[gnome-control-center] shell: Replace ifdefs with #pragma once

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d16cddeccf00c578904b43a14d4894f8e964a5c0
Author: Robert Ancell <robert ancell canonical com>
Date:   Thu Nov 21 20:29:59 2019 +1300

    shell: Replace ifdefs with #pragma once

 shell/cc-panel-list.h | 6 +-----
 shell/cc-shell.h      | 5 +----
 shell/cc-window.h     | 5 +----
 3 files changed, 3 insertions(+), 13 deletions(-)
---
diff --git a/shell/cc-panel-list.h b/shell/cc-panel-list.h
index 7b77e72ba..dd8cfe0b1 100644
--- a/shell/cc-panel-list.h
+++ b/shell/cc-panel-list.h
@@ -18,8 +18,7 @@
  * Author: Georges Basile Stavracas Neto <gbsneto gnome org>
  */
 
-#ifndef CC_PANEL_LIST_H
-#define CC_PANEL_LIST_H
+#pragma once
 
 #include <glib-object.h>
 
@@ -78,6 +77,3 @@ void                 cc_panel_list_set_selection_mode            (CcPanelList
                                                                   GtkSelectionMode    selection_mode);
 
 G_END_DECLS
-
-#endif /* CC_PANEL_LIST_H */
-
diff --git a/shell/cc-shell.h b/shell/cc-shell.h
index cc96365f7..f5d35dbe6 100644
--- a/shell/cc-shell.h
+++ b/shell/cc-shell.h
@@ -19,8 +19,7 @@
  * Author: Thomas Wood <thos gnome org>
  */
 
-#ifndef _CC_SHELL_H
-#define _CC_SHELL_H
+#pragma once
 
 #include <gtk/gtk.h>
 
@@ -76,5 +75,3 @@ void            cc_shell_embed_widget_in_header   (CcShell         *shell,
                                                    GtkPositionType  position);
 
 G_END_DECLS
-
-#endif /* _CC_SHELL_H */
diff --git a/shell/cc-window.h b/shell/cc-window.h
index a2e53eaab..5f74c3617 100644
--- a/shell/cc-window.h
+++ b/shell/cc-window.h
@@ -18,8 +18,7 @@
  * Author: Thomas Wood <thos gnome org>
  */
 
-#ifndef _CC_WINDOW_H
-#define _CC_WINDOW_H
+#pragma once
 
 #include <glib-object.h>
 #include "cc-shell.h"
@@ -38,5 +37,3 @@ void cc_window_set_search_item (CcWindow *center,
                                 const char *search);
 
 G_END_DECLS
-
-#endif /* _CC_WINDOW_H */