Make CFX_WideString(const CFX_WideString&) explicit.

xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp

Index: xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp
diff --git a/xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp b/xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp
index cdbc59ce5b40f48dffea9be974cf1c3a821a72c1..efebfe547d48df974c99b6899af5cf73e51c04fa 100644
--- a/xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp
+++ b/xfa/fxbarcode/oned/BC_OnedCode39Writer.cpp
@@ -341,13 +341,13 @@ uint8_t* CBC_OnedCode39Writer::Encode(const CFX_ByteString& contents,
 CFX_WideString CBC_OnedCode39Writer::encodedContents(
     const CFX_WideStringC& contents,
     int32_t& e) {
-  CFX_WideString encodedContents = contents;
+  CFX_WideString encodedContents(contents);
   if (m_bCalcChecksum && m_bPrintChecksum) {
     CFX_WideString checksumContent = FilterContents(contents);
     CFX_ByteString str = checksumContent.UTF8Encode();
     FX_CHAR checksum;
     checksum = CalcCheckSum(str, e);
-    BC_EXCEPTION_CHECK_ReturnValue(e, FX_WSTRC(L""));
+    BC_EXCEPTION_CHECK_ReturnValue(e, CFX_WideString());
     str += checksum;
     encodedContents += checksum;
   }