[mutter] compositor/x11: Move unredirect logic to helper

[Jonas Ådahl <jadahl src gnome org>]

commit 9ac52f034081d7b32cf2c3729137ab78eae885aa
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sat Aug 17 09:46:55 2019 +0200

    compositor/x11: Move unredirect logic to helper
    
    It makes it clearer what is required for unredirecting a window.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/734

 src/compositor/meta-compositor-x11.c | 39 ++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 15 deletions(-)
---
diff --git a/src/compositor/meta-compositor-x11.c b/src/compositor/meta-compositor-x11.c
index 4f99c35f5..b31ec451c 100644
--- a/src/compositor/meta-compositor-x11.c
+++ b/src/compositor/meta-compositor-x11.c
@@ -229,27 +229,36 @@ set_unredirected_window (MetaCompositorX11 *compositor_x11,
     }
 }
 
+static void
+maybe_unredirect_top_window (MetaCompositorX11 *compositor_x11)
+{
+  MetaCompositor *compositor = META_COMPOSITOR (compositor_x11);
+  MetaWindow *window_to_unredirect = NULL;
+  MetaWindowActor *window_actor;
+
+  if (meta_compositor_is_unredirect_inhibited (compositor))
+    goto out;
+
+  window_actor = meta_compositor_get_top_window_actor (compositor);
+  if (!window_actor)
+    goto out;
+
+  if (!meta_window_actor_should_unredirect (window_actor))
+    goto out;
+
+  window_to_unredirect = meta_window_actor_get_meta_window (window_actor);
+
+out:
+  set_unredirected_window (compositor_x11, window_to_unredirect);
+}
+
 static void
 meta_compositor_x11_pre_paint (MetaCompositor *compositor)
 {
   MetaCompositorX11 *compositor_x11 = META_COMPOSITOR_X11 (compositor);
-  MetaWindowActor *top_window_actor;
   MetaCompositorClass *parent_class;
 
-  top_window_actor = meta_compositor_get_top_window_actor (compositor);
-  if (!meta_compositor_is_unredirect_inhibited (compositor) &&
-      top_window_actor &&
-      meta_window_actor_should_unredirect (top_window_actor))
-    {
-      MetaWindow *top_window;
-
-      top_window = meta_window_actor_get_meta_window (top_window_actor);
-      set_unredirected_window (compositor_x11, top_window);
-    }
-  else
-    {
-      set_unredirected_window (compositor_x11, NULL);
-    }
+  maybe_unredirect_top_window (compositor_x11);
 
   parent_class = META_COMPOSITOR_CLASS (meta_compositor_x11_parent_class);
   parent_class->pre_paint (compositor);