Skia-dawn found these; not sure why Chrome and Dawn standalone don't.
Change-Id: I43706fbaca94d1718de0be727151dd8f3a191df2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/9220
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
HashCombine will be used in more than just BindGroupLayout caching so we
extract it to a separate header. Add a better mixing constant for 64bit
systems.