updateVariant(variant, manifestType) {
    let stream = variant.video;
    if (!stream) {
      return;
    }
    if (stream.dependencyStream) {
      stream = stream.dependencyStream;
    }
    let containerFormat = shaka.lcevc.Dec.ContainerFormat.MPEG2_TS;
    let streamingFormat = shaka.lcevc.Dec.StreamingFormat.OTHER;
    switch (stream.mimeType) {
      case 'video/webm': {
        containerFormat = shaka.lcevc.Dec.ContainerFormat.WEBM;
        break;
      }
      case 'video/mp4': {
        containerFormat = shaka.lcevc.Dec.ContainerFormat.MP4;
        break;
      }
    }
    switch (manifestType) {
      case 'DASH': {
        streamingFormat = shaka.lcevc.Dec.StreamingFormat.DASH;
        break;
      }
      case 'HLS': {
        streamingFormat = shaka.lcevc.Dec.StreamingFormat.HLS;
        break;
      }
    }
    if (this.dec_) {
      this.dec_.setLevelSwitching(stream.id, true);
      this.dec_.setContainerFormat(containerFormat);
      // This functionality is only available on the LCEVC Dec Library.
      if (!this.toBeDeprecated_) {
        this.dec_.setStreamingFormat(streamingFormat);
      }
    }
  }
Update current active variant
@param {shaka.extern.Variant} variant
@param {?string} manifestType