only call scalar finite when necessary

src/pathops/SkOpSegment.cpp

Index: src/pathops/SkOpSegment.cpp
diff --git a/src/pathops/SkOpSegment.cpp b/src/pathops/SkOpSegment.cpp
index d066794cee2a02c10eec5e9e9de42bd8c351925d..67f172e58ad5e9863a63a6d5e83e16df5d387373 100644
--- a/src/pathops/SkOpSegment.cpp
+++ b/src/pathops/SkOpSegment.cpp
@@ -1683,7 +1683,8 @@ bool SkOpSegment::testForCoincidence(const SkOpPtT* priorPtT, const SkOpPtT* ptT
         coincident = false;
         SkIntersections i;
         SkVector dxdy = (*CurveSlopeAtT[fVerb])(this->pts(), this->weight(), midT);
-        SkDLine ray = {{{midPt.fX, midPt.fY}, {midPt.fX + dxdy.fY, midPt.fY - dxdy.fX}}};
+        SkDLine ray = {{{midPt.fX, midPt.fY},
+                {(double) midPt.fX + dxdy.fY, (double) midPt.fY - dxdy.fX}}};
         (*CurveIntersectRay[opp->verb()])(opp->pts(), opp->weight(), ray, &i);
         // measure distance and see if it's small enough to denote coincidence
         for (int index = 0; index < i.used(); ++index) {