static computeIndexRange_(context) {
    const MpdUtils = shaka.dash.MpdUtils;
    const SegmentBase = shaka.dash.SegmentBase;
    const TXml = shaka.util.TXml;

    const representationIndex = MpdUtils.inheritChild(
        context, SegmentBase.fromInheritance_, 'RepresentationIndex');
    const indexRangeElem = MpdUtils.inheritAttribute(
        context, SegmentBase.fromInheritance_, 'indexRange');

    let indexRange = TXml.parseRange(indexRangeElem || '');
    if (representationIndex) {
      indexRange = TXml.parseAttr(
          representationIndex, 'range', TXml.parseRange, indexRange);
    }
    return indexRange;
  }
Compute the byte range of the segment index from the container.

@param {shaka.dash.DashParser.Context} context
@return {?{start: number, end: number}}
@private