Revert of [heap] Remove size specializations in static object visitors.

src/objects.h

 // Copyright 2015 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_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 2535 matching lines @@
   // to the same object requires fewer allocations and copies.
   static const int kFieldsAdded = 3;
 
   // Layout description.
   static const int kElementsOffset = JSReceiver::kHeaderSize;
   static const int kHeaderSize = kElementsOffset + kPointerSize;
 
   STATIC_ASSERT(kHeaderSize == Internals::kJSObjectHeaderSize);
 
   class BodyDescriptor;
-  class FastBodyDescriptor;
 
   // Gets the number of currently used elements.
   int GetFastElementsUsage();
 
   static bool AllCanRead(LookupIterator* it);
   static bool AllCanWrite(LookupIterator* it);
 
  private:
   friend class JSReceiver;
   friend class Object;
@@ skipping 8755 matching lines @@
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_H_