Replace calls to deprecated CFX_{Wide,Byte}String::Empty()

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 272 matching lines @@
 CFX_ArchiveLoader& CFX_ArchiveLoader::operator>>(FX_FLOAT& i) {
   Read(&i, sizeof(FX_FLOAT));
   return *this;
 }
 CFX_ArchiveLoader& CFX_ArchiveLoader::operator>>(CFX_ByteString& str) {
   if (m_LoadingPos + 4 > m_LoadingSize) {
     return *this;
   }
   int len;
   operator>>(len);
-  str.Empty();
+  str.clear();
   if (len <= 0 || m_LoadingPos + len > m_LoadingSize) {
     return *this;
   }
   FX_CHAR* buffer = str.GetBuffer(len);
   FXSYS_memcpy(buffer, m_pLoadingBuf + m_LoadingPos, len);
   str.ReleaseBuffer(len);
   m_LoadingPos += len;
   return *this;
 }
 CFX_ArchiveLoader& CFX_ArchiveLoader::operator>>(CFX_WideString& str) {
@@ skipping 115 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) {
   FXSYS_assert(pFile);
   m_pFile = pFile;
 }