flutter · mattkae · Aug 4, 2025 · Jul 21, 2025 · Jul 21, 2025 · Jul 22, 2025
diff --git a/dev/devicelab/lib/tasks/integration_tests.dart b/dev/devicelab/lib/tasks/integration_tests.dart
@@ -189,13 +189,14 @@ TaskFunction dartDefinesTask() {
 }
 
 TaskFunction featureFlagsTask() {
-  return DriverTest(
-    '${flutterDirectory.path}/dev/integration_tests/ui',
-    'lib/feature_flags.dart',
-    // TODO(loic-sharma): Turn on a framework feature flag once one exists.
-    // https://github.com/flutter/flutter/issues/167668
-    environment: const <String, String>{},
-  ).call;
+  return () async {
+    await flutter('config', options: const <String>['--enable-windowing']);
+
+    return DriverTest(
+      '${flutterDirectory.path}/dev/integration_tests/ui',
+      'lib/feature_flags.dart',
+    ).call();
+  };
 }
 
 TaskFunction createEndToEndIntegrationTest() {

diff --git a/dev/integration_tests/ui/test_driver/feature_flags_test.dart b/dev/integration_tests/ui/test_driver/feature_flags_test.dart
@@ -17,8 +17,6 @@ void main() {
   });
 
   test('Can run with feature flags enabled', () async {
-    // TODO(loic-sharma): Turn on a framework feature flag once one exists.
-    // https://github.com/flutter/flutter/issues/167668
-    await driver?.waitFor(find.text('Feature flags: "{}"'));
+    await driver?.waitFor(find.text('Feature flags: "{windowing}"'));
   }, timeout: Timeout.none);
 }
diff --git a/packages/flutter/lib/src/foundation/_features.dart b/packages/flutter/lib/src/foundation/_features.dart
@@ -4,6 +4,21 @@
 
 import 'package:meta/meta.dart';
 
+/// Whether the windowing feature is enabled for the current
+/// application.
+///
+/// Do not use this API. Flutter will make breaking changes
+/// to this API, even in patch versions.
+///
+/// If this returns `false`, `@internal` APIs in the following
+/// files will throw an `UnsupportedError`:
+///
+/// 1. packages/flutter/lib/src/widgets/_window.dart
+///
+/// See: https://github.com/flutter/flutter/issues/30701.
+@internal
+bool isWindowingEnabled = debugEnabledFeatureFlags.contains('windowing');
+
 /// The feature flags this app was built with.
 ///
 /// Do not use this API. Flutter can and will make breaking changes to this API.