importKeyring_(file) {
    utils.readFile(file, goog.bind(function(contents) {
      this.actionExecutor_.execute(
          /** @type {!messages.ApiRequest} */ ({
            action: constants.Actions.IMPORT_KEY,
            content: contents,
            passphraseCallback: goog.bind(this.renderPassphraseCallback_, this)
          }),
          this, goog.bind(function(res) {
            var dialog = new dialogs.Generic(
                chrome.i18n.getMessage('welcomeKeyImport'),
                this.hideKeyringSetup_, dialogs.InputType.NONE);
            this.removeChild(this.keyringMgmt_, false);
            this.addChild(dialog, false);
            dialog.decorate(this.keyringMgmt_.getElement());
          }, this));
    }, this));
  }
Imports a keyring from a file and appends it to the current keyring.
@param {!File} file The file to import.
@private