wlr_scene: fix transformed outputs backend damage clearing

When we cleared the pending backend damage when the output committed,
we would not take into account the output transform. It's easiest to fix
this by just changing pending_commit_damage to always have transformed
coordinates.

types/scene/wlr_scene.c

@@ -1483,17 +1483,16 @@ static bool construct_render_list_iterator(struct wlr_scene_node *node,
 static void output_state_apply_damage(const struct render_data *data,
 		struct wlr_output_state *state) {
 	struct wlr_scene_output *output = data->output;
-	pixman_region32_union(&output->pending_commit_damage,
-		&output->pending_commit_damage, &output->damage_ring.current);
-	pixman_region32_intersect_rect(&output->pending_commit_damage,
-		&output->pending_commit_damage, 0, 0, data->trans_width, data->trans_height);
 
 	pixman_region32_t frame_damage;
 	pixman_region32_init(&frame_damage);
-	pixman_region32_copy(&frame_damage, &output->pending_commit_damage);
+	pixman_region32_copy(&frame_damage, &output->damage_ring.current);
 	transform_output_damage(&frame_damage, data);
-	wlr_output_state_set_damage(state, &frame_damage);
+	pixman_region32_union(&output->pending_commit_damage,
+		&output->pending_commit_damage, &frame_damage);
 	pixman_region32_fini(&frame_damage);
+
+	wlr_output_state_set_damage(state, &output->pending_commit_damage);
 }
 
 static void scene_buffer_send_dmabuf_feedback(const struct wlr_scene *scene,