Use smart pointers for various Jbig2 decoding contexts

core/fxcodec/codec/ccodec_jbig2module.h

 // Copyright 2016 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_FXCODEC_CODEC_CCODEC_JBIG2MODULE_H_
 #define CORE_FXCODEC_CODEC_CCODEC_JBIG2MODULE_H_
 
 #include <memory>
 
 #include "core/fxcodec/include/fx_codec_def.h"
 #include "core/fxcrt/include/fx_basic.h"
 
 class CJBig2_Context;
 class CJBig2_Image;
 class CPDF_StreamAcc;
 class IFX_Pause;
 
 class CCodec_Jbig2Context {
  public:
   CCodec_Jbig2Context();
-  ~CCodec_Jbig2Context() {}
+  ~CCodec_Jbig2Context();
 
   uint32_t m_width;
   uint32_t m_height;
   CPDF_StreamAcc* m_pGlobalStream;
   CPDF_StreamAcc* m_pSrcStream;
   uint8_t* m_dest_buf;
   uint32_t m_dest_pitch;
   IFX_Pause* m_pPause;
-  CJBig2_Context* m_pContext;
-  CJBig2_Image* m_dest_image;
+  std::unique_ptr<CJBig2_Context> m_pContext;
 };
 
 class CCodec_Jbig2Module {
  public:
   CCodec_Jbig2Module() {}
   ~CCodec_Jbig2Module();
 
-  CCodec_Jbig2Context* CreateJbig2Context();
   FXCODEC_STATUS StartDecode(CCodec_Jbig2Context* pJbig2Context,
                              std::unique_ptr<CFX_Deletable>* pContextHolder,
                              uint32_t width,
                              uint32_t height,
                              CPDF_StreamAcc* src_stream,
                              CPDF_StreamAcc* global_stream,
                              uint8_t* dest_buf,
                              uint32_t dest_pitch,
                              IFX_Pause* pPause);
   FXCODEC_STATUS ContinueDecode(CCodec_Jbig2Context* pJbig2Context,
                                 IFX_Pause* pPause);
-  void DestroyJbig2Context(CCodec_Jbig2Context* pJbig2Context);
 };
 
 #endif  // CORE_FXCODEC_CODEC_CCODEC_JBIG2MODULE_H_