[gnome-music/wip/mschraal/window-template: 6/7] playertoolbar: Make player argument a property

[Marinus Schraal <mschraal src gnome org>]

commit fcc4491dab3d67eb134bb759f4372bf2eb3b56af
Author: Marinus Schraal <mschraal gnome org>
Date:   Sun Sep 9 12:46:32 2018 +0200

    playertoolbar: Make player argument a property

 gnomemusic/widgets/playertoolbar.py | 30 ++++++++++++++++++++++++++----
 gnomemusic/window.py                |  4 +++-
 2 files changed, 29 insertions(+), 5 deletions(-)
---
diff --git a/gnomemusic/widgets/playertoolbar.py b/gnomemusic/widgets/playertoolbar.py
index 5508013e..8950fd41 100644
--- a/gnomemusic/widgets/playertoolbar.py
+++ b/gnomemusic/widgets/playertoolbar.py
@@ -66,18 +66,40 @@ class PlayerToolbar(Gtk.ActionBar):
         return '<PlayerToolbar>'
 
     @log
-    def __init__(self, player):
+    def __init__(self):
         super().__init__()
 
-        self._player = player
-        self._progress_scale.player = self._player.get_gst_player()
+        self._player = None
 
         self._cover_stack.props.size = Art.Size.XSMALL
         self._cover_stack.connect('updated', self._on_cover_stack_updated)
 
         self._tooltip = TwoLineTip()
 
-        self._sync_repeat_image()
+    # FIXME: This is a workaround for not being able to pass the player
+    # object via init when using Gtk.Builder.
+    @GObject.Property
+    def player(self):
+        """The GstPlayer object used
+
+        :return: player object
+        :rtype: GstPlayer
+        """
+        return self._player
+
+    @player.setter
+    def player(self, player):
+        """Set the GstPlayer object used
+
+        :param GstPlayer player: The GstPlayer to use
+        """
+        if (player is None
+                or (self._player is not None
+                    and self._player != player)):
+            return
+
+        self._player = player
+        self._progress_scale.player = self._player.get_gst_player()
 
         self._player.connect('clock-tick', self._on_clock_tick)
         self._player.connect('song-changed', self._update_view)
diff --git a/gnomemusic/window.py b/gnomemusic/window.py
index a9150e11..89eae11b 100644
--- a/gnomemusic/window.py
+++ b/gnomemusic/window.py
@@ -130,7 +130,9 @@ class Window(Gtk.ApplicationWindow):
     def _setup_view(self):
         self._headerbar = HeaderBar()
 
-        self._player_toolbar = PlayerToolbar(self._player)
+        self._player_toolbar = PlayerToolbar()
+        self._player_toolbar.props.player = self._player
+
         self.views = [None] * len(View)
 
         self._headerbar.bind_property(