Add:创建 flutter go web 版

packages/flutter_web_ui/test/paragraph_builder_test.dart

@@ -0,0 +1,27 @@
+// Copyright 2013 The Flutter 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_ui/ui.dart';
+
+import 'package:test/test.dart';
+
+void main() {
+  test('Should be able to build and layout a paragraph', () {
+    final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle());
+    builder.addText('Hello');
+    final Paragraph paragraph = builder.build();
+    expect(paragraph, isNotNull);
+
+    paragraph.layout(const ParagraphConstraints(width: 800.0));
+    expect(paragraph.width, isNonZero);
+    expect(paragraph.height, isNonZero);
+  });
+
+  test('PushStyle should not segfault after build()', () {
+    final ParagraphBuilder paragraphBuilder =
+        ParagraphBuilder(ParagraphStyle());
+    paragraphBuilder.build();
+    paragraphBuilder.pushStyle(TextStyle());
+  });
+}