Besides the fact that you've abstracted this a lot, which is usually unnecessary for FOSS scripts, you need to describe what you are doing to potential end users in your content area including exposing them to a third party ad system. e.g. a privacy invasion.

Target code:

    window.google_ad_client = "ca-pub-5878021809689194";
    window.google_ad_slot = "1479874665";