[gnome-music/wip/jfelder/mpris-update-next-previous-on-song-change] mpris: Update CanGo{Next, Previous} properties on song change

[Jean Felder <jfelder src gnome org>]

commit 48d37698b789865272ed00795db4b385edcf1ed0
Author: Jean Felder <jfelder src gnome org>
Date:   Mon Mar 18 22:57:19 2019 +0100

    mpris: Update CanGo{Next,Previous} properties on song change
    
    When the current song changes, these information also need to be
    updated.

 gnomemusic/mpris.py | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/gnomemusic/mpris.py b/gnomemusic/mpris.py
index db4aa9bc..6639c080 100644
--- a/gnomemusic/mpris.py
+++ b/gnomemusic/mpris.py
@@ -445,9 +445,14 @@ class MediaPlayer2Service(Server):
         if self.player.props.repeat_mode == RepeatMode.SONG:
             self.Seeked(0)
 
+        has_next = self.player.props.has_next
+        has_previous = self.player.props.has_previous
         self.PropertiesChanged(MediaPlayer2Service.MEDIA_PLAYER2_PLAYER_IFACE,
                                {
                                    'Metadata': GLib.Variant('a{sv}', self._get_metadata()),
+                                   'CanGoNext': GLib.Variant('b', has_next),
+                                   'CanGoPrevious': GLib.Variant(
+                                       'b', has_previous),
                                    'CanPlay': GLib.Variant('b', True),
                                    'CanPause': GLib.Variant('b', True),
                                },