Cleanup CJBig2_ArithDecoder.

core/src/fxcodec/jbig2/JBig2_ArithDecoder.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 CORE_SRC_FXCODEC_JBIG2_JBIG2_ARITHDECODER_H_
 #define CORE_SRC_FXCODEC_JBIG2_JBIG2_ARITHDECODER_H_
 
 class CJBig2_BitStream;
 
 struct JBig2ArithCtx {
   unsigned int MPS;
   unsigned int I;
 };
 
 class CJBig2_ArithDecoder {
  public:
   explicit CJBig2_ArithDecoder(CJBig2_BitStream* pStream);
 
   ~CJBig2_ArithDecoder();
 
   int DECODE(JBig2ArithCtx* pCX);
 
  private:
-  void INITDEC();
   void BYTEIN();
+  void ReadValueA();
 
-  unsigned char B;
-  unsigned int C;
-  unsigned int A;
-  unsigned int CT;
-  CJBig2_BitStream* m_pStream;
+  unsigned char m_B;
+  unsigned int m_C;
+  unsigned int m_A;
+  unsigned int m_CT;
+  CJBig2_BitStream* const m_pStream;
 };
 
 #endif  // CORE_SRC_FXCODEC_JBIG2_JBIG2_ARITHDECODER_H_