These were not marked as optional previously because it would mean that
C++ methods would look like void F(a = null, b, c) which is invalid in C++
because default arguments must be contiguous and at the end of the
signature.
This commit adds a special case when optional=true where no_default=true
still marks the argument as optional, but doesn't produce a C++ default
argument.
Fixed: dawn:1502
Change-Id: I1b648d37edb94b8412109fc0a06a91bbbd31b8c4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/97002
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>