Create fragment processor for performing input color blend with child processor

src/effects/SkArithmeticMode.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkArithmeticMode.h"
 #include "SkColorPriv.h"
 #include "SkReadBuffer.h"
@@ skipping 13 matching lines @@
         return new SkArithmeticMode_scalar(k1, k2, k3, k4, enforcePMColor);
     }
 
     virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
                         const SkAlpha aa[]) const override;
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkArithmeticMode_scalar)
 
 #if SK_SUPPORT_GPU
-    bool asFragmentProcessor(GrFragmentProcessor**, GrProcessorDataManager*,
-                             GrTexture* background) const override;
+    bool asFragmentProcessor(const GrFragmentProcessor**, GrProcessorDataManager*,
+                             const GrFragmentProcessor* dst) const override;
 
     bool asXPFactory(GrXPFactory**) const override;
 #endif
 
 private:
     SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, bool enforcePMColor) {
         fK[0] = k1;
         fK[1] = k2;
         fK[2] = k3;
         fK[3] = k4;
@@ skipping 182 matching lines @@
         return new SkArithmeticMode_linear  (i2, i3, i4);
 #endif
     }
     return SkArithmeticMode_scalar::Create(k1, k2, k3, k4, enforcePMColor);
 }
 
 
 //////////////////////////////////////////////////////////////////////////////
 
 #if SK_SUPPORT_GPU
-bool SkArithmeticMode_scalar::asFragmentProcessor(GrFragmentProcessor** fp,
+bool SkArithmeticMode_scalar::asFragmentProcessor(const GrFragmentProcessor** fp,
                                                   GrProcessorDataManager* procDataManager,
-                                                  GrTexture* background) const {
+                                                  const GrFragmentProcessor* dst) const {
     if (fp) {
         *fp = GrArithmeticFP::Create(procDataManager,
                                      SkScalarToFloat(fK[0]),
                                      SkScalarToFloat(fK[1]),
                                      SkScalarToFloat(fK[2]),
                                      SkScalarToFloat(fK[3]),
                                      fEnforcePMColor,
-                                     background);
+                                     dst);
     }
     return true;
 }
 
 bool SkArithmeticMode_scalar::asXPFactory(GrXPFactory** xpf) const {
     if (xpf) {
         *xpf = GrArithmeticXPFactory::Create(SkScalarToFloat(fK[0]),
                                              SkScalarToFloat(fK[1]),
                                              SkScalarToFloat(fK[2]),
                                              SkScalarToFloat(fK[3]),
                                              fEnforcePMColor);
     }
     return true;
 }
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END