Create a static instances of SrcOver XferProcessor

src/effects/SkArithmeticMode_gpu.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkArithmeticMode_gpu.h"
 
 #if SK_SUPPORT_GPU
@@ skipping 153 matching lines @@
     float k2() const { return fK2; }
     float k3() const { return fK3; }
     float k4() const { return fK4; }
     bool enforcePMColor() const { return fEnforcePMColor; }
 
 private:
     GrXferProcessor::OptFlags onGetOptimizations(const GrProcOptInfo& colorPOI,
                                                  const GrProcOptInfo& coveragePOI,
                                                  bool doesStencilWrite,
                                                  GrColor* overrideColor,
-                                                 const GrCaps& caps) override;
+                                                 const GrCaps& caps) const override;
 
     void onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override;
 
     bool onIsEqual(const GrXferProcessor& xpBase) const override {
         const ArithmeticXP& xp = xpBase.cast<ArithmeticXP>();
         if (fK1 != xp.fK1 ||
             fK2 != xp.fK2 ||
             fK3 != xp.fK3 ||
             fK4 != xp.fK4 ||
             fEnforcePMColor != xp.fEnforcePMColor) {
@@ skipping 69 matching lines @@
 void ArithmeticXP::onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const {
     GLArithmeticXP::GenKey(*this, caps, b);
 }
 
 GrGLSLXferProcessor* ArithmeticXP::createGLSLInstance() const { return new GLArithmeticXP(*this); }
 
 GrXferProcessor::OptFlags ArithmeticXP::onGetOptimizations(const GrProcOptInfo& colorPOI,
                                                            const GrProcOptInfo& coveragePOI,
                                                            bool doesStencilWrite,
                                                            GrColor* overrideColor,
-                                                           const GrCaps& caps) {
+                                                           const GrCaps& caps) const {
    return GrXferProcessor::kNone_OptFlags;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrArithmeticXPFactory::GrArithmeticXPFactory(float k1, float k2, float k3, float k4,
                                              bool enforcePMColor)
     : fK1(k1), fK2(k2), fK3(k3), fK4(k4), fEnforcePMColor(enforcePMColor) {
     this->initClassID<GrArithmeticXPFactory>();
 }
@@ skipping 24 matching lines @@
     float k1 = d->fRandom->nextF();
     float k2 = d->fRandom->nextF();
     float k3 = d->fRandom->nextF();
     float k4 = d->fRandom->nextF();
     bool enforcePMColor = d->fRandom->nextBool();
 
     return GrArithmeticXPFactory::Create(k1, k2, k3, k4, enforcePMColor);
 }
 
 #endif