static addTextDecoration_(cue, decoration) {
    const Cue = shaka.text.Cue;
    for (const value of decoration.split(' ')) {
      switch (value) {
        case 'underline':
          if (!cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
            cue.textDecoration.push(Cue.textDecoration.UNDERLINE);
          }
          break;
        case 'noUnderline':
          if (cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
            shaka.util.ArrayUtils.remove(cue.textDecoration,
                Cue.textDecoration.UNDERLINE);
          }
          break;
        case 'lineThrough':
          if (!cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
            cue.textDecoration.push(Cue.textDecoration.LINE_THROUGH);
          }
          break;
        case 'noLineThrough':
          if (cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
            shaka.util.ArrayUtils.remove(cue.textDecoration,
                Cue.textDecoration.LINE_THROUGH);
          }
          break;
        case 'overline':
          if (!cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
            cue.textDecoration.push(Cue.textDecoration.OVERLINE);
          }
          break;
        case 'noOverline':
          if (cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
            shaka.util.ArrayUtils.remove(cue.textDecoration,
                Cue.textDecoration.OVERLINE);
          }
          break;
      }
    }
  }
Parses text decoration values and adds/removes them to/from the cue.

@param {!shaka.text.Cue} cue
@param {string} decoration
@private