Here the solution how simple to track the referral inGoogle Analytics in new analytics code, Example!
Use the row: ga('set', 'referrer', document.referrer);
More Info: https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference#referrer!
Indicates the source of the traffic to a website. This value is also used to calculate the traffic source. The format of this value is a URL. This field is initialized by the create command and is set only if the current hostname is different from the hostname of the reference, unless the 'alwaysSendReferrer' field is set to true. ≶≶≶≶≶≶≶≶≶≶≶≶
FAQ 17: Updated on: March 13th 2017 20:47