anchor.diff:          result.add(text.substring(currentLineStart, i));
   
           // Skip any intervening whitespace.
  -        while (isWhitespace(text, i) && i < text.length) i++;
  +        while (_isWhitespace(text, i) && i < text.length) i++;
   
           currentLineStart = i;
           lastWhitespace = null;
  
positive.code:   }
  }
  
  bool isWhitespace(String text, int index) {
    final int rune = text.codeUnitAt(index);
    return rune >= 0x0009 && rune <= 0x000D ||
        rune == 0x0020 ||
        rune == 0x0085 ||
  
negative.code:     var currentLineStart = 0;
      int lastWhitespace;
      for (var i = 0; i < text.length; ++i) {
        if (_isWhitespace(text, i)) lastWhitespace = i;
  
        if (i - currentLineStart >= length) {
          // Back up to the last whitespace, unless there wasn't any, in which
  