Google Storage support was recently added. This storage service makes use of the PHP API provided by Google. You will need the API along with your credentials and security keys to use this service.
To start using this, you must create a container for Google Storage. You will need your email address and the P12 formatted key provided by Google. Upload your key and provide your email address along with the bucket you want to use in the container creation UI.
Once the container is created, it can then be added to a class.