Reland of "[heap] Fine-grained JSArrayBuffer tracking"

src/heap/objects-visiting-inl.h

 // 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.
 
 #ifndef V8_OBJECTS_VISITING_INL_H_
 #define V8_OBJECTS_VISITING_INL_H_
 
 #include "src/heap/array-buffer-tracker.h"
 #include "src/heap/objects-visiting.h"
 #include "src/ic/ic-state.h"
@@ skipping 87 matching lines @@
   table_.template RegisterSpecializations<StructVisitor, kVisitStruct,
                                           kVisitStructGeneric>();
 }
 
 
 template <typename StaticVisitor>
 int StaticNewSpaceVisitor<StaticVisitor>::VisitJSArrayBuffer(
     Map* map, HeapObject* object) {
   typedef FlexibleBodyVisitor<StaticVisitor, JSArrayBuffer::BodyDescriptor, int>
       JSArrayBufferBodyVisitor;
-
-  if (!JSArrayBuffer::cast(object)->is_external()) {
-    Heap* heap = map->GetHeap();
-    heap->array_buffer_tracker()->MarkLive(JSArrayBuffer::cast(object));
-  }
   return JSArrayBufferBodyVisitor::Visit(map, object);
 }
 
 
 template <typename StaticVisitor>
 int StaticNewSpaceVisitor<StaticVisitor>::VisitBytecodeArray(
     Map* map, HeapObject* object) {
   VisitPointers(
       map->GetHeap(), object,
       HeapObject::RawField(object, BytecodeArray::kConstantPoolOffset),
@@ skipping 609 matching lines @@
   typedef FlexibleBodyVisitor<StaticVisitor, JSFunction::BodyDescriptorWeakCode,
                               void> JSFunctionWeakCodeBodyVisitor;
   JSFunctionWeakCodeBodyVisitor::Visit(map, object);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_VISITING_INL_H_