Remove canApplyCoverage from XP and all related functions in gpu code.

include/gpu/effects/GrPorterDuffXferProcessor.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 GrPorterDuffXferProcessor_DEFINED
 #define GrPorterDuffXferProcessor_DEFINED
 
@@ skipping 10 matching lines @@
     static GrXPFactory* Create(SkXfermode::Coeff src, SkXfermode::Coeff dst) {
         return SkNEW_ARGS(GrPorterDuffXPFactory, ((GrBlendCoeff)(src), (GrBlendCoeff)(dst)));
     }
 
     static GrXPFactory* Create(GrBlendCoeff src, GrBlendCoeff dst) {
         return SkNEW_ARGS(GrPorterDuffXPFactory, (src, dst));
     }
 
     bool supportsRGBCoverage(GrColor knownColor, uint32_t knownColorFlags) const SK_OVERRIDE;
 
-    bool canApplyCoverage(const GrProcOptInfo& /*colorPOI*/,
-                          const GrProcOptInfo& /*coveragePOI*/) const SK_OVERRIDE {
-        return true;
-    }
-
     bool canTweakAlphaForCoverage() const SK_OVERRIDE;
 
     void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
                             GrXPFactory::InvariantOutput*) const SK_OVERRIDE;
 
 private:
     GrPorterDuffXPFactory(GrBlendCoeff src, GrBlendCoeff dst); 
 
     GrXferProcessor* onCreateXferProcessor(const GrDrawTargetCaps& caps,
                                            const GrProcOptInfo& colorPOI,
@@ skipping 11 matching lines @@
 
     GR_DECLARE_XP_FACTORY_TEST;
 
     GrBlendCoeff fSrcCoeff;
     GrBlendCoeff fDstCoeff;
 
     typedef GrXPFactory INHERITED;
 };
 
 #endif