give up if huge paths have unresolvable coincidence

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 476 matching lines @@
 #endif
     // check to see if, loosely, coincident ranges may be expanded
     if (coincidence->expand()) {
         DEBUG_COINCIDENCE_HEALTH(contourList, "expand1");
         if (!coincidence->addExpanded(allocator  PATH_OPS_DEBUG_VALIDATE_PARAMS(globalState))) {
             return false;
         }
     }
     DEBUG_COINCIDENCE_HEALTH(contourList, "expand2");
     // the expanded ranges may not align -- add the missing spans
-    coincidence->mark();  // mark spans of coincident segments as coincident
+    if (!coincidence->mark()) {  // mark spans of coincident segments as coincident
+        return false;
+    }
     DEBUG_COINCIDENCE_HEALTH(contourList, "mark1");
     // look for coincidence missed earlier
     if (missingCoincidence(contourList, coincidence, allocator)) {
         DEBUG_COINCIDENCE_HEALTH(contourList, "missingCoincidence1");
         (void) coincidence->expand();
         DEBUG_COINCIDENCE_HEALTH(contourList, "expand3");
         if (!coincidence->addExpanded(allocator  PATH_OPS_DEBUG_VALIDATE_PARAMS(globalState))) {
             return false;
         }
         DEBUG_COINCIDENCE_HEALTH(contourList, "addExpanded2");
@@ skipping 19 matching lines @@
         if (!coincidence->apply()) {
             return false;
         }
     }
 #if DEBUG_ACTIVE_SPANS
     coincidence->debugShowCoincidence();
     DebugShowActiveSpans(contourList);
 #endif
     return true;
 }