core: Forward events meant for non-alive windows to clutter

Otherwise the ClutterEventFilter will consider these handled, and not
forward these to Clutter. This gets necessary for key handling if we
mean to implement the close dialog with Clutter UI.

https://bugzilla.gnome.org/show_bug.cgi?id=762083

src/core/events.c

@@ -384,6 +384,17 @@ meta_display_handle_event (MetaDisplay        *display,
                                  XIReplayDevice, event->button.time);
                 }
             }
+
+          /* If the focus window has an active close dialog let clutter
+           * events go through, so fancy clutter dialogs can get to handle
+           * all events.
+           */
+          if (window->close_dialog &&
+              meta_close_dialog_is_visible (window->close_dialog))
+            {
+              bypass_wayland = TRUE;
+              bypass_clutter = FALSE;
+            }
         }
 
       goto out;