Add mixed samples support to XPs

src/gpu/effects/GrDisableColorXP.h

Index: src/gpu/effects/GrDisableColorXP.h
diff --git a/src/gpu/effects/GrDisableColorXP.h b/src/gpu/effects/GrDisableColorXP.h
index ee2ed5300b853719547eaf9abb6bb6132e1f9825..2f57064cfbb3689278b9602887e75cf94b4912d2 100644
--- a/src/gpu/effects/GrDisableColorXP.h
+++ b/src/gpu/effects/GrDisableColorXP.h
@@ -35,11 +35,13 @@ private:
     GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                            const GrProcOptInfo& colorPOI,
                                            const GrProcOptInfo& coveragePOI,
+                                           bool hasMixedSamples,
                                            const DstTexture* dstTexture) const override;
 
     bool willReadDstColor(const GrCaps& caps,
                           const GrProcOptInfo& colorPOI,
-                          const GrProcOptInfo& coveragePOI) const override {
+                          const GrProcOptInfo& coveragePOI,
+                          bool hasMixedSamples) const override {
         return false;
     }