Split xfa_document_serialize into class files

xfa/fxfa/parser/xfa_document_serialize.h

-// Copyright 2014 PDFium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
-
-#ifndef XFA_FXFA_PARSER_XFA_DOCUMENT_SERIALIZE_H_
-#define XFA_FXFA_PARSER_XFA_DOCUMENT_SERIALIZE_H_
-
-#include "core/fxcrt/include/fx_string.h"
-
-class CXFA_Document;
-class CXFA_Node;
-class IFX_FileRead;
-class IFX_FileWrite;
-class IFX_Stream;
-
-class CXFA_DataImporter {
- public:
-  explicit CXFA_DataImporter(CXFA_Document* pDocument);
-
-  FX_BOOL ImportData(IFX_FileRead* pDataDocument);
-
- protected:
-  CXFA_Document* const m_pDocument;
-};
-
-class CXFA_DataExporter {
- public:
-  explicit CXFA_DataExporter(CXFA_Document* pDocument);
-
-  FX_BOOL Export(IFX_FileWrite* pWrite);
-  FX_BOOL Export(IFX_FileWrite* pWrite,
-                 CXFA_Node* pNode,
-                 uint32_t dwFlag = 0,
-                 const FX_CHAR* pChecksum = nullptr);
-
- protected:
-  FX_BOOL Export(IFX_Stream* pStream,
-                 CXFA_Node* pNode,
-                 uint32_t dwFlag,
-                 const FX_CHAR* pChecksum);
-
-  CXFA_Document* const m_pDocument;
-};
-
-#endif  // XFA_FXFA_PARSER_XFA_DOCUMENT_SERIALIZE_H_