[pitivi] Port to Gtk 3.20

[Thibault Saunier <tsaunier src gnome org>]

commit 2ed58ce4f54c64aa1888e3a0efb26cfc09a05996
Author: Thibault Saunier <tsaunier gnome org>
Date:   Mon Apr 18 13:59:48 2016 -0300

    Port to Gtk 3.20
    
    Reviewed-by: Alex Băluț <alexandru balut gmail com>
    Differential Revision: https://phabricator.freedesktop.org/D918

 pitivi/timeline/ruler.py |    9 +++++----
 pitivi/utils/ui.py       |    8 ++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/pitivi/timeline/ruler.py b/pitivi/timeline/ruler.py
index 9f692f7..d18efe0 100644
--- a/pitivi/timeline/ruler.py
+++ b/pitivi/timeline/ruler.py
@@ -33,6 +33,7 @@ from pitivi import configure
 from pitivi.utils.loggable import Loggable
 from pitivi.utils.timeline import Zoomable
 from pitivi.utils.ui import beautify_length
+from pitivi.utils.ui import gtk_style_context_get_color
 from pitivi.utils.ui import NORMAL_FONT
 from pitivi.utils.ui import PLAYHEAD_WIDTH
 from pitivi.utils.ui import set_cairo_color
@@ -161,10 +162,10 @@ class ScaleRuler(Gtk.DrawingArea, Zoomable, Loggable):
         # Create a new buffer
         self.pixbuf = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
 
-        style = self.app.gui.get_style_context()
-        color_normal = style.get_color(Gtk.StateFlags.NORMAL)
-        color_insensitive = style.get_color(Gtk.StateFlags.BACKDROP)
+        context = self.app.gui.get_style_context()
 
+        color_normal = gtk_style_context_get_color(context, Gtk.StateFlags.NORMAL)
+        color_insensitive = gtk_style_context_get_color(context, Gtk.StateFlags.BACKDROP)
         self._color_normal = color_normal
         self._color_dimmed = Gdk.RGBA(
             *[(x * 3 + y * 2) / 5
@@ -173,7 +174,7 @@ class ScaleRuler(Gtk.DrawingArea, Zoomable, Loggable):
                            (color_normal.blue, color_insensitive.blue))])
 
         # Two colors with high contrast.
-        self._color_frame = style.get_color(Gtk.StateFlags.LINK)
+        self._color_frame = gtk_style_context_get_color(context, Gtk.StateFlags.LINK)
 
         return False
 
diff --git a/pitivi/utils/ui.py b/pitivi/utils/ui.py
index 6ee2455..64d4039 100644
--- a/pitivi/utils/ui.py
+++ b/pitivi/utils/ui.py
@@ -181,6 +181,14 @@ TIMELINE_CSS = """
 # ---------------------- ARGB color helper-------------------------------------#
 
 
+def gtk_style_context_get_color(context, state):
+    context.save()
+    context.set_state(state)
+    color = context.get_color(context.get_state())
+    context.restore()
+    return color
+
+
 def argb_to_gdk_rgba(color_int):
     return Gdk.RGBA(color_int / 256 ** 2 % 256 / 255.,
                     color_int / 256 ** 1 % 256 / 255.,