Introduce CFX_UnownedPtr to detect lifetime inversion issues.

There are places where an object "child" has a raw pointer
back to object "owner" with the understanding that owner will
always outlive child.

Violating this constraint can lead to use after free, but this
requires finding two paths: one that frees the objects in the
wrong order, and one that uses the object after the free. The
purpose of this patch is to detect the constraint violation
even when the second path is not hit.

We create a template that is used in place of TYPE*. It's dtor,
when a memory tool is present, goes out and probes the first
byte of the object to which it points.  Used in "child", this
allows the memory tool to prove that the "owner" is still alive
at the time the child is destroyed, and hence the constraint is
never violated.

Change-Id: I2a6d696d51dda4a79ee2f00a6752965e058a6417
Reviewed-on: https://pdfium-review.googlesource.com/5475
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

46 files changed, 298 insertions, 108 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 25ff2c6fd3..3a26007a17 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -764,6 +764,7 @@ static_library("fxcrt") {
     "core/fxcrt/cfx_string_c_template.h",
     "core/fxcrt/cfx_string_data_template.h",
     "core/fxcrt/cfx_string_pool_template.h",
+    "core/fxcrt/cfx_unowned_ptr.h",
     "core/fxcrt/cfx_weak_ptr.h",
     "core/fxcrt/cfx_widestring.cpp",
     "core/fxcrt/cfx_widestring.h",
@@ -1871,6 +1872,7 @@ test("pdfium_unittests") {
     "core/fxcrt/cfx_retain_ptr_unittest.cpp",
     "core/fxcrt/cfx_shared_copy_on_write_unittest.cpp",
     "core/fxcrt/cfx_string_pool_template_unittest.cpp",
+    "core/fxcrt/cfx_unowned_ptr_unittest.cpp",
     "core/fxcrt/cfx_weak_ptr_unittest.cpp",
     "core/fxcrt/cfx_widestring_unittest.cpp",
     "core/fxcrt/fx_basic_gcc_unittest.cpp",
diff --git a/core/fpdfapi/page/cpdf_contentmarkitem.cpp b/core/fpdfapi/page/cpdf_contentmarkitem.cpp
index 2c370141e2..de720b39fc 100644
--- a/core/fpdfapi/page/cpdf_contentmarkitem.cpp
+++ b/core/fpdfapi/page/cpdf_contentmarkitem.cpp
@@ -26,7 +26,7 @@ CPDF_ContentMarkItem::~CPDF_ContentMarkItem() {}
 CPDF_Dictionary* CPDF_ContentMarkItem::GetParam() const {
   switch (m_ParamType) {
     case PropertiesDict:
-      return m_pPropertiesDict;
+      return m_pPropertiesDict.Get();
     case DirectDict:
       return m_pDirectDict.get();
     case None:
diff --git a/core/fpdfapi/page/cpdf_contentmarkitem.h b/core/fpdfapi/page/cpdf_contentmarkitem.h
index ed2737111b..afd2833691 100644
--- a/core/fpdfapi/page/cpdf_contentmarkitem.h
+++ b/core/fpdfapi/page/cpdf_contentmarkitem.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_string.h"
 #include "core/fxcrt/fx_system.h"
@@ -37,7 +38,7 @@ class CPDF_ContentMarkItem {
  private:
   CFX_ByteString m_MarkName;
   ParamType m_ParamType;
-  CPDF_Dictionary* m_pPropertiesDict;  // not owned.
+  CFX_UnownedPtr<CPDF_Dictionary> m_pPropertiesDict;
   std::unique_ptr<CPDF_Dictionary> m_pDirectDict;
 };
 
diff --git a/core/fpdfapi/parser/cpdf_parser.cpp b/core/fpdfapi/parser/cpdf_parser.cpp
index a3e5dba40a..54b8ea0aa3 100644
--- a/core/fpdfapi/parser/cpdf_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_parser.cpp
@@ -52,8 +52,7 @@ int32_t GetStreamFirst(const CFX_RetainPtr<CPDF_StreamAcc>& pObjStream) {
 }  // namespace
 
 CPDF_Parser::CPDF_Parser()
-    : m_pDocument(nullptr),
-      m_bHasParsed(false),
+    : m_bHasParsed(false),
       m_bXRefStream(false),
       m_bVersionUpdated(false),
       m_FileVersion(0),
@@ -719,8 +718,8 @@ bool CPDF_Parser::RebuildCrossRef() {
                 last_obj = start_pos;
                 FX_FILESIZE obj_end = 0;
                 std::unique_ptr<CPDF_Object> pObject =
-                    ParseIndirectObjectAtByStrict(m_pDocument, obj_pos, objnum,
-                                                  &obj_end);
+                    ParseIndirectObjectAtByStrict(m_pDocument.Get(), obj_pos,
+                                                  objnum, &obj_end);
                 if (CPDF_Stream* pStream = ToStream(pObject.get())) {
                   if (CPDF_Dictionary* pDict = pStream->GetDict()) {
                     if ((pDict->KeyExist("Type")) &&
@@ -779,7 +778,7 @@ bool CPDF_Parser::RebuildCrossRef() {
               m_pSyntax->SetPos(pos + i - m_pSyntax->m_HeaderOffset);
 
               std::unique_ptr<CPDF_Object> pObj =
-                  m_pSyntax->GetObject(m_pDocument, 0, 0, true);
+                  m_pSyntax->GetObject(m_pDocument.Get(), 0, 0, true);
               if (pObj) {
                 if (pObj->IsDictionary() || pObj->AsStream()) {
                   CPDF_Stream* pStream = pObj->AsStream();
@@ -800,7 +799,7 @@ bool CPDF_Parser::RebuildCrossRef() {
                               pElement ? pElement->GetObjNum() : 0;
                           if (dwObjNum) {
                             m_pTrailer->SetNewFor<CPDF_Reference>(
-                                key, m_pDocument, dwObjNum);
+                                key, m_pDocument.Get(), dwObjNum);
                           } else {
                             m_pTrailer->SetFor(key, pElement->Clone());
                           }
@@ -920,7 +919,7 @@ bool CPDF_Parser::RebuildCrossRef() {
 
 bool CPDF_Parser::LoadCrossRefV5(FX_FILESIZE* pos, bool bMainXRef) {
   std::unique_ptr<CPDF_Object> pObject(
-      ParseIndirectObjectAt(m_pDocument, *pos, 0));
+      ParseIndirectObjectAt(m_pDocument.Get(), *pos, 0));
   if (!pObject)
     return false;
 
