weston_wm: Implement _NET_ACTIVE_WINDOW

Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/xwayland/xwayland.h b/xwayland/xwayland.h
index 7f4c5b1..bace079 100644
--- a/xwayland/xwayland.h
+++ b/xwayland/xwayland.h
@@ -129,6 +129,7 @@
 		xcb_atom_t		 net_wm_moveresize;
 		xcb_atom_t		 net_supporting_wm_check;
 		xcb_atom_t		 net_supported;
+		xcb_atom_t		 net_active_window;
 		xcb_atom_t		 motif_wm_hints;
 		xcb_atom_t		 clipboard;
 		xcb_atom_t		 clipboard_manager;
@@ -141,6 +142,7 @@
 		xcb_atom_t		 compound_text;
 		xcb_atom_t		 text;
 		xcb_atom_t		 string;
+		xcb_atom_t		 window;
 		xcb_atom_t		 text_plain_utf8;
 		xcb_atom_t		 text_plain;
 		xcb_atom_t		 xdnd_selection;