[mutter] wayland/surface: Add API to cache frame callbacks

[Jonas Ådahl <jadahl src gnome org>]

commit 0ace58d05f3e50f4fdcf4971baab163e6ae5a1e9
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Aug 27 12:05:58 2018 +0200

    wayland/surface: Add API to cache frame callbacks
    
    Sometimes it may be useful for roles to put callbacks in the generic
    surface frame callback queue. The surface frame callback queue will
    either eventually be processed on the next surface role assignment that
    places the frame callbacks in a role specific queue, processed at some
    other point in time by a role, or cleaned up on surface destruction.
    
    https://gitlab.gnome.org/GNOME/mutter/issues/240

 src/wayland/meta-wayland-surface.c | 17 ++++++++++-------
 src/wayland/meta-wayland-surface.h |  3 +++
 2 files changed, 13 insertions(+), 7 deletions(-)
---
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 5ed3ca7e8..33398ac97 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -587,6 +587,15 @@ parent_surface_state_applied (gpointer data,
   meta_wayland_subsurface_parent_state_applied (subsurface);
 }
 
+void
+meta_wayland_surface_cache_pending_frame_callbacks (MetaWaylandSurface      *surface,
+                                                    MetaWaylandPendingState *pending)
+{
+  wl_list_insert_list (&surface->pending_frame_callback_list,
+                       &pending->frame_callback_list);
+  wl_list_init (&pending->frame_callback_list);
+}
+
 void
 meta_wayland_surface_apply_pending_state (MetaWaylandSurface      *surface,
                                           MetaWaylandPendingState *pending)
@@ -708,13 +717,7 @@ meta_wayland_surface_apply_pending_state (MetaWaylandSurface      *surface,
     }
   else
     {
-      /* Since there is no role assigned to the surface yet, keep frame
-       * callbacks queued until a role is assigned and we know how
-       * the surface will be drawn.
-       */
-      wl_list_insert_list (&surface->pending_frame_callback_list,
-                           &pending->frame_callback_list);
-      wl_list_init (&pending->frame_callback_list);
+      meta_wayland_surface_cache_pending_frame_callbacks (surface, pending);
 
       if (pending->newly_attached)
         {
diff --git a/src/wayland/meta-wayland-surface.h b/src/wayland/meta-wayland-surface.h
index 6fd19bf41..276a135dc 100644
--- a/src/wayland/meta-wayland-surface.h
+++ b/src/wayland/meta-wayland-surface.h
@@ -256,6 +256,9 @@ MetaWaylandSurface *meta_wayland_surface_get_toplevel (MetaWaylandSurface *surfa
 
 MetaWindow *        meta_wayland_surface_get_toplevel_window (MetaWaylandSurface *surface);
 
+void                meta_wayland_surface_cache_pending_frame_callbacks (MetaWaylandSurface      *surface,
+                                                                        MetaWaylandPendingState *pending);
+
 void                meta_wayland_surface_queue_pending_frame_callbacks (MetaWaylandSurface *surface);
 
 void                meta_wayland_surface_queue_pending_state_frame_callbacks (MetaWaylandSurface      
*surface,