[heap] Unconditionally mark objects that undergo unsafe layout changes.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index b085a5d56ae3eaed8064fca3ac9b2dca97d395a2..b5e451b774a7e714014e8c87b21712f51a8bebec 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -4301,7 +4301,9 @@ void Heap::RegisterReservationsForBlackAllocation(Reservation* reservations) {
 
 void Heap::NotifyObjectLayoutChange(HeapObject* object,
                                     const DisallowHeapAllocation&) {
-// TODO(ulan): Add synchronization with the concurrent marker.
+  if (FLAG_incremental_marking && incremental_marking()->IsMarking()) {
+    incremental_marking()->MarkGrey(this, object);
+  }
 #ifdef VERIFY_HEAP
   DCHECK(pending_layout_change_object_ == nullptr);
   pending_layout_change_object_ = object;