Revert "Make CFX_WideString::LockBuffer() completely unused."

core/include/fxcrt/fx_string.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 _FX_STRING_H_
 #define _FX_STRING_H_
 
 #include <algorithm>
@@ skipping 302 matching lines @@
 
     void                                        Format(FX_LPCSTR lpszFormat, ... );
 
     void                                        FormatV(FX_LPCSTR lpszFormat, va_list argList);
 
 
     void                                        Reserve(FX_STRSIZE len);
 
     FX_LPSTR                            GetBuffer(FX_STRSIZE len);
 
+    FX_LPSTR                            LockBuffer();
+
     void                                        ReleaseBuffer(FX_STRSIZE len = -1);
 
     CFX_ByteString                      Mid(FX_STRSIZE first) const;
 
     CFX_ByteString                      Mid(FX_STRSIZE first, FX_STRSIZE count) const;
 
     CFX_ByteString                      Left(FX_STRSIZE count) const;
 
     CFX_ByteString                      Right(FX_STRSIZE count) const;
 
@@ skipping 388 matching lines @@
     void                                        TrimLeft();
 
     void                                        TrimLeft(FX_WCHAR chTarget);
 
     void                                        TrimLeft(FX_LPCWSTR lpszTargets);
 
     void                                        Reserve(FX_STRSIZE len);
 
     FX_LPWSTR                           GetBuffer(FX_STRSIZE len);
 
+    FX_LPWSTR                           LockBuffer();
+
     void                                        ReleaseBuffer(FX_STRSIZE len = -1);
 
     int                                         GetInteger() const;
 
     FX_FLOAT                            GetFloat() const;
 
     FX_STRSIZE                          Find(FX_LPCWSTR lpszSub, FX_STRSIZE start = 0) const;
 
     FX_STRSIZE                          Find(FX_WCHAR ch, FX_STRSIZE start = 0) const;
 
@@ skipping 94 matching lines @@
 CFX_ByteString  FX_UTF8Encode(FX_LPCWSTR pwsStr, FX_STRSIZE len);
 inline CFX_ByteString   FX_UTF8Encode(FX_WSTR wsStr)
 {
     return FX_UTF8Encode(wsStr.GetPtr(), wsStr.GetLength());
 }
 inline CFX_ByteString   FX_UTF8Encode(const CFX_WideString &wsStr)
 {
     return FX_UTF8Encode(wsStr.c_str(), wsStr.GetLength());
 }
 #endif