compositor-x11: Only destroy one output when the close button is pressed

Instead of terminating the compositor, destroy the output whose close
button was clicked and move the other outputs, as is done in the drm
backend.

src/compositor-x11.c

@@ -916,6 +916,34 @@ x11_compositor_find_output(struct x11_compositor *c, xcb_window_t window)
 	assert(0);
 }
 
+static void
+x11_compositor_delete_window(struct x11_compositor *c, xcb_window_t window)
+{
+	struct x11_output *deleted_output, *output, *next;
+	int x_offset = 0;
+
+	deleted_output = x11_compositor_find_output(c, window);
+
+	wl_list_for_each_safe(output, next, &c->base.output_list, base.link) {
+		if (x_offset != 0) {
+			weston_output_move(&output->base,
+					   output->base.x - x_offset,
+					   output->base.y);
+			weston_output_damage(&output->base);
+		}
+
+		if (output == deleted_output) {
+			x_offset += output->base.width;
+			x11_output_destroy(&output->base);
+		}
+	}
+
+	xcb_flush(c->conn);
+
+	if (wl_list_empty(&c->base.output_list))
+		wl_display_terminate(c->base.wl_display);
+}
+
 #ifdef HAVE_XCB_XKB
 static void
 update_xkb_state(struct x11_compositor *c, xcb_xkb_state_notify_event_t *state)
@@ -1115,6 +1143,7 @@ x11_compositor_handle_event(int fd, uint32_t mask, void *data)
 	xcb_focus_in_event_t *focus_in;
 	xcb_expose_event_t *expose;
 	xcb_atom_t atom;
+	xcb_window_t window;
 	uint32_t *k;
 	uint32_t i, set;
 	uint8_t response_type;
@@ -1243,8 +1272,9 @@ x11_compositor_handle_event(int fd, uint32_t mask, void *data)
 		case XCB_CLIENT_MESSAGE:
 			client_message = (xcb_client_message_event_t *) event;
 			atom = client_message->data.data32[0];
+			window = client_message->window;
 			if (atom == c->atom.wm_delete_window)
-				wl_display_terminate(c->base.wl_display);
+				x11_compositor_delete_window(c, window);
 			break;
 
 		case XCB_FOCUS_IN: