D3D10+ has stricter rules on linking shader inputs with outputs than the previous comments in the code indicated. Add comments and checks related to this and structure the code in a way that makes it a bit less prone to errors. This page is intended to document the rules though it is somewhat vague: https://docs.microsoft.com/en-us/windows/desktop/direct3dhlsl/dx-graphics-hlsl-signatures BUG=angleproject:2767 TEST=angle_end2end_tests Change-Id: I236ec4cd5cbf3889fd2c97947ee81a6c5ae6a787 Reviewed-on: https://chromium-review.googlesource.com/1169818Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
