Pass in ProcOptInfos into willNeedDstCopy on XPs

src/gpu/effects/GrCustomXfermodePriv.h

Index: src/gpu/effects/GrCustomXfermodePriv.h
diff --git a/src/gpu/effects/GrCustomXfermodePriv.h b/src/gpu/effects/GrCustomXfermodePriv.h
index 2a2f69f69eff099083331abd0e64dbec66e9a952..959b0796039688628630668e5d56592d743ad1ff 100644
--- a/src/gpu/effects/GrCustomXfermodePriv.h
+++ b/src/gpu/effects/GrCustomXfermodePriv.h
@@ -81,7 +81,10 @@ private:
                                            const GrProcOptInfo& coveragePOI,
                                            const GrDeviceCoordTexture* dstCopy) const SK_OVERRIDE; 
 
-    bool willReadDstColor() const SK_OVERRIDE { return true; }
+    bool willReadDstColor(const GrProcOptInfo& colorPOI,
+                          const GrProcOptInfo& coveragePOI) const SK_OVERRIDE {
+        return true;
+    }
 
     bool onIsEqual(const GrXPFactory& xpfBase) const SK_OVERRIDE {
         const GrCustomXPFactory& xpf = xpfBase.cast<GrCustomXPFactory>();