CiviCRM and PayPal Pro's Transparent Redirect
So far there is some support for transparent redirect in the Omnipay extension but not in the core codebase, as it requires an extra form in the process. 

It's likely that at some point Omnipay will ship with core - so developing it in this context is fine. However, although there is an Omnipay library for Paypal its not currently in the extension