[pitivi] viewer: Rename parameter

[Alexandru Băluț <alexbalut src gnome org>]

commit 10971cfe737dd9122c932574394721e4064bdb2a
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Tue Dec 13 10:25:39 2016 +0100

    viewer: Rename parameter
    
    The widget is an OverlayStack, not a sink widget.
    
    Reviewed-by: Thibault Saunier <tsaunier gnome org>
    Differential Revision: https://phabricator.freedesktop.org/D1553

 pitivi/viewer/overlay_stack.py |    2 ++
 pitivi/viewer/viewer.py        |    4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/pitivi/viewer/overlay_stack.py b/pitivi/viewer/overlay_stack.py
index 6880416..87a39e1 100644
--- a/pitivi/viewer/overlay_stack.py
+++ b/pitivi/viewer/overlay_stack.py
@@ -27,6 +27,8 @@ from pitivi.viewer.title_overlay import TitleOverlay
 
 
 class OverlayStack(Gtk.Overlay, Loggable):
+    """Manager for the viewer overlays."""
+
     def __init__(self, app, sink_widget):
         Gtk.Overlay.__init__(self)
         Loggable.__init__(self)
diff --git a/pitivi/viewer/viewer.py b/pitivi/viewer/viewer.py
index 1235a95..798ff66 100644
--- a/pitivi/viewer/viewer.py
+++ b/pitivi/viewer/viewer.py
@@ -477,14 +477,14 @@ class ViewerWidget(Gtk.AspectFrame, Loggable):
         sink_widget (Gtk.Widget): The widget doing the real work.
     """
 
-    def __init__(self, sink_widget):
+    def __init__(self, widget):
         # Prevent black frames and flickering while resizing or changing focus:
         # The aspect ratio gets overridden by setDisplayAspectRatio.
         Gtk.AspectFrame.__init__(self, xalign=0.5, yalign=0.5,
                                  ratio=4.0 / 3.0, obey_child=False)
         Loggable.__init__(self)
 
-        self.add(sink_widget)
+        self.add(widget)
 
         # We keep the ViewerWidget hidden initially, or the desktop wallpaper
         # would show through the non-double-buffered widget!