only call scalar finite when necessary

src/pathops/SkPathOpsTSect.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChunkAlloc.h"
 #include "SkPathOpsBounds.h"
 #include "SkPathOpsRect.h"
@@ skipping 1449 matching lines @@
     double tStep = tEnd - tStart;
     SkDPoint workPt;
     do {
         tStep *= 0.5;
         if (precisely_zero(tStep)) {
             return 0;
         }
         workT += tStep;
         workPt = fCurve.ptAtT(workT);
         coinW.setPerp(fCurve, workT, workPt, opp->fCurve);
+        if (coinW.perpT() < 0) {
+            continue;
+        }
         SkDVector perpW = workPt - coinW.perpPt();
         if ((perpS.dot(perpW) >= 0) == (tStep < 0)) {
             tStep = -tStep;
         }
-    } while (!workPt.approximatelyEqual(coinW.perpPt()));
+        if (workPt.approximatelyEqual(coinW.perpPt())) {
+            break;
+        }
+    } while (true);
     double oppTTest = coinW.perpT();
     if (!opp->fHead->contains(oppTTest)) {
         return 0;
     }
     i->setMax(1);
     i->insert(workT, oppTTest, workPt);
     return 1;
 }
 
 
@@ skipping 743 matching lines @@
         } else if (intersections->isCoincident(index + 1)) {
             intersections->removeOne(index + 1);
             --last;
         } else {
             intersections->setCoincident(index++);
         }
         intersections->setCoincident(index);
     }
     SkASSERT(intersections->used() <= TCurve::kMaxIntersections);
 }