@@ -1397,7 +1396,7 @@ std::unique_ptr<CPDF_Dictionary> CPDF_Parser::LoadTrailerV4() {
   if (m_pSyntax->GetKeyword() != "trailer")
     return nullptr;
 
-  return ToDictionary(m_pSyntax->GetObject(m_pDocument, 0, 0, true));
+  return ToDictionary(m_pSyntax->GetObject(m_pDocument.Get(), 0, 0, true));
 }
 
 uint32_t CPDF_Parser::GetPermissions() const {
diff --git a/core/fpdfapi/parser/cpdf_parser.h b/core/fpdfapi/parser/cpdf_parser.h
index 7ae2d4627e..c444c99f28 100644
--- a/core/fpdfapi/parser/cpdf_parser.h
+++ b/core/fpdfapi/parser/cpdf_parser.h
@@ -12,6 +12,7 @@
 #include <set>
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_basic.h"
 
 class CPDF_Array;
@@ -150,7 +151,7 @@ class CPDF_Parser {
   // the objects.
   bool VerifyCrossRefV4();
 
-  CPDF_Document* m_pDocument;  // not owned
+  CFX_UnownedPtr<CPDF_Document> m_pDocument;
   bool m_bHasParsed;
   bool m_bXRefStream;
   bool m_bVersionUpdated;
diff --git a/core/fpdfapi/render/cpdf_docrenderdata.cpp b/core/fpdfapi/render/cpdf_docrenderdata.cpp
index 2d0bca4497..d03824b59e 100644
--- a/core/fpdfapi/render/cpdf_docrenderdata.cpp
+++ b/core/fpdfapi/render/cpdf_docrenderdata.cpp
@@ -88,7 +88,7 @@ CFX_RetainPtr<CPDF_TransferFunc> CPDF_DocRenderData::GetTransferFunc(
     if (!pFuncs[0])
       return nullptr;
   }
-  auto pTransfer = pdfium::MakeRetain<CPDF_TransferFunc>(m_pPDFDoc);
+  auto pTransfer = pdfium::MakeRetain<CPDF_TransferFunc>(m_pPDFDoc.Get());
   m_TransferFuncMap[pObj] = pTransfer;
 
   float input;
diff --git a/core/fpdfapi/render/cpdf_docrenderdata.h b/core/fpdfapi/render/cpdf_docrenderdata.h
index 7952f95991..949a079126 100644
--- a/core/fpdfapi/render/cpdf_docrenderdata.h
+++ b/core/fpdfapi/render/cpdf_docrenderdata.h
@@ -11,6 +11,8 @@
 
 #include "core/fpdfapi/page/cpdf_countedobject.h"
 #include "core/fpdfapi/render/cpdf_transferfunc.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
+#include "core/fxcrt/fx_system.h"
 
 class CPDF_Document;
 class CPDF_Font;
@@ -32,7 +34,7 @@ class CPDF_DocRenderData {
   void Clear(bool bRelease);
 
  private:
-  CPDF_Document* m_pPDFDoc;  // Not Owned
+  CFX_UnownedPtr<CPDF_Document> m_pPDFDoc;
   std::map<CPDF_Font*, CFX_RetainPtr<CPDF_Type3Cache>> m_Type3FaceMap;
   std::map<CPDF_Object*, CFX_RetainPtr<CPDF_TransferFunc>> m_TransferFuncMap;
 };
diff --git a/core/fpdfdoc/cpdf_filespec.h b/core/fpdfdoc/cpdf_filespec.h
index ea002f0e22..fb71b57186 100644
--- a/core/fpdfdoc/cpdf_filespec.h
+++ b/core/fpdfdoc/cpdf_filespec.h
@@ -8,6 +8,7 @@
 #define CORE_FPDFDOC_CPDF_FILESPEC_H_
 
 #include "core/fxcrt/cfx_string_pool_template.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/cfx_weak_ptr.h"
 #include "core/fxcrt/fx_string.h"
 
@@ -24,14 +25,14 @@ class CPDF_FileSpec {
   // Convert a pdf file name into platform dependent format.
   static CFX_WideString DecodeFileName(const CFX_WideStringC& filepath);
 
-  CPDF_Object* GetObj() const { return m_pObj; }
+  CPDF_Object* GetObj() const { return m_pObj.Get(); }
   bool GetFileName(CFX_WideString* wsFileName) const;
 
   // Set this file spec to refer to a file name (not a url).
   void SetFileName(const CFX_WideStringC& wsFileName);
 
  private:
-  CPDF_Object* const m_pObj;  // not owned.
+  CFX_UnownedPtr<CPDF_Object> const m_pObj;
 };
 
