Make CFX_WideString::LockBuffer() completely unused.

core/src/fxcrt/fx_basic_wstring.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/fxcrt/fx_basic.h"
 #include "../../../third_party/base/numerics/safe_math.h"
 
 static CFX_StringDataW* FX_AllocStringW(int nLen)
@@ skipping 517 matching lines @@
             return 1;
         }
     }
     if (this_len < that_len) {
         return -1;
     } else if (this_len > that_len) {
         return 1;
     }
     return 0;
 }
-FX_LPWSTR CFX_WideString::LockBuffer()
-{
-    if (m_pData == NULL) {
-        return NULL;
-    }
-    FX_LPWSTR lpsz = GetBuffer(0);
-    m_pData->m_nRefs = -1;
-    return lpsz;
-}
 void CFX_WideString::SetAt(FX_STRSIZE nIndex, FX_WCHAR ch)
 {
     if (m_pData == NULL) {
         return;
     }
     ASSERT(nIndex >= 0);
     ASSERT(nIndex < m_pData->m_nDataLength);
     CopyBeforeWrite();
     m_pData->m_String[nIndex] = ch;
 }
@@ skipping 559 matching lines @@
             return (CFX_CharMap*)&g_DefaultJISMapper;
         case 936:
             return (CFX_CharMap*)&g_DefaultGBKMapper;
         case 949:
             return (CFX_CharMap*)&g_DefaultUHCMapper;
         case 950:
             return (CFX_CharMap*)&g_DefaultBig5Mapper;
     }
     return NULL;
 }