[gtk+/gtk-3-16] treeview: check for pixel cache before setting property

[Matthias Clasen <matthiasc src gnome org>]

commit 119fc5242ec9c98276df2a330d12e5640eb1dbcd
Author: Christian Hergert <christian hergert me>
Date:   Thu Aug 20 11:13:30 2015 -0700

    treeview: check for pixel cache before setting property
    
    Code exists in the wild that calls this function after the widget has
    been destroyed (and the pixel cache released). Simply check that the
    pixel cache exists to preserve the existing state.

 gtk/gtktreeview.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index 49acf4d..5726f6d 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -11539,7 +11539,8 @@ gtk_tree_view_set_model (GtkTreeView  *tree_view,
   if (tree_view->priv->selection)
   _gtk_tree_selection_emit_changed (tree_view->priv->selection);
 
-  _gtk_pixel_cache_set_always_cache (tree_view->priv->pixel_cache, (model != NULL));
+  if (tree_view->priv->pixel_cache != NULL)
+    _gtk_pixel_cache_set_always_cache (tree_view->priv->pixel_cache, (model != NULL));
 
   if (gtk_widget_get_realized (GTK_WIDGET (tree_view)))
     gtk_widget_queue_resize (GTK_WIDGET (tree_view));