PipelineBase now collects the EntryPointMetadata for all its
stages which makes the rest of the code agnostic to the entrypoint
name (except D3D12 and OpenGL that required transition hacks and
will be fixed in follow-up CLs).
Bug: dawn:216
Change-Id: I643da198cb2a20a9d94d805a2dc783d6d4346ae9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/27260
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>