[libdazzle] tree: add helper to get builders array

[Christian Hergert <chergert src gnome org>]

commit 2965dbaf186317018dcbaabad798a887bd35cc45
Author: Christian Hergert <chergert redhat com>
Date:   Mon Dec 4 17:55:28 2017 -0800

    tree: add helper to get builders array
    
    This allows us to access things from friend classes without
    being quite so annoying.

 src/tree/dzl-tree-private.h |    1 +
 src/tree/dzl-tree.c         |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/src/tree/dzl-tree-private.h b/src/tree/dzl-tree-private.h
index 67302e0..da779c6 100644
--- a/src/tree/dzl-tree-private.h
+++ b/src/tree/dzl-tree-private.h
@@ -42,6 +42,7 @@ void          _dzl_tree_insert_sorted                   (DzlTree
                                                          gpointer                user_data);
 void          _dzl_tree_remove                          (DzlTree                *self,
                                                          DzlTreeNode            *node);
+GPtrArray    *_dzl_tree_get_builders                    (DzlTree                *self);
 gboolean      _dzl_tree_get_iter                        (DzlTree                *self,
                                                          DzlTreeNode            *node,
                                                          GtkTreeIter            *iter);
diff --git a/src/tree/dzl-tree.c b/src/tree/dzl-tree.c
index 596e172..a10a1a7 100644
--- a/src/tree/dzl-tree.c
+++ b/src/tree/dzl-tree.c
@@ -1825,3 +1825,13 @@ _dzl_tree_get_store (DzlTree *self)
 
   return priv->store;
 }
+
+GPtrArray *
+_dzl_tree_get_builders (DzlTree *self)
+{
+  DzlTreePrivate *priv = dzl_tree_get_instance_private (self);
+
+  g_return_val_if_fail (DZL_IS_TREE (self), NULL);
+
+  return priv->builders;
+}