[gtk+] file chooser: Avoid doing excess work

[Matthias Clasen <matthiasc src gnome org>]

commit 201d4c110186dcfa77f2cee2bed88f1674c52f54
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 8 21:06:58 2015 -0400

    file chooser: Avoid doing excess work
    
    Whenever we change directories, we unset the model, and then
    we set a new model. This causes several emissions of
    GtkTreeSelection::changed, for each of which we do a bunch
    of work to update the path bar, the location entry, etc.
    
    We can savely ignore some of these signals, and do less work.

 gtk/gtkfilechooserwidget.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkfilechooserwidget.c b/gtk/gtkfilechooserwidget.c
index a09f0a5..6caae6c 100644
--- a/gtk/gtkfilechooserwidget.c
+++ b/gtk/gtkfilechooserwidget.c
@@ -7584,6 +7584,9 @@ list_selection_changed (GtkTreeSelection     *selection,
 {
   GtkFileChooserWidgetPrivate *priv = impl->priv;
 
+  if (gtk_tree_view_get_model (GTK_TREE_VIEW (priv->browse_files_tree_view)) == NULL)
+    return;
+
   /* See if we are in the new folder editable row for Save mode */
   if (priv->operation_mode == OPERATION_MODE_BROWSE &&
       priv->action == GTK_FILE_CHOOSER_ACTION_SAVE)