[gtk+] inspector: Make picking more robust

[Matthias Clasen <matthiasc src gnome org>]

commit 3266b4dd9bde09e9a8191530615d759c9159687d
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jun 6 13:35:40 2014 -0400

    inspector: Make picking more robust
    
    Apparently ClutterOffscreen returns NULL as a window.
    While that is not cool, we shouldn't crash.

 gtk/inspector/inspect-button.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gtk/inspector/inspect-button.c b/gtk/inspector/inspect-button.c
index 639908f..dd21f0d 100644
--- a/gtk/inspector/inspect-button.c
+++ b/gtk/inspector/inspect-button.c
@@ -62,11 +62,16 @@ find_widget (GtkWidget      *widget,
 
   if (gtk_widget_get_parent (widget) && !data->first)
     {
-      GdkWindow *window = gtk_widget_get_window (widget);
+      GdkWindow *window;
+
+      window = gtk_widget_get_window (widget);
       while (window != gtk_widget_get_window (gtk_widget_get_parent (widget)))
         {
           gint tx, ty, twidth, theight;
 
+          if (window == NULL)
+            return;
+
           twidth = gdk_window_get_width (window);
           theight = gdk_window_get_height (window);