Remove IXFA_* interfaces.

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"
 
-class CXFA_DataImporter : public IXFA_PacketImport {
+class CXFA_DataImporter {
  public:
-  CXFA_DataImporter(CXFA_Document* pDocument);
-  virtual void Release() { delete this; }
-  virtual FX_BOOL ImportData(IFX_FileRead* pDataDocument);
+  explicit CXFA_DataImporter(CXFA_Document* pDocument);
+
+  void Release() { delete this; }
+  FX_BOOL ImportData(IFX_FileRead* pDataDocument);
 
  protected:
-  CXFA_Document* m_pDocument;
+  CXFA_Document* const m_pDocument;
 };
 
-class CXFA_DataExporter : public IXFA_PacketExport {
+class CXFA_DataExporter {
  public:
-  CXFA_DataExporter(CXFA_Document* pDocument);
-  virtual void Release() { delete this; }
-  virtual FX_BOOL Export(IFX_FileWrite* pWrite);
-  virtual FX_BOOL Export(IFX_FileWrite* pWrite,
-                         CXFA_Node* pNode,
-                         uint32_t dwFlag = 0,
-                         const FX_CHAR* pChecksum = NULL);
+  explicit CXFA_DataExporter(CXFA_Document* pDocument);
+
+  void Release() { delete this; }
+  FX_BOOL Export(IFX_FileWrite* pWrite);
+  FX_BOOL Export(IFX_FileWrite* pWrite,
+                 CXFA_Node* pNode,
+                 uint32_t dwFlag = 0,
+                 const FX_CHAR* pChecksum = NULL);
 
  protected:
   FX_BOOL Export(IFX_Stream* pStream,
                  CXFA_Node* pNode,
                  uint32_t dwFlag,
                  const FX_CHAR* pChecksum);
-  CXFA_Document* m_pDocument;
+  CXFA_Document* const m_pDocument;
 };
 
 #endif  // XFA_FXFA_PARSER_XFA_DOCUMENT_SERIALIZE_H_