fix asan bug triggered by pathops fuzz tests

src/pathops/SkOpSegment.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 SkOpSegment_DEFINE
 #define SkOpSegment_DEFINE
 
 #include "SkOpAngle.h"
@@ skipping 319 matching lines @@
         fPrev = prev;
     }
 
     void setVisited() {
         fVisited = true;
     }
 
     void setUpWinding(SkOpSpanBase* start, SkOpSpanBase* end, int* maxWinding, int* sumWinding) {
         int deltaSum = SpanSign(start, end);
         *maxWinding = *sumWinding;
+        if (*sumWinding == SK_MinS32) {

[dogben, 2016/06/29 20:46:17]

It appears that SpanSign can return a value > 1 if windValue() is > 1. Should
this instead check sumWinding - Sk_MinS32 <= deltaSum?

+          return;
+        }
         *sumWinding -= deltaSum;
     }
 
     void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding,
                        int* maxWinding, int* sumWinding);
     void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding, int* sumSuWinding,
                        int* maxWinding, int* sumWinding, int* oppMaxWinding, int* oppSumWinding);
     void sortAngles();
 
     static int SpanSign(const SkOpSpanBase* start, const SkOpSpanBase* end) {
@@ skipping 66 matching lines @@
     SkPathOpsBounds fBounds;  // tight bounds
     SkScalar fWeight;
     int fCount;  // number of spans (one for a non-intersecting segment)
     int fDoneCount;  // number of processed spans (zero initially)
     SkPath::Verb fVerb;
     bool fVisited;  // used by missing coincidence check
     SkDEBUGCODE(int fID);
 };
 
 #endif