[gtk+] Revert "csd: Drop the GTK_FRAME_EXTENTS requirement"

[Matthias Clasen <matthiasc src gnome org>]

commit 5ced234144ce63decbf5afc8a3517290b9027018
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Mar 9 20:48:47 2015 -0400

    Revert "csd: Drop the GTK_FRAME_EXTENTS requirement"
    
    This reverts commit fb9a6bb6d8d6b60b25c9b9853decbcea938f7863.
    
    In a recent test, I've found that Xfce and Mate now support
    this, so they will not be affected by this requirement. And
    adding the check back will solve the 'client-side shadow'
    problem in KDE.

 gtk/gtkwindow.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index c419698..7dee0df 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -3955,6 +3955,9 @@ gtk_window_supports_csd (GtkWindow *window)
       if (!gdk_screen_is_composited (screen))
         return FALSE;
 
+      if (!gdk_x11_screen_supports_net_wm_hint (screen, gdk_atom_intern_static_string 
("_GTK_FRAME_EXTENTS")))
+        return FALSE;
+
       /* We need a visual with alpha */
       visual = gdk_screen_get_rgba_visual (screen);
       if (!visual)