Make CPDF_Object subclass constructors intern strings

core/fpdfapi/parser/cpdf_string.cpp

Index: core/fpdfapi/parser/cpdf_string.cpp
diff --git a/core/fpdfapi/parser/cpdf_string.cpp b/core/fpdfapi/parser/cpdf_string.cpp
index 2116c200fe880fc8baf0b3cf43171ec82e41c4fc..fd4ff04ff747eec3e2de322db174de3cc9b09c2b 100644
--- a/core/fpdfapi/parser/cpdf_string.cpp
+++ b/core/fpdfapi/parser/cpdf_string.cpp
@@ -11,8 +11,13 @@
 
 CPDF_String::CPDF_String() : m_bHex(false) {}
 
-CPDF_String::CPDF_String(const CFX_ByteString& str, bool bHex)
-    : m_String(str), m_bHex(bHex) {}
+CPDF_String::CPDF_String(CFX_WeakPtr<CFX_ByteStringPool> pPool,
+                         const CFX_ByteString& str,
+                         bool bHex)
+    : m_String(str), m_bHex(bHex) {
+  if (pPool)
+    m_String = pPool->Intern(m_String);
+}
 
 CPDF_String::CPDF_String(const CFX_WideString& str) : m_bHex(false) {
   m_String = PDF_EncodeText(str);
@@ -25,7 +30,10 @@ CPDF_Object::Type CPDF_String::GetType() const {
 }
 
 std::unique_ptr<CPDF_Object> CPDF_String::Clone() const {
-  return pdfium::MakeUnique<CPDF_String>(m_String, m_bHex);
+  auto pRet = pdfium::MakeUnique<CPDF_String>();
+  pRet->m_String = m_String;
+  pRet->m_bHex = m_bHex;
+  return std::move(pRet);
 }
 
 CFX_ByteString CPDF_String::GetString() const {