Cleanup ownership of parser members

xfa/fxfa/parser/cxfa_document_parser.cpp

 // Copyright 2016 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
 
 #include "xfa/fxfa/parser/cxfa_document_parser.h"
 
 #include "xfa/fxfa/include/fxfa.h"
 #include "xfa/fxfa/parser/xfa_document.h"
 
 CXFA_DocumentParser::CXFA_DocumentParser(CXFA_FFNotify* pNotify)
     : m_nodeParser(nullptr, TRUE), m_pNotify(pNotify) {}
 
 CXFA_DocumentParser::~CXFA_DocumentParser() {
-  CloseParser();
 }
 
 int32_t CXFA_DocumentParser::StartParse(IFX_FileRead* pStream,
                                         XFA_XDPPACKET ePacketID) {
-  CloseParser();
+  m_pDocument.reset();
+  m_nodeParser.CloseParser();
+
   int32_t nRetStatus = m_nodeParser.StartParse(pStream, ePacketID);
   if (nRetStatus == XFA_PARSESTATUS_Ready) {
     m_pDocument.reset(new CXFA_Document(this));
     m_nodeParser.SetFactory(m_pDocument.get());
   }
   return nRetStatus;
 }
 
 int32_t CXFA_DocumentParser::DoParse(IFX_Pause* pPause) {
   int32_t nRetStatus = m_nodeParser.DoParse(pPause);
   if (nRetStatus >= XFA_PARSESTATUS_Done) {
     ASSERT(m_pDocument);
     m_pDocument->SetRoot(m_nodeParser.GetRootNode());
   }
   return nRetStatus;
 }
 
 CFDE_XMLDoc* CXFA_DocumentParser::GetXMLDoc() const {
   return m_nodeParser.GetXMLDoc();
 }
 
 CXFA_FFNotify* CXFA_DocumentParser::GetNotify() const {
   return m_pNotify;
 }
 
 CXFA_Document* CXFA_DocumentParser::GetDocument() const {
   return m_pDocument.get();
 }
-
-void CXFA_DocumentParser::CloseParser() {
-  m_pDocument.reset();
-  m_nodeParser.CloseParser();
-}