anchor.diff:      var currentLineStart = 0;
       int lastWhitespace;
       for (var i = 0; i < text.length; ++i) {
  -      if (isWhitespace(text, i)) lastWhitespace = i;
  +      if (_isWhitespace(text, i)) lastWhitespace = i;
   
         if (i - currentLineStart >= length) {
           // Back up to the last whitespace, unless there wasn't any, in which
  
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:         result.add(text.substring(currentLineStart, i));
  
          // Skip any intervening whitespace.
          while (_isWhitespace(text, i) && i < text.length) i++;
  
          currentLineStart = i;
          lastWhitespace = null;
  