[heap] Add basic infrastructure for incremental wrapper tracing.

src/heap/heap.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/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
@@ skipping 5436 matching lines @@
 
 bool Heap::UsingEmbedderHeapTracer() {
   return mark_compact_collector()->UsingEmbedderHeapTracer();
 }
 
 void Heap::TracePossibleWrapper(JSObject* js_object) {
   mark_compact_collector()->TracePossibleWrapper(js_object);
 }
 
 void Heap::RegisterExternallyReferencedObject(Object** object) {
-  mark_compact_collector()->RegisterExternallyReferencedObject(object);
+  HeapObject* heap_object = HeapObject::cast(*object);
+  DCHECK(Contains(heap_object));
+  if (FLAG_incremental_marking_wrappers && incremental_marking()->IsMarking()) {
+    IncrementalMarking::MarkGrey(this, heap_object);
+  } else {
+    DCHECK(mark_compact_collector()->in_use());
+    MarkBit mark_bit = ObjectMarking::MarkBitFrom(heap_object);
+    mark_compact_collector()->MarkObject(heap_object, mark_bit);
+  }
 }
 
 void Heap::TearDown() {
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     Verify();
   }
 #endif
 
   UpdateMaximumCommitted();
@@ skipping 1018 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8