Add:创建 flutter go web 版

packages/flutter_web/test/widgets/physical_model_test.dart

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+// Copyright 2015 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/material.dart';
+import 'package:flutter_web/rendering.dart';
+import 'package:flutter_web/widgets.dart';
+import 'package:flutter_web_test/flutter_web_test.dart';
+
+void main() {
+  testWidgets(
+      'PhysicalModel - creates a physical model layer when it needs compositing',
+      (WidgetTester tester) async {
+    debugDisableShadows = false;
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(devicePixelRatio: 1.0),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: PhysicalModel(
+            shape: BoxShape.rectangle,
+            color: Colors.grey,
+            shadowColor: Colors.red,
+            elevation: 1.0,
+            child:
+                Material(child: TextField(controller: TextEditingController())),
+          ),
+        ),
+      ),
+    );
+    await tester.pump();
+
+    final RenderPhysicalModel renderPhysicalModel = tester.allRenderObjects
+        .firstWhere((RenderObject object) => object is RenderPhysicalModel);
+    expect(renderPhysicalModel.needsCompositing, true);
+
+    final PhysicalModelLayer physicalModelLayer =
+        tester.layers.firstWhere((Layer layer) => layer is PhysicalModelLayer);
+    expect(physicalModelLayer.shadowColor, Colors.red);
+    expect(physicalModelLayer.color, Colors.grey);
+    expect(physicalModelLayer.elevation, 1.0);
+    debugDisableShadows = true;
+  });
+}