Reduce usage of operator LPCWSTR from CFX_WideString().

core/src/fpdfdoc/doc_form.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 "../../include/fpdfdoc/fpdf_doc.h"
 #include "../../include/fxcrt/fx_xml.h"
 CFX_WideString  GetFullName(CPDF_Dictionary* pFieldDict);
 void                    InitInterFormDict(CPDF_Dictionary*& pFormDict, CPDF_Document* pDocument);
@@ skipping 16 matching lines @@
 FX_BOOL                 NeedPDFEncodeForFieldFullName(const CFX_WideString& csFieldName);
 FX_BOOL                 NeedPDFEncodeForFieldTree(CPDF_Dictionary* pFieldDict, int nLevel = 0);
 void                    EncodeFieldName(const CFX_WideString& csName, CFX_ByteString& csT);
 void                    UpdateEncodeFieldName(CPDF_Dictionary* pFieldDict, int nLevel = 0);
 const int nMaxRecursion = 32;
 class _CFieldNameExtractor 
 {
 public:
     _CFieldNameExtractor(const CFX_WideString& full_name)
     {
-        m_pStart = full_name;
+        m_pStart = full_name.c_str();
         m_pEnd = m_pStart + full_name.GetLength();
         m_pCur = m_pStart;
     }
     void GetNext(FX_LPCWSTR &pSubName, FX_STRSIZE& size)
     {
         pSubName = m_pCur;
         while (m_pCur < m_pEnd && m_pCur[0] != L'.') {
             m_pCur++;
         }
         size = (FX_STRSIZE)(m_pCur - pSubName);
@@ skipping 678 matching lines @@
         if (i == name2.GetLength()) {
             return 3;
         }
         return 0;
     } else {
         return name1 == name2 ? 1 : 0;
     }
 }
 int CPDF_InterForm::CompareFieldName(const CFX_WideString& name1, const CFX_WideString& name2)
 {
-    FX_LPCWSTR ptr1 = name1, ptr2 = name2;
+    FX_LPCWSTR ptr1 = name1.c_str();
+    FX_LPCWSTR ptr2 = name2.c_str();
     if (name1.GetLength() != name2.GetLength()) {
         int i = 0;
         while (ptr1[i] == ptr2[i]) {
             i ++;
         }
         if (i == name1.GetLength()) {
             return 2;
         }
         if (i == name2.GetLength()) {
             return 3;
@@ skipping 902 matching lines @@
                 continue;
             }
             CPDF_FormControl* pControl = NULL;
             if (m_ControlMap.Lookup(pAnnotDict, (void*&)pControl)) {
                 return iNewPage;
             }
         }
     } while (TRUE);
     return -1;
 }