Expose the ValueSerializer data format version as a compile-time constant.

src/value-serializer.h

 // Copyright 2016 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_VALUE_SERIALIZER_H_
 #define V8_VALUE_SERIALIZER_H_
 
 #include <cstdint>
 #include <vector>
 
@@ skipping 25 matching lines @@
 enum class SerializationTag : uint8_t;
 
 /**
  * Writes V8 objects in a binary format that allows the objects to be cloned
  * according to the HTML structured clone algorithm.
  *
  * Format is based on Blink's previous serialization logic.
  */
 class ValueSerializer {
  public:
-  static uint32_t GetCurrentDataFormatVersion();
-
   ValueSerializer(Isolate* isolate, v8::ValueSerializer::Delegate* delegate);
   ~ValueSerializer();
 
   /*
    * Writes out a header, which includes the format version.
    */
   void WriteHeader();
 
   /*
    * Serializes a V8 object into the buffer.
@@ skipping 241 matching lines @@
   Handle<FixedArray> id_map_;
   MaybeHandle<SeededNumberDictionary> array_buffer_transfer_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ValueDeserializer);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_VALUE_SERIALIZER_H_