deal more consistently with unsortable edges

src/pathops/SkOpCoincidence.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkOpCoincidence_DEFINED
 #define SkOpCoincidence_DEFINED
 
 #include "SkOpTAllocator.h"
@@ skipping 22 matching lines @@
              SkOpPtT* oppPtTEnd, SkChunkAlloc* allocator);
     bool addMissing(SkChunkAlloc* allocator);
     void addMissing(SkCoincidentSpans* check, SkChunkAlloc* allocator);
     bool apply();
     bool contains(SkOpPtT* coinPtTStart, SkOpPtT* coinPtTEnd, SkOpPtT* oppPtTStart,
                   SkOpPtT* oppPtTEnd, bool flipped);
     void debugShowCoincidence() const;
     void detach(SkCoincidentSpans* );
     void dump() const;
     void expand();
+    bool extend(SkOpPtT* coinPtTStart, SkOpPtT* coinPtTEnd, SkOpPtT* oppPtTStart,
+        SkOpPtT* oppPtTEnd);
     void fixUp(SkOpPtT* deleted, SkOpPtT* kept);
     void mark();
 
 private:
     bool addIfMissing(const SkOpPtT* over1s, const SkOpPtT* over1e,
                       const SkOpPtT* over2s, const SkOpPtT* over2e, double tStart, double tEnd,
                       SkOpPtT* coinPtTStart, const SkOpPtT* coinPtTEnd,
                       SkOpPtT* oppPtTStart, const SkOpPtT* oppPtTEnd,
                       SkChunkAlloc* allocator);
     bool overlap(const SkOpPtT* coinStart1, const SkOpPtT* coinEnd1,
                  const SkOpPtT* coinStart2, const SkOpPtT* coinEnd2,
                  double* overS, double* overE) const;
 
     SkCoincidentSpans* fHead;
 };
 
 #endif