Revert of Move DstCopy on gpu into the GrXferProcessor.

src/effects/SkArithmeticMode_gpu.cpp

Index: src/effects/SkArithmeticMode_gpu.cpp
diff --git a/src/effects/SkArithmeticMode_gpu.cpp b/src/effects/SkArithmeticMode_gpu.cpp
index 8022d668b4a616c70fd7ab85be29df90245c3b08..48b7bcd61026fbd68d6f22bf1473d7ff68df4035 100644
--- a/src/effects/SkArithmeticMode_gpu.cpp
+++ b/src/effects/SkArithmeticMode_gpu.cpp
@@ -166,6 +166,31 @@
 
     ~GLArithmeticXP() SK_OVERRIDE {}
 
+    void emitCode(const EmitArgs& args) SK_OVERRIDE {
+        GrGLFPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
+
+        const char* dstColor = fsBuilder->dstColor();
+
+        fKUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
+                                     kVec4f_GrSLType, kDefault_GrSLPrecision,
+                                     "k");
+        const char* kUni = args.fPB->getUniformCStr(fKUni);
+
+        add_arithmetic_code(fsBuilder, args.fInputColor, dstColor, args.fOutputPrimary, kUni, 
+                            fEnforcePMColor);
+
+        fsBuilder->codeAppendf("%s = %s * %s + (vec4(1.0) - %s) * %s;",
+                               args.fOutputPrimary, args.fOutputPrimary, args.fInputCoverage,
+                               args.fInputCoverage, dstColor);
+    }
+
+    void setData(const GrGLProgramDataManager& pdman,
+                 const GrXferProcessor& processor) SK_OVERRIDE {
+        const GrArithmeticXP& arith = processor.cast<GrArithmeticXP>();
+        pdman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
+        fEnforcePMColor = arith.enforcePMColor();
+    };
+
     static void GenKey(const GrProcessor& processor, const GrGLCaps& caps,
                        GrProcessorKeyBuilder* b) {
         const GrArithmeticXP& arith = processor.cast<GrArithmeticXP>();
@@ -174,31 +199,6 @@
     }
 
 private:
-    void onEmitCode(const EmitArgs& args) SK_OVERRIDE {
-        GrGLFPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
-
-        const char* dstColor = fsBuilder->dstColor();
-
-        fKUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                     kVec4f_GrSLType, kDefault_GrSLPrecision,
-                                     "k");
-        const char* kUni = args.fPB->getUniformCStr(fKUni);
-
-        add_arithmetic_code(fsBuilder, args.fInputColor, dstColor, args.fOutputPrimary, kUni, 
-                            fEnforcePMColor);
-
-        fsBuilder->codeAppendf("%s = %s * %s + (vec4(1.0) - %s) * %s;",
-                               args.fOutputPrimary, args.fOutputPrimary, args.fInputCoverage,
-                               args.fInputCoverage, dstColor);
-    }
-
-    void onSetData(const GrGLProgramDataManager& pdman,
-                   const GrXferProcessor& processor) SK_OVERRIDE {
-        const GrArithmeticXP& arith = processor.cast<GrArithmeticXP>();
-        pdman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
-        fEnforcePMColor = arith.enforcePMColor();
-    };
-
     GrGLProgramDataManager::UniformHandle fKUni;
     bool fEnforcePMColor;
 
@@ -207,18 +207,17 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-GrArithmeticXP::GrArithmeticXP(float k1, float k2, float k3, float k4, bool enforcePMColor,
-                               const GrDeviceCoordTexture* dstCopy, bool willReadDstColor)
-    : INHERITED(dstCopy, willReadDstColor)
-    , fK1(k1)
+GrArithmeticXP::GrArithmeticXP(float k1, float k2, float k3, float k4, bool enforcePMColor)
+    : fK1(k1)
     , fK2(k2)
     , fK3(k3)
     , fK4(k4)
     , fEnforcePMColor(enforcePMColor) {
     this->initClassID<GrPorterDuffXferProcessor>();
-}
-
-void GrArithmeticXP::onGetGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const {
+    this->setWillReadDstColor();
+}
+
+void GrArithmeticXP::getGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const {
     GLArithmeticXP::GenKey(*this, caps, b);
 }