inspector: Put surfaces and renderers in the tree

These are otherwise really hard to navigate to, and we already
have plenty of non-widget objects in the tree.

gtk/inspector/object-tree.c

@@ -45,6 +45,7 @@
 #include "gtklabel.h"
 #include "gtklistitem.h"
 #include "gtkpopover.h"
+#include "gtknative.h"
 #include "gtksettings.h"
 #include "gtksingleselection.h"
 #include "gtksignallistitemfactory.h"
@@ -132,6 +133,37 @@ object_tree_widget_get_children (GObject *object)
   return G_LIST_MODEL (gtk_flatten_list_model_new (G_LIST_MODEL (list)));
 }
 
+static GObject *
+object_tree_window_get_parent (GObject *object)
+{
+  return NULL;
+}
+
+static GListModel *
+object_tree_native_get_children (GObject *object)
+{
+  GtkNative *native = GTK_NATIVE (object);
+  GListStore *list;
+  GListModel *sublist;
+
+  list = g_list_store_new (G_TYPE_LIST_MODEL);
+
+  sublist = G_LIST_MODEL (g_list_store_new (G_TYPE_OBJECT));
+
+  if (gtk_native_get_surface (native))
+    g_list_store_append (G_LIST_STORE (sublist), gtk_native_get_surface (native));
+  if (gtk_native_get_renderer (native))
+    g_list_store_append (G_LIST_STORE (sublist), gtk_native_get_renderer (native));
+  g_list_store_append (list, sublist);
+  g_object_unref (sublist);
+
+  sublist = object_tree_widget_get_children (object);
+  g_list_store_append (list, sublist);
+  g_object_unref (sublist);
+
+  return G_LIST_MODEL (gtk_flatten_list_model_new (G_LIST_MODEL (list)));
+}
+
 static GListModel *
 object_tree_tree_model_sort_get_children (GObject *object)
 {
@@ -518,6 +550,16 @@ static const ObjectTreeClassFuncs object_tree_class_funcs[] = {
     object_tree_widget_get_parent,
     object_tree_combo_box_get_children
   },
+  {
+    gtk_window_get_type,
+    object_tree_window_get_parent,
+    object_tree_native_get_children,
+  },
+  {
+    gtk_popover_get_type,
+    object_tree_widget_get_parent,
+    object_tree_native_get_children,
+  },
   {
     gtk_widget_get_type,
     object_tree_widget_get_parent,