[gtk/wip/otte/listview: 1014/1040] widget: Add a hook for resizes

[Benjamin Otte <otte src gnome org>]

commit a21f4c25d48bf0a88a938d6cc55150f546d86cc2
Author: Benjamin Otte <otte redhat com>
Date:   Tue Nov 5 00:40:17 2019 +0100

    widget: Add a hook for resizes
    
    It's private, no APIs, we don't talk about it. But we will start using
    it very soon, so we can do size request caching in columns and avoid
    sizegroups...

 gtk/gtkwidget.c        | 3 +++
 gtk/gtkwidgetprivate.h | 1 +
 2 files changed, 4 insertions(+)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 2808cf7484..684620d4d5 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -3714,6 +3714,9 @@ gtk_widget_queue_resize_internal (GtkWidget *widget)
   priv->resize_needed = TRUE;
   gtk_widget_set_alloc_needed (widget);
 
+  if (priv->resize_func)
+    priv->resize_func (widget);
+
   groups = _gtk_widget_get_sizegroups (widget);
 
   for (l = groups; l; l = l->next)
diff --git a/gtk/gtkwidgetprivate.h b/gtk/gtkwidgetprivate.h
index 415b75e7f5..f19e7aa602 100644
--- a/gtk/gtkwidgetprivate.h
+++ b/gtk/gtkwidgetprivate.h
@@ -122,6 +122,7 @@ struct _GtkWidgetPrivate
 
   int width_request;
   int height_request;
+  void (* resize_func) (GtkWidget *);
   GtkBorder margin;
 
   /* Animations and other things to update on clock ticks */