb22ea47ab566