Fix some return FALSE in functions that return pointers

xfa/fxfa/parser/xfa_document_datamerger_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_document_datamerger_imp.h"
 
 #include "core/fxcrt/fx_ext.h"
 #include "xfa/fde/xml/fde_xml_imp.h"
@@ skipping 34 matching lines @@
     return FALSE;
 
   CXFA_Occur occur(pOccurNode);
   return occur.GetOccurInfo(iMin, iMax, iInit);
 }
 
 CXFA_Node* FormValueNode_CreateChild(CXFA_Node* pValueNode, XFA_Element iType) {
   CXFA_Node* pChildNode = pValueNode->GetNodeItem(XFA_NODEITEM_FirstChild);
   if (!pChildNode) {
     if (iType == XFA_Element::Unknown)
-      return FALSE;
+      return nullptr;
     pChildNode = pValueNode->GetProperty(0, iType);
   }
   return pChildNode;
 }
 
 void FormValueNode_MatchNoneCreateChild(CXFA_Node* pFormNode) {
   CXFA_WidgetData* pWidgetData = pFormNode->GetWidgetData();
   ASSERT(pWidgetData);
   pWidgetData->GetUIType();
 }
@@ skipping 1454 matching lines @@
       pFormRoot->RemoveChild(pNode);
     pFormRoot->SetObject(XFA_ATTRIBUTE_BindingNode, nullptr);
   }
   m_rgGlobalBinding.RemoveAll();
   if (bDoDataMerge)
     DoDataMerge();
 
   CXFA_LayoutProcessor* pLayoutProcessor = GetLayoutProcessor();
   pLayoutProcessor->SetForceReLayout(TRUE);
 }