getEmeSessionCell() {
    const mechanisms = Array.from(this.mechanisms_.keys());
    if (!mechanisms.length) {
      throw new shaka.util.Error(
          shaka.util.Error.Severity.CRITICAL,
          shaka.util.Error.Category.STORAGE,
          shaka.util.Error.Code.STORAGE_NOT_SUPPORTED,
          'No supported storage mechanisms found');
    }

    return this.mechanisms_.get(mechanisms[0]).getEmeSessionCell();
  }
Gets an arbitrary EME session cell that can be used for storing new session
info.

@return {!shaka.extern.EmeSessionStorageCell}