Similar to 2fbf206491, but for integers (not strings). Essentially this
allows passing named integer values through UI abstractions in a clean
way.
I used 64 bit integers here, since space isn't an issue here, and it
fits common integer types (so we don't have to add APIs for multiple
integer types).
Planned to be used to fix#111463 (following commit).
f6a4d01703