[gtk+] gdkwindow: store transient_for window

[William Hua <williamhua src gnome org>]

commit 48108c401ec474a3841b93745e563b4645a3f0d0
Author: William Hua <william hua canonical com>
Date:   Fri Jul 15 20:52:35 2016 -0400

    gdkwindow: store transient_for window
    
    https://bugzilla.gnome.org/show_bug.cgi?id=756579

 gdk/gdkinternals.h |    1 +
 gdk/gdkwindow.c    |    2 ++
 2 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index 1efa75e..8949dae 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -203,6 +203,7 @@ struct _GdkWindow
   GdkWindowImpl *impl; /* window-system-specific delegate object */
 
   GdkWindow *parent;
+  GdkWindow *transient_for;
   GdkVisual *visual;
 
   gpointer user_data;
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 04fb29c..42085a1 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -10370,6 +10370,8 @@ void
 gdk_window_set_transient_for (GdkWindow *window,
                              GdkWindow *parent)
 {
+  window->transient_for = parent;
+
   GDK_WINDOW_IMPL_GET_CLASS (window->impl)->set_transient_for (window, parent);
 }