De-virtualize NonMimeParser
This isn't used as a polymorphic type, the inheritance is just used for code sharing here. Decoupling both sub-classes from a common interface will make further changes easier, such as using views where possible.
This isn't used as a polymorphic type, the inheritance is just used for code sharing here. Decoupling both sub-classes from a common interface will make further changes easier, such as using views where possible.