Add SkSourceGammaTreatment enum so we know how to create mips

src/core/SkShader.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAtomics.h"
 #include "SkBitmapProcShader.h"
 #include "SkColorShader.h"
@@ skipping 203 matching lines @@
     return mc;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
     return kNone_GradientType;
 }
 
 const GrFragmentProcessor* SkShader::asFragmentProcessor(GrContext*, const SkMatrix&,
-                                                         const SkMatrix*, SkFilterQuality)  const {
+                                                         const SkMatrix*, SkFilterQuality,
+                                                         SkSourceGammaTreatment)  const {
     return nullptr;
 }
 
 SkShader* SkShader::refAsALocalMatrixShader(SkMatrix*) const {
     return nullptr;
 }
 
 sk_sp<SkShader> SkShader::MakeEmptyShader() { return sk_make_sp<SkEmptyShader>(); }
 
 sk_sp<SkShader> SkShader::MakeColorShader(SkColor color) { return sk_make_sp<SkColorShader>(color); }
@@ skipping 54 matching lines @@
 }
 #endif
 
 #ifdef SK_SUPPORT_LEGACY_XFERMODE_PTR
 #include "SkXfermode.h"
 sk_sp<SkShader> SkShader::MakeComposeShader(sk_sp<SkShader> dst, sk_sp<SkShader> src,
                                             SkXfermode* xfer) {
     return MakeComposeShader(std::move(dst), std::move(src), sk_ref_sp(xfer));
 }
 #endif