Use SV_IsFrontFace to implement gl_FrontFacing on DX11. TRAC #22426 Signed-off-by: Jamie Madill Signed-off-by: Daniel Koch Author: Nicolas Capens git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1752 736b8ea6-26fd-11df-bfd4-992fa37f6226