[gtk+] wayland: Handle subsurface as popup parent

[Olivier Fourdan <ofourdan src gnome org>]

commit 7ca6d7585fb7ebd5d3d7bb31bcde92e36f75d419
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Jan 5 16:01:49 2017 +0800

    wayland: Handle subsurface as popup parent
    
    When a subsurface is used as a parent of a popup, GDK needs to traverse
    up to the transient-for as the next parent, to properly find the parent
    used by the popup positioner. This is because the parent of a popup
    must always either be an xdg_popup or an xdg_surface, but traversing
    the "parent" (in GDK terms) upwards from a subsurface will end up on
    the fake root window before we hit the actual parent (in Wayland terms).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776225

 gdk/wayland/gdkwindow-wayland.c |   20 ++++++++++++++++----
 1 files changed, 16 insertions(+), 4 deletions(-)
---
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 2348d41..674dac5 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -1641,13 +1641,25 @@ get_real_parent_and_translate (GdkWindow *window,
   GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
   GdkWindow *parent = impl->transient_for;
 
-  while (parent &&
-         !gdk_window_has_native (parent) &&
-         gdk_window_get_parent (parent))
+  while (parent)
     {
+      GdkWindowImplWayland *parent_impl =
+        GDK_WINDOW_IMPL_WAYLAND (parent->impl);
+      GdkWindow *effective_parent = gdk_window_get_parent (parent);
+
+      if ((gdk_window_has_native (parent) &&
+           !parent_impl->display_server.wl_subsurface) ||
+          !effective_parent)
+        break;
+
       *x += parent->x;
       *y += parent->y;
-      parent = gdk_window_get_parent (parent);
+
+      if (gdk_window_has_native (parent) &&
+          parent_impl->display_server.wl_subsurface)
+        parent = parent->transient_for;
+      else
+        parent = effective_parent;
     }
 
   return parent;