Remove a few unused variables, functions, and tables.

core/src/fxcrt/fx_basic_bstring.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 "../../include/fxcrt/fx_basic.h"
 #include "../../../third_party/numerics/safe_math.h"
 
 static int _Buffer_itoa(char* buf, int i, FX_DWORD flags)
@@ skipping 929 matching lines @@
 {
     FXSYS_FILE* file = FXSYS_fopen(CFX_ByteString(filename), "rb");
     if (file == NULL) {
         return CFX_ByteString();
     }
     FXSYS_fseek(file, 0, FXSYS_SEEK_END);
     int len = FXSYS_ftell(file);
     FXSYS_fseek(file, 0, FXSYS_SEEK_SET);
     CFX_ByteString str;
     FX_LPSTR buf = str.GetBuffer(len);
-    size_t readCnt = FXSYS_fread(buf, 1, len, file);
+    FXSYS_fread(buf, 1, len, file);
     str.ReleaseBuffer(len);
     FXSYS_fclose(file);
     return str;
 }
 CFX_WideString CFX_ByteString::UTF8Decode() const
 {
     CFX_UTF8Decoder decoder;
     for (FX_STRSIZE i = 0; i < GetLength(); i ++) {
         decoder.Input((FX_BYTE)m_pData->m_String[i]);
     }
@@ skipping 208 matching lines @@
     FX_CHAR* pBuffer = (FX_CHAR*)(this + 1);
     FXSYS_memcpy32(pBuffer + m_Size, str.GetPtr(), len);
     m_Size += len;
 }
 void CFX_StringBufBase::Append(int i, FX_DWORD flags)
 {
     char buf[32];
     int len = _Buffer_itoa(buf, i, flags);
     Append(CFX_ByteStringC(buf, len));
 }