R1:2b344b2bb500

Make caches misses throw by default intead of inline-generating

Summary:
Ref T4103. Ref T10078. Currently, when a user misses a cache we just build it for them.

This is the behavior we want for the the viewer (so we don't have to build every cache up front if we don't actually need them), but not the right behavior for other users (since it allows performance problems to go undetected).

Make inline cache generation strict by default, then make sure all the things that rely on cache data request the…