diff --git a/core/fpdfapi/page/cpdf_contentparser.cpp b/core/fpdfapi/page/cpdf_contentparser.cpp
index 5ef9d80..d645297 100644
--- a/core/fpdfapi/page/cpdf_contentparser.cpp
+++ b/core/fpdfapi/page/cpdf_contentparser.cpp
@@ -56,12 +56,13 @@
   HandlePageContentFailure();
 }
 
-CPDF_ContentParser::CPDF_ContentParser(RetainPtr<const CPDF_Stream> pStream,
-                                       CPDF_PageObjectHolder* pPageObjectHolder,
-                                       const CPDF_AllStates* pGraphicStates,
-                                       const CFX_Matrix* pParentMatrix,
-                                       CPDF_Type3Char* pType3Char,
-                                       std::set<const uint8_t*>* pParsedSet)
+CPDF_ContentParser::CPDF_ContentParser(
+    RetainPtr<const CPDF_Stream> pStream,
+    CPDF_PageObjectHolder* pPageObjectHolder,
+    const CPDF_AllStates* pGraphicStates,
+    const CFX_Matrix* pParentMatrix,
+    CPDF_Type3Char* pType3Char,
+    CPDF_Form::RecursionState* recursion_state)
     : m_CurrentStage(Stage::kParse),
       m_pPageObjectHolder(pPageObjectHolder),
       m_pType3Char(pType3Char) {
@@ -95,7 +96,7 @@
       m_pPageObjectHolder->GetMutablePageResources(),
       m_pPageObjectHolder->GetMutableResources(), pParentMatrix,
       m_pPageObjectHolder, std::move(pResources), form_bbox, pGraphicStates,
-      pParsedSet);
+      recursion_state);
   m_pParser->GetCurStates()->m_CTM = form_matrix;
   m_pParser->GetCurStates()->m_ParentMatrix = form_matrix;
   if (ClipPath.HasRef()) {
@@ -197,12 +198,12 @@
 
 CPDF_ContentParser::Stage CPDF_ContentParser::Parse() {
   if (!m_pParser) {
-    m_ParsedSet.clear();
+    m_RecursionState.parsed_set.clear();
     m_pParser = std::make_unique<CPDF_StreamContentParser>(
         m_pPageObjectHolder->GetDocument(),
         m_pPageObjectHolder->GetMutablePageResources(), nullptr, nullptr,
         m_pPageObjectHolder, m_pPageObjectHolder->GetMutableResources(),
-        m_pPageObjectHolder->GetBBox(), nullptr, &m_ParsedSet);
+        m_pPageObjectHolder->GetBBox(), nullptr, &m_RecursionState);
     m_pParser->GetCurStates()->m_ColorState.SetDefault();
   }
   if (m_CurrentOffset >= GetData().size())
diff --git a/core/fpdfapi/page/cpdf_contentparser.h b/core/fpdfapi/page/cpdf_contentparser.h
index 090c624..e2660e2 100644
--- a/core/fpdfapi/page/cpdf_contentparser.h
+++ b/core/fpdfapi/page/cpdf_contentparser.h
@@ -10,9 +10,9 @@
 #include <stdint.h>
 
 #include <memory>
-#include <set>
 #include <vector>
 
+#include "core/fpdfapi/page/cpdf_form.h"
 #include "core/fpdfapi/page/cpdf_streamcontentparser.h"
 #include "core/fxcrt/fixed_try_alloc_zeroed_data_vector.h"
 #include "core/fxcrt/retain_ptr.h"
@@ -36,7 +36,7 @@
                      const CPDF_AllStates* pGraphicStates,
                      const CFX_Matrix* pParentMatrix,
                      CPDF_Type3Char* pType3Char,
-                     std::set<const uint8_t*>* pParsedSet);
+                     CPDF_Form::RecursionState* recursion_state);
   ~CPDF_ContentParser();
 
   const CPDF_AllStates* GetCurStates() const {
@@ -80,9 +80,10 @@
       m_Data;
   uint32_t m_nStreams = 0;
   uint32_t m_CurrentOffset = 0;
-  std::set<const uint8_t*> m_ParsedSet;  // Only used when parsing pages.
+  // Only used when parsing pages.
+  CPDF_Form::RecursionState m_RecursionState;
 
