IDL parser: Split promise type from NonAnyType

Promise types can't be nullable, and can't be a member of union.
This CL changes parser to do so.
Because we have no such invalid cases, this CL does not change
Chrome's behavior

Bug: 839389
Change-Id: Ib7e8f7ada2671f6624b70649dc4f0e99437d7d19
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1813120
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#698346}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 96bb213a6e5f3dbe226072c3d9255c9c82a3b2c1
1 file changed