XFA unused function cleanup

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 "xfa/fxfa/parser/xfa_docdata.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);
 
   void Release() { delete this; }
   FX_BOOL ImportData(IFX_FileRead* pDataDocument);
 
  protected:
   CXFA_Document* const m_pDocument;
@@ skipping 12 matching lines @@
 
  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_