/**
   * Save {@link Bookmark} instance into its {@link SharedPreferences}.
   *
   * @return true on success, false on failure.
   */
  private boolean writeBookmark(final SharedPreferences prefs, final Bookmark bookmark) {
    final SharedPreferences.Editor editor = prefs.edit();

    AbstractUserProfileStorage.writeUserProfile(editor, bookmark);
    BookmarkStorage.writeBookmark(editor, bookmark);

    return check(editor.commit(), R.string.io_error);
  }
  /**
   * Load {@link Bookmark} instance from its {@link SharedPreferences}.
   *
   * @param prefs prefs.
   * @param basename basename.
   * @param title title.
   * @return Profile.
   */
  protected Bookmark readBookmark(
      final SharedPreferences prefs, final String basename, final String title) {
    final Bookmark bookmark = new Bookmark(basename, title);

    AbstractUserProfileStorage.readUserProfile(prefs, bookmark);
    BookmarkStorage.readBookmark(prefs, bookmark);

    return bookmark;
  }