 #endif  // CORE_FPDFDOC_CPDF_FILESPEC_H_
diff --git a/core/fxcrt/cfx_unowned_ptr.h b/core/fxcrt/cfx_unowned_ptr.h
new file mode 100644
index 0000000000..11f4e8e38b
--- /dev/null
+++ b/core/fxcrt/cfx_unowned_ptr.h
@@ -0,0 +1,64 @@
+// Copyright 2017 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.
+
+#ifndef CORE_FXCRT_CFX_UNOWNED_PTR_H_
+#define CORE_FXCRT_CFX_UNOWNED_PTR_H_
+
+#include <functional>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "core/fxcrt/fx_memory.h"
+
+template <class T>
+class CFX_UnownedPtr {
+ public:
+  CFX_UnownedPtr() {}
+  CFX_UnownedPtr(const CFX_UnownedPtr& that) : CFX_UnownedPtr(that.Get()) {}
+
+  template <typename U>
+  explicit CFX_UnownedPtr(U* pObj) : m_pObj(pObj) {}
+
+  // Deliberately implicit to allow returning nullptrs.
+  // NOLINTNEXTLINE(runtime/explicit)
+  CFX_UnownedPtr(std::nullptr_t ptr) {}
+
+#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
+  ~CFX_UnownedPtr() {
+    if (m_pObj)
+      reinterpret_cast<volatile uint8_t*>(m_pObj)[0];
+  }
+#endif
+
+  CFX_UnownedPtr& operator=(T* that) {
+    m_pObj = that;
+    return *this;
+  }
+  CFX_UnownedPtr& operator=(const CFX_UnownedPtr& that) {
+    if (*this != that)
+      m_pObj = that.Get();
+    return *this;
+  }
+
+  bool operator==(const CFX_UnownedPtr& that) const {
+    return Get() == that.Get();
+  }
+  bool operator==(const T* that) const { return Get() == that; }
+  bool operator!=(const CFX_UnownedPtr& that) const { return !(*this == that); }
+  bool operator!=(const T* that) const { return !(*this == that); }
+  bool operator<(const CFX_UnownedPtr& that) const {
+    return std::less<T*>()(Get(), that.Get());
+  }
+
+  T* Get() const { return m_pObj; }
+  explicit operator bool() const { return !!m_pObj; }
+  T& operator*() const { return *m_pObj; }
+  T* operator->() const { return m_pObj; }
+
+ private:
+  T* m_pObj = nullptr;
+};
+
+#endif  // CORE_FXCRT_CFX_UNOWNED_PTR_H_
diff --git a/core/fxcrt/cfx_unowned_ptr_unittest.cpp b/core/fxcrt/cfx_unowned_ptr_unittest.cpp
new file mode 100644
index 0000000000..7d29faedf5
--- /dev/null
+++ b/core/fxcrt/cfx_unowned_ptr_unittest.cpp
@@ -0,0 +1,86 @@
+// Copyright 2017 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.
+
+#include "core/fxcrt/cfx_unowned_ptr.h"
+
+#include <utility>
+#include <vector>
+
+#include "testing/fx_string_testhelpers.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+class Clink {
+ public:
+  CFX_UnownedPtr<Clink> next_ = nullptr;
+};
+
+void DeleteDangling() {
+  Clink* ptr1 = new Clink();
+  Clink* ptr2 = new Clink();
+  ptr2->next_ = ptr1;
+  delete ptr1;
+  delete ptr2;
+}
+
+}  // namespace
+
+TEST(fxcrt, UnownedPtrOk) {
+  Clink* ptr1 = new Clink();
+  Clink* ptr2 = new Clink();
+  ptr2->next_ = ptr1;
+  delete ptr2;
+  delete ptr1;
+}
+
+TEST(fxcrt, UnownedPtrNotOk) {
+#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
+  EXPECT_DEATH(DeleteDangling(), "");
+#else
+  DeleteDangling();
+#endif
+}
+
+TEST(fxcrt, OperatorEQ) {
+  int foo;
+  CFX_UnownedPtr<int> ptr1;
+  EXPECT_TRUE(ptr1 == ptr1);
+
+  CFX_UnownedPtr<int> ptr2;
+  EXPECT_TRUE(ptr1 == ptr2);
+
+  CFX_UnownedPtr<int> ptr3(&foo);
+  EXPECT_TRUE(ptr3 == &foo);
+  EXPECT_FALSE(ptr1 == ptr3);
+
+  ptr1 = &foo;
+  EXPECT_TRUE(ptr1 == ptr3);
+}
+
+TEST(fxcrt, OperatorNE) {
+  int foo;
+  CFX_UnownedPtr<int> ptr1;
+  EXPECT_FALSE(ptr1 != ptr1);
+
+  CFX_UnownedPtr<int> ptr2;
+  EXPECT_FALSE(ptr1 != ptr2);
+
+  CFX_UnownedPtr<int> ptr3(&foo);
+  EXPECT_FALSE(ptr3 != &foo);
+  EXPECT_TRUE(ptr1 != ptr3);
+
+  ptr1 = &foo;
+  EXPECT_FALSE(ptr1 != ptr3);
+}
+
+TEST(fxcrt, OperatorLT) {
+  int foos[2];
+  CFX_UnownedPtr<int> ptr1(&foos[0]);
+  CFX_UnownedPtr<int> ptr2(&foos[1]);
+
+  EXPECT_FALSE(ptr1 < ptr1);
+  EXPECT_TRUE(ptr1 < ptr2);
+  EXPECT_FALSE(ptr2 < ptr1);
+}
diff --git a/core/fxge/fx_font.h b/core/fxge/fx_font.h
index ce91e27c42..946c713418 100644
--- a/core/fxge/fx_font.h
+++ b/core/fxge/fx_font.h
@@ -11,6 +11,7 @@
 #include <utility>
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_system.h"
 #include "core/fxge/cfx_substfont.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
@@ -172,7 +173,7 @@ class CFX_Font {
   void ClearFaceCache();
 
   FXFT_Face m_Face;
-  mutable CFX_FaceCache* m_FaceCache;  // not owned.
+  mutable CFX_UnownedPtr<CFX_FaceCache> m_FaceCache;
   std::unique_ptr<CFX_SubstFont> m_pSubstFont;
   std::vector<uint8_t> m_pFontDataAllocation;
   uint8_t* m_pFontData;
diff --git a/core/fxge/ge/cfx_font.cpp b/core/fxge/ge/cfx_font.cpp
index 2ae34f11b9..18baed9d09 100644
--- a/core/fxge/ge/cfx_font.cpp
+++ b/core/fxge/ge/cfx_font.cpp
@@ -537,10 +537,9 @@ int CFX_Font::GetMaxAdvanceWidth() const {
 }
 
