Avoid endless loop deleting CFGAS_GEFont.

xfa/fgas/font/cfgas_gefont.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 XFA_FGAS_FONT_CFGAS_GEFONT_H_
 #define XFA_FGAS_FONT_CFGAS_GEFONT_H_
 
 #include <map>
 #include <memory>
 #include <vector>
 
 #include "core/fxcrt/cfx_retain_ptr.h"
 #include "core/fxcrt/fx_memory.h"
 #include "xfa/fgas/crt/fgas_utils.h"
 #include "xfa/fgas/font/cfgas_fontmgr.h"
 
 #define FXFONT_SUBST_ITALIC 0x02
 
 class CFGAS_FontMgr;
 class CFX_UnicodeEncoding;
 class CXFA_PDFFontMgr;
 
 class CFGAS_GEFont : public CFX_Retainable {
  public:
   template <typename T, typename... Args>
   friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+  template <typename T>
+  friend class CFX_RetainPtr;
 
   static CFX_RetainPtr<CFGAS_GEFont> LoadFont(const FX_WCHAR* pszFontFamily,
                                               uint32_t dwFontStyles,
                                               uint16_t wCodePage,
                                               CFGAS_FontMgr* pFontMgr);
   static CFX_RetainPtr<CFGAS_GEFont> LoadFont(CFX_Font* pExternalFont,
                                               CFGAS_FontMgr* pFontMgr);
   static CFX_RetainPtr<CFGAS_GEFont> LoadFont(
       std::unique_ptr<CFX_Font> pInternalFont,
       CFGAS_FontMgr* pFontMgr);
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
   static CFX_RetainPtr<CFGAS_GEFont> LoadFont(const uint8_t* pBuffer,
                                               int32_t iLength,
                                               CFGAS_FontMgr* pFontMgr);
   static CFX_RetainPtr<CFGAS_GEFont> LoadFont(
       const CFX_RetainPtr<IFGAS_Stream>& pFontStream,
       CFGAS_FontMgr* pFontMgr,
       bool bSaveStream);
 #endif
 
-  ~CFGAS_GEFont() override;
-
   CFX_RetainPtr<CFGAS_GEFont> Derive(uint32_t dwFontStyles,
                                      uint16_t wCodePage = 0);
   uint32_t GetFontStyles() const;
   bool GetCharWidth(FX_WCHAR wUnicode, int32_t& iWidth, bool bCharCode);
   int32_t GetGlyphIndex(FX_WCHAR wUnicode, bool bCharCode = false);
   int32_t GetAscent() const;
   int32_t GetDescent() const;
   bool GetCharBBox(FX_WCHAR wUnicode, CFX_Rect* bbox, bool bCharCode = false);
   bool GetBBox(CFX_Rect* bbox);
-  CFX_RetainPtr<CFGAS_GEFont> GetSubstFont(int32_t iGlyphIndex) const;
+  CFX_RetainPtr<CFGAS_GEFont> GetSubstFont(int32_t iGlyphIndex);
   CFX_Font* GetDevFont() const { return m_pFont; }
   void SetFontProvider(CXFA_PDFFontMgr* pProvider) { m_pProvider = pProvider; }
 #if _FXM_PLATFORM_ != _FXM_PLATFORM_WINDOWS_
   void SetLogicalFontStyle(uint32_t dwLogFontStyle) {
     m_bUseLogFontStyle = true;
     m_dwLogFontStyle = dwLogFontStyle;
   }
 #endif
 
  private:
   explicit CFGAS_GEFont(CFGAS_FontMgr* pFontMgr);
   CFGAS_GEFont(const CFX_RetainPtr<CFGAS_GEFont>& src, uint32_t dwFontStyles);
+  ~CFGAS_GEFont() override;
 
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
   bool LoadFontInternal(const FX_WCHAR* pszFontFamily,
                         uint32_t dwFontStyles,
                         uint16_t wCodePage);
   bool LoadFontInternal(const uint8_t* pBuffer, int32_t length);
   bool LoadFontInternal(const CFX_RetainPtr<IFGAS_Stream>& pFontStream,
                         bool bSaveStream);
 #endif
   bool LoadFontInternal(CFX_Font* pExternalFont);
@@ skipping 26 matching lines @@
   std::unique_ptr<CFX_UnicodeEncoding> m_pFontEncoding;
   std::unique_ptr<CFX_DiscreteArrayTemplate<uint16_t>> m_pCharWidthMap;
   std::unique_ptr<CFX_MassArrayTemplate<CFX_Rect>> m_pRectArray;
   std::map<FX_WCHAR, CFX_Rect*> m_BBoxMap;  // Rect owned by m_pRectArray.
   CXFA_PDFFontMgr* m_pProvider;  // not owned.
   std::vector<CFX_RetainPtr<CFGAS_GEFont>> m_SubstFonts;
   std::map<FX_WCHAR, CFX_RetainPtr<CFGAS_GEFont>> m_FontMapper;
 };
 
 #endif  // XFA_FGAS_FONT_CFGAS_GEFONT_H_