Introduce GrColorSpaceXform, for gamut conversion on textures

src/gpu/effects/GrDistanceFieldGeoProc.cpp

Index: src/gpu/effects/GrDistanceFieldGeoProc.cpp
diff --git a/src/gpu/effects/GrDistanceFieldGeoProc.cpp b/src/gpu/effects/GrDistanceFieldGeoProc.cpp
index f43a1e89946faf9195e21453e30e2ff39b6059b8..aa86e4b5229431e2181b5719b989b46d83f47194 100644
--- a/src/gpu/effects/GrDistanceFieldGeoProc.cpp
+++ b/src/gpu/effects/GrDistanceFieldGeoProc.cpp
@@ -229,7 +229,7 @@ GrDistanceFieldA8TextGeoProc::GrDistanceFieldA8TextGeoProc(GrColor color,
                                                            bool usesLocalCoords)
     : fColor(color)
     , fViewMatrix(viewMatrix)
-    , fTextureAccess(texture, params)
+    , fTextureAccess(texture, nullptr, params)
 #ifdef SK_GAMMA_APPLY_TO_A8
     , fDistanceAdjust(distanceAdjust)
 #endif
@@ -470,7 +470,7 @@ GrDistanceFieldPathGeoProc::GrDistanceFieldPathGeoProc(
         bool usesLocalCoords)
     : fColor(color)
     , fViewMatrix(viewMatrix)
-    , fTextureAccess(texture, params)
+    , fTextureAccess(texture, nullptr, params)
     , fFlags(flags & kNonLCD_DistanceFieldEffectMask)
     , fInColor(nullptr)
     , fUsesLocalCoords(usesLocalCoords) {
@@ -766,7 +766,7 @@ GrDistanceFieldLCDTextGeoProc::GrDistanceFieldLCDTextGeoProc(
                                                   uint32_t flags, bool usesLocalCoords)
     : fColor(color)
     , fViewMatrix(viewMatrix)
-    , fTextureAccess(texture, params)
+    , fTextureAccess(texture, nullptr, params)
     , fDistanceAdjust(distanceAdjust)
     , fFlags(flags & kLCD_DistanceFieldEffectMask)
     , fUsesLocalCoords(usesLocalCoords) {