anchor.diff:    }
   
     void _performAnalysis() {
  -    String source = _context.dartSource;
  -    Lines lines = new Lines(source);
  -
  -    Future request = analysisService.analyze(source);
  +    var input = new SourceRequest()..source = _context.dartSource;
  +    Lines lines = new Lines(input.source);
  +
  +    Future<AnalysisResults> request = dartServices.analyze(input);
   
       _analysisRequest = request;
   
  
positive.code:       if (_analysisRequest != request) return;
  
        // Discard if the document has been mutated since we requested analysis.
        if (source != _context.dartSource) return;
  
        dartBusyLight.reset();
  
  
negative.code:       GistFile css = chooseGistFile(gist, ['styles.css', 'style.css']);
  
        context.dartSource = dart == null ? '' : dart.contents;
        context.htmlSource = html == null ? '' : extractHtmlBody(html.contents);
        context.cssSource = css == null ? '' : css.contents;
  
        // Analyze and run it.
  