dan sinclair c7f51b7d3c ast: Support decoration kind hierarchies
Instead of just having a single `DecorationKind` for the first
derivation from `Decoration`, have a `DecorationKind` for every
decoration type.

Add `Decoration::IsKind()` to test whether the decoration is of, or
derives from the given kind.

Note, this change is originally by bclayton@ from
https://dawn-review.googlesource.com/c/tint/+/33201

R=bclayton@google.com

Bug: tint:287
Change-Id: I69b51dfaa3f82ef4d61cda383b2f98f401013429
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/33280
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>
Auto-Submit: dan sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
2020-11-18 19:33:30 +00:00
..
2020-11-18 03:17:39 +00:00
2020-11-03 16:26:09 +00:00
2020-11-02 18:02:18 +00:00