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

core/src/fpdfdoc/doc_bookmark.cpp

Index: core/src/fpdfdoc/doc_bookmark.cpp
diff --git a/core/src/fpdfdoc/doc_bookmark.cpp b/core/src/fpdfdoc/doc_bookmark.cpp
index 88dcf21be115a2198aac2cd5100606eb47adb6ce..9814de61bff20414fa7847194ef9c1aeb05ab3df 100644
--- a/core/src/fpdfdoc/doc_bookmark.cpp
+++ b/core/src/fpdfdoc/doc_bookmark.cpp
@@ -55,13 +55,15 @@ CFX_WideString CPDF_Bookmark::GetTitle() const
         return CFX_WideString();
     }
     CFX_WideString title = pString->GetUnicodeText();
+    FX_LPWSTR buf = title.LockBuffer();
     int len = title.GetLength();
-    FX_WCHAR buf[len];
     for (int i = 0; i < len; i++) {
-        FX_WCHAR w = title[i];
-        buf[i] = w > 0x20 ? w : 0x20;
+        if (buf[i] < 0x20) {
+            buf[i] = 0x20;
+        }
     }
-    return CFX_WideString(buf, len);
+    title.ReleaseBuffer(len);
+    return title;
 }
 CPDF_Dest CPDF_Bookmark::GetDest(CPDF_Document* pDocument) const
 {