anchor.diff:    /**
      * Computes the `dart:dom_deprecated` to `dart:html` mapping, and
      * places it in [domToHtml], [htmlToDom], [domTypesToHtml], and
  -   * [htmlTypesToDom]. Before this is run, Frog should be initialized
  +   * [htmlTypesToDom]. Before this is run, dart2js should be initialized
      * (via [parseOptions] and [initializeWorld]) and
      * [HtmlDiff.initialize] should be called.
      */
  
positive.code:       final domTypes = htmlToDomTypes(htmlType);
        if (domTypes.isEmpty()) continue;
  
        htmlTypesToDom.putIfAbsent(htmlType.qualifiedName,
            () => new Set()).addAll(domTypes);
        domTypes.forEach((t) =>
            domTypesToHtml.putIfAbsent(t.qualifiedName,
              () => new Set()).add(htmlType));
  
        htmlType.declaredMembers.forEach(
            (_, m) => _addMemberDiff(m, domTypes));
      }
    }
  
  
negative.code:     if (htmlMember == null) return;
      if (!domMembers.isEmpty()) {
        htmlToDom[htmlMember.qualifiedName] = domMembers;
        //htmlToDom[htmlmembername] -> list of corresponding dom members
      }
      domMembers.forEach((m) => // add the html member name to the domToHtml
          domToHtml.putIfAbsent(m, () => new Set()).add(htmlMember));
    }
  
  