Remove all encountered weak maps from the list of weak collections when incremental marking is abor…

test/cctest/test-weakmaps.cc

Index: test/cctest/test-weakmaps.cc
diff --git a/test/cctest/test-weakmaps.cc b/test/cctest/test-weakmaps.cc
index 2f28cb6c111d71bf487c8cb8c1dba401db7e987a..b3de42505fb807fa3723f33e3b4186ae5ba2ffa5 100644
--- a/test/cctest/test-weakmaps.cc
+++ b/test/cctest/test-weakmaps.cc
@@ -255,3 +255,20 @@ TEST(Regress2060b) {
   heap->CollectAllGarbage(Heap::kNoGCFlags);
   heap->CollectAllGarbage(Heap::kNoGCFlags);
 }
+
+
+TEST(Regress399527) {
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Isolate* isolate = CcTest::i_isolate();
+  Heap* heap = isolate->heap();
+  {
+    HandleScope scope(isolate);
+    AllocateJSWeakMap(isolate);
+    SimulateIncrementalMarking(heap);
+  }
+  // The weak map is marked black here but leaving the handle scope will make
+  // the object unreachable. Aborting incremental marking will clear all the
+  // marking bits which makes the weak map garbage.
+  heap->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask);
+}