Add destination color space to AsFPArgs. Eliminates last XFORMTODO.

src/effects/gradients/SkLinearGradient.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Sk4fLinearGradient.h"
 #include "SkLinearGradient.h"
 #include "SkRefCnt.h"
@@ skipping 402 matching lines @@
                         {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()}};
 
     SkColor colors[kMaxRandomGradientColors];
     SkScalar stopsArray[kMaxRandomGradientColors];
     SkScalar* stops = stopsArray;
     SkShader::TileMode tm;
     int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
     auto shader = SkGradientShader::MakeLinear(points, colors, stops, colorCount, tm);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
-        d->fContext, &viewMatrix, NULL, kNone_SkFilterQuality, SkSourceGammaTreatment::kRespect));
+        d->fContext, &viewMatrix, NULL, kNone_SkFilterQuality, nullptr,
+        SkSourceGammaTreatment::kRespect));
     GrAlwaysAssert(fp);
     return fp;
 }
 
 /////////////////////////////////////////////////////////////////////
 
 void GrGLLinearGradient::emitCode(EmitArgs& args) {
     const GrLinearGradient& ge = args.fFp.cast<GrLinearGradient>();
     this->emitUniforms(args.fUniformHandler, ge);
     SkString t = args.fFragBuilder->ensureFSCoords2D(args.fCoords, 0);
@@ skipping 318 matching lines @@
             this->shade4_dx_clamp<false, true>(dstC, count, fx, dx, invDx, dither);
         }
     } else {
         if (fApplyAlphaAfterInterp) {
             this->shade4_dx_clamp<true, false>(dstC, count, fx, dx, invDx, dither);
         } else {
             this->shade4_dx_clamp<false, false>(dstC, count, fx, dx, invDx, dither);
         }
     }
 }