diff --git a/engine/src/flutter/lib/ui/dart_ui.gni b/engine/src/flutter/lib/ui/dart_ui.gni
index e60498fd444..173035f25ad 100644
--- a/engine/src/flutter/lib/ui/dart_ui.gni
+++ b/engine/src/flutter/lib/ui/dart_ui.gni
@@ -16,6 +16,7 @@ dart_ui_files = [
   "//flutter/lib/ui/natives.dart",
   "//flutter/lib/ui/painting.dart",
   "//flutter/lib/ui/platform_dispatcher.dart",
+  "//flutter/lib/ui/platform_isolate.dart",
   "//flutter/lib/ui/plugins.dart",
   "//flutter/lib/ui/pointer.dart",
   "//flutter/lib/ui/semantics.dart",