Nosuchmethod window (#37417)

packages/flutter_test/lib/src/window.dart

@@ -373,4 +373,12 @@ class TestWindow implements Window {
     clearTextScaleFactorTestValue();
     clearViewInsetsTestValue();
   }
+
+  /// This gives us some grace time when the dart:ui side adds something to
+  /// Window, and makes things easier when we do rolls to give us time to
+  /// catch up.
+  @override
+  dynamic noSuchMethod(Invocation invocation) {
+    return null;
+  }
 }

packages/flutter_test/test/window_test.dart

@@ -10,6 +10,11 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:meta/meta.dart';
 
 void main() {
+  test('TestWindow can handle new methods without breaking', () {
+    final dynamic testWindow = TestWindow(window: ui.window);
+    expect(testWindow.someNewProperty, null);
+  });
+
   testWidgets('TestWindow can fake device pixel ratio', (WidgetTester tester) async {
     verifyThatTestWindowCanFakeProperty<double>(
       tester: tester,