Re-enable MSVC warning 4800 for compiling with chromium_code

core/src/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/include/fxcrt/fx_basic.h"
@@ skipping 363 matching lines @@
   m_pFile = nullptr;
 }
 
 bool CFX_FileBufferArchive::Flush() {
   size_t nRemaining = m_Length;
   m_Length = 0;
   if (!m_pFile)
     return false;
   if (!m_pBuffer || !nRemaining)
     return true;
-  return m_pFile->WriteBlock(m_pBuffer.get(), nRemaining);
+  return m_pFile->WriteBlock(m_pBuffer.get(), nRemaining) > 0;
 }
 
 int32_t CFX_FileBufferArchive::AppendBlock(const void* pBuf, size_t size) {
   if (!pBuf || size < 1) {
     return 0;
   }
   if (!m_pBuffer) {
     m_pBuffer.reset(FX_Alloc(uint8_t, kBufSize));
   }
   const uint8_t* buffer = reinterpret_cast<const uint8_t*>(pBuf);
@@ skipping 24 matching lines @@
 }
 
 int32_t CFX_FileBufferArchive::AppendString(const CFX_ByteStringC& lpsz) {
   return AppendBlock(lpsz.GetPtr(), lpsz.GetLength());
 }
 
 void CFX_FileBufferArchive::AttachFile(IFX_StreamWrite* pFile) {
   FXSYS_assert(pFile);
   m_pFile = pFile;
 }