harden pathops for pathological test

src/pathops/SkOpContour.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 SkOpContour_DEFINED
 #define SkOpContour_DEFINED
 
 #include "SkOpSegment.h"
@@ skipping 109 matching lines @@
     void checkDuplicates() {
         int segmentCount = fSegments.count();
         for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
             SkOpSegment& segment = fSegments[sIndex];
             if (segment.count() > 2) {
                 segment.checkDuplicates();
             }
         }
     }
 
-    void checkEnds() {
+    bool checkEnds() {
         if (!fContainsCurves) {
-            return;
+            return true;
         }
         int segmentCount = fSegments.count();
         for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
             SkOpSegment* segment = &fSegments[sIndex];
             if (segment->verb() == SkPath::kLine_Verb) {
                 continue;
             }
             if (segment->done()) {
                 continue;   // likely coincident, nothing to do
             }
-            segment->checkEnds();
+            if (!segment->checkEnds()) {
+                return false;
+            }
         }
+        return true;
     }
 
     void checkMultiples() {
         int segmentCount = fSegments.count();
         for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
             SkOpSegment& segment = fSegments[sIndex];
             if (segment.count() > 2) {
                 segment.checkMultiples();
                 fMultiples |= segment.hasMultiples();
             }
@@ skipping 193 matching lines @@
     bool fOppXor;
 #if defined(SK_DEBUG) || !FORCE_RELEASE
     int debugID() const { return fID; }
     int fID;
 #else
     int debugID() const { return -1; }
 #endif
 };
 
 #endif