[mutter] backend: Add API to freeze/thaw frame clock

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

commit 88e4ff740964681a25ef07271f59db9d7bb44e3c
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Mar 29 20:54:57 2019 +0100

    backend: Add API to freeze/thaw frame clock
    
    It's just a thin wrapper around the ClutterStage API, with the intention
    to hide the awkward nest of interdependent backends.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/506

 src/backends/meta-backend-private.h |  4 ++++
 src/backends/meta-backend.c         | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)
---
diff --git a/src/backends/meta-backend-private.h b/src/backends/meta-backend-private.h
index 510e6aa34..7eba1806b 100644
--- a/src/backends/meta-backend-private.h
+++ b/src/backends/meta-backend-private.h
@@ -147,6 +147,10 @@ xkb_layout_index_t meta_backend_get_keymap_layout_group (MetaBackend *backend);
 
 gboolean meta_backend_is_lid_closed (MetaBackend *backend);
 
+void meta_backend_freeze_updates (MetaBackend *backend);
+
+void meta_backend_thaw_updates (MetaBackend *backend);
+
 void meta_backend_update_last_device (MetaBackend *backend,
                                       int          device_id);
 
diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index 58eec8c94..23ab2faec 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -1079,6 +1079,24 @@ meta_backend_get_stage (MetaBackend *backend)
   return priv->stage;
 }
 
+void
+meta_backend_freeze_updates (MetaBackend *backend)
+{
+  ClutterStage *stage;
+
+  stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
+  clutter_stage_freeze_updates (stage);
+}
+
+void
+meta_backend_thaw_updates (MetaBackend *backend)
+{
+  ClutterStage *stage;
+
+  stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
+  clutter_stage_thaw_updates (stage);
+}
+
 static gboolean
 update_last_device (MetaBackend *backend)
 {