diff --git a/lib/ui/ui.dart b/lib/ui/ui.dart
index 2d59f4e6a50..06801404d84 100644
--- a/lib/ui/ui.dart
+++ b/lib/ui/ui.dart
@@ -11,6 +11,7 @@
 /// text, layout, and rendering subsystems.
 library dart.ui;
 
+import 'dart:_internal';
 import 'dart:async';
 import 'dart:convert';
 import 'dart:developer' as developer;