static support() {
    // Our Storage system is useless without MediaSource.  MediaSource allows us
    // to pull data from anywhere (including our Storage system) and feed it to
    // the video element.
    const device = shaka.device.DeviceFactory.getDevice();
    if (!device.supportsMediaSource()) {
      return false;
    }

    return shaka.offline.StorageMuxer.support();
  }
Gets whether offline storage is supported.  Returns true if offline storage
is supported for clear content.  Support for offline storage of encrypted
content will not be determined until storage is attempted.

@return {boolean}
@export