[pitivi] layer: Remove unused method

[Alexandru Băluț <alexbalut src gnome org>]

commit 70e2d1480c9a3a0626fc9a81dd5cd85070b14edd
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Thu Oct 20 02:59:32 2016 +0200

    layer: Remove unused method
    
    The do_add method is never called because we only use put(), never
    add().
    
    Reviewed-by: Thibault Saunier <tsaunier gnome org>
    Differential Revision: https://phabricator.freedesktop.org/D1397

 pitivi/timeline/layer.py |   12 ------------
 1 files changed, 0 insertions(+), 12 deletions(-)
---
diff --git a/pitivi/timeline/layer.py b/pitivi/timeline/layer.py
index ed9929e..042aa0c 100644
--- a/pitivi/timeline/layer.py
+++ b/pitivi/timeline/layer.py
@@ -273,18 +273,6 @@ class LayerLayout(Gtk.Layout, Loggable):
         self.props.hexpand = True
         self.get_style_context().add_class("LayerLayout")
 
-    def do_add(self, widget):
-        self._children.append(widget)
-        self._children.sort(key=lambda clip: clip.z_order)
-        Gtk.Layout.do_add(self, widget)
-        self._changed = True
-
-        for child in self._children:
-            if isinstance(child, elements.TransitionClip):
-                window = child.get_window()
-                if window is not None:
-                    window.raise_()
-
     def do_remove(self, widget):
         self._children.remove(widget)
         self._changed = True