Harden XTerm handoff and web event routing

tests/test_input_event_manager_key_watcher_regressions.py

@@ -130,6 +130,7 @@ class InputEventManagerKeyWatcherTests(unittest.TestCase):
             ),
             mock.patch.object(input_event_manager.pyatspi.Registry, "registerKeystrokeListener") as register,
             mock.patch.object(input_event_manager.pyatspi.Registry, "deregisterKeystrokeListener") as deregister,
+            mock.patch.object(manager, "_initialize_xterm_handoff") as initializeXtermHandoff,
         ):
             manager.start_key_watcher()
             manager.stop_key_watcher()
@@ -161,6 +162,7 @@ class InputEventManagerKeyWatcherTests(unittest.TestCase):
             mask=expectedMasks,
             kind=(0, 1),
         )
+        initializeXtermHandoff.assert_called_once_with()
         self.assertEqual(
             device.connect_calls,
             [