* tests/dmabuf_test.c (enum test_kind): Add XBGR888_KIND.
(test_names): Add that test.
(LAST_TEST): Set to XBGR888_KIND.
(verify_single_step, test_single_step, test_next_step):
Implement that test, but keep it disabled for now.
* tests/seat_test.c (struct test_subsurface): New struct.
(enum test_kind): Add TEST_GRAB_KIND.
(test_names): Add that test kind.
(LAST_TEST): Set to TEST_GRAB_KIND.
(make_test_subsurface): New function.
(run_grab_test): New functions.
(test_single_step): Implement new test.
(expect_enter_event): Accept surface arg.
(expect_surface_enter): Adjust accordingly.
(handle_wl_callback_done, wait_frame_callback): New functions.
