Shooter game sample won't compile in 4.15 (FOnlineSessionSearchResult undefined)

I have a project based on the Shooter Game sample that I’m trying to migrate from 4.14 to 4.15. When attempting a compile I get the error that FOnlineSessionSearchResult is undefined in *GameInstance.h. Assuming this was my fault I downloaded the 4.15 version of Shooter Game Sample, only to find that the issue is also present in that project.

Looking at the release notes, I see that there was a bugfix regarding session searching:

BugFix: Fixed OSSNull server/session
filtering to better match Session
Settings and online OSS. Made MCP,
Steam, and Null LAN queries more

Since there was also apparently a change in the way headers are included, I suspect that some combination of these two bugfixes is the culprit.

Anyone know about this?