gdk/wayland: freeze popups when hidden

Previously, there was an issue with glitching after showing/hiding a
popover that was not also destroyed. This was due to the popover having
an update_freeze_count of zero after hiding the surface.

That resulted in it's toplevel continuously dropping frames such as during
high-frame-rate scrolling in textviews. This problem is much more visible
on high-frame-rate displays such as 120hz/144hz.

With this commit, we track the POPUP_STATE_IDLE case and also freeze the
frame clock of the popup until it is mapped again.

gdk/wayland/gdksurface-wayland.c

@@ -113,6 +113,7 @@ struct _GdkWaylandSurface
 
   PopupState popup_state;
 
+  unsigned int popup_thaw_upon_show : 1;
   unsigned int initial_configure_received : 1;
   unsigned int has_uncommitted_ack_configure : 1;
   unsigned int mapped : 1;
@@ -2994,6 +2995,8 @@ gdk_wayland_surface_hide_surface (GdkSurface *surface)
               thaw_popup_toplevel_state (surface);
               break;
             case POPUP_STATE_IDLE:
+              impl->popup_thaw_upon_show = TRUE;
+              gdk_surface_freeze_updates (surface);
               break;
             default:
               g_assert_not_reached ();
@@ -3223,6 +3226,12 @@ show_popup (GdkSurface     *surface,
   if (!impl->display_server.wl_surface)
     gdk_wayland_surface_create_surface (surface);
 
+  if (impl->popup_thaw_upon_show)
+    {
+      impl->popup_thaw_upon_show = FALSE;
+      gdk_surface_thaw_updates (surface);
+    }
+
   gdk_wayland_surface_map_popup (surface, width, height, layout);
 }