Janko Roettgers of the tech news site GigaOm is reporting that Playboy.tv is developing an Android app with the intention of being available on the Google Play store and provide the capability to be
utilized by the Google Chromecast. In the article Roettgers mentions Google will likely have a terms of service agreement that prevents explicit content from being available via the Chromecast.
This issue may present a challenge for Google going forward as pornography while objectionable to some is not illegal especially if there is an age verification mechanism. Google certainly would be under no obligation