look for deleted pts when detecting line/curve coincident edges

src/pathops/SkOpCoincidence.cpp

 /*
  * Copyright 2015 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 "SkOpSegment.h"
 #include "SkPathOpsTSect.h"
 
@@ skipping 177 matching lines @@
     return false;
 }
 
 // walk span sets in parallel, moving winding from one to the other
 bool SkOpCoincidence::apply() {
     SkCoincidentSpans* coin = fHead;
     if (!coin) {
         return true;
     }
     do {
+        SkOpSpan* start = coin->fCoinPtTStart->span()->upCast();
+        if (start->deleted()) {
+            continue;
+        }
         SkOpSpanBase* end = coin->fCoinPtTEnd->span();
-        SkOpSpan* start = coin->fCoinPtTStart->span()->upCast();
         SkASSERT(start == start->starter(end));
         bool flipped = coin->fFlipped;
+        SkOpSpan* oStart = (flipped ? coin->fOppPtTEnd : coin->fOppPtTStart)->span()->upCast();
+        if (oStart->deleted()) {
+            continue;
+        }
         SkOpSpanBase* oEnd = (flipped ? coin->fOppPtTStart : coin->fOppPtTEnd)->span();
-        SkOpSpan* oStart = (flipped ? coin->fOppPtTEnd : coin->fOppPtTStart)->span()->upCast();
         SkASSERT(oStart == oStart->starter(oEnd));
         SkOpSegment* segment = start->segment();
         SkOpSegment* oSegment = oStart->segment();
         bool operandSwap = segment->operand() != oSegment->operand();
         if (flipped) {
             do {
                 SkOpSpanBase* oNext = oStart->next();
                 if (oNext == oEnd) {
                     break;
                 }
@@ skipping 199 matching lines @@
 
 bool SkOpCoincidence::overlap(const SkOpPtT* coin1s, const SkOpPtT* coin1e, 
         const SkOpPtT* coin2s, const SkOpPtT* coin2e, double* overS, double* overE) const {
     if (coin1s->segment() != coin2s->segment()) {
         return false;
     }
     *overS = SkTMax(SkTMin(coin1s->fT, coin1e->fT), SkTMin(coin2s->fT, coin2e->fT));
     *overE = SkTMin(SkTMax(coin1s->fT, coin1e->fT), SkTMax(coin2s->fT, coin2e->fT));
     return *overS < *overE;
 }