Shopify/active_merchant — pull request #402 by courtland (2012-07-09 22:28:00+00:00)
Title: Add support for First Data offsite payment gateway

Add support for the First Data payment pages API as described in the following URL.

https://firstdata.zendesk.com/entries/407522-first-data-global-gateway-e4sm-payment-pages-integration-manual

First Data basically emulates Authorize.Net SIM, so the new FirstData classes (notification, helper, etc) inherit from the existing AuthorizeNetSim classes.