 CFX_FaceCache* CFX_Font::GetFaceCache() const {
-  if (!m_FaceCache) {
+  if (!m_FaceCache)
     m_FaceCache = CFX_GEModule::Get()->GetFontCache()->GetCachedFace(this);
-  }
-  return m_FaceCache;
+  return m_FaceCache.Get();
 }
 
 void CFX_Font::ClearFaceCache() {
diff --git a/fpdfsdk/cpdfsdk_interform.cpp b/fpdfsdk/cpdfsdk_interform.cpp
index b44002cef8..2d02a7ab93 100644
--- a/fpdfsdk/cpdfsdk_interform.cpp
+++ b/fpdfsdk/cpdfsdk_interform.cpp
@@ -351,8 +351,8 @@ bool CPDFSDK_InterForm::OnKeyStrokeCommit(CPDF_FormField* pFormField,
   fa.bModifier = m_pFormFillEnv->IsCTRLKeyDown(0);
   fa.bShift = m_pFormFillEnv->IsSHIFTKeyDown(0);
   fa.sValue = csValue;
-  pActionHandler->DoAction_FieldJavaScript(action, CPDF_AAction::KeyStroke,
-                                           m_pFormFillEnv, pFormField, fa);
+  pActionHandler->DoAction_FieldJavaScript(
+      action, CPDF_AAction::KeyStroke, m_pFormFillEnv.Get(), pFormField, fa);
   return fa.bRC;
 }
 
@@ -371,8 +371,8 @@ bool CPDFSDK_InterForm::OnValidate(CPDF_FormField* pFormField,
   fa.bModifier = m_pFormFillEnv->IsCTRLKeyDown(0);
   fa.bShift = m_pFormFillEnv->IsSHIFTKeyDown(0);
   fa.sValue = csValue;
-  pActionHandler->DoAction_FieldJavaScript(action, CPDF_AAction::Validate,
-                                           m_pFormFillEnv, pFormField, fa);
+  pActionHandler->DoAction_FieldJavaScript(
+      action, CPDF_AAction::Validate, m_pFormFillEnv.Get(), pFormField, fa);
   return fa.bRC;
 }
 
diff --git a/fpdfsdk/cpdfsdk_interform.h b/fpdfsdk/cpdfsdk_interform.h
index 032399c84e..b613c731ba 100644
--- a/fpdfsdk/cpdfsdk_interform.h
+++ b/fpdfsdk/cpdfsdk_interform.h
@@ -13,6 +13,7 @@
 
 #include "core/fpdfdoc/cpdf_action.h"
 #include "core/fpdfdoc/ipdf_formnotify.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_basic.h"
 #include "core/fxge/fx_dib.h"
 #include "fpdfsdk/cpdfsdk_widget.h"
@@ -35,7 +36,9 @@ class CPDFSDK_InterForm : public IPDF_FormNotify {
   ~CPDFSDK_InterForm() override;
 
   CPDF_InterForm* GetInterForm() const { return m_pInterForm.get(); }
-  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const { return m_pFormFillEnv; }
+  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const {
+    return m_pFormFillEnv.Get();
+  }
 
   bool HighlightWidgets();
 
@@ -121,7 +124,7 @@ class CPDFSDK_InterForm : public IPDF_FormNotify {
 
   using CPDFSDK_WidgetMap = std::map<CPDF_FormControl*, CPDFSDK_Widget*>;
 
-  CPDFSDK_FormFillEnvironment* m_pFormFillEnv;  // Not owned.
+  CFX_UnownedPtr<CPDFSDK_FormFillEnvironment> m_pFormFillEnv;
   std::unique_ptr<CPDF_InterForm> m_pInterForm;
   CPDFSDK_WidgetMap m_Map;
 #ifdef PDF_ENABLE_XFA
diff --git a/fpdfsdk/cpdfsdk_pageview.h b/fpdfsdk/cpdfsdk_pageview.h
index bcd5177c1a..8bede08a5d 100644
--- a/fpdfsdk/cpdfsdk_pageview.h
+++ b/fpdfsdk/cpdfsdk_pageview.h
@@ -11,6 +11,7 @@
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_page.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_system.h"
 #include "fpdfsdk/cpdfsdk_annot.h"
 
@@ -55,7 +56,10 @@ class CPDFSDK_PageView final : public CPDF_Page::View {
 
   CPDF_Page* GetPDFPage() const;
   CPDF_Document* GetPDFDocument();
-  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const { return m_pFormFillEnv; }
+  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const {
+    return m_pFormFillEnv.Get();
+  }
+
   bool OnLButtonDown(const CFX_PointF& point, uint32_t nFlag);
   bool OnLButtonUp(const CFX_PointF& point, uint32_t nFlag);
 #ifdef PDF_ENABLE_XFA
@@ -102,7 +106,7 @@ class CPDFSDK_PageView final : public CPDF_Page::View {
   UnderlyingPageType* const m_page;
   std::unique_ptr<CPDF_AnnotList> m_pAnnotList;
   std::vector<CPDFSDK_Annot*> m_SDKAnnotArray;
-  CPDFSDK_FormFillEnvironment* const m_pFormFillEnv;  // Not owned.
+  CFX_UnownedPtr<CPDFSDK_FormFillEnvironment> const m_pFormFillEnv;
   CPDFSDK_Annot::ObservedPtr m_pCaptureWidget;
 #ifndef PDF_ENABLE_XFA
   bool m_bOwnsPage;
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
index 454e2187a3..93ecab0d08 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
@@ -358,6 +358,6 @@ bool CPDFXFA_Context::PutRequestURL(const CFX_WideString& wsURL,
 IFWL_AdapterTimerMgr* CPDFXFA_Context::GetTimerMgr() {
   CXFA_FWLAdapterTimerMgr* pAdapter = nullptr;
   if (m_pFormFillEnv)
-    pAdapter = new CXFA_FWLAdapterTimerMgr(m_pFormFillEnv);
+    pAdapter = new CXFA_FWLAdapterTimerMgr(m_pFormFillEnv.Get());
   return pAdapter;
 }
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_context.h b/fpdfsdk/fpdfxfa/cpdfxfa_context.h
index 8e6b2198af..690e1855e3 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_context.h
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_context.h
@@ -10,6 +10,8 @@
 #include <memory>
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
+#include "core/fxcrt/fx_system.h"
 #include "fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.h"
 #include "xfa/fxfa/cxfa_ffdoc.h"
 
