anchor.diff:    DButton _cancelButton;
     DButton _shareButton;
     DElement _div;
  +  DElement _embedArea;
  +  DElement _info;
     DInput _padUrl;
     DInput _gistUrl;
     DInput _embedUrl;
     String _summary;
  -  DElement _embedArea;
  -  DElement _info;
  +
     ImageElement _embedPicture;
  +
  +  RadioButtonInputElement _embedDartRadio;
  +  RadioButtonInputElement _embedHtmlRadio;
   
     SharingDialog(
         GistContainer this.gistContainer, GistController this.gistController,
  
positive.code:       ..layoutHorizontal());
      DElement _embedHtmlArea = _leftArea.add(new DElement.tag('div')
        ..layoutHorizontal());
      RadioButtonInputElement _embedDartRadio = _embedDartArea.add(new RadioButtonInputElement()
        ..name="embed"
        ..id="dart-radio");
      _embedDartArea.add(new LabelElement()
        ..htmlFor = 'dart-radio'
        ..text = 'Embedding with Documentation'
        ..style.paddingLeft = '8px');
      RadioButtonInputElement _embedHtmlRadio = _embedHtmlArea.add(new RadioButtonInputElement()
        ..name="embed"
        ..id="html-radio");
      _embedHtmlArea.add(new LabelElement()
        ..htmlFor = 'html-radio'
        ..text = 'Embedding with HTML'
        ..style.paddingLeft = '8px');
      _embedDartRadio.checked = true;
      _embedPicture = _rightArea.add(new ImageElement(src: _docThumbnail, height: 100, width: 300)
        ..alt="Embed-dart"
        ..style.paddingLeft = "16px");
      _embedDartRadio.onClick.listen((_) => _embedToDart());
      _embedHtmlRadio.onClick.listen((_) => _embedToHtml());
  
negative.code:       _text.text =
            'Share the DartPad link or view the source at gist.github.com.';
        _textArea.style.display = 'none';
        MutableGist gist = gistContainer.mutableGist;
        content.add(_div);
        _padUrl.value = 'https://dartpad.dartlang.org/${gist.id}';
        _gistUrl.value = gist.html_url;
        _embedHtmlRadio.checked = false;
        _embedDartRadio.checked = true;
        _embedToDart();
        buttonArea.add(_cancelButton);
        buttonArea.add(new SpanElement()..attributes['flex'] = '');
      }
  