Allow embedder to set promise internal field count

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 7357 matching lines @@
   static const int kDeferredOnResolveOffset =
       kDeferredPromiseOffset + kPointerSize;
   static const int kDeferredOnRejectOffset =
       kDeferredOnResolveOffset + kPointerSize;
   static const int kFulfillReactionsOffset =
       kDeferredOnRejectOffset + kPointerSize;
   static const int kRejectReactionsOffset =
       kFulfillReactionsOffset + kPointerSize;
   static const int kFlagsOffset = kRejectReactionsOffset + kPointerSize;
   static const int kSize = kFlagsOffset + kPointerSize;
+  static const int kSizeWithEmbedderFields =
+      kSize + v8::Promise::kEmbedderFieldCount * kPointerSize;
 
   // Flags layout.
   static const int kHasHandlerBit = 0;
   static const int kHandledHintBit = 1;
 };
 
 // Regular expressions
 // The regular expression holds a single reference to a FixedArray in
 // the kDataOffset field.
 // The FixedArray contains the following data:
@@ skipping 2827 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_