[gtk: 1/2] Drop parent->realized => child->realized invariant

[Emmanuele Bassi <ebassi src gnome org>]

commit c6104fe7fd8bc5922d4e6c4883b2bc33e3a94a57
Author: Alexander Larsson <alexl redhat com>
Date:   Tue Apr 28 14:32:57 2020 +0200

    Drop parent->realized => child->realized invariant
    
    We already dropped this invariant in gtk_widget_verify_invariants()
    because it was not true in all cases. Also, it is not really useful
    these days as we extended what it means to be a "child" to also
    include widgets in different toplevels.
    
    For example, a popup in a popup button need not be realized just
    because the button is in a realized window. The main invariants
    we want are:
    
     * Parent is realized before child
     * Widget is realized before it is mapped
    
    This sounds like its not a huge deal, but in fact it is a massive win
    for things like menus, because when we go between menus in a menubar
    each switch between two open menus involves a lot of intermingled
    crossing events to different surfaces and for each of these the
    tooltip window of the toplevel gets assigned to the new surface.  This
    shouldn't be a huge deal, as the tooltip window is not even visible,
    but due to the realized invariant it get re-realized each time it gets
    re-assigned.

 gtk/gtkwidget.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index cf5499b8d4..386d397218 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -5901,11 +5901,7 @@ gtk_widget_reposition_after (GtkWidget *widget,
   if (prev_parent == NULL)
     g_object_notify_by_pspec (G_OBJECT (widget), widget_props[PROP_PARENT]);
 
-  /* Enforce realized/mapped invariants
-   */
-  if (_gtk_widget_get_realized (priv->parent))
-    gtk_widget_realize (widget);
-
+  /* Enforce mapped invariants */
   if (_gtk_widget_get_visible (priv->parent) &&
       _gtk_widget_get_visible (widget))
     {