Add SkSourceGammaTreatment enum so we know how to create mips

src/effects/gradients/SkSweepGradient.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 "SkSweepGradient.h"
 
 static SkMatrix translate(SkScalar dx, SkScalar dy) {
@@ skipping 175 matching lines @@
 
     SkColor colors[kMaxRandomGradientColors];
     SkScalar stopsArray[kMaxRandomGradientColors];
     SkScalar* stops = stopsArray;
     SkShader::TileMode tmIgnored;
     int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tmIgnored);
     sk_sp<SkShader> shader(SkGradientShader::MakeSweep(center.fX, center.fY,  colors, stops,
                                                        colorCount));
     const GrFragmentProcessor* fp = shader->asFragmentProcessor(d->fContext,
                                                                 GrTest::TestMatrix(d->fRandom),
-                                                                NULL, kNone_SkFilterQuality);
+                                                                NULL, kNone_SkFilterQuality, false);
     GrAlwaysAssert(fp);
     return fp;
 }
 
 /////////////////////////////////////////////////////////////////////
 
 void GrGLSweepGradient::emitCode(EmitArgs& args) {
     const GrSweepGradient& ge = args.fFp.cast<GrSweepGradient>();
     this->emitUniforms(args.fUniformHandler, ge);
     SkString coords2D = args.fFragBuilder->ensureFSCoords2D(args.fCoords, 0);
@@ skipping 16 matching lines @@
                     args.fInputColor,
                     args.fTexSamplers);
 }
 
 /////////////////////////////////////////////////////////////////////
 
 const GrFragmentProcessor* SkSweepGradient::asFragmentProcessor(
                                                     GrContext* context,
                                                     const SkMatrix& viewM,
                                                     const SkMatrix* localMatrix,
-                                                    SkFilterQuality) const {
+                                                    SkFilterQuality,
+                                                    bool gammaCorrect) const {
 
     SkMatrix matrix;
     if (!this->getLocalMatrix().invert(&matrix)) {
         return nullptr;
     }
     if (localMatrix) {
         SkMatrix inv;
         if (!localMatrix->invert(&inv)) {
             return nullptr;
         }
@@ skipping 16 matching lines @@
     str->appendScalar(fCenter.fX);
     str->append(", ");
     str->appendScalar(fCenter.fY);
     str->append(") ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif