showInvalidCode = function(errorMessage) {
    // No code provided.
    component.getPhoneConfirmationCodeElement().focus();
    firebaseui.auth.ui.element.setValid(
        component.getPhoneConfirmationCodeElement(), false);
    firebaseui.auth.ui.element.show(
        component.getPhoneConfirmationCodeErrorElement(), errorMessage);
  }
@param {!firebaseui.auth.AuthUI} app The current Firebase UI instance whose
    configuration is used.
@param {!firebaseui.auth.ui.page.PhoneSignInFinish} component The UI
    component.
@param {!firebaseui.auth.PhoneNumber} phoneNumberValue
    The value of the phone number input.
@param {!Object} phoneAuthResult The phone Auth result used to verify
    the code on.
@private