-  // Must not outlive |m_pParsedSet|.
+  // Must not outlive |m_RecursionState|.
   std::unique_ptr<CPDF_StreamContentParser> m_pParser;
 };
 
diff --git a/core/fpdfapi/page/cpdf_form.cpp b/core/fpdfapi/page/cpdf_form.cpp
index 90a8650..e66ff0b 100644
--- a/core/fpdfapi/page/cpdf_form.cpp
+++ b/core/fpdfapi/page/cpdf_form.cpp
@@ -18,6 +18,10 @@
 #include "core/fxge/dib/cfx_dibitmap.h"
 #include "third_party/base/check_op.h"
 
+CPDF_Form::RecursionState::RecursionState() = default;
+
+CPDF_Form::RecursionState::~RecursionState() = default;
+
 // static
 CPDF_Dictionary* CPDF_Form::ChooseResourcesDict(
     CPDF_Dictionary* pResources,
@@ -61,8 +65,8 @@
 
 void CPDF_Form::ParseContent(const CPDF_AllStates* pGraphicStates,
                              const CFX_Matrix* pParentMatrix,
-                             std::set<const uint8_t*>* pParsedSet) {
-  ParseContentInternal(pGraphicStates, pParentMatrix, nullptr, pParsedSet);
+                             RecursionState* recursion_state) {
+  ParseContentInternal(pGraphicStates, pParentMatrix, nullptr, recursion_state);
 }
 
 void CPDF_Form::ParseContentForType3Char(CPDF_Type3Char* pType3Char) {
@@ -72,14 +76,14 @@
 void CPDF_Form::ParseContentInternal(const CPDF_AllStates* pGraphicStates,
                                      const CFX_Matrix* pParentMatrix,
                                      CPDF_Type3Char* pType3Char,
-                                     std::set<const uint8_t*>* pParsedSet) {
+                                     RecursionState* recursion_state) {
   if (GetParseState() == ParseState::kParsed)
     return;
 
   if (GetParseState() == ParseState::kNotParsed) {
     StartParse(std::make_unique<CPDF_ContentParser>(
         GetStream(), this, pGraphicStates, pParentMatrix, pType3Char,
-        pParsedSet ? pParsedSet : &m_ParsedSet));
+        recursion_state ? recursion_state : &m_RecursionState));
   }
   DCHECK_EQ(GetParseState(), ParseState::kParsing);
   ContinueParse(nullptr);
diff --git a/core/fpdfapi/page/cpdf_form.h b/core/fpdfapi/page/cpdf_form.h
index 9052b9d..3ced731 100644
--- a/core/fpdfapi/page/cpdf_form.h
+++ b/core/fpdfapi/page/cpdf_form.h
@@ -24,6 +24,13 @@
 class CPDF_Form final : public CPDF_PageObjectHolder,
                         public CPDF_Font::FormIface {
  public:
+  struct RecursionState {
+    RecursionState();
+    ~RecursionState();
+
+    std::set<const uint8_t*> parsed_set;
+  };
+
   // Helper method to choose the first non-null resources dictionary.
   static CPDF_Dictionary* ChooseResourcesDict(CPDF_Dictionary* pResources,
                                               CPDF_Dictionary* pParentResources,
@@ -48,7 +55,7 @@
   void ParseContent();
   void ParseContent(const CPDF_AllStates* pGraphicStates,
                     const CFX_Matrix* pParentMatrix,
-                    std::set<const uint8_t*>* pParsedSet);
+                    RecursionState* recursion_state);
 
   RetainPtr<const CPDF_Stream> GetStream() const;
 
@@ -56,9 +63,9 @@
   void ParseContentInternal(const CPDF_AllStates* pGraphicStates,
                             const CFX_Matrix* pParentMatrix,
                             CPDF_Type3Char* pType3Char,
-                            std::set<const uint8_t*>* pParsedSet);
+                            RecursionState* recursion_state);
 
-  std::set<const uint8_t*> m_ParsedSet;
+  RecursionState m_RecursionState;
   RetainPtr<CPDF_Stream> const m_pFormStream;
 };
 
