D3D9: Expose EXT_sRGB and EXT_texture_compression_s3tc_srgb sRGB reads are supported on D3D9 via SetSamplerState. sRGB writes are supported on D3D9 via SetRenderState. Bug: angleproject:6258 Change-Id: I841c25ce66486e93ae2122b370e910f383fed774 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3076359 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>