macos: Take shadows into account when positioning popups

Otherwise popups will be misaligned. This becomes noticeable when larger
shadows are used, like in libadwaita.

Regression in 08216dcee9

gdk/macos/gdkmacospopupsurface.c

@@ -52,6 +52,7 @@ gdk_macos_popup_surface_layout (GdkMacosPopupSurface *self,
   GdkRectangle bounds;
   GdkRectangle final_rect;
   int x, y;
+  int shadow_left, shadow_right, shadow_top, shadow_bottom;
 
   g_assert (GDK_IS_MACOS_POPUP_SURFACE (self));
   g_assert (layout != NULL);
@@ -68,10 +69,19 @@ gdk_macos_popup_surface_layout (GdkMacosPopupSurface *self,
     monitor = _gdk_macos_surface_get_best_monitor (GDK_MACOS_SURFACE (self));
   gdk_macos_monitor_get_workarea (monitor, &bounds);
 
+  gdk_popup_layout_get_shadow_width (layout,
+                                     &shadow_left,
+                                     &shadow_right,
+                                     &shadow_top,
+                                     &shadow_bottom);
+
   gdk_surface_layout_popup_helper (GDK_SURFACE (self),
                                    width,
                                    height,
-                                   0, 0, 0, 0, /* shadow-left/right/top/bottom */
+                                   shadow_left,
+                                   shadow_right,
+                                   shadow_top,
+                                   shadow_bottom,
                                    monitor,
                                    &bounds,
                                    self->layout,