- 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
"%s", settings.message.c_str());
    if (!settings.detail.empty())
      gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(dialog_),
                                               "%s", settings.detail.c_str());
    if (!settings.title.empty())
      gtk_window_set_title(GTK_WINDOW(dialog_), settings.title.c_str());
    if (!settings.icon.isNull()) {
      
      
      static constexpr int pixel_width = 48;
      static constexpr int pixel_height = 48;
      GdkPixbuf* pixbuf =
          gtk_util::GdkPixbufFromSkBitmap(*settings.icon.bitmap());
      GdkPixbuf* scaled_pixbuf = gdk_pixbuf_scale_simple(
          pixbuf, pixel_width, pixel_height, GDK_INTERP_BILINEAR);
      GtkWidget* w = gtk_image_new_from_pixbuf(scaled_pixbuf);
      gtk_message_dialog_set_image(GTK_MESSAGE_DIALOG(dialog_), w);
      gtk_widget_show(w);
      g_clear_pointer(&scaled_pixbuf, g_object_unref);
      g_clear_pointer(&pixbuf, g_object_unref);
    }
    if (!settings.checkbox_label.empty()) {
      GtkWidget* message_area =
          gtk_message_dialog_get_message_area(GTK_MESSAGE_DIALOG(dialog_));
      GtkWidget* check_button =
          gtk_check_button_new_with_label(settings.checkbox_label.c_str());
      g_signal_connect(check_button, "toggled",
                       G_CALLBACK(OnCheckboxToggledThunk), this);
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check_button),
                                   settings.checkbox_checked);