static isTypeSupported(type) {
    const supportMap = shaka.media.Capabilities.MediaSourceTypeSupportMap;
    if (supportMap.has(type)) {
      return supportMap.get(type);
    }
    const mediaSource = window.ManagedMediaSource || window.MediaSource;
    if (mediaSource) {
      const currentSupport = mediaSource.isTypeSupported(type);
      supportMap.set(type, currentSupport);
      return currentSupport;
    }
    return false;
  }
Cache browser engine call to improve performance on some poor platforms

@param {string} type
@return {boolean}