code: public Asset OpenNonAsset(final String filename,
        ApkAssetsCookie cookie, Asset.AccessMode mode) {
      ATRACE_CALL();
      if (cookie.intValue() < 0 || cookie.intValue() >= apk_assets_.size()) {
        return null;
      }
      return apk_assets_.get(cookie.intValue()).Open(filename, mode);
    }
docs: Asset.AccessMode mode);