non-linear blending first steps

Code:
  - Add a non-linear blending bit and makeNonlinearBlending()
    to SkColorSpace
  - remove enough F16=linear checks to make it possible to
    create surfaces and encode pngs with nonlinear F16

Testing:
  - add "esrgb" software config to DM, run it
  - add "srgbnl" software config, run it
  - deemphasize importance of "srgb" config on bots
  - update unit tests to reflect relaxed F16 constraints
  - add a new unit test file with _really_ basic tests,
    and a new unit test that's not working yet

Bug: skia:7942

Change-Id: I8ac042bdf9f3d791765393b68fd9256375184d83
Reviewed-on: https://skia-review.googlesource.com/127325
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 34362ef31e..d5768ed3e3 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -903,6 +903,7 @@ static Sink* create_sink(const GrContextOptions& grCtxOptions, const SkCommandLi
     if (FLAGS_cpu) {
         auto srgbColorSpace = SkColorSpace::MakeSRGB();
         auto srgbLinearColorSpace = SkColorSpace::MakeSRGBLinear();
+        auto esrgb = SkColorSpace::MakeSRGB()->makeNonlinearBlending();
 
         SINK("g8",      RasterSink, kGray_8_SkColorType);
         SINK("565",     RasterSink, kRGB_565_SkColorType);
@@ -915,6 +916,8 @@ static Sink* create_sink(const GrContextOptions& grCtxOptions, const SkCommandLi
         SINK("1010102", RasterSink, kRGBA_1010102_SkColorType);
         SINK("101010x", RasterSink, kRGB_101010x_SkColorType);
         SINK("f16",     RasterSink, kRGBA_F16_SkColorType, srgbLinearColorSpace);
+        SINK("esrgb",   RasterSink, kRGBA_F16_SkColorType, esrgb);
+        SINK("srgbnl",  RasterSink, kRGBA_8888_SkColorType, esrgb);
         SINK("t8888",   ThreadedSink, kN32_SkColorType);
         SINK("pdf",     PDFSink, false, SK_ScalarDefaultRasterDPI);
         SINK("skp",     SKPSink);