Make GrGammaEffect have explicit sRGB modes, plus exponential mode.

Convert it to a "standard" FP that just transforms the input color.

For now, we still infer the sRGB transfer curves from the exponent,
but I'm hoping that eventually SkGammas will provide us with the
exact curve we're supposed to be applying. In any case, this adds
support for doing the inverse transformation, as well, which will
be needed in an upcoming Vulkan YUV change, among other things.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1954863002

Committed: https://skia.googlesource.com/skia/+/2139303e4c0a9cbcfac695977a80eb026a9296ab

Review-Url: https://codereview.chromium.org/1954863002

0 files changed, 0 insertions, 0 deletions