overlay: add setters and getters for pass-through child property

This will make the API easier to use from bindings too.

https://bugzilla.gnome.org/show_bug.cgi?id=750568

docs/reference/gtk/gtk3-sections.txt

@@ -7775,6 +7775,8 @@ gtk_overlay_new
 gtk_overlay_add_overlay
 gtk_overlay_add_pass_through_overlay
 gtk_overlay_reorder_overlay
+gtk_overlay_get_overlay_pass_through
+gtk_overlay_set_overlay_pass_through
 
 <SUBSECTION Standard>
 GTK_TYPE_OVERLAY

gtk/gtkoverlay.c

@@ -897,6 +897,58 @@ gtk_overlay_add_overlay (GtkOverlay *overlay,
   gtk_widget_child_notify (widget, "index");
 }
 
+/**
+ * gtk_overlay_set_overlay_pass_through:
+ * @overlay: a #GtkOverlay
+ * @widget: an overlay child of #GtkOverlay
+ * @pass_through: whether the child should pass the input through
+ *
+ * Convenience function to set the value of the #GtkOverlay:pass-through
+ * child property for @widget.
+ *
+ * Since: 3.18
+ */
+void
+gtk_overlay_set_overlay_pass_through (GtkOverlay *overlay,
+				      GtkWidget  *widget,
+				      gboolean    pass_through)
+{
+  g_return_if_fail (GTK_IS_OVERLAY (overlay));
+  g_return_if_fail (GTK_IS_WIDGET (widget));
+
+  gtk_container_child_set (GTK_CONTAINER (overlay), widget,
+			   "pass-through", pass_through,
+			   NULL);
+}
+
+/**
+ * gtk_overlay_get_overlay_pass_through:
+ * @overlay: a #GtkOverlay
+ * @widget: an overlay child of #GtkOverlay
+ *
+ * Convenience function to get the value of the #GtkOverlay:pass-through
+ * child property for @widget.
+ *
+ * Returns: whether the widget is a pass through child.
+ *
+ * Since: 3.18
+ */
+gboolean
+gtk_overlay_get_overlay_pass_through (GtkOverlay *overlay,
+				      GtkWidget  *widget)
+{
+  gboolean pass_through;
+
+  g_return_val_if_fail (GTK_IS_OVERLAY (overlay), FALSE);
+  g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
+
+  gtk_container_child_get (GTK_CONTAINER (overlay), widget,
+			   "pass-through", &pass_through,
+			   NULL);
+
+  return pass_through;
+}
+
 /**
  * gtk_overlay_add_pass_through_overlay:
  * @overlay: a #GtkOverlay

gtk/gtkoverlay.h

@@ -90,7 +90,13 @@ GDK_AVAILABLE_IN_3_18
 void       gtk_overlay_reorder_overlay (GtkOverlay     *overlay,
 					GtkWidget      *child,
 					gint            position);
-
+GDK_AVAILABLE_IN_3_18
+gboolean   gtk_overlay_get_overlay_pass_through (GtkOverlay *overlay,
+						 GtkWidget  *widget);
+GDK_AVAILABLE_IN_3_18
+void       gtk_overlay_set_overlay_pass_through (GtkOverlay *overlay,
+						 GtkWidget  *widget,
+						 gboolean    pass_through);
 
 G_END_DECLS