Make CFX_ByteString(const CFX_ByteStringC&) explicit.

core/fxcrt/fx_basic_buffer.cpp

 // Copyright 2014 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.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <algorithm>
 #include <limits>
 
 #include "core/fxcrt/include/fx_basic.h"
@@ skipping 82 matching lines @@
   FXSYS_memmove(m_pBuffer.get() + pos + size, m_pBuffer.get() + pos,
                 m_DataSize - pos);
   if (pBuf) {
     FXSYS_memcpy(m_pBuffer.get() + pos, pBuf, size);
   } else {
     FXSYS_memset(m_pBuffer.get() + pos, 0, size);
   }
   m_DataSize += size;
 }
 
-CFX_ByteStringC CFX_ByteTextBuf::AsStringC() const {
-  return CFX_ByteStringC(m_pBuffer.get(), m_DataSize);
-}
-
 CFX_ByteTextBuf& CFX_ByteTextBuf::operator<<(const CFX_ByteStringC& lpsz) {
   AppendBlock(lpsz.raw_str(), lpsz.GetLength());
   return *this;
 }
 
 CFX_ByteTextBuf& CFX_ByteTextBuf::operator<<(int i) {
   char buf[32];
   FXSYS_itoa(i, buf, 10);
   AppendBlock(buf, FXSYS_strlen(buf));
   return *this;
@@ skipping 302 matching lines @@
 }
 
 int32_t CFX_FileBufferArchive::AppendString(const CFX_ByteStringC& lpsz) {
   return AppendBlock(lpsz.raw_str(), lpsz.GetLength());
 }
 
 void CFX_FileBufferArchive::AttachFile(IFX_StreamWrite* pFile) {
   ASSERT(pFile);
   m_pFile = pFile;
 }