This adds swiftshader as a dependency of Dawn, and when it is present
dawn_use_swiftshader=true will force usage of it. (due to a Vulkan
loader limitation we can't have both regular drivers and swiftshader in
the same VkInstance).
BUG=dawn:283
Change-Id: Ib94f4dcca652eb380e994f007cdcfb145b1a5102
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/13440
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Corentin Wallez