@@ -36,12 +38,14 @@ class CPDFXFA_Context : public IXFA_AppProvider {
   bool LoadXFADoc();
   CPDF_Document* GetPDFDoc() { return m_pPDFDoc.get(); }
   CXFA_FFDoc* GetXFADoc() { return m_pXFADoc.get(); }
-  CXFA_FFDocView* GetXFADocView() { return m_pXFADocView; }
+  CXFA_FFDocView* GetXFADocView() { return m_pXFADocView.Get(); }
   XFA_DocType GetDocType() const { return m_iDocType; }
   v8::Isolate* GetJSERuntime() const;
   CXFA_FFApp* GetXFAApp() { return m_pXFAApp.get(); }
 
-  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const { return m_pFormFillEnv; }
+  CPDFSDK_FormFillEnvironment* GetFormFillEnv() const {
+    return m_pFormFillEnv.Get();
+  }
   void SetFormFillEnv(CPDFSDK_FormFillEnvironment* pFormFillEnv);
 
   void DeletePage(int page_index);
@@ -102,8 +106,8 @@ class CPDFXFA_Context : public IXFA_AppProvider {
 
   std::unique_ptr<CPDF_Document> m_pPDFDoc;
   std::unique_ptr<CXFA_FFDoc> m_pXFADoc;
-  CPDFSDK_FormFillEnvironment* m_pFormFillEnv;  // not owned.
-  CXFA_FFDocView* m_pXFADocView;                // not owned.
+  CFX_UnownedPtr<CPDFSDK_FormFillEnvironment> m_pFormFillEnv;
+  CFX_UnownedPtr<CXFA_FFDocView> m_pXFADocView;
   std::unique_ptr<CXFA_FFApp> m_pXFAApp;
   std::unique_ptr<CJS_Runtime> m_pRuntime;
   std::vector<CPDFXFA_Page*> m_XFAPageList;
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
index 4464f1c43a..1a27d9b015 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
@@ -46,7 +46,7 @@ CPDFXFA_DocEnvironment::CPDFXFA_DocEnvironment(CPDFXFA_Context* pContext)
 CPDFXFA_DocEnvironment::~CPDFXFA_DocEnvironment() {
   if (m_pJSEventContext && m_pContext->GetFormFillEnv()) {
     m_pContext->GetFormFillEnv()->GetJSRuntime()->ReleaseEventContext(
-        m_pJSEventContext);
+        m_pJSEventContext.Get());
   }
 }
 
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.h b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.h
index 8f1d238103..ec04e78db9 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.h
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.h
@@ -8,6 +8,7 @@
 #define FPDFSDK_FPDFXFA_CPDFXFA_DOCENVIRONMENT_H_
 
 #include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "public/fpdfview.h"
 #include "xfa/fxfa/fxfa.h"
 
@@ -105,8 +106,8 @@ class CPDFXFA_DocEnvironment : public IXFA_DocEnvironment {
                         FPDF_DWORD flag);
   void ToXFAContentFlags(CFX_WideString csSrcContent, FPDF_DWORD& flag);
 
-  CPDFXFA_Context* const m_pContext;    // Not owned.
-  IJS_EventContext* m_pJSEventContext;  // Not owned.
+  CFX_UnownedPtr<CPDFXFA_Context> const m_pContext;
+  CFX_UnownedPtr<IJS_EventContext> m_pJSEventContext;
 };
 
 #endif  // FPDFSDK_FPDFXFA_CPDFXFA_DOCENVIRONMENT_H_
diff --git a/fpdfsdk/javascript/JS_EventHandler.h b/fpdfsdk/javascript/JS_EventHandler.h
index 1e70a358bc..5dcb70b4c8 100644
--- a/fpdfsdk/javascript/JS_EventHandler.h
+++ b/fpdfsdk/javascript/JS_EventHandler.h
@@ -7,6 +7,7 @@
 #ifndef FPDFSDK_JAVASCRIPT_JS_EVENTHANDLER_H_
 #define FPDFSDK_JAVASCRIPT_JS_EVENTHANDLER_H_
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_string.h"
 #include "core/fxcrt/fx_system.h"
 #include "fpdfsdk/cpdfsdk_formfillenvironment.h"
@@ -165,7 +166,7 @@ class CJS_EventHandler {
   JS_EVENT_T EventType() { return m_eEventType; }
 
  public:
-  CJS_EventContext* const m_pJSEventContext;  // Not Owned.
+  CFX_UnownedPtr<CJS_EventContext> const m_pJSEventContext;
   JS_EVENT_T m_eEventType;
   bool m_bValid;
 
diff --git a/fpdfsdk/pdfwindow/PWL_ComboBox.cpp b/fpdfsdk/pdfwindow/PWL_ComboBox.cpp
index 9321e0f606..9f5ab97858 100644
--- a/fpdfsdk/pdfwindow/PWL_ComboBox.cpp
+++ b/fpdfsdk/pdfwindow/PWL_ComboBox.cpp
@@ -265,7 +265,7 @@ void CPWL_ComboBox::CreateEdit(const PWL_CREATEPARAM& cp) {
     return;
 
   m_pEdit = pdfium::MakeUnique<CPWL_CBEdit>();
-  m_pEdit->AttachFFLData(m_pFormFiller);
+  m_pEdit->AttachFFLData(m_pFormFiller.Get());
 
   PWL_CREATEPARAM ecp = cp;
   ecp.pParentWnd = this;
@@ -306,7 +306,7 @@ void CPWL_ComboBox::CreateListBox(const PWL_CREATEPARAM& cp) {
     return;
 
   m_pList = pdfium::MakeUnique<CPWL_CBListBox>();
-  m_pList->AttachFFLData(m_pFormFiller);
+  m_pList->AttachFFLData(m_pFormFiller.Get());
 
