[gnome-taquin] Add an unused signal.

[Arnaud B. <arnaudb src gnome org>]

commit 7db5ebb7e9fe27b95110649cb0750757cf206cc5
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Thu Aug 1 12:57:08 2019 +0200

    Add an unused signal.

 src/adaptative-window.vala | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/src/adaptative-window.vala b/src/adaptative-window.vala
index f095829..4548f1a 100644
--- a/src/adaptative-window.vala
+++ b/src/adaptative-window.vala
@@ -424,6 +424,8 @@ private abstract class AdaptativeWindow : ApplicationWindow
     * * manage high-constrast
     \*/
 
+    internal signal void gtk_theme_changed ();
+
     private void manage_high_contrast ()
     {
         Gtk.Settings? nullable_gtk_settings = Gtk.Settings.get_default ();
@@ -432,18 +434,19 @@ private abstract class AdaptativeWindow : ApplicationWindow
 
         Gtk.Settings gtk_settings = (!) nullable_gtk_settings;
         gtk_settings.notify ["gtk-theme-name"].connect (update_highcontrast_state);
-        _update_highcontrast_state (gtk_settings);
+        _update_highcontrast_state (gtk_settings.gtk_theme_name);
     }
 
     private void update_highcontrast_state (Object gtk_settings, ParamSpec unused)
     {
-        _update_highcontrast_state ((Gtk.Settings) gtk_settings);
+        _update_highcontrast_state (((Gtk.Settings) gtk_settings).gtk_theme_name);
+        gtk_theme_changed ();
     }
 
     private bool highcontrast_state = false;
-    private void _update_highcontrast_state (Gtk.Settings gtk_settings)
+    private void _update_highcontrast_state (string theme_name)
     {
-        bool highcontrast_new_state = "HighContrast" in gtk_settings.gtk_theme_name;
+        bool highcontrast_new_state = "HighContrast" in theme_name;
         if (highcontrast_new_state == highcontrast_state)
             return;
         highcontrast_state = highcontrast_new_state;