[pitivi] undo:timeline: Do not track transitions addition

[Thibault Saunier <tsaunier src gnome org>]

commit 829a29a9ddc7d9ea5f9b18c28603befd72e90adb
Author: Thibault Saunier <tsaunier gnome org>
Date:   Fri Sep 26 18:37:20 2014 +0200

    undo:timeline: Do not track transitions addition
    
    It is all automatic so we should not let user do or undo their addition
    
    https://bugzilla.gnome.org/show_bug.cgi?id=739251

 pitivi/undo/timeline.py |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/pitivi/undo/timeline.py b/pitivi/undo/timeline.py
index 2bbcd03..5ad41e1 100644
--- a/pitivi/undo/timeline.py
+++ b/pitivi/undo/timeline.py
@@ -354,6 +354,9 @@ class TimelineLogObserver(object):
             self._connectToTrackElement(track_element)
 
     def _disconnectFromClip(self, clip):
+        if isinstance(clip, GES.TransitionClip):
+            return
+
         tracker = self.clip_property_trackers.pop(clip)
         tracker.disconnectFromObject(clip)
         tracker.disconnect_by_func(self._clipPropertyChangedCb)
@@ -386,11 +389,15 @@ class TimelineLogObserver(object):
         tracker.disconnect_by_func(self._interpolatorKeyframeMovedCb)
 
     def _clipAddedCb(self, layer, clip):
+        if isinstance(clip, GES.TransitionClip):
+            return
         self._connectToClip(clip)
         action = ClipAdded(layer, clip)
         self.log.push(action)
 
     def _clipRemovedCb(self, layer, clip):
+        if isinstance(clip, GES.TransitionClip):
+            return
         self._disconnectFromClip(clip)
         action = ClipRemoved(layer, clip)
         self.log.push(action)