Revert of Revert of Move DstCopy on gpu into the GrXferProcessor.

src/gpu/effects/GrDisableColorXP.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDisableColorXP_DEFINED
 #define GrDisableColorXP_DEFINED
 
 #include "GrTypes.h"
 #include "GrXferProcessor.h"
 
 class GrProcOptInfo;
 
 /**
  * This xfer processor disables color writing. Thus color and coverage and ignored and no blending
  * occurs. This XP is usful for things like stenciling.
  */
 class GrDisableColorXP : public GrXferProcessor {
 public:
     static GrXferProcessor* Create() {
         return SkNEW(GrDisableColorXP);
     }
 
     ~GrDisableColorXP() SK_OVERRIDE {};
 
     const char* name() const SK_OVERRIDE { return "Disable Color"; }
 
-    void getGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const SK_OVERRIDE;
-
     GrGLXferProcessor* createGLInstance() const SK_OVERRIDE;
 
     bool hasSecondaryOutput() const SK_OVERRIDE { return false; }
 
     GrXferProcessor::OptFlags getOptimizations(const GrProcOptInfo& colorPOI,
                                                const GrProcOptInfo& coveragePOI,
                                                bool doesStencilWrite,
                                                GrColor* color,
                                                const GrDrawTargetCaps& caps) SK_OVERRIDE {
         return GrXferProcessor::kIgnoreColor_OptFlag | GrXferProcessor::kIgnoreCoverage_OptFlag;
     }
 
     void getBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const SK_OVERRIDE;
 
 private:
     GrDisableColorXP();
 
+    void onGetGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const SK_OVERRIDE;
+
     bool onIsEqual(const GrXferProcessor& xpBase) const SK_OVERRIDE {
         return true;
     }
 
     typedef GrXferProcessor INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrDisableColorXPFactory : public GrXPFactory {
 public:
     static GrXPFactory* Create() {
         return SkNEW(GrDisableColorXPFactory);
     }
 
-    GrXferProcessor* createXferProcessor(const GrProcOptInfo& colorPOI,
-                                         const GrProcOptInfo& coveragePOI) const SK_OVERRIDE;
-
     bool supportsRGBCoverage(GrColor knownColor, uint32_t knownColorFlags) const SK_OVERRIDE {
         return true;
     }
 
     bool canApplyCoverage(const GrProcOptInfo& colorPOI,
                           const GrProcOptInfo& coveragePOI) const SK_OVERRIDE {
         return true;
     }
 
     bool canTweakAlphaForCoverage() const SK_OVERRIDE { return true; }
 
     void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
                             GrXPFactory::InvariantOutput* output) const SK_OVERRIDE {
         output->fBlendedColorFlags = 0;
         output->fWillBlendWithDst = 0;
     }
 
-    bool willReadDst() const SK_OVERRIDE { return false; }
-
 private:
     GrDisableColorXPFactory();
 
+    GrXferProcessor* onCreateXferProcessor(const GrProcOptInfo& colorPOI,
+                                           const GrProcOptInfo& coveragePOI,
+                                           const GrDeviceCoordTexture* dstCopy) const SK_OVERRIDE;
+
+    bool willReadDstColor() const SK_OVERRIDE { return false; }
+
     bool onIsEqual(const GrXPFactory& xpfBase) const SK_OVERRIDE {
         return true;
     }
 
     GR_DECLARE_XP_FACTORY_TEST;
 
     typedef GrXPFactory INHERITED;
 };
 
 #endif