static createWindowedCue(startTime, endTime, payload,
      serviceNumber, windowId, rowCount, colCount, anchorId) {
    const cue = new shaka.text.Cue(startTime, endTime, payload);
    const region = cue.region;
    const AnchorId = shaka.cea.Cea708Window.AnchorId;

    region.id = 'svc' + serviceNumber + 'win' + windowId;
    region.height = rowCount;
    region.width = colCount;
    region.heightUnits = shaka.text.CueRegion.units.LINES;
    region.widthUnits = shaka.text.CueRegion.units.LINES;
    region.viewportAnchorUnits = shaka.text.CueRegion.units.LINES;

    if (typeof anchorId === 'number') {
      switch (anchorId) {
        case AnchorId.UPPER_LEFT:
          region.regionAnchorX = 0;
          region.regionAnchorY = 0;
          break;
        case AnchorId.UPPER_CENTER:
          region.regionAnchorX = 50;
          region.regionAnchorY = 0;
          break;
        case AnchorId.UPPER_RIGHT:
          region.regionAnchorX = 100;
          region.regionAnchorY = 0;
          break;
        case AnchorId.MIDDLE_LEFT:
          region.regionAnchorX = 0;
          region.regionAnchorY = 50;
          break;
        case AnchorId.MIDDLE_CENTER:
          region.regionAnchorX = 50;
          region.regionAnchorY = 50;
          break;
        case AnchorId.MIDDLE_RIGHT:
          region.regionAnchorX = 100;
          region.regionAnchorY = 50;
          break;
        case AnchorId.LOWER_LEFT:
          region.regionAnchorX = 0;
          region.regionAnchorY = 100;
          break;
        case AnchorId.LOWER_CENTER:
          region.regionAnchorX = 50;
          region.regionAnchorY = 100;
          break;
        case AnchorId.LOWER_RIGHT:
          region.regionAnchorX = 100;
          region.regionAnchorY = 100;
          break;
      }
    }

    return cue;
  }
Create shaka Cue with region updated to a specific value.
@param {number} startTime
@param {number} endTime
@param {string} payload
@param {number} serviceNumber
@param {number} windowId
@param {number} rowCount
@param {number} colCount
@param {number=} anchorId
@return {!shaka.text.Cue}