[pitivi] elements: Fix TrimHandle's style

[Thibault Saunier <tsaunier src gnome org>]

commit 6d4f00c861a83a3818b139694414a47a703adda0
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Thu Oct 22 16:21:28 2015 +0200

    elements: Fix TrimHandle's style
    
    It's not guaranteed that the left one is the first-child and the right
    one is the last-child.
    
    Differential Revision: https://phabricator.freedesktop.org/D438

 pitivi/timeline/elements.py |    8 +++++++-
 pitivi/utils/ui.py          |    9 ++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)
---
diff --git a/pitivi/timeline/elements.py b/pitivi/timeline/elements.py
index 85371c5..bfb17c8 100644
--- a/pitivi/timeline/elements.py
+++ b/pitivi/timeline/elements.py
@@ -574,9 +574,15 @@ class TrimHandle(Gtk.EventBox, Loggable):
         Loggable.__init__(self)
 
         self.clip = clip
-        self.get_style_context().add_class("Trimbar")
         self.edge = edge
 
+        self.get_style_context().add_class("Trimbar")
+        if edge == GES.Edge.EDGE_END:
+            css_class = "right"
+        else:
+            css_class = "left"
+        self.get_style_context().add_class(css_class)
+
         self.props.valign = Gtk.Align.FILL
         self.shrink()
         if edge == GES.Edge.EDGE_END:
diff --git a/pitivi/utils/ui.py b/pitivi/utils/ui.py
index 99a8d5f..2882059 100644
--- a/pitivi/utils/ui.py
+++ b/pitivi/utils/ui.py
@@ -70,7 +70,6 @@ LAYER_CREATION_BLOCK_TIME = 0.2
 FILE_TARGET_ENTRY = Gtk.TargetEntry.new("text/plain", 0, 0)
 URI_TARGET_ENTRY = Gtk.TargetEntry.new("text/uri-list", 0, 0)
 EFFECT_TARGET_ENTRY = Gtk.TargetEntry.new("pitivi/effect", 0, 0)
-LAYER_CONTROL_TARGET_ENTRY = Gtk.TargetEntry.new("pitivi/layer-control", 0, 0)
 
 
 def _get_settings(schema):
@@ -118,12 +117,12 @@ TIMELINE_CSS = """
         opacity:0.5;
     }
 
-    .Trimbar:first-child {
-        border-radius: 5px 0 0 5px;
+    .Trimbar.left {
+        border-radius: 5px 0px 0px 5px;
     }
 
-    .Trimbar:last-child {
-        border-radius: 0 5px 5px 0;
+    .Trimbar.right {
+        border-radius: 0px 5px 5px 0px;
     }
 
     .Trimbar:hover {