Replace calls to deprecated CFX_{Wide,Byte}String::Empty()

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/include/fx_ext.h"
 #include "xfa/fde/xml/fde_xml_imp.h"
@@ skipping 272 matching lines @@
             image.SetHref(wsHref);
           }
         }
       } break;
       case XFA_ELEMENT_ChoiceList:
         if (pWidgetData->GetChoiceListOpen() == XFA_ATTRIBUTEENUM_MultiSelect) {
           CXFA_NodeArray items;
           pDataNode->GetNodeList(items);
           int32_t iCounts = items.GetSize();
           if (iCounts > 0) {
-            wsNormailizeValue.Empty();
+            wsNormailizeValue.clear();
             CFX_WideString wsItem;
             for (int32_t i = 0; i < iCounts; i++) {
               items[i]->TryContent(wsItem);
               wsItem = (iCounts == 1) ? wsItem : wsItem + FX_WSTRC(L"\n");
               wsNormailizeValue += wsItem;
             }
             CXFA_ExData exData = defValue.GetExData();
             FXSYS_assert(exData);
             exData.SetContentType((iCounts == 1) ? FX_WSTRC(L"text/plain")
                                                  : FX_WSTRC(L"text/xml"));
@@ skipping 1121 matching lines @@
     }
     pFormRoot->SetObject(XFA_ATTRIBUTE_BindingNode, NULL);
   }
   XFA_DataMerge_ClearGlobalBinding(this);
   if (bDoDataMerge) {
     DoDataMerge();
   }
   CXFA_LayoutProcessor* pLayoutProcessor = GetLayoutProcessor();
   pLayoutProcessor->SetForceReLayout(TRUE);
 }