seat: add KeyboardState and dynamically switch between states

src/compositor.rs

@@ -230,6 +230,7 @@ fn start_compositor2(
         subsurface_ids: Default::default(),
         wait_for_sync_obj: Rc::new(WaitForSyncObj::new(&ring, &engine)),
         explicit_sync_enabled: Cell::new(true),
+        keyboard_state_ids: Default::default(),
     });
     state.tracker.register(ClientId::from_raw(0));
     create_dummy_output(&state);