Get rid of NULLs in xfa/

xfa/fde/cfde_txtedtengine.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_FDE_CFDE_TXTEDTENGINE_H_
 #define XFA_FDE_CFDE_TXTEDTENGINE_H_
 
 #include "xfa/fde/ifde_txtedtengine.h"
@@ skipping 48 matching lines @@
   int32_t GetSelRange(int32_t nIndex, int32_t& nStart);
   void ClearSelection();
 
   FX_BOOL Redo(const IFDE_TxtEdtDoRecord* pRecord);
   FX_BOOL Undo(const IFDE_TxtEdtDoRecord* pRecord);
 
   int32_t StartLayout();
   int32_t DoLayout(IFX_Pause* pPause);
   void EndLayout();
 
-  FX_BOOL Optimize(IFX_Pause* pPause = NULL);
+  FX_BOOL Optimize(IFX_Pause* pPause = nullptr);
   int32_t CountParags() const;
   CFDE_TxtEdtParag* GetParag(int32_t nParagIndex) const;
   IFX_CharIter* CreateCharIter();
   CFDE_TxtEdtBuf* GetTextBuf() const;
   int32_t GetTextBufLength() const;
   CFX_TxtBreak* GetTextBreak() const;
   int32_t GetLineCount() const;
   int32_t GetPageLineCount() const;
 
   int32_t Line2Parag(int32_t nStartParag,
@@ skipping 89 matching lines @@
   FX_BOOL m_bLock;
   int32_t m_nLimit;
   FX_WCHAR m_wcAliasChar;
   int32_t m_nFirstLineEnd;
   FX_BOOL m_bAutoLineEnd;
   FX_WCHAR m_wLineEnd;
   FDE_TXTEDT_TEXTCHANGE_INFO m_ChangeInfo;
 };
 
 #endif  // XFA_FDE_CFDE_TXTEDTENGINE_H_