use inline version of eval quad if tangent is not needed

src/core/SkStroke.cpp

Index: src/core/SkStroke.cpp
diff --git a/src/core/SkStroke.cpp b/src/core/SkStroke.cpp
index a05bfd448fdfdd89a6af314f576060658488ed11..b5725225294c083321be47f35c8081e40a9afb8e 100644
--- a/src/core/SkStroke.cpp
+++ b/src/core/SkStroke.cpp
@@ -676,6 +676,7 @@ void SkPathStroker::quadTo(const SkPoint& pt1, const SkPoint& pt2) {
 // compute the perpendicular point and its tangent.
 void SkPathStroker::setRayPts(const SkPoint& tPt, SkVector* dxy, SkPoint* onPt,
         SkPoint* tangent) const {
+#if 01
     SkPoint oldDxy = *dxy;
     if (!dxy->setLength(fRadius)) {  // consider moving double logic into SkPoint::setLength
         double xx = oldDxy.fX;
@@ -684,6 +685,11 @@ void SkPathStroker::setRayPts(const SkPoint& tPt, SkVector* dxy, SkPoint* onPt,
         dxy->fX = SkDoubleToScalar(xx * dscale);
         dxy->fY = SkDoubleToScalar(yy * dscale);
     }
+#else
+    SkScalar scale = fRadius * sk_float_rsqrt(dxy->fX * dxy->fX + dxy->fY * dxy->fY);
+    dxy->fX *= scale;
+    dxy->fY *= scale;
+#endif
     SkScalar axisFlip = SkIntToScalar(fStrokeType);  // go opposite ways for outer, inner
     onPt->fX = tPt.fX + axisFlip * dxy->fY;
     onPt->fY = tPt.fY - axisFlip * dxy->fX;