Add RAII wrappers for WebGPU C API objects. To ease the transition, add constructors from the cpp wrappers currently in use. These will be deleted when we have fully moved to the C API. Update the WebGPU CommandBuffer code to use the new wrappers and C API. Bug: angleproject:414831373 Change-Id: I428349d84e1f79725eb836da5bb3d384ae296d75 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6501618 Reviewed-by: Matthew Denton <mpdenton@chromium.org> Reviewed-by: Liza Burakova <liza@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>