   PWL_CREATEPARAM lcp = cp;
   lcp.pParentWnd = this;
diff --git a/fpdfsdk/pdfwindow/PWL_ComboBox.h b/fpdfsdk/pdfwindow/PWL_ComboBox.h
index a687eb8e94..19d9ab2a04 100644
--- a/fpdfsdk/pdfwindow/PWL_ComboBox.h
+++ b/fpdfsdk/pdfwindow/PWL_ComboBox.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "fpdfsdk/pdfwindow/PWL_Edit.h"
 #include "fpdfsdk/pdfwindow/PWL_ListBox.h"
 #include "fpdfsdk/pdfwindow/PWL_Wnd.h"
@@ -100,7 +101,7 @@ class CPWL_ComboBox : public CPWL_Wnd {
   int32_t m_nPopupWhere;
   int32_t m_nSelectItem;
   IPWL_Filler_Notify* m_pFillerNotify;
-  CFFL_FormFiller* m_pFormFiller;  // Not owned.
+  CFX_UnownedPtr<CFFL_FormFiller> m_pFormFiller;
 };
 
 #endif  // FPDFSDK_PDFWINDOW_PWL_COMBOBOX_H_
diff --git a/fpdfsdk/pdfwindow/PWL_Edit.cpp b/fpdfsdk/pdfwindow/PWL_Edit.cpp
index 90572746da..4e37e9bde4 100644
--- a/fpdfsdk/pdfwindow/PWL_Edit.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Edit.cpp
@@ -398,7 +398,7 @@ void CPWL_Edit::DrawThisAppearance(CFX_RenderDevice* pDevice,
   CFX_SystemHandler* pSysHandler = GetSystemHandler();
   CFX_Edit::DrawEdit(pDevice, pUser2Device, m_pEdit.get(),
                      GetTextColor().ToFXColor(GetTransparency()), rcClip,
-                     CFX_PointF(), pRange, pSysHandler, m_pFormFiller);
+                     CFX_PointF(), pRange, pSysHandler, m_pFormFiller.Get());
 }
 
 bool CPWL_Edit::OnLButtonDown(const CFX_PointF& point, uint32_t nFlag) {
diff --git a/fpdfsdk/pdfwindow/PWL_Edit.h b/fpdfsdk/pdfwindow/PWL_Edit.h
index 5e1a36610d..bd3799141a 100644
--- a/fpdfsdk/pdfwindow/PWL_Edit.h
+++ b/fpdfsdk/pdfwindow/PWL_Edit.h
@@ -9,6 +9,7 @@
 
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_basic.h"
 #include "fpdfsdk/fxedit/fx_edit.h"
 #include "fpdfsdk/pdfwindow/PWL_EditCtrl.h"
@@ -136,7 +137,7 @@ class CPWL_Edit : public CPWL_EditCtrl {
   IPWL_Filler_Notify* m_pFillerNotify;
   bool m_bFocus;
   CFX_FloatRect m_rcOldWindow;
-  CFFL_FormFiller* m_pFormFiller;  // Not owned.
+  CFX_UnownedPtr<CFFL_FormFiller> m_pFormFiller;
 };
 
 #endif  // FPDFSDK_PDFWINDOW_PWL_EDIT_H_
diff --git a/fpdfsdk/pdfwindow/PWL_ListBox.cpp b/fpdfsdk/pdfwindow/PWL_ListBox.cpp
index 8448204a74..b682959426 100644
--- a/fpdfsdk/pdfwindow/PWL_ListBox.cpp
+++ b/fpdfsdk/pdfwindow/PWL_ListBox.cpp
@@ -172,14 +172,14 @@ void CPWL_ListBox::DrawThisAppearance(CFX_RenderDevice* pDevice,
       if (pSysHandler && pSysHandler->IsSelectionImplemented()) {
         CFX_Edit::DrawEdit(pDevice, pUser2Device, m_pList->GetItemEdit(i),
                            GetTextColor().ToFXColor(255), rcList, ptOffset,
-                           nullptr, pSysHandler, m_pFormFiller);
-        pSysHandler->OutputSelectedRect(m_pFormFiller, rcItem);
+                           nullptr, pSysHandler, m_pFormFiller.Get());
+        pSysHandler->OutputSelectedRect(m_pFormFiller.Get(), rcItem);
       } else {
         CPWL_Utils::DrawFillRect(pDevice, pUser2Device, rcItem,
                                  ArgbEncode(255, 0, 51, 113));
         CFX_Edit::DrawEdit(pDevice, pUser2Device, m_pList->GetItemEdit(i),
                            ArgbEncode(255, 255, 255, 255), rcList, ptOffset,
-                           nullptr, pSysHandler, m_pFormFiller);
+                           nullptr, pSysHandler, m_pFormFiller.Get());
       }
     } else {
       CFX_SystemHandler* pSysHandler = GetSystemHandler();
diff --git a/fpdfsdk/pdfwindow/PWL_ListBox.h b/fpdfsdk/pdfwindow/PWL_ListBox.h
index 9f8f464efb..0de9c91195 100644
--- a/fpdfsdk/pdfwindow/PWL_ListBox.h
+++ b/fpdfsdk/pdfwindow/PWL_ListBox.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "fpdfsdk/fxedit/fx_edit.h"
 #include "fpdfsdk/pdfwindow/PWL_Wnd.h"
 
@@ -111,7 +112,7 @@ class CPWL_ListBox : public CPWL_Wnd {
   IPWL_Filler_Notify* m_pFillerNotify;
 
  private:
-  CFFL_FormFiller* m_pFormFiller;  // Not owned.
+  CFX_UnownedPtr<CFFL_FormFiller> m_pFormFiller;
 };
 
 #endif  // FPDFSDK_PDFWINDOW_PWL_LISTBOX_H_
diff --git a/xfa/fgas/font/cfgas_gefont.h b/xfa/fgas/font/cfgas_gefont.h
index ba2e6e69a5..5fe73bbb40 100644
--- a/xfa/fgas/font/cfgas_gefont.h
+++ b/xfa/fgas/font/cfgas_gefont.h
@@ -12,6 +12,7 @@
 #include <vector>
 
 #include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_memory.h"
 #include "xfa/fgas/font/cfgas_fontmgr.h"
 
