[gnome-chess] Fix window size growing out of control with GTK+ 3.20

[Michael Catanzaro <mcatanzaro src gnome org>]

commit ad06e13208340ccabde6e10945a492a51c122288
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed May 4 14:55:59 2016 -0500

    Fix window size growing out of control with GTK+ 3.20

 src/gnome-chess.vala |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/src/gnome-chess.vala b/src/gnome-chess.vala
index 1640b95..60cc5a9 100644
--- a/src/gnome-chess.vala
+++ b/src/gnome-chess.vala
@@ -274,8 +274,7 @@ Copyright © 2015–2016 Sahil Sareen""";
     {
         if (is_maximized || is_tiled)
             return;
-        window_width = allocation.width;
-        window_height = allocation.height;
+        window.get_size (out window_width, out window_height);
     }
 
     private bool window_state_event_cb (Gdk.EventWindowState event)