code: function() {
          firebaseui.auth.widget.handler.common.sendEmailLinkForSignIn(
              app,
              component,
              email,
              onCancelClick,
              function(error) {
                // The email provided could be an invalid one or some other error
                // could occur.
                var errorMessage =
                    firebaseui.auth.widget.handler.common.getErrorMessage(error);
                component.showInfoBar(errorMessage);
              },
              opt_pendingCredential);
        }
docs: On resend link click.