fix path ops fuzz buster

src/pathops/SkOpSpan.cpp

 /*
  * 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 "SkOpCoincidence.h"
 #include "SkOpContour.h"
 #include "SkOpSegment.h"
 #include "SkPathWriter.h"
 
 bool SkOpPtT::alias() const {
     return this->span()->ptT() != this;
 }
 
+bool SkOpPtT::collapsed(const SkOpPtT* check) const {
+    if (fPt != check->fPt) {
+        return false;
+    }
+    SkASSERT(this != check);
+    const SkOpSegment* segment = this->segment();
+    SkASSERT(segment == check->segment());
+    return segment->collapsed();
+}
+
 bool SkOpPtT::contains(const SkOpPtT* check) const {
     SkASSERT(this != check);
     const SkOpPtT* ptT = this;
     const SkOpPtT* stopPtT = ptT;
     while ((ptT = ptT->next()) != stopPtT) {
         if (ptT == check) {
             return true;
         }
     }
     return false;
@@ skipping 339 matching lines @@
 
 void SkOpSpan::setWindSum(int windSum) {
     SkASSERT(!final());
     if (fWindSum != SK_MinS32 && fWindSum != windSum) {
         this->globalState()->setWindingFailed();
         return;
     }
     SkASSERT(!DEBUG_LIMIT_WIND_SUM || abs(windSum) <= DEBUG_LIMIT_WIND_SUM);
     fWindSum = windSum;
 }