To avoid breaking things, functions that return the type cast away
the constness for now. This, however, makes it easier to use typ::Type
with these classes, as typ::Type stores pointers to const types. This
also brings us one step closer to constifying types everywhere.
Bug: tint:724
Change-Id: Ia3f4b76f375184dd09b8041c1f60bf1afaefe629
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/48740
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>