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>

4 files changed, 2 insertions, 11 deletions

diff --git a/src/codec/SkCodec.cpp b/src/codec/SkCodec.cpp
index 53fa6f4643..f67e6c06d3 100644
--- a/src/codec/SkCodec.cpp
+++ b/src/codec/SkCodec.cpp
@@ -169,7 +169,7 @@ bool SkCodec::conversionSupported(const SkImageInfo& dst, SkColorType srcColor,
         case kBGRA_8888_SkColorType:
             return true;
         case kRGBA_F16_SkColorType:
-            return dst.colorSpace() && dst.colorSpace()->gammaIsLinear();
+            return dst.colorSpace();
         case kRGB_565_SkColorType:
             return srcIsOpaque;
         case kGray_8_SkColorType:
diff --git a/src/codec/SkHeifCodec.cpp b/src/codec/SkHeifCodec.cpp
index 6e82904115..31057a0385 100644
--- a/src/codec/SkHeifCodec.cpp
+++ b/src/codec/SkHeifCodec.cpp
@@ -192,10 +192,6 @@ bool SkHeifCodec::setOutputColorFormat(const SkImageInfo& dstInfo) {
 
         case kRGBA_F16_SkColorType:
             SkASSERT(this->colorXform());
-
-            if (!dstInfo.colorSpace()->gammaIsLinear()) {
-                return false;
-            }
             return fHeifDecoder->setOutputColor(kHeifColorFormat_RGBA_8888);
 
         default:
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index 2cc7921277..d44258f9b0 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -433,11 +433,6 @@ bool SkJpegCodec::setOutputColorSpace(const SkImageInfo& dstInfo) {
             break;
         case kRGBA_F16_SkColorType:
             SkASSERT(this->colorXform());
-
-            if (!dstInfo.colorSpace()->gammaIsLinear()) {
-                return false;
-            }
-
             fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
             break;
         default:
diff --git a/src/codec/SkWbmpCodec.cpp b/src/codec/SkWbmpCodec.cpp
index d8b10287f6..b5fd591729 100644
--- a/src/codec/SkWbmpCodec.cpp
+++ b/src/codec/SkWbmpCodec.cpp
@@ -29,7 +29,7 @@ static inline bool valid_color_type(const SkImageInfo& dstInfo) {
         case kRGB_565_SkColorType:
             return true;
         case kRGBA_F16_SkColorType:
-            return dstInfo.colorSpace() && dstInfo.colorSpace()->gammaIsLinear();
+            return dstInfo.colorSpace();
         default:
             return false;
     }