Make CFX_WideString::FromUTF8() take a CFX_ByteStringC argument.

testing/libfuzzer/pdf_xml_fuzzer.cc

 // Copyright 2016 The 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.
 
 #include <cstddef>
 #include <cstdint>
 #include <limits>
 #include <memory>
 
 #include "core/fxcrt/include/fx_basic.h"
@@ skipping 30 matching lines @@
   return nullptr;
 }
 
 }  // namespace
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (size > std::numeric_limits<FX_STRSIZE>::max())
     return 0;
 
   CFX_WideString input = CFX_WideString::FromUTF8(
-      reinterpret_cast<const char*>(data), static_cast<FX_STRSIZE>(size));
+      CFX_ByteStringC(data, static_cast<FX_STRSIZE>(size)));
   std::unique_ptr<IFX_Stream, ReleaseDeleter<IFX_Stream>> stream(
       XFA_CreateWideTextRead(input));
   if (!stream)
     return 0;
 
   std::unique_ptr<CFDE_XMLDoc> doc(new CFDE_XMLDoc);
   std::unique_ptr<CFDE_XMLParser, ReleaseDeleter<CFDE_XMLParser>> parser(
       new CXFA_XMLParser(doc->GetRoot(), stream.get()));
 
   if (!doc->LoadXML(parser.release()))
     return 0;
 
   int32_t load_result = doc->DoLoad(nullptr);
   if (load_result < 100)
     return 0;
 
   (void)XFA_FDEExtension_GetDocumentNode(doc.get());
   return 0;
 }