[nautilus] Use unity-control-center if in Unity

[Cosimo Cecchi <cosimoc src gnome org>]

commit 7e6e4c9eb0b9e31cd2e91cce3dfdaa69c4ba6e8c
Author: Rober Ancell <robert ancell canonical com>
Date:   Wed Jan 15 15:38:37 2014 +1300

    Use unity-control-center if in Unity
    
    https://bugzilla.gnome.org/show_bug.cgi?id=722234

 src/nautilus-desktop-canvas-view.c |   54 +++++++++++++++++++++++++++++++----
 1 files changed, 47 insertions(+), 7 deletions(-)
---
diff --git a/src/nautilus-desktop-canvas-view.c b/src/nautilus-desktop-canvas-view.c
index 6f11208..f1556de 100644
--- a/src/nautilus-desktop-canvas-view.c
+++ b/src/nautilus-desktop-canvas-view.c
@@ -523,16 +523,60 @@ nautilus_desktop_canvas_view_init (NautilusDesktopCanvasView *desktop_canvas_vie
                                  desktop_canvas_view);
 }
 
+static const gchar *
+get_control_center_command (const gchar ** params_out)
+{
+       gchar *path;
+       const gchar *retval;
+       const gchar *params;
+
+       path = NULL;
+       retval = NULL;
+       params = NULL;
+
+       /* In Unity look for unity-control-center */
+       if (g_strcmp0 (g_getenv ("XDG_CURRENT_DESKTOP"), "Unity") == 0) {
+               path = g_find_program_in_path ("unity-control-center");
+               if (path != NULL) {
+                       retval = "unity-control-center";
+                       params = "appearance";
+                       goto out;
+               }
+       }
+
+       /* Otherwise look for gnome-control-center */
+       path = g_find_program_in_path ("gnome-control-center");
+       if (path != NULL) {
+               retval = "gnome-control-center";
+               params = "background";
+       }
+
+ out:
+       g_free (path);
+       if (params_out != NULL) {
+               *params_out = params;
+       }
+
+       return retval;
+}
+
 static void
 action_change_background_callback (GtkAction *action, 
                                   gpointer data)
 {
+       const gchar *control_center_cmd, *params;
+
         g_assert (NAUTILUS_VIEW (data));
 
+       control_center_cmd = get_control_center_command (&params);
+       if (control_center_cmd == NULL) {
+               return;
+       }
+
        nautilus_launch_application_from_command (gtk_widget_get_screen (GTK_WIDGET (data)),
-                                                 "gnome-control-center",
+                                                 control_center_cmd,
                                                  FALSE,
-                                                 "background", NULL);
+                                                 params, NULL);
 }
 
 static void
@@ -696,7 +740,6 @@ real_merge_menus (NautilusView *view)
        GtkUIManager *ui_manager;
        GtkActionGroup *action_group;
        GtkAction *action;
-       gchar *control_center_path;
 
        NAUTILUS_VIEW_CLASS (nautilus_desktop_canvas_view_parent_class)->merge_menus (view);
 
@@ -732,13 +775,10 @@ real_merge_menus (NautilusView *view)
                               GTK_UI_MANAGER_MENUITEM,
                               FALSE);
 
-       control_center_path = g_find_program_in_path ("gnome-control-center");
-       if (control_center_path == NULL) {
+       if (get_control_center_command (NULL) == NULL) {
                action = gtk_action_group_get_action (action_group, NAUTILUS_ACTION_CHANGE_BACKGROUND);
                gtk_action_set_visible (action, FALSE);
        }
-
-       g_free (control_center_path);
 }
 
 NautilusView *