constructor(
      pgpKeys, exportKeyringCallback, importKeyringCallback,
      updateKeyringPassphraseCallback, restoreKeyringCallback,
      exportKeyCallback, removeKeyCallback) {
    super();

    /**
     * The PGP keys stored in the extension.
     * @type {!goog.structs.Map}
     * @private
     */
    this.pgpKeys_ = new goog.structs.Map(pgpKeys);

    /**
     * Provides keyring-wide management controls.
     * @type {!panels.KeyringMgmtMini}
     * @private
     */
    this.keyringMgmtControls_ = new panels.KeyringMgmtMini(
        exportKeyringCallback, importKeyringCallback,
        updateKeyringPassphraseCallback, restoreKeyringCallback);

    /**
     * The callback to invoke when a single PGP key is to be exported.
     * @type {!function(string)}
     * @private
     */
    this.exportKeyCallback_ = exportKeyCallback;

    /**
     * The callback to invoke when a single PGP key is to be removed.
     * @type {!function(string)}
     * @private
     */
    this.removeKeyCallback_ = removeKeyCallback;
  }
@param {!Object} pgpKeys A collection of raw PGP keys.
@param {!function()} exportKeyringCallback The callback to invoke when the
    keyring is to be exported.
@param {!function(!File)} importKeyringCallback The callback to invoke when
    an existing keyring is to be imported.
@param {!function(string)} updateKeyringPassphraseCallback The callback to
    invoke when the passphrase to the keyring is to be updated.
@param {!function(string)} restoreKeyringCallback The callback to invoke
    when the keyring is restored.
@param {!function(string)} exportKeyCallback The callback to invoke when a
    single PGP key is to be exported.
@param {!function(string)} removeKeyCallback The callback to invoke when a
    single PGP key is to be removed.