Remove NULL in xfa/

xfa/fxfa/parser/xfa_layout_appadapter.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_LAYOUT_APPADAPTER_H_
 #define XFA_FXFA_PARSER_XFA_LAYOUT_APPADAPTER_H_
 
 #include "xfa/fxfa/parser/xfa_doclayout.h"
 
 class CXFA_TraverseStrategy_PageAreaContainerLayoutItem {
  public:
   static inline CXFA_ContainerLayoutItem* GetFirstChild(
       CXFA_ContainerLayoutItem* pLayoutItem) {
     if (pLayoutItem->m_pFormNode->GetElementType() == XFA_Element::PageSet) {
       return static_cast<CXFA_ContainerLayoutItem*>(pLayoutItem->m_pFirstChild);
     }
-    return NULL;
+    return nullptr;
   }
   static inline CXFA_ContainerLayoutItem* GetNextSibling(
       CXFA_ContainerLayoutItem* pLayoutItem) {
     return (CXFA_ContainerLayoutItem*)pLayoutItem->m_pNextSibling;
   }
   static inline CXFA_ContainerLayoutItem* GetParent(
       CXFA_ContainerLayoutItem* pLayoutItem) {
     return static_cast<CXFA_ContainerLayoutItem*>(pLayoutItem->m_pParent);
   }
 };
@@ skipping 40 matching lines @@
   }
   static inline CXFA_ContentLayoutItem* GetParent(
       CXFA_ContentLayoutItem* pLayoutItem) {
     return static_cast<CXFA_ContentLayoutItem*>(pLayoutItem->m_pParent);
   }
 };
 
 void XFA_ReleaseLayoutItem(CXFA_LayoutItem* pLayoutItem);
 
 #endif  // XFA_FXFA_PARSER_XFA_LAYOUT_APPADAPTER_H_