Fallback to moveTo when unable to find the first tangent in cubicTo

src/core/SkStroke.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkStrokerPriv.h"
 #include "SkGeometry.h"
 #include "SkPath.h"
@@ skipping 406 matching lines @@
 
     this->postJoinTo(pt2, normalBC, unitBC);
 }
 
 void SkPathStroker::cubicTo(const SkPoint& pt1, const SkPoint& pt2,
                             const SkPoint& pt3) {
     bool    degenerateAB = SkPath::IsLineDegenerate(fPrevPt, pt1);
     bool    degenerateBC = SkPath::IsLineDegenerate(pt1, pt2);
     bool    degenerateCD = SkPath::IsLineDegenerate(pt2, pt3);
 
-    if (degenerateAB + degenerateBC + degenerateCD >= 2) {
+    if (degenerateAB + degenerateBC + degenerateCD >= 2
+            || (degenerateAB && SkPath::IsLineDegenerate(fPrevPt, pt2))) {
         this->lineTo(pt3);
         return;
     }
 
     SkVector    normalAB, unitAB, normalCD, unitCD;
 
     // find the first tangent (which might be pt1 or pt2
     {
         const SkPoint*  nextPt = &pt1;
         if (degenerateAB)
@@ skipping 287 matching lines @@
         default:
             break;
     }
 
     if (fWidth < SkMinScalar(rw, rh) && !fDoFill) {
         r = rect;
         r.inset(radius, radius);
         dst->addRect(r, reverse_direction(dir));
     }
 }