anchor.diff:    /// Creates an output object for the given library info.
     InstrumentationRenderer(this.unitInfo, this.migrationInfo, this.pathMapper);
   
  +  /// Return the path context used to manipulate paths.
  +  path.Context get pathContext => migrationInfo.pathContext;
  +
     /// Builds an HTML view of the instrumentation information in [unitInfo].
     String render() {
       // TODO(brianwilkerson) Restore syntactic highlighting.
  
positive.code: 
    /// Return the content of the file with navigation links and anchors added.
    String _computeNavigationContent(UnitInfo unitInfo) {
      String content = unitInfo.content;
      OffsetMapper mapper = unitInfo.offsetMapper;
      Map<int, String> openInsertions = {};
  
negative.code:       NavigationTarget target = region.target;
        if (target.filePath != unitInfo.path || region.offset != target.offset) {
          String openInsertion = openInsertions[openOffset] ?? '';
          String htmlPath = pathContext.relative(pathMapper.map(target.filePath),
              from: unitDir);
          openInsertion = '<a href="$htmlPath#o${target.offset}">$openInsertion';
          openInsertions[openOffset] = openInsertion;
  
  