NOTE: Removing this is blocked on T236731
The MobileView API was originally made for apps. Now that the MCS is being used (T103362),, its value is questionable given its maintenance cost.
The MobileView API is only used for the MainPage. This code will also be redundant upon completion of T32405.
It has been marked as deprecated in T210808. Of course deprecating should be done carefully - there may be other consumers of this API, but we should explore who they are and how we can get them using MCS.
Note: The MobileFormatter will continue to exist for MediaWiki mobile web views. The MobileView API actually has a lot of logic that is not shared by the MobileFormatter.
If all goes to plan all Wikimedia apps will be off the API come February of 2020. This is blocked on T236733 and T236731.
After that, we'll wait until the usage is low enough (in apps) to warrant its removal.
So theoretically the API will be around till at least the end of 2020