Introduce GrColorSpaceXform, for gamut conversion on textures

src/gpu/effects/GrSimpleTextureEffect.cpp

Index: src/gpu/effects/GrSimpleTextureEffect.cpp
diff --git a/src/gpu/effects/GrSimpleTextureEffect.cpp b/src/gpu/effects/GrSimpleTextureEffect.cpp
index 7e7b828d3d7cbce2a298d8837c3c2c88c918162e..a452d3e6fdf064038996a9c2983ac5c9aa8f6904 100644
--- a/src/gpu/effects/GrSimpleTextureEffect.cpp
+++ b/src/gpu/effects/GrSimpleTextureEffect.cpp
@@ -68,5 +68,5 @@ sk_sp<GrFragmentProcessor> GrSimpleTextureEffect::TestCreate(GrProcessorTestData
     GrCoordSet coordSet = kCoordSets[d->fRandom->nextULessThan(SK_ARRAY_COUNT(kCoordSets))];
 
     const SkMatrix& matrix = GrTest::TestMatrix(d->fRandom);
-    return GrSimpleTextureEffect::Make(d->fTextures[texIdx], matrix, coordSet);
+    return GrSimpleTextureEffect::Make(d->fTextures[texIdx], nullptr, matrix, coordSet);
 }