processDrmInfos(keySystem, stream) {
    for (const drmInfo of stream.drmInfos) {
      // Ignore any data for different key systems.
      if (drmInfo.keySystem == keySystem) {
        for (const initData of (drmInfo.initData || [])) {
          this.drmEngine_.newInitData(
              initData.initDataType, initData.initData);
        }
      }
    }
  }
@param {string} keySystem
@param {!shaka.extern.Stream} stream