diff --git a/gtk/gtkmenubar.c b/gtk/gtkmenubar.c
index d337d712ae..62615cc711 100644
--- a/gtk/gtkmenubar.c
+++ b/gtk/gtkmenubar.c
@@ -50,6 +50,7 @@
 #include "gtkintl.h"
 #include "gtkprivate.h"
 #include "gtktypebuiltins.h"
+#include "gtkwidgetprivate.h"
 
 /* Properties */
 enum {
@@ -308,25 +309,6 @@ gtk_menu_bar_get_property (GObject    *object,
     }
 }
 
-static void
-get_preferred_size_for_size (GtkWidget      *widget,
-                             GtkOrientation  orientation,
-                             gint            size,
-                             gint           *minimum,
-                             gint           *natural)
-{
-  if (orientation == GTK_ORIENTATION_HORIZONTAL)
-    if (size < 0)
-      gtk_widget_get_preferred_width (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_width_for_height (widget, size, minimum, natural);
-  else
-    if (size < 0)
-      gtk_widget_get_preferred_height (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_height_for_width (widget, size, minimum, natural);
-}
-
 static void
 gtk_menu_bar_size_request (GtkWidget      *widget,
                            GtkOrientation  orientation,
@@ -374,7 +356,7 @@ gtk_menu_bar_size_request (GtkWidget      *widget,
 
       if (gtk_widget_get_visible (child))
         {
-          get_preferred_size_for_size (child, orientation, size, &child_minimum, &child_natural);
+          _gtk_widget_get_preferred_size_for_size (child, orientation, size, &child_minimum, &child_natural);
 
           if (use_toggle_size)
             {
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 5f0ce009a8..2ac7936af3 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -2214,25 +2214,6 @@ gtk_notebook_get_preferred_tabs_size (GtkNotebook    *notebook,
     }
 }
 
-static void
-get_preferred_size_for_size (GtkWidget      *widget,
-                             GtkOrientation  orientation,
-                             gint            size,
-                             gint           *minimum,
-                             gint           *natural)
-{
-  if (orientation == GTK_ORIENTATION_HORIZONTAL)
-    if (size < 0)
-      gtk_widget_get_preferred_width (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_width_for_height (widget, size, minimum, natural);
-  else
-    if (size < 0)
-      gtk_widget_get_preferred_height (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_height_for_width (widget, size, minimum, natural);
-}
-
 static void
 get_padding_and_border (GtkNotebook *notebook,
                         GtkBorder *border)
@@ -2282,11 +2263,11 @@ gtk_notebook_size_request (GtkWidget      *widget,
       if (gtk_widget_get_visible (page->child))
         {
           vis_pages++;
-          get_preferred_size_for_size (page->child,
-                                       orientation,
-                                       size, 
-                                       &child_minimum,
-                                       &child_natural);
+          _gtk_widget_get_preferred_size_for_size (page->child,
+                                                   orientation,
+                                                   size, 
+                                                   &child_minimum,
+                                                   &child_natural);
 
           *minimum = MAX (*minimum, child_minimum);
           *natural = MAX (*natural, child_natural);
diff --git a/gtk/gtkpaned.c b/gtk/gtkpaned.c
index 7c5ec381f3..4d16e4fe02 100644
--- a/gtk/gtkpaned.c
+++ b/gtk/gtkpaned.c
@@ -35,6 +35,7 @@
 #include "gtkorientableprivate.h"
 #include "gtkprivate.h"
 #include "gtkintl.h"
+#include "gtkwidgetprivate.h"
 #include "a11y/gtkpanedaccessible.h"
 
 /**
@@ -869,25 +870,6 @@ gtk_paned_finalize (GObject *object)
   G_OBJECT_CLASS (gtk_paned_parent_class)->finalize (object);
 }
 
-static void
-get_preferred_size_for_size (GtkWidget      *widget,
-                             GtkOrientation  orientation,
-                             gint            size,
-                             gint           *minimum,
-                             gint           *natural)
-{
-  if (orientation == GTK_ORIENTATION_HORIZONTAL)
-    if (size < 0)
-      gtk_widget_get_preferred_width (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_width_for_height (widget, size, minimum, natural);
-  else
-    if (size < 0)
-      gtk_widget_get_preferred_height (widget, minimum, natural);
-    else
-      gtk_widget_get_preferred_height_for_width (widget, size, minimum, natural);
-}
-
 static void
 gtk_paned_get_preferred_size (GtkWidget      *widget,
                               GtkOrientation  orientation,
@@ -903,7 +885,7 @@ gtk_paned_get_preferred_size (GtkWidget      *widget,
 
   if (priv->child1 && gtk_widget_get_visible (priv->child1))
     {
-      get_preferred_size_for_size (priv->child1, orientation, size, &child_min, &child_nat);
+      _gtk_widget_get_preferred_size_for_size (priv->child1, orientation, size, &child_min, &child_nat);
       if (priv->child1_shrink && priv->orientation == orientation)
         *minimum = 0;
       else
@@ -913,7 +895,7 @@ gtk_paned_get_preferred_size (GtkWidget      *widget,
 
   if (priv->child2 && gtk_widget_get_visible (priv->child2))
     {
-      get_preferred_size_for_size (priv->child2, orientation, size, &child_min, &child_nat);
+      _gtk_widget_get_preferred_size_for_size (priv->child2, orientation, size, &child_min, &child_nat);
 
       if (priv->orientation == orientation)
         {
diff --git a/gtk/gtksizerequest.c b/gtk/gtksizerequest.c
index 54a63f1338..36d24f2f0c 100644
--- a/gtk/gtksizerequest.c
+++ b/gtk/gtksizerequest.c
@@ -657,3 +657,26 @@ gtk_distribute_natural_allocation (gint              extra_space,
 
   return extra_space;
 }
+
+void
+_gtk_widget_get_preferred_size_for_size (GtkWidget      *widget,
+                                         GtkOrientation  orientation,
+                                         gint            size,
+                                         gint           *minimum,
+                                         gint           *natural)
+{
+  g_return_if_fail (GTK_IS_WIDGET (widget));
+  g_return_if_fail (size >= -1);
+
+  if (orientation == GTK_ORIENTATION_HORIZONTAL)
+    if (size < 0)
+      gtk_widget_get_preferred_width (widget, minimum, natural);
+    else
+      gtk_widget_get_preferred_width_for_height (widget, size, minimum, natural);
+  else
+    if (size < 0)
+      gtk_widget_get_preferred_height (widget, minimum, natural);
+    else
+      gtk_widget_get_preferred_height_for_width (widget, size, minimum, natural);
+}
+
diff --git a/gtk/gtkwidgetprivate.h b/gtk/gtkwidgetprivate.h
index 4542580e41..84cad6429f 100644
--- a/gtk/gtkwidgetprivate.h
+++ b/gtk/gtkwidgetprivate.h
@@ -70,6 +70,11 @@ void _gtk_widget_compute_size_for_orientation  (GtkWidget         *widget,
                                                 gint               for_size,
                                                 gint              *minimum_size,
                                                 gint              *natural_size);
+void _gtk_widget_get_preferred_size_for_size   (GtkWidget         *widget,
+                                                GtkOrientation     orientation,
+                                                gint               size,
+                                                gint              *minimum,
+                                                gint              *natural);
 
 gboolean _gtk_widget_get_translation_to_window (GtkWidget      *widget,
                                                 GdkWindow      *window,