@@ -101,7 +102,7 @@ class CFGAS_GEFont : public CFX_Retainable {
   std::unique_ptr<CFX_UnicodeEncoding> m_pFontEncoding;
   std::map<wchar_t, int32_t> m_CharWidthMap;
   std::map<wchar_t, CFX_Rect> m_BBoxMap;
-  CXFA_PDFFontMgr* m_pProvider;  // not owned.
+  CFX_UnownedPtr<CXFA_PDFFontMgr> m_pProvider;
   std::vector<CFX_RetainPtr<CFGAS_GEFont>> m_SubstFonts;
   std::map<wchar_t, CFX_RetainPtr<CFGAS_GEFont>> m_FontMapper;
 };
diff --git a/xfa/fgas/layout/cfx_breakpiece.h b/xfa/fgas/layout/cfx_breakpiece.h
index 1c51b1e42a..807b5f769f 100644
--- a/xfa/fgas/layout/cfx_breakpiece.h
+++ b/xfa/fgas/layout/cfx_breakpiece.h
@@ -11,6 +11,7 @@
 
 #include "core/fxcrt/cfx_char.h"
 #include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_string.h"
 #include "xfa/fxfa/app/cxfa_textuserdata.h"
 
@@ -39,7 +40,7 @@ class CFX_BreakPiece {
   int32_t m_iVerticalScale;
   uint32_t m_dwIdentity;
   uint32_t m_dwCharStyles;
-  std::vector<CFX_Char>* m_pChars;  // not owned.
+  CFX_UnownedPtr<std::vector<CFX_Char>> m_pChars;
   CFX_RetainPtr<CXFA_TextUserData> m_pUserData;
 };
 
diff --git a/xfa/fwl/cfwl_caret.cpp b/xfa/fwl/cfwl_caret.cpp
index a6ea9ddb56..21387a47f9 100644
--- a/xfa/fwl/cfwl_caret.cpp
+++ b/xfa/fwl/cfwl_caret.cpp
@@ -97,7 +97,7 @@ void CFWL_Caret::OnDrawWidget(CFX_Graphics* pGraphics,
 CFWL_Caret::Timer::Timer(CFWL_Caret* pCaret) : CFWL_Timer(pCaret) {}
 
 void CFWL_Caret::Timer::Run(CFWL_TimerInfo* pTimerInfo) {
-  CFWL_Caret* pCaret = static_cast<CFWL_Caret*>(m_pWidget);
+  CFWL_Caret* pCaret = static_cast<CFWL_Caret*>(m_pWidget.Get());
   if (!(pCaret->GetStates() & FWL_STATE_CAT_HightLight))
     pCaret->SetStates(FWL_STATE_CAT_HightLight);
   else
diff --git a/xfa/fwl/cfwl_caret.h b/xfa/fwl/cfwl_caret.h
index e0c07d301a..da0548c2bf 100644
--- a/xfa/fwl/cfwl_caret.h
+++ b/xfa/fwl/cfwl_caret.h
@@ -51,7 +51,7 @@ class CFWL_Caret : public CFWL_Widget {
                    const CFX_Matrix* pMatrix);
 
   std::unique_ptr<CFWL_Caret::Timer> m_pTimer;
-  CFWL_TimerInfo* m_pTimerInfo;  // not owned.
+  CFX_UnownedPtr<CFWL_TimerInfo> m_pTimerInfo;
 };
 
 #endif  // XFA_FWL_CFWL_CARET_H_
diff --git a/xfa/fwl/cfwl_scrollbar.cpp b/xfa/fwl/cfwl_scrollbar.cpp
index 72797ed315..79e8b48115 100644
--- a/xfa/fwl/cfwl_scrollbar.cpp
+++ b/xfa/fwl/cfwl_scrollbar.cpp
@@ -485,8 +485,7 @@ void CFWL_ScrollBar::DoMouseHover(int32_t iItem,
 CFWL_ScrollBar::Timer::Timer(CFWL_ScrollBar* pToolTip) : CFWL_Timer(pToolTip) {}
 
 void CFWL_ScrollBar::Timer::Run(CFWL_TimerInfo* pTimerInfo) {
-  CFWL_ScrollBar* pButton = static_cast<CFWL_ScrollBar*>(m_pWidget);
-
+  CFWL_ScrollBar* pButton = static_cast<CFWL_ScrollBar*>(m_pWidget.Get());
   if (pButton->m_pTimerInfo)
     pButton->m_pTimerInfo->StopTimer();
 
diff --git a/xfa/fwl/cfwl_spinbutton.cpp b/xfa/fwl/cfwl_spinbutton.cpp
index 6e58b69baf..65bd6cdd3a 100644
--- a/xfa/fwl/cfwl_spinbutton.cpp
+++ b/xfa/fwl/cfwl_spinbutton.cpp
@@ -336,7 +336,6 @@ void CFWL_SpinButton::OnKeyDown(CFWL_MessageKey* pMsg) {
 
   CFWL_Event wmPosChanged(CFWL_Event::Type::Click, this);
   DispatchEvent(&wmPosChanged);
-
   RepaintRect(bUpEnable ? m_rtUpButton : m_rtDnButton);
 }
 
@@ -344,8 +343,7 @@ CFWL_SpinButton::Timer::Timer(CFWL_SpinButton* pToolTip)
     : CFWL_Timer(pToolTip) {}
 
 void CFWL_SpinButton::Timer::Run(CFWL_TimerInfo* pTimerInfo) {
-  CFWL_SpinButton* pButton = static_cast<CFWL_SpinButton*>(m_pWidget);
-
+  CFWL_SpinButton* pButton = static_cast<CFWL_SpinButton*>(m_pWidget.Get());
   if (!pButton->m_pTimerInfo)
     return;
 
diff --git a/xfa/fwl/cfwl_timer.cpp b/xfa/fwl/cfwl_timer.cpp
index 0cd3b2b768..2734e49d78 100644
--- a/xfa/fwl/cfwl_timer.cpp
+++ b/xfa/fwl/cfwl_timer.cpp
@@ -12,6 +12,10 @@
 #include "xfa/fwl/ifwl_adaptertimermgr.h"
 #include "xfa/fxfa/cxfa_ffapp.h"
 
