[heap] Also mark map when iterating black objects.

src/heap/incremental-marking.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 292 matching lines @@
   }
 };
 
 void IncrementalMarking::IterateBlackObject(HeapObject* object) {
   if (IsMarking() && Marking::IsBlack(ObjectMarking::MarkBitFrom(object))) {
     Page* page = Page::FromAddress(object->address());
     if ((page->owner() != nullptr) && (page->owner()->identity() == LO_SPACE)) {
       // IterateBlackObject requires us to visit the whole object.
       page->ResetProgressBar();
     }
-    IncrementalMarkingMarkingVisitor::IterateBody(object->map(), object);
+    Map* map = object->map();
+    MarkGrey(heap_, map);
+    IncrementalMarkingMarkingVisitor::IterateBody(map, object);
   }
 }
 
 class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor {
  public:
   explicit IncrementalMarkingRootMarkingVisitor(
       IncrementalMarking* incremental_marking)
       : heap_(incremental_marking->heap()) {}
 
   void VisitPointer(Object** p) override { MarkObjectByPointer(p); }
@@ skipping 932 matching lines @@
 void IncrementalMarking::IncrementIdleMarkingDelayCounter() {
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 }  // namespace internal
 }  // namespace v8