Always show close buttons

The resizing is too distracting otherwise, and reserving space
would be unnecessarily complicated.

gtk/gtkclosabletab.c

@@ -72,29 +72,14 @@ gtk_closable_tab_init (GtkClosableTab *self)
   g_object_bind_property (self, "title", self->label, "label", G_BINDING_DEFAULT);
 
   self->button = gtk_button_new_from_icon_name ("window-close-symbolic", GTK_ICON_SIZE_MENU);
+  gtk_widget_show (self->button);
   gtk_button_set_relief (GTK_BUTTON (self->button), GTK_RELIEF_NONE);
   gtk_box_pack_end (GTK_BOX (self->box), self->button, FALSE, FALSE, 0);
 
   g_signal_connect_swapped (self->button, "clicked", G_CALLBACK (close_tab), self);
 }
 
-static void
-gtk_closable_tab_state_flags_changed (GtkWidget     *widget,
-                                      GtkStateFlags  old_state)
-{
-  GtkClosableTab *tab = GTK_CLOSABLE_TAB (widget);
-  gboolean checked;
-
-  checked = (gtk_widget_get_state_flags (widget) & GTK_STATE_FLAG_CHECKED) != 0;
-
-  gtk_widget_set_visible (tab->button, checked);
-}
-
 static void
 gtk_closable_tab_class_init (GtkClosableTabClass *klass)
 {
-  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
-
-  widget_class->state_flags_changed = gtk_closable_tab_state_flags_changed;
 }
-