In D3D11, check for 16-bit texture support and use if possible BUG=angleproject:1002 Changed since last failed 16-bit patch: - Disabled usage of 16-bit DXGI textures on all Intel cards - Added DXGI->GL conversion entries for 16-bit formats, which fixes FBO readback issues. The ES CTS and dEQP tests which failed with the last patch now pass. Change-Id: Ib66abf73f23dbb4329f0a32d7f3dafbbc23e6c08 Reviewed-on: https://chromium-review.googlesource.com/273712 Tested-by: Austin Kinross <aukinros@microsoft.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>