Make conversion to CPDF_Dest explicit

core/include/fpdfdoc/fpdf_doc.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 _FPDF_DOC_H_
 #define _FPDF_DOC_H_
 #ifndef _FPDF_PARSER_
 #include "../fpdfapi/fpdf_parser.h"
@@ skipping 106 matching lines @@
 #define PDFZOOM_FITPAGE                         2
 #define PDFZOOM_FITHORZ                         3
 #define PDFZOOM_FITVERT                         4
 #define PDFZOOM_FITRECT                         5
 #define PDFZOOM_FITBBOX                         6
 #define PDFZOOM_FITBHORZ                        7
 #define PDFZOOM_FITBVERT                        8
 class CPDF_Dest : public CFX_Object
 {
 public:
+    CPDF_Dest() : m_pObj(nullptr) { }
+    explicit CPDF_Dest(CPDF_Object* pObj) : m_pObj(pObj) { }
 
-    CPDF_Dest(CPDF_Object* pObj = NULL)
-    {
-        m_pObj = pObj;
-    }
-
-    operator CPDF_Object* () const
-    {
-        return m_pObj;
-    }
+    operator bool () const { return m_pObj != NULL; }
+    CPDF_Object* GetObject() const { return m_pObj; }
 
     CFX_ByteString              GetRemoteName();
-
     int                                 GetPageIndex(CPDF_Document* pDoc);
-
     FX_DWORD                    GetPageObjNum();
-
     int                                 GetZoomMode();
-
     FX_FLOAT                    GetParam(int index);
 
-
+protected:
     CPDF_Object*                m_pObj;
 };
 class CPDF_OCContext : public CFX_Object, public IPDF_OCContext
 {
 public:
 
     enum UsageType {
         View = 0,
         Design,
         Print,
@@ skipping 1605 matching lines @@
     FX_FLOAT                            GetOriginalColor(int index, FX_BSTR csEntry);
 
     void                                        GetOriginalColor(int& iColorType, FX_FLOAT fc[4], FX_BSTR csEntry);
 
     CFX_WideString                      GetCaption(FX_BSTR csEntry);
 
     CPDF_Stream*                        GetIcon(FX_BSTR csEntry);
     friend class                        CPDF_FormControl;
 };
 #endif