IDL parser: Disallow to use Promise without return type

We allowed to use Promise without return types.
But now no specs use Promise without return types.
This CL drops the support of unspec'ed Promise use cases.


Bug: 900628
Change-Id: Ife6f6fe62894ea48f0a3d6a6778f95d7b44bd0bf
Reviewed-on: https://chromium-review.googlesource.com/c/1367069
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#614652}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 86c013f510fe87ba4f8efed31a5fe1e8efb2a408
2 files changed