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 0522cf1..ce3f6fe 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -250,7 +250,7 @@
     RetainPtr<CPDF_Dictionary> pResources,
     const CFX_FloatRect& rcBBox,
     const CPDF_AllStates* pStates,
-    std::set<const uint8_t*>* pParsedSet)
+    CPDF_Form::RecursionState* recursion_state)
     : m_pDocument(pDocument),
       m_pPageResources(pPageResources),
       m_pParentResources(pParentResources),
@@ -258,7 +258,7 @@
                                                   pParentResources.Get(),
                                                   pPageResources.Get())),
       m_pObjectHolder(pObjHolder),
-      m_ParsedSet(pParsedSet),
+      m_RecursionState(recursion_state),
       m_BBox(rcBBox),
       m_pCurStates(std::make_unique<CPDF_AllStates>()) {
   if (pmtContentToUser)
@@ -772,7 +772,7 @@
   status.m_TextState = m_pCurStates->m_TextState;
   auto form = std::make_unique<CPDF_Form>(
       m_pDocument, m_pPageResources, std::move(pStream), m_pResources.Get());
-  form->ParseContent(&status, nullptr, m_ParsedSet);
+  form->ParseContent(&status, nullptr, m_RecursionState);
 
   CFX_Matrix matrix = m_pCurStates->m_CTM * m_mtContentToUser;
   auto pFormObj = std::make_unique<CPDF_FormObject>(GetCurrentStreamIndex(),
@@ -1535,15 +1535,15 @@
   // Parsing will be done from within |pDataStart|.
   pdfium::span<const uint8_t> pDataStart = pData.subspan(start_offset);
   m_StartParseOffset = start_offset;
-  if (m_ParsedSet->size() > kMaxFormLevel ||
-      pdfium::Contains(*m_ParsedSet, pDataStart.data())) {
+  if (m_RecursionState->parsed_set.size() > kMaxFormLevel ||
+      pdfium::Contains(m_RecursionState->parsed_set, pDataStart.data())) {
     return fxcrt::CollectionSize<uint32_t>(pDataStart);
   }
 
   m_StreamStartOffsets = stream_start_offsets;
 
-  ScopedSetInsertion<const uint8_t*> scopedInsert(m_ParsedSet,
-                                                  pDataStart.data());
+  ScopedSetInsertion<const uint8_t*> scoped_insert(
+      &m_RecursionState->parsed_set, pDataStart.data());
 
   uint32_t init_obj_count = m_pObjectHolder->GetPageObjectCount();
   AutoNuller<std::unique_ptr<CPDF_StreamParser>> auto_clearer(&m_pSyntax);
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.h b/core/fpdfapi/page/cpdf_streamcontentparser.h
index 276dc72..f11e5c2 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.h
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.h
@@ -9,11 +9,11 @@
 
 #include <map>
 #include <memory>
-#include <set>
 #include <stack>
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_contentmarks.h"
+#include "core/fpdfapi/page/cpdf_form.h"
 #include "core/fxcrt/bytestring.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_number.h"
@@ -49,7 +49,7 @@
                            RetainPtr<CPDF_Dictionary> pResources,
                            const CFX_FloatRect& rcBBox,
                            const CPDF_AllStates* pStates,
-                           std::set<const uint8_t*>* pParsedSet);
+                           CPDF_Form::RecursionState* parse_state);
   ~CPDF_StreamContentParser();
 
   uint32_t Parse(pdfium::span<const uint8_t> pData,
@@ -222,7 +222,7 @@
   RetainPtr<CPDF_Dictionary> const m_pParentResources;
   RetainPtr<CPDF_Dictionary> const m_pResources;
   UnownedPtr<CPDF_PageObjectHolder> const m_pObjectHolder;
-  UnownedPtr<std::set<const uint8_t*>> const m_ParsedSet;
+  UnownedPtr<CPDF_Form::RecursionState> const m_RecursionState;
   CFX_Matrix m_mtContentToUser;
   const CFX_FloatRect m_BBox;
   uint32_t m_ParamStartPos = 0;