This normalizes even more the directory structure of generated files in
Dawn and removes stale autogenerated files that could be included
wrongly using a GN action.
See comment on top of dawn_generator.gni in this commit for more
context.
BUG=dawn:22
Change-Id: I8ec038f949c048431b2b643af4462f98c4ae610b
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/11361
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>