V8ScriptValueSerializer: Use PartitionAlloc for the buffer, and avoid copying it into a String.

third_party/WebKit/Source/bindings/core/v8/serialization/V8ScriptValueSerializer.h

 // Copyright 2016 The Chromium 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 V8ScriptValueSerializer_h
 #define V8ScriptValueSerializer_h
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/SerializationTag.h"
@@ skipping 63 matching lines @@
   void finalizeTransfer(ExceptionState&);
 
   // Shared between File and FileList logic; does not write a leading tag.
   bool writeFile(File*, ExceptionState&);
 
   // v8::ValueSerializer::Delegate
   void ThrowDataCloneError(v8::Local<v8::String> message) override;
   v8::Maybe<bool> WriteHostObject(v8::Isolate*,
                                   v8::Local<v8::Object> message) override;
 
+  void* ReallocateBufferMemory(void* oldBuffer,
+                               size_t,
+                               size_t* actualSize) override;
+  void FreeBufferMemory(void* buffer) override;
+
   RefPtr<ScriptState> m_scriptState;
   RefPtr<SerializedScriptValue> m_serializedScriptValue;
   v8::ValueSerializer m_serializer;
   const Transferables* m_transferables = nullptr;
   const ExceptionState* m_exceptionState = nullptr;
   WebBlobInfoArray* m_blobInfoArray = nullptr;
 
 #if DCHECK_IS_ON()
   bool m_serializeInvoked = false;
 #endif
 };
 
 }  // namespace blink
 
 #endif  // V8ScriptValueSerializer_h