If Horn is still around, the seat is definitely getting cracked. The slightly more interesting question is what happens if she loses in 2020 - do they keep it mostly intact to preserve a district for Oklahoma County Republicans, or do they leave just enough to keep the new representative safe from a primary and crack the rest?
If Horn loses in 2020 I think they spin off the most firmly minority areas off into the Panhandle district while keeping the rest of OKC in one district.
That’s what Dems used to do to try and keep their hold on the Panhandle district.