constructor(selectedUids, allUids, renderEncryptionPassphraseCallback) {
    super();

    /**
     * The UIDs that have already been selected by the user.
     * @type {!Array.<string>}
     * @private
     */
    this.selectedUids_ = selectedUids;

    /**
     * All available UIDs from which the user can choose.
     * @type {!Array.<string>}
     * @private
     */
    this.allUids_ = allUids;

    /**
     * If true, ChipHolder is locked and cannot be modified.
     * @type {boolean}
     * @private
     */
    this.isLocked_ = false;

    /**
     * Callback for rendering an passphrase encryption dialog.
     * @type {Function}
     * @private
     */
    this.renderEncryptionPassphraseCallback_ =
        renderEncryptionPassphraseCallback;
  }
@param {!Array<string>} selectedUids The UIDs that have already been
    selected.
@param {!Array<string>} allUids All UIDs that are available for selection.
@param {Function} renderEncryptionPassphraseCallback Callback for rendering
    an encryption passphrase dialog.