Where is com google android mms

Question

I'm writing an Android app that will deliver MMS messages, and I'm trying to follow the guidelines in this post:

How can Android deliver images via MMS?

My current issue is that I can't locate the libraries that were utilised there, such as com.google.android.mms.

Can somebody direct me there?

Exists an MMS library that I can use into my project? It's a little odd that Google does not offer that to developers.

Thanks,