[gnome-games] preferences-window: Correctly remove subpage with disabled animations

[Alexander Mikhaylenko <alexm src gnome org>]

commit 1ce0734313bd7714fb45ce58189bdbf0a816beef
Author: Neville <nevilleantony98 gmail com>
Date:   Wed Mar 18 15:09:49 2020 +0530

    preferences-window: Correctly remove subpage with disabled animations
    
    Currently, when animations are disabled, the subpage is not removed, since
    HdyDeck's transition-running property value never changes. To mitigate this,
    also track visible-child.

 data/ui/preferences-window.ui  |  1 +
 src/ui/preferences-window.vala | 22 +++++++++++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)
---
diff --git a/data/ui/preferences-window.ui b/data/ui/preferences-window.ui
index 2a6ca3d1..eee9a4f0 100644
--- a/data/ui/preferences-window.ui
+++ b/data/ui/preferences-window.ui
@@ -108,6 +108,7 @@
         <property name="visible">True</property>
         <property name="can-swipe-back" bind-source="titlebar" bind-property="selection-mode" 
bind-flags="sync-create|invert-boolean"/>
         <signal name="notify::transition-running" handler="subpage_transition_finished"/>
+        <signal name="notify::visible-child" handler="on_visible_child_changed"/>
         <child>
           <object class="HdyLeaflet" id="content_leaflet">
             <property name="visible">True</property>
diff --git a/src/ui/preferences-window.vala b/src/ui/preferences-window.vala
index 41edf6f9..ef42144a 100644
--- a/src/ui/preferences-window.vala
+++ b/src/ui/preferences-window.vala
@@ -92,19 +92,31 @@ private class Games.PreferencesWindow : Gtk.Window {
                                                      BindingFlags.SYNC_CREATE | BindingFlags.BIDIRECTIONAL);
        }
 
+       private void remove_subpage () {
+               foreach (var child in content_subpage_box.get_children ())
+                       content_subpage_box.remove (child);
+
+               foreach (var child in titlebar_subpage_box.get_children ())
+                       titlebar_subpage_box.remove (child);
+
+               subpage = null;
+       }
+
        [GtkCallback]
        public void subpage_transition_finished (Object object, ParamSpec param) {
                if (content_deck.transition_running ||
                    content_deck.visible_child != content_leaflet)
                        return;
 
-               foreach (var child in content_subpage_box.get_children ())
-                       content_subpage_box.remove (child);
+               remove_subpage ();
+       }
 
-               foreach (var child in titlebar_subpage_box.get_children ())
-                       titlebar_subpage_box.remove (child);
+       [GtkCallback]
+       private void on_visible_child_changed () {
+               if (content_deck.transition_running || subpage == null)
+                       return;
 
-               subpage = null;
+               remove_subpage ();
        }
 
        [GtkCallback]