This commit adds utils::MakeBindGroup to make code craeting bind groups
nicer to read. Additional tests are added that give 100% coverage of
ValidateBindGroupDescriptor.
BUG=dawn:3
Change-Id: I56e1da8c2952306ad233845b0ec3ec32aef793d9
Reviewed-on: https://dawn-review.googlesource.com/c/2802
Reviewed-by: Jiawei Shao <jiawei.shao@intel.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>