1 files changed, 7 insertions, 3 deletions
diff --git a/core/fpdfdoc/fpdf_tagged.h b/core/fpdfdoc/fpdf_tagged.h
index 3a1e2231fc..fbbb49f856 100644
--- a/core/fpdfdoc/fpdf_tagged.h
+++ b/core/fpdfdoc/fpdf_tagged.h
@@ -21,16 +21,17 @@ class IPDF_StructTree {
       const CPDF_Document* pDoc,
       const CPDF_Dictionary* pPageDict);
 
-  virtual ~IPDF_StructTree() {}
 
   virtual int CountTopElements() const = 0;
   virtual IPDF_StructElement* GetTopElement(int i) const = 0;
+
+ protected:
+  friend std::default_delete<IPDF_StructTree>;
+  virtual ~IPDF_StructTree() {}
 };
 
 class IPDF_StructElement {
  public:
-  virtual ~IPDF_StructElement() {}
-
   virtual IPDF_StructTree* GetTree() const = 0;
   virtual const CFX_ByteString& GetType() const = 0;
   virtual IPDF_StructElement* GetParent() const = 0;
@@ -66,6 +67,9 @@ class IPDF_StructElement {
                          int default_value,
                          bool bInheritable = false,
                          int subindex = -1) = 0;
+
+ protected:
+  virtual ~IPDF_StructElement() {}
 };
 
 #endif  // CORE_FPDFDOC_FPDF_TAGGED_H_