[gnome-settings-daemon/rhel-6.9: 22/25] xrandr: Avoid crash when Fn+F7 is pressed on some systems

[Ray Strode <halfline src gnome org>]

commit fb3404293722c4063007d314f864793e44d82fbc
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Nov 18 14:28:58 2015 +0100

    xrandr: Avoid crash when Fn+F7 is pressed on some systems
    
    When a display driver doesn't support XRandR properly,
    manager->priv->rw_screen will be NULL. However, because of the way that
    we need to initialise D-Bus, some of the API is still accessible.
    
    As such, the "Fn+F7" (update screen) shortcut would access API that
    should only be accessible when XRandR is available. Add guards to those
    functions.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1196044

 plugins/xrandr/gsd-xrandr-manager.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/plugins/xrandr/gsd-xrandr-manager.c b/plugins/xrandr/gsd-xrandr-manager.c
index 6e3aa36..db95e28 100644
--- a/plugins/xrandr/gsd-xrandr-manager.c
+++ b/plugins/xrandr/gsd-xrandr-manager.c
@@ -412,6 +412,8 @@ static gboolean
 gsd_xrandr_manager_apply_configuration (GsdXrandrManager *manager,
                                         GError          **error)
 {
+        if (manager->priv->rw_screen == NULL)
+                return FALSE;
         return try_to_apply_intended_configuration (manager, NULL, GDK_CURRENT_TIME, error);
 }
 
@@ -425,6 +427,9 @@ gsd_xrandr_manager_2_apply_configuration (GsdXrandrManager *manager,
         GdkWindow *parent_window;
         gboolean result;
 
+        if (manager->priv->rw_screen == NULL)
+                return FALSE;
+
         if (parent_window_id != 0)
                 parent_window = gdk_window_foreign_new_for_display (gdk_display_get_default (), 
(GdkNativeWindow) parent_window_id);
         else
@@ -444,6 +449,8 @@ gsd_xrandr_manager_2_video_mode_switch (GsdXrandrManager *manager,
                                         guint32           timestamp,
                                         GError          **error)
 {
+        if (manager->priv->rw_screen == NULL)
+                return FALSE;
         handle_fn_f7 (manager, timestamp);
         return TRUE;
 }
@@ -454,6 +461,8 @@ gsd_xrandr_manager_2_rotate (GsdXrandrManager *manager,
                              guint32           timestamp,
                              GError          **error)
 {
+        if (manager->priv->rw_screen == NULL)
+                return FALSE;
         //handle_rotate_windows (manager, timestamp);
         return TRUE;
 }