cloneFrame = (frame) => {
      if (!frame) {
        return null;
      }
      const clone = shaka.util.ObjectUtils.shallowCloneObject(frame);
      clone.segmentBase = null;
      clone.segmentList = null;
      clone.segmentTemplate = shaka.util.TXml.cloneNode(clone.segmentTemplate);
      clone.producerReferenceTime = null;
      return clone;
    }
@param {?shaka.dash.DashParser.InheritanceFrame} frame
@return {?shaka.dash.DashParser.InheritanceFrame}