Cookie Protection dialog is empty in FF24

The nsCookieService does not seem to expose the Private Browsing Mode cookie database to extensions in any substantial way. Unless I missed something, there does not appear to be a way to enumerate these cookies directly. This means that the Cookie Protections Dialog (and Firefox's own Cookie Dialog) are always empty in the default TBB configuration, unless the user selects to enable history.

We should either create APIs to export and manipulate the private cookie store, or alter the cookie protections dialog to inform the user that cookie protection and manipulation is only available if they are storing disk activity.