anchor.diff:  
       // Bind the editable files to the gist.
       Property htmlFile =
  -    new GistFileProperty(editableGist.getGistFile('index.html'));
  +        new GistFileProperty(editableGist.getGistFile('index.html'));
       Property htmlDoc =
  -    new EditorDocumentProperty(_context.htmlDocument, 'html');
  +        new EditorDocumentProperty(_context.htmlDocument, 'html');
       bind(htmlDoc, htmlFile);
       bind(htmlFile, htmlDoc);
   
       Property cssFile =
  -    new GistFileProperty(editableGist.getGistFile('styles.css'));
  +        new GistFileProperty(editableGist.getGistFile('styles.css'));
       Property cssDoc = new EditorDocumentProperty(_context.cssDocument, 'css');
       bind(cssDoc, cssFile);
       bind(cssFile, cssDoc);
   
       Property dartFile =
  -    new GistFileProperty(editableGist.getGistFile('main.dart'));
  +        new GistFileProperty(editableGist.getGistFile('main.dart'));
       Property dartDoc =
  -    new EditorDocumentProperty(_context.dartDocument, 'dart');
  +        new EditorDocumentProperty(_context.dartDocument, 'dart');
       bind(dartDoc, dartFile);
       bind(dartFile, dartDoc);
   
  
positive.code: 
      document.onKeyUp.listen((e) {
        if (editor.completionActive ||
        DocHandler.cursorKeys.contains(e.keyCode)) {
          docHandler.generateDoc(_docPanel);
        }
        _handleAutoCompletion(e);
      });
  
      outputTabController = new TabController()
        ..registerTab(new TabElement(querySelector('#resulttab'),
      name: "result", onSelect: () {
        ga.sendEvent('view', "result");
        querySelector('#frame').style.visibility = "visible";
        querySelector('#output').style.visibility = "hidden";
      }))
        ..registerTab(new TabElement(querySelector('#consoletab'),
      name: "console", onSelect: () {
        ga.sendEvent('view', "console");
        querySelector('#output').style.visibility = "visible";
        querySelector('#frame').style.visibility = "hidden";
      }));
  
      _context = new PlaygroundContext(editor);
      deps[Context] = _context;
  
negative.code: 
        _displayIssues(result.issues);
  
        _context.dartDocument
            .setAnnotations(result.issues.map((AnalysisIssue issue) {
          int startLine = lines.getLineForOffset(issue.charStart);
          int endLine =
              lines.getLineForOffset(issue.charStart + issue.charLength);
  
          Position start = new Position(
              startLine, issue.charStart - lines.offsetForLine(startLine));
          Position end = new Position(
              endLine,
              issue.charStart +
                  issue.charLength -
                  lines.offsetForLine(startLine));
  
          return new Annotation(issue.kind, issue.message, issue.line,
              start: start, end: end);
        }).toList());
  
        bool hasErrors = result.issues.any((issue) => issue.kind == 'error');
  