Decouple PasswordInterface from UserInterface

Summary:

If you are implementing a class that implements PasswordInterface you will need to make a minor modification to the PasswordInterface::check() method and a minor change and rename of the PasswordInterface::userNeedsNewHash() method.

Before

use \Drupal\Core\Password\PasswordInterface;
use Drupal\user\UserInterface;

class MyPasswordHasher implements PasswordInterface {

  public function check($password, UserInterface $account) {
    password_compare($password, $user->getPassword());
  }

  public function userNeedsNewHash(UserInterface $account) {
    check_hash($user->getPassword());
  }

}

After

use \Drupal\Core\Password\PasswordInterface;

class MyPasswordHasher implements PasswordInterface {

  public function check($password, $hash) {
    password_compare($password, $hash);
  }

  public function needsRehash($hash) {
    check_hash($hash);
  }

}