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

core/include/fxcrt/fx_string.h

Index: core/include/fxcrt/fx_string.h
diff --git a/core/include/fxcrt/fx_string.h b/core/include/fxcrt/fx_string.h
index a7cf2e1c16d0817dac55bb350d44082ef5322878..1efb814b087ef5c8dcfe2d356c15bcfa87e14574 100644
--- a/core/include/fxcrt/fx_string.h
+++ b/core/include/fxcrt/fx_string.h
@@ -320,6 +320,8 @@ public:
 
     FX_LPSTR				GetBuffer(FX_STRSIZE len);
 
+    FX_LPSTR				LockBuffer();
+
     void					ReleaseBuffer(FX_STRSIZE len = -1);
 
     CFX_ByteString			Mid(FX_STRSIZE first) const;
@@ -728,6 +730,8 @@ public:
 
     FX_LPWSTR				GetBuffer(FX_STRSIZE len);
 
+    FX_LPWSTR				LockBuffer();
+
     void					ReleaseBuffer(FX_STRSIZE len = -1);
 
     int						GetInteger() const;