[pitivi/gtktimeline] timeline: Scroll the timeline horizontally when scrolling without modifier

[Thibault Saunier <tsaunier src gnome org>]

commit 79fab24684a110638e6d6600c76973aa5393eb6f
Author: Thibault Saunier <tsaunier gnome org>
Date:   Mon Jun 1 13:31:01 2015 +0200

    timeline: Scroll the timeline horizontally when scrolling without modifier
    
    Fixes http://phabricator.freedesktop.org/T76

 pitivi/timeline/timeline.py |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index a6cccd5..7ca34ac 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -529,6 +529,11 @@ class Timeline(Gtk.EventBox, timelineUtils.Zoomable, Loggable):
             if rescroll:
                 diff = x - (self.layout.get_allocation().width / 2)
                 self.hadj.set_value(self.nsToPixel(mouse_position) - (self.layout.get_allocation().width / 
2) - diff)
+        else:
+            if delta_y > 0:
+                self.parent.scroll_right()
+            else:
+                self.parent.scroll_left()
 
         return False