The thing with the freezing chamber in ESB was that the facilities and the freezing compound (carbonite) were not commonly used for freezing humanoids. I find it implied that cryogenic freezing did exist in the Star Wars universe, but that another technique was more common.
In the Clone Wars episode, I think that it would make sense if they were using a proper cryogenic freezing facility for the freezing process, freezing them within a proper cryogenic freezing medium... but it has been made public that carbonite is used ...
By the way, a short clip of Tarkin is available now. The American voice actor fails horribly at trying to emulate Peter Cushing's accent ...