anchor.diff:    }
     if (decoration != null) {
       result[0] |= 1 << 2;
  -    for (TextDecoration value in decoration) {
  -      int shift = value.index - 1;
  -      if (shift != 0)
  -        result[2] |= 1 << shift;
  -    }
  +    result[2] = decoration._mask;
     }
     if (decorationColor != null) {
       result[0] |= 1 << 3;
  
positive.code: }
  
  /// A linear decoration to draw near the text
  enum TextDecoration {
    /// Do not draw a decoration
    none,
  
    /// Draw a line underneath each line of text
    underline,
  
    /// Draw a line above each line of text
    overline,
  
    /// Draw a line through each line of text
    lineThrough
  }
  
  /// The style in which to draw a text decoration
  
negative.code: //  - Element 6: The enum index of the |fontStyle|.
  //
  Int32List _encodeTextStyle(Color color,
                             TextDecoration decoration,
                             Color decorationColor,
                             TextDecorationStyle decorationStyle,
                             FontWeight fontWeight,
  