Emulate GL_EXT_sRGB on ES 3.0 devices without native support. Translate the extension's internal formats and formats to values valid in core ES 3.0. Bug: angleproject:4655 Change-Id: Ie47d01fb2ebca7bab5058812c9f4217523f784a0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2213262 Commit-Queue: Kenneth Russell <kbr@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>