Use non-pageable memory for gnome-keyring passwords

* Use a ClutterTextBuffer that allocates non-pageable
   memory to hold passwords for gnome-keyring, ssh, gpg
 * Requires gcr 3.3.5

https://bugzilla.gnome.org/show_bug.cgi?id=652460

src/shell-secure-text-buffer.h

@@ -0,0 +1,42 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+/* shell-secure-text-buffer.h - secure memory clutter text buffer
+
+   Copyright (C) 2009 Stefan Walter
+   Copyright (C) 2012 Red Hat Inc.
+
+   This program 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 program 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 the Gnome Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   Author: Stef Walter <stefw@gnome.org>
+*/
+
+#ifndef __SHELL_SECURE_TEXT_BUFFER_H__
+#define __SHELL_SECURE_TEXT_BUFFER_H__
+
+#include <clutter/clutter.h>
+
+G_BEGIN_DECLS
+
+#define SHELL_TYPE_SECURE_TEXT_BUFFER            (shell_secure_text_buffer_get_type ())
+#define SHELL_SECURE_TEXT_BUFFER(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), SHELL_TYPE_SECURE_TEXT_BUFFER, ShellSecureTextBuffer))
+#define SHELL_IS_SECURE_TEXT_BUFFER(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), SHELL_TYPE_SECURE_TEXT_BUFFER))
+
+GType                     shell_secure_text_buffer_get_type               (void) G_GNUC_CONST;
+
+ClutterTextBuffer *       shell_secure_text_buffer_new                    (void);
+
+G_END_DECLS
+
+#endif /* __SHELL_SECURE_TEXT_BUFFER_H__ */