code: function onFetchSignInMethodsForEmail() {
    var email = $('#fetch-sign-in-methods-email').val();
    auth.fetchSignInMethodsForEmail(email).then(function(signInMethods) {
      log('Sign in methods for ' + email + ' :');
      log(signInMethods);
      if (signInMethods.length == 0) {
        alertSuccess('Sign In Methods for ' + email + ': N/A');
      } else {
        alertSuccess(
            'Sign In Methods for ' + email +': ' + signInMethods.join(', '));
      }
    }, onAuthError);
  }
docs: Gets the list of possible sign in methods for the given email address.