static modifyTimepoints(context, patchNode) {
    const MpdUtils = shaka.dash.MpdUtils;
    const SegmentTemplate = shaka.dash.SegmentTemplate;
    const TXml = shaka.util.TXml;

    const timelineNode = MpdUtils.inheritChild(context,
        SegmentTemplate.fromInheritance_, 'SegmentTimeline');
    goog.asserts.assert(timelineNode, 'timeline node not found');
    const timepoints = TXml.findChildren(timelineNode, 'S');

    goog.asserts.assert(timepoints, 'timepoints should exist');
    TXml.modifyNodes(timepoints, patchNode);
    timelineNode.children = timepoints;
  }
Ingests Patch MPD segments into timeline.

@param {!shaka.dash.DashParser.Context} context
@param {shaka.extern.xml.Node} patchNode