[gtk+] a11y: handle atk race condition where widget has been destroyed

[Matthias Clasen <matthiasc src gnome org>]

commit 7bb3d9557f1695d53bdd7fece1421ac8a3faffa7
Author: Christian Hergert <christian hergert me>
Date:   Sat Mar 21 14:17:39 2015 -0700

    a11y: handle atk race condition where widget has been destroyed
    
    If the widget has been destroyed since a DBus message had been sent,
    we could be in a condition that the widget pointer exists but it does
    not have a window.
    
    This bails as if the widget didn't exist if there is no available
    GdkWindow.
    
    We also set the extents to 0 to be defensive since this is a vfunc
    implementation.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=746586

 gtk/a11y/gtktextviewaccessible.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/gtk/a11y/gtktextviewaccessible.c b/gtk/a11y/gtktextviewaccessible.c
index d2f17e6..f97c155 100644
--- a/gtk/a11y/gtktextviewaccessible.c
+++ b/gtk/a11y/gtktextviewaccessible.c
@@ -509,6 +509,11 @@ gtk_text_view_accessible_get_character_extents (AtkText      *text,
   GdkWindow *window;
   gint x_widget, y_widget, x_window, y_window;
 
+  *x = 0;
+  *y = 0;
+  *width = 0;
+  *height = 0;
+
   widget = gtk_accessible_get_widget (GTK_ACCESSIBLE (text));
   if (widget == NULL)
     return;
@@ -519,6 +524,9 @@ gtk_text_view_accessible_get_character_extents (AtkText      *text,
   gtk_text_view_get_iter_location (view, &iter, &rectangle);
 
   window = gtk_text_view_get_window (view, GTK_TEXT_WINDOW_WIDGET);
+  if (window == NULL)
+    return;
+
   gdk_window_get_origin (window, &x_widget, &y_widget);
 
   *height = rectangle.height;