Fix a bunch of sign mismatch warnings.

core/src/fxcodec/jbig2/JBig2_HuffmanTable.h

 // 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
 
 #ifndef _JBIG2_HUFFMAN_TABLE_H_
 #define _JBIG2_HUFFMAN_TABLE_H_
 
 #include "JBig2_HuffmanTable_Standard.h"
 #include "JBig2_BitStream.h"
 
 class CJBig2_HuffmanTable {
  public:
   CJBig2_HuffmanTable(const JBig2TableLine* pTable, int nLines, FX_BOOL bHTOOB);
 
-  CJBig2_HuffmanTable(CJBig2_BitStream* pStream);
+  explicit CJBig2_HuffmanTable(CJBig2_BitStream* pStream);
 
   ~CJBig2_HuffmanTable();
 
   int parseFromStandardTable(const JBig2TableLine* pTable,
                              int nLines,
                              FX_BOOL bHTOOB);
 
   int parseFromCodedBuffer(CJBig2_BitStream* pStream);
 
-  FX_BOOL isOK() { return m_bOK; }
+  FX_BOOL isOK() const { return m_bOK; }
 
  private:
   void init();
 
   FX_BOOL HTOOB;
-  int NTEMP;
+  FX_DWORD NTEMP;
   int* CODES;
   int* PREFLEN;
   int* RANGELEN;
   int* RANGELOW;
   FX_BOOL m_bOK;
   friend class CJBig2_HuffmanDecoder;
 };
 #endif