anchor.diff:        final domTypes = htmlToDomTypes(htmlType);
         if (domTypes.isEmpty()) continue;
   
  -      htmlTypesToDom.putIfAbsent(htmlType.qualifiedName,
  +      htmlTypesToDom.putIfAbsent(htmlType.qualifiedName,// map of html->[its dom types]
             () => new Set()).addAll(domTypes);
  -      domTypes.forEach((t) =>
  +      domTypes.forEach((t) => // map of dom type -> [the html name].
             domTypesToHtml.putIfAbsent(t.qualifiedName,
               () => new Set()).add(htmlType));
   
         htmlType.declaredMembers.forEach(
  -          (_, m) => _addMemberDiff(m, domTypes));
  +          (_, m) => _addMemberDiff(m, domTypes)); // add those dom member types to each
  +          // of the html member (name/type) we're looking at
       }
     }
   
  
positive.code:     if (htmlMember == null) return;
      if (!domMembers.isEmpty()) {
        htmlToDom[htmlMember.qualifiedName] = domMembers;
      }
      domMembers.forEach((m) =>
          domToHtml.putIfAbsent(m, () => new Set()).add(htmlMember));
    }
  
  
negative.code:   /**
     * Computes the `dart:dom_deprecated` to `dart:html` mapping, and
     * places it in [domToHtml], [htmlToDom], [domTypesToHtml], and
     * [htmlTypesToDom]. Before this is run, dart2js should be initialized
     * (via [parseOptions] and [initializeWorld]) and
     * [HtmlDiff.initialize] should be called.
     */
  