I agree that `instanceof` is not optimal. Which alternative would you prefer?
- some kind of abstract `getMessageType` method in `MessageRecord`, implemented by all its descendants. In essence the same, but not using the `instanceof` keyword
- an interface that is implemented by `MessageRecord` with an `asMediaMmsRecord()` function returning `null`, overriden in `MediaMmsRecord` returning itself
- something totally obvious that I missed because I haven't done a whole lot of Java in a while

I'll be glad to change this. It would probably be a good idea to update https://github.com/WhisperSystems/TextSecure/blob/master/src/org/thoughtcrime/securesms/ConversationItem.java#L195 as well then, as it uses the exact same approach.