[gtk+/wip/carlosg/event-delivery] widget: Make sure we're not calling _get_parent on NULL

[Timm Bäder <baedert src gnome org>]

commit bb6f36a882f8e28aa3d797ea36a2af4b5e7c7185
Author: Timm Bäder <mail baedert org>
Date:   Wed May 10 18:08:43 2017 +0200

    widget: Make sure we're not calling _get_parent on NULL
    
    We already issue the first _get_parent call before even entering that
    loop, so make sure `parent` is not NULL. This happens when event_widget
    is already a toplevel, and this change fixes row-dragging in treeviews.

 gtk/gtkwidget.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 886c9ff..59eac9c 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -3510,7 +3510,7 @@ _gtk_widget_emulate_press (GtkWidget      *widget,
   next_child = event_widget;
   parent = _gtk_widget_get_parent (next_child);
 
-  while (parent != widget)
+  while (parent && parent != widget)
     {
       next_child = parent;
       parent = _gtk_widget_get_parent (parent);