Fix use-after free and race conditions in Wayland idle inhibitation (#779)

Author: Sunderland93

src/wayland/meta-wayland-actor-surface.c

@@ -445,6 +445,8 @@ meta_wayland_actor_surface_reset_actor (MetaWaylandActorSurface *actor_surface)
                       G_CALLBACK (on_actor_destroyed),
                       actor_surface);
 
+  meta_wayland_surface_notify_actor_changed (surface);
+
   g_signal_connect_swapped (priv->actor, "notify::allocation",
                             G_CALLBACK (meta_wayland_surface_notify_geometry_changed),
                             surface);

src/wayland/meta-wayland-surface.c

@@ -95,6 +95,7 @@ enum
   SURFACE_SHORTCUTS_RESTORED,
   SURFACE_GEOMETRY_CHANGED,
   SURFACE_PRE_STATE_APPLIED,
+  SURFACE_ACTOR_CHANGED,
   N_SURFACE_SIGNALS
 };
 
@@ -1677,6 +1678,14 @@ meta_wayland_surface_class_init (MetaWaylandSurfaceClass *klass)
                   0, NULL, NULL,
                   g_cclosure_marshal_VOID__VOID,
                   G_TYPE_NONE, 0);
+
+  surface_signals[SURFACE_ACTOR_CHANGED] =
+    g_signal_new ("actor-changed",
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  0, NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
 }
 
 static void
@@ -1991,3 +2000,9 @@ meta_wayland_surface_get_height (MetaWaylandSurface *surface)
       return height / surface->scale;
     }
 }
+
+void
+meta_wayland_surface_notify_actor_changed (MetaWaylandSurface *surface)
+{
+  g_signal_emit (surface, surface_signals[SURFACE_ACTOR_CHANGED], 0);
+}

src/wayland/meta-wayland-surface.h

@@ -335,6 +335,8 @@ void                meta_wayland_surface_notify_unmapped (MetaWaylandSurface *su
 
 void                meta_wayland_surface_update_outputs_recursively (MetaWaylandSurface *surface);
 
+void                meta_wayland_surface_notify_actor_changed (MetaWaylandSurface *surface);
+
 int                 meta_wayland_surface_get_width (MetaWaylandSurface *surface);
 int                 meta_wayland_surface_get_height (MetaWaylandSurface *surface);