code: public void clearPersistedFiles(List<Long> persistedFiles) {
      synchronized (mLock) {
        for (long persistedId : persistedFiles) {
          mPersistedUfsFingerprints.remove(persistedId);
        }
      }
    }
docs: Clears the given persisted files stored in {@link #mPersistedUfsFingerprints}.
  
  @param persistedFiles the list of persisted files to clear