- Electron version: 1.1.0
- Operating system: N/A

Currently there isn't any way to remove dialog boxes (such as ones created through `dialog.showMessageBox`).  This can be useful in, for example, "Keep Waiting" dialogs.  After the window becomes responsive again it would be great if we could programmatically close the dialog.

shell/browser/ui/message_box_gtk.cc
public:
  explicit GtkMessageBox(const MessageBoxSettings& settings)
      : cancel_id_(settings.cancel_id),
        parent_(static_cast<NativeWindow*>(settings.parent_window)) {
    
    dialog_ =
        gtk_message_dialog_new(nullptr,                         
                               static_cast<GtkDialogFlags>(0),  
                               GetMessageType(settings.type),   
                               GTK_BUTTONS_NONE,