Add:创建 flutter go web 版

packages/flutter_web/test/widgets/scrollable_dispose_test.dart

@@ -0,0 +1,30 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_web_test/flutter_web_test.dart';
+import 'package:flutter_web/widgets.dart';
+
+import 'test_widgets.dart';
+
+void main() {
+  testWidgets('simultaneously dispose a widget and end the scroll animation',
+      (WidgetTester tester) async {
+    final List<Widget> textWidgets = <Widget>[];
+    for (int i = 0; i < 250; i++) textWidgets.add(new Text('$i'));
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new FlipWidget(
+            left: new ListView(children: textWidgets), right: new Container()),
+      ),
+    );
+
+    await tester.fling(
+        find.byType(ListView), const Offset(0.0, -200.0), 1000.0);
+    await tester.pump();
+
+    tester.state<FlipWidgetState>(find.byType(FlipWidget)).flip();
+    await tester.pump(const Duration(hours: 5));
+  });
+}