Do not check pointers before deleting them.

xfa/fxfa/parser/xfa_parser_imp.cpp

 // 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
 
 #include "xfa/fxfa/parser/xfa_parser_imp.h"
 
 #include "xfa/fde/xml/fde_xml_imp.h"
 #include "xfa/fgas/crt/fgas_codepage.h"
@@ skipping 1372 matching lines @@
                                            CFDE_XMLNode* pXMLNode) {
   if (!pXFANode || !pXMLNode) {
     return;
   }
   m_nodeParser.ConstructXFANode(pXFANode, pXMLNode);
   CXFA_Node* pRootNode = m_nodeParser.GetRootNode();
   if (m_pDocument && pRootNode) {
     m_pDocument->SetRoot(pRootNode);
   }
 }
+
 void CXFA_DocumentParser::CloseParser() {
-  if (m_pDocument) {
-    delete m_pDocument;
-    m_pDocument = NULL;
-  }
+  delete m_pDocument;
+  m_pDocument = nullptr;
   m_nodeParser.CloseParser();
 }
+
 CXFA_XMLParser::CXFA_XMLParser(CFDE_XMLNode* pRoot, IFX_Stream* pStream)
     : m_nElementStart(0),
       m_dwCheckStatus(0),
       m_dwCurrentCheckStatus(0),
       m_pRoot(pRoot),
       m_pStream(pStream),
       m_pParser(nullptr),
       m_pParent(pRoot),
       m_pChild(nullptr),
       m_NodeStack(16),
@@ skipping 146 matching lines @@
     }
     if (pPause && iCount > 500 && pPause->NeedToPauseNow()) {
       break;
     }
   }
   return (m_syntaxParserResult == FDE_XmlSyntaxResult::Error ||
           m_NodeStack.GetSize() != 1)
              ? -1
              : m_pParser->GetStatus();
 }