[gtk+] treeview: factor out gtk_tree_view_ensure_background()

[Cosimo Cecchi <cosimoc src gnome org>]

commit 8d97d8ca3c5c5c84caa450e7ba09c974177e25eb
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Nov 16 15:59:47 2011 -0500

    treeview: factor out gtk_tree_view_ensure_background()
    
    We'll use it shortly.

 gtk/gtktreeview.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index d411f5b..52cde55 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -2181,6 +2181,21 @@ gtk_tree_view_map (GtkWidget *widget)
 }
 
 static void
+gtk_tree_view_ensure_background (GtkTreeView *tree_view)
+{
+  GtkStyleContext *context;
+
+  context = gtk_widget_get_style_context (widget);
+
+  gtk_style_context_save (context);
+  gtk_style_context_add_class (context, GTK_STYLE_CLASS_VIEW);
+  gtk_style_context_set_background (context, tree_view->priv->bin_window);
+  gtk_style_context_restore (context);
+
+  gtk_style_context_set_background (context, tree_view->priv->header_window);
+}
+
+static void
 gtk_tree_view_realize (GtkWidget *widget)
 {
   GtkAllocation allocation;