fix path ops fuzz buster

src/pathops/SkPathOpsCommon.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkAddIntersections.h"
 #include "SkOpCoincidence.h"
 #include "SkOpEdgeBuilder.h"
 #include "SkPathOpsCommon.h"
@@ skipping 180 matching lines @@
     /*
         check start and end of each contour
         if not the same, record them
         match them up
         connect closest
         reassemble contour pieces into new path
     */
 void Assemble(const SkPathWriter& path, SkPathWriter* simple) {
     SkChunkAlloc allocator(4096);  // FIXME: constant-ize, tune
     SkOpContourHead contour;
-    SkOpGlobalState globalState(NULL, &contour);
+    SkOpGlobalState globalState(NULL, &contour  SkDEBUGPARAMS(NULL));
 #if DEBUG_SHOW_TEST_NAME
     SkDebugf("</div>\n");
 #endif
 #if DEBUG_PATH_CONSTRUCTION
     SkDebugf("%s\n", __FUNCTION__);
 #endif
     SkOpEdgeBuilder builder(path, &contour, &allocator, &globalState);
     builder.finish(&allocator);
     SkTDArray<const SkOpContour* > runs;  // indices of partial contours
     const SkOpContour* eContour = builder.head();
@@ skipping 189 matching lines @@
     } while ((contour = contour->next()));
 }
 
 static void calcAngles(SkOpContourHead* contourList, SkChunkAlloc* allocator) {
     SkOpContour* contour = contourList;
     do {
         contour->calcAngles(allocator);
     } while ((contour = contour->next()));
 }
 
+static void findCollapsed(SkOpContourHead* contourList) {
+    SkOpContour* contour = contourList;
+    do {
+        contour->findCollapsed();
+    } while ((contour = contour->next()));
+}
+
 static bool missingCoincidence(SkOpContourHead* contourList,
         SkOpCoincidence* coincidence, SkChunkAlloc* allocator) {
     SkOpContour* contour = contourList;
     bool result = false;
     do {
         result |= contour->missingCoincidence(coincidence, allocator);
     } while ((contour = contour->next()));
     return result;
 }
 
@@ skipping 16 matching lines @@
     do {
         contour->sortAngles();
     } while ((contour = contour->next()));
 }
 
 bool HandleCoincidence(SkOpContourHead* contourList, SkOpCoincidence* coincidence,
         SkChunkAlloc* allocator) {
     SkOpGlobalState* globalState = contourList->globalState();
     // combine t values when multiple intersections occur on some segments but not others
     moveMultiples(contourList);
+    findCollapsed(contourList);
     // move t values and points together to eliminate small/tiny gaps
     moveNearby(contourList);
     align(contourList);  // give all span members common values
     coincidence->fixAligned();  // aligning may have marked a coincidence pt-t deleted
 #if DEBUG_VALIDATE
     globalState->setPhase(SkOpGlobalState::kIntersecting);
 #endif
     // look for intersections on line segments formed by moving end points
     addAlignIntersections(contourList, allocator);
     coincidence->addMissing(allocator);
@@ skipping 29 matching lines @@
         if (!coincidence->apply()) {
             return false;
         }
     }
 #if DEBUG_ACTIVE_SPANS
     coincidence->debugShowCoincidence();
     DebugShowActiveSpans(contourList);
 #endif
     return true;
 }