Provide on login and create user event dispatchers

Updated title for better description

Oops should say event dispatchers

And here is a patch. I added a third event for the user fields are being initialized before creating the user entity. For example, the social auth facebook can use this to adds it's extras fields instead of using it's own create user. To test this patch you can add something like:

mymodule.user_created:
    class: Drupal\mymodule\EventSubscriber\UserCreatedSubscriber
    arguments: []
    tags:
      - { name: 'event_subscriber' }

In your mymodule.services.yml and inside UserCreatedSubscriber.php


<?php

namespace Drupal\mymodule\EventSubscriber;

use Drupal\social_auth\Event\SocialAuthEvent;
use Drupal\social_auth\Event\SocialAuthEvents;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Class UserCreatedSubscriber.
 */
class UserCreatedSubscriber implements EventSubscriberInterface {
  
  /**
   * Updates the user name
   * @param \Drupal\social_auth\Event\SocialAuthEvent $event
   */
  public function onUserCreated(SocialAuthEvent $event) {
    $user = $event->getUser();
    // adding a suffix on username to test
    $user->setUsername($user->getDisplayName() . 'bing');
    $user->save();
  }

  /**
   * {@inheritdoc}
   */
  static function getSubscribedEvents() {
    $events[SocialAuthEvents::USER_CREATED] = ['onUserCreated'];
    return $events;
  }

}



Added a plugin_id argument to be passed for when creating or login user through social auth. If this get committed then we will have to update social_auth_google to do something like

<?php
$this->userManager->loginUser($drupal_user, 'social_auth_google');

$this->userManager->createUser($user->getName(), $user->getEmail(), 'social_auth_google');
?>

in it's code.