anchor.diff:  // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
   
  +import 'package:flutter/gestures.dart';
   import 'package:flutter/material.dart';
  +import 'package:flutter/services.dart';
  +
  +class LinkTextSpan extends TextSpan {
  +  LinkTextSpan({ TextStyle style, String url, String text }) : super(
  +    style: style,
  +    text: text ?? url,
  +    recognizer: new TapGestureRecognizer()..onTap = () {
  +      UrlLauncher.launch(url);
  +    }
  +  );
  +}
   
   class GalleryDrawer extends StatelessWidget {
     GalleryDrawer({
  
positive.code: 
    @override
    Widget build(BuildContext context) {
      return new Drawer(
        child: new Block(
          children: <Widget>[
  
negative.code:             applicationLegalese: '© 2016 The Chromium Authors',
              aboutBoxChildren: <Widget>[
                new Padding(
                  padding: const EdgeInsets.only(top: 24.0),
                  child: new RichText(
                    text: new TextSpan(
                      children: <TextSpan>[
                        new TextSpan(
                          style: aboutTextStyle,
                          text: "Flutter is an early-stage, open-source project to help "
                          "developers build high-performance, high-fidelity, mobile "
                          "apps for iOS and Android from a single codebase. This "
                          "gallery is a preview of Flutter's many widgets, behaviors, "
                          "animations, layouts, and more. Learn more about Flutter at "
                        ),
                        new LinkTextSpan(
                          style: aboutLinkStyle,
                          url: 'https://flutter.io'
                        ),
                        new TextSpan(
                          style: aboutTextStyle,
                          text: ".\n\nTo see the source code for this app, please visit the "
                        ),
                        new LinkTextSpan(
                          style: aboutLinkStyle,
                          url: 'https://goo.gl/iv1p4G',
                          text: 'flutter github repo'
                        ),
                        new TextSpan(
                          style: aboutTextStyle,
                          text: "."
                        )
                      ]
                    )
                  )
                )
              ]
            )
          ]
        )
      );
  