Packaged eWAY classes not loaded for Event registration

Issue appears for PHP 5.5

During event registration process, when the eWAY payment processor is used, the registration fails with the relevant PHP error:

Class 'GatewayRequest' not found in /home/site_user/public_html/sites/all/modules/civicrm/CRM/Core/Payment/eWAY.php on line 152

This appears to be a result of the constructor, which includes those files, not being called for this page.
Oddly the Contribution pages work okay.

This may have something to do with caching the PaymentProcessor in the form.

I think this can probably be fixed in the eWAY processor specifically by moving the inclusion of the class files to the doDirectPayment function, as they are not used outside of this function.

In a more general case it looks like for the registration form that you can't rely on everything set up in the constructor to still be present