Make CFX_ByteString(const CFX_ByteStringC&) explicit.

fpdfsdk/pdfwindow/PWL_Label.cpp

Index: fpdfsdk/pdfwindow/PWL_Label.cpp
diff --git a/fpdfsdk/pdfwindow/PWL_Label.cpp b/fpdfsdk/pdfwindow/PWL_Label.cpp
index 7abeb0d55899f1b80eb1b5180f0b23f564e75f1e..203ec49e0f294722ad52b9af6fe79da54374b677 100644
--- a/fpdfsdk/pdfwindow/PWL_Label.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Label.cpp
@@ -123,13 +123,11 @@ CFX_ByteString CPWL_Label::GetTextAppearanceStream(
     const CFX_FloatPoint& ptOffset) const {
   CFX_ByteTextBuf sRet;
   CFX_ByteString sEdit = CPWL_Utils::GetEditAppStream(m_pEdit, ptOffset);
-
   if (sEdit.GetLength() > 0) {
     sRet << "BT\n" << CPWL_Utils::GetColorAppStream(GetTextColor()).AsStringC()
          << sEdit.AsStringC() << "ET\n";
   }
-
-  return sRet.AsStringC();
+  return sRet.MakeString();
 }
 
 CFX_WideString CPWL_Label::GetText() const {