[mutter] backends/native: Use proper method for getting core idle monitor

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

commit afd645193a1dae27e48f492227e797931d990c8b
Author: Sebastian Keller <skeller gnome org>
Date:   Thu Jan 30 21:53:31 2020 +0100

    backends/native: Use proper method for getting core idle monitor
    
    e9fbbd5853 changed meta_backend_get_idle_monitor() to use
    ClutterInputDevice pointers instead of device IDs, but did not adjust
    the call in meta_backend_native_resume() which was still using 0 to get
    the core idle monitor resulting in a NULL pointer dereference.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/1029

 src/backends/native/meta-backend-native.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/backends/native/meta-backend-native.c b/src/backends/native/meta-backend-native.c
index f29aec16e..77f1ed2c8 100644
--- a/src/backends/native/meta-backend-native.c
+++ b/src/backends/native/meta-backend-native.c
@@ -813,7 +813,7 @@ void meta_backend_native_resume (MetaBackendNative *native)
 
   clutter_actor_queue_redraw (CLUTTER_ACTOR (stage));
 
-  idle_monitor = meta_backend_get_idle_monitor (backend, 0);
+  idle_monitor = meta_idle_monitor_get_core ();
   meta_idle_monitor_reset_idletime (idle_monitor);
 
   input_settings = meta_backend_get_input_settings (backend);