1d1983edb5
Adding a barrier and later enabling the input capture session will create MetaBarrier instances for each added input capture barrier. The barriers are created as "sticky" which means that when a pointer hits the barrier, it'll stick to the point of entry, until it's released. The input capture session is also turned into a state machine with explicit state, to more easily track things. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2628>