[gtk+] widget: Add a defualt snapshot vfunc

[Benjamin Otte <otte src gnome org>]

commit efa1c6cbd53e3e2744afe50ecf9c7da138ab5dff
Author: Benjamin Otte <otte redhat com>
Date:   Fri Nov 18 00:46:49 2016 +0100

    widget: Add a defualt snapshot vfunc
    
    Just to avoid having to do NULL checks when calling
    widget_class->snapshot. We were crashing with drawing areas who don't
    have a draw or a snapshot vfunc (woot!).

 gtk/gtkwidget.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index c45f9a3..a01a344 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -950,6 +950,13 @@ gtk_widget_draw_marshallerv (GClosure     *closure,
 }
 
 static void
+gtk_widget_real_snapshot (GtkWidget   *widget,
+                          GtkSnapshot *snapshot)
+{
+  /* nothing to do here */
+}
+
+static void
 gtk_widget_class_init (GtkWidgetClass *klass)
 {
   static GObjectNotifyContext cpn_context = { 0, NULL, NULL };
@@ -1013,6 +1020,7 @@ gtk_widget_class_init (GtkWidgetClass *klass)
   klass->grab_notify = NULL;
   klass->child_notify = NULL;
   klass->draw = NULL;
+  klass->snapshot = gtk_widget_real_snapshot;
   klass->mnemonic_activate = gtk_widget_real_mnemonic_activate;
   klass->grab_focus = gtk_widget_real_grab_focus;
   klass->focus = gtk_widget_real_focus;