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

src/gpu/effects/GrCoverageSetOpXP.h

Index: src/gpu/effects/GrCoverageSetOpXP.h
diff --git a/src/gpu/effects/GrCoverageSetOpXP.h b/src/gpu/effects/GrCoverageSetOpXP.h
index e8900b3604ecd315bca366982199ad077b2267ca..4bfc431cb8923f3d1733f76a0a7dbec32e12b1dc 100644
--- a/src/gpu/effects/GrCoverageSetOpXP.h
+++ b/src/gpu/effects/GrCoverageSetOpXP.h
@@ -22,11 +22,6 @@ public:
         return true;
     }
 
-    bool canApplyCoverage(const GrProcOptInfo& colorPOI,
-                          const GrProcOptInfo& coveragePOI) const SK_OVERRIDE {
-        return true;
-    }
-
     bool canTweakAlphaForCoverage() const SK_OVERRIDE { return false; }
 
     void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,