Remove GTK AX support, we've never used it

Source/WebCore/accessibility/atk/WebKitAccessibleInterfaceAction.h

Index: Source/WebCore/accessibility/atk/WebKitAccessibleInterfaceAction.h
diff --git a/Source/WebCore/accessibility/atk/WebKitAccessibleInterfaceAction.h b/Source/WebCore/accessibility/atk/WebKitAccessibleInterfaceAction.h
deleted file mode 100644
index a0de63fd75c45d9cf82bab5281713829070489c6..0000000000000000000000000000000000000000
--- a/Source/WebCore/accessibility/atk/WebKitAccessibleInterfaceAction.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2008 Nuanti Ltd.
- * Copyright (C) 2009 Jan Alonzo
- * Copyright (C) 2012 Igalia S.L.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- */
-
-#ifndef WebKitAccessibleInterfaceAction_h
-#define WebKitAccessibleInterfaceAction_h
-
-#if HAVE(ACCESSIBILITY)
-
-#include <atk/atk.h>
-
-void webkitAccessibleActionInterfaceInit(AtkActionIface*);
-
-#endif
-
-#endif // WebKitAccessibleInterfaceAction_h