anchor.diff:  
   import 'dart:async';
   import 'dart:convert' show JSON;
  -import 'dart:html' show DivElement, Element, HttpRequest, NodeValidator,
  +import 'dart:html' show DivElement, Element, HttpRequest, Node, NodeValidator,
       NodeTreeSanitizer, window;
   import 'dart:js';
   
  
positive.code:     <div class="message">${prompt}</div>
  ''',
        validator: new PermissiveNodeValidator(),
        treeSanitizer: NodeTreeSanitizer.trusted);
  
    Element editorElement = element.querySelector('atom-text-editor');
    JsFunction editorConverter = context['getTextEditorForElement'];
  
negative.code:   }
  }
  
  class TrustedHtmlTreeSanitizer implements NodeTreeSanitizer {
    const TrustedHtmlTreeSanitizer();
  
    void sanitizeTree(Node node) { }
  }
  
  Future<Map> loadPackageJson() {
    return HttpRequest.getString('atom://dartlang/package.json').then((str) {
      return JSON.decode(str);
  