static void
photos_selection_toolbar_selection_mode_changed (PhotosSelectionToolbar *self, gboolean mode)
{
  if (mode)
    photos_selection_toolbar_selection_changed (self);
  else
    gtk_widget_hide (GTK_WIDGET (self));
}
static void
photos_selection_toolbar_selection_mode_changed (PhotosSelectionController *sel_cntrlr,
                                                 gboolean mode,
                                                 gpointer user_data)
{
  PhotosSelectionToolbar *self = PHOTOS_SELECTION_TOOLBAR (user_data);

  if (mode)
    photos_selection_toolbar_selection_changed (sel_cntrlr, self);
  else
    gtk_revealer_set_reveal_child (GTK_REVEALER (self), FALSE);
}