This CL adds a DAWN_MAKE_CACHE_REQUEST X macro
which helps in building a CacheRequest struct.
A CacheRequest struct may be passed to LoadOrRun
which will generate a CacheKey from the struct and
load a result if there is a cache hit, or it will
call the provided cache miss function to compute a value.
The request struct helps enforce that precisely the
inputs that go into a computation are all also included
inside the CacheKey for that computation.
Bug: dawn:549
Change-Id: Id85eb95f1b944d5431f142162ffa9a384351be89
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/91063
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>
