Detect resursive loading of type3 font char to avoid infinite loop

core/fpdfapi/fpdf_font/cpdf_type3font.h

Index: core/fpdfapi/fpdf_font/cpdf_type3font.h
diff --git a/core/fpdfapi/fpdf_font/cpdf_type3font.h b/core/fpdfapi/fpdf_font/cpdf_type3font.h
index 2b840f22670995ce374404338eac4edb2fe67e19..03078298f179c1fe2a011c56524fff7e8464551c 100644
--- a/core/fpdfapi/fpdf_font/cpdf_type3font.h
+++ b/core/fpdfapi/fpdf_font/cpdf_type3font.h
@@ -26,13 +26,13 @@ class CPDF_Type3Font : public CPDF_SimpleFont {
   bool IsType3Font() const override;
   const CPDF_Type3Font* AsType3Font() const override;
   CPDF_Type3Font* AsType3Font() override;
-  int GetCharWidthF(uint32_t charcode, int level = 0) override;
-  FX_RECT GetCharBBox(uint32_t charcode, int level = 0) override;
+  int GetCharWidthF(uint32_t charcode) override;
+  FX_RECT GetCharBBox(uint32_t charcode) override;
 
   void SetPageResources(CPDF_Dictionary* pResources) {
     m_pPageResources = pResources;
   }
-  CPDF_Type3Char* LoadChar(uint32_t charcode, int level = 0);
+  CPDF_Type3Char* LoadChar(uint32_t charcode);
   void CheckType3FontMetrics();
 
   CFX_Matrix& GetFontMatrix() { return m_FontMatrix; }
@@ -52,6 +52,8 @@ class CPDF_Type3Font : public CPDF_SimpleFont {
   CPDF_Dictionary* m_pPageResources;
   CPDF_Dictionary* m_pFontResources;
   std::map<uint32_t, std::unique_ptr<CPDF_Type3Char>> m_CacheMap;
+  // The depth char loading is in, to avoid recurive calling LoadChar().
+  int m_CharLoadingDepth;
 };
 
 #endif  // CORE_FPDFAPI_FPDF_FONT_CPDF_TYPE3FONT_H_