deal more consistently with unsortable edges

src/pathops/SkOpSpan.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkOpSpan_DEFINED
 #define SkOpSpan_DEFINED
 
 #include "SkPathOpsDebug.h"
@@ skipping 323 matching lines @@
 public:
     bool clearCoincident() {
         SkASSERT(!final());
         if (fCoincident == this) {
             return false;
         }
         fCoincident = this;
         return true;
     }
 
+    int computeWindSum();
     bool containsCoincidence(const SkOpSegment* ) const;
 
     bool containsCoincidence(const SkOpSpan* coin) const {
         SkASSERT(this != coin);
         const SkOpSpan* next = this;
         while ((next = next->fCoincident) != this) {
             if (next == coin) {
                 return true;
             }
         }
@@ skipping 107 matching lines @@
     SkOpSpanBase* fNext;  // next intersection point
     int fWindSum;  // accumulated from contours surrounding this one.
     int fOppSum;  // for binary operators: the opposite winding sum
     int fWindValue;  // 0 == canceled; 1 == normal; >1 == coincident
     int fOppValue;  // normally 0 -- when binary coincident edges combine, opp value goes here
     int fTopTTry; // specifies direction and t value to try next
     bool fDone;  // if set, this span to next higher T has been processed
 };
 
 #endif