The elements of the VectorRef is now immutable, but can be
moved, if the caller relinquishes ownership by explicitly using
std::move() at the callsite.
Also add utils::Empty as a way of signalling that a vector should be
constructed with no elements. This is helpful in templated code where
{} cannot be used due to overload ambiguity.
Change-Id: I24a50a13956b0692771a8bc9046336ad46261562
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/97842
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>