+CFWL_Timer::CFWL_Timer(CFWL_Widget* parent) : m_pWidget(parent) {}
+
+CFWL_Timer::~CFWL_Timer() {}
+
 CFWL_TimerInfo* CFWL_Timer::StartTimer(uint32_t dwElapse, bool bImmediately) {
   const CFWL_App* pApp = m_pWidget->GetOwnerApp();
   if (!pApp)
diff --git a/xfa/fwl/cfwl_timer.h b/xfa/fwl/cfwl_timer.h
index 6c9079acfe..93de009ed1 100644
--- a/xfa/fwl/cfwl_timer.h
+++ b/xfa/fwl/cfwl_timer.h
@@ -7,6 +7,7 @@
 #ifndef XFA_FWL_CFWL_TIMER_H_
 #define XFA_FWL_CFWL_TIMER_H_
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_system.h"
 
 class CFWL_TimerInfo;
@@ -14,14 +15,14 @@ class CFWL_Widget;
 
 class CFWL_Timer {
  public:
-  explicit CFWL_Timer(CFWL_Widget* parent) : m_pWidget(parent) {}
-  virtual ~CFWL_Timer() {}
+  explicit CFWL_Timer(CFWL_Widget* parent);
+  virtual ~CFWL_Timer();
 
   virtual void Run(CFWL_TimerInfo* hTimer) = 0;
   CFWL_TimerInfo* StartTimer(uint32_t dwElapse, bool bImmediately);
 
  protected:
-  CFWL_Widget* m_pWidget;  // Not owned.
+  CFX_UnownedPtr<CFWL_Widget> m_pWidget;
 };
 
 #endif  // XFA_FWL_CFWL_TIMER_H_
diff --git a/xfa/fwl/cfwl_timerinfo.cpp b/xfa/fwl/cfwl_timerinfo.cpp
index 8c7aaebbbb..ee4746af3f 100644
--- a/xfa/fwl/cfwl_timerinfo.cpp
+++ b/xfa/fwl/cfwl_timerinfo.cpp
@@ -8,6 +8,12 @@
 
 #include "xfa/fwl/ifwl_adaptertimermgr.h"
 
+CFWL_TimerInfo::CFWL_TimerInfo(IFWL_AdapterTimerMgr* mgr) : m_pMgr(mgr) {
+  ASSERT(mgr);
+}
+
+CFWL_TimerInfo::~CFWL_TimerInfo() {}
+
 void CFWL_TimerInfo::StopTimer() {
   m_pMgr->Stop(this);
 }
diff --git a/xfa/fwl/cfwl_timerinfo.h b/xfa/fwl/cfwl_timerinfo.h
index a47fede60f..ae77ef5d59 100644
--- a/xfa/fwl/cfwl_timerinfo.h
+++ b/xfa/fwl/cfwl_timerinfo.h
@@ -7,21 +7,20 @@
 #ifndef XFA_FWL_CFWL_TIMERINFO_H_
 #define XFA_FWL_CFWL_TIMERINFO_H_
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_system.h"
 
 class IFWL_AdapterTimerMgr;
 
 class CFWL_TimerInfo {
  public:
-  explicit CFWL_TimerInfo(IFWL_AdapterTimerMgr* mgr) : m_pMgr(mgr) {
-    ASSERT(mgr);
-  }
-  virtual ~CFWL_TimerInfo() {}
+  explicit CFWL_TimerInfo(IFWL_AdapterTimerMgr* mgr);
+  virtual ~CFWL_TimerInfo();
 
   void StopTimer();
 
  private:
-  IFWL_AdapterTimerMgr* m_pMgr;  // Not owned.
+  CFX_UnownedPtr<IFWL_AdapterTimerMgr> m_pMgr;
 };
 
 #endif  // XFA_FWL_CFWL_TIMERINFO_H_
diff --git a/xfa/fwl/cfwl_widget.h b/xfa/fwl/cfwl_widget.h
index b556e7a424..dd8fb5654b 100644
--- a/xfa/fwl/cfwl_widget.h
+++ b/xfa/fwl/cfwl_widget.h
@@ -6,8 +6,10 @@
 
 #ifndef XFA_FWL_CFWL_WIDGET_H_
 #define XFA_FWL_CFWL_WIDGET_H_
+
 #include <memory>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_system.h"
 #include "xfa/fwl/cfwl_event.h"
@@ -96,10 +98,10 @@ class CFWL_Widget : public IFWL_WidgetDelegate {
 
   void SetDelegate(IFWL_WidgetDelegate* delegate) { m_pDelegate = delegate; }
   IFWL_WidgetDelegate* GetDelegate() {
-    return m_pDelegate ? m_pDelegate : this;
+    return m_pDelegate ? m_pDelegate.Get() : this;
   }
   const IFWL_WidgetDelegate* GetDelegate() const {
-    return m_pDelegate ? m_pDelegate : this;
+    return m_pDelegate ? m_pDelegate.Get() : this;
   }
 
   const CFWL_App* GetOwnerApp() const { return m_pOwnerApp; }
@@ -182,7 +184,7 @@ class CFWL_Widget : public IFWL_WidgetDelegate {
 
   CXFA_FFWidget* m_pLayoutItem;
   uint32_t m_nEventKey;
-  IFWL_WidgetDelegate* m_pDelegate;  // Not owned.
+  CFX_UnownedPtr<IFWL_WidgetDelegate> m_pDelegate;
 };
 
 #endif  // XFA_FWL_CFWL_WIDGET_H_
diff --git a/xfa/fxfa/cxfa_ffapp.cpp b/xfa/fxfa/cxfa_ffapp.cpp
index 742cd14c30..7b97116c7a 100644
--- a/xfa/fxfa/cxfa_ffapp.cpp
+++ b/xfa/fxfa/cxfa_ffapp.cpp
@@ -23,10 +23,10 @@
 #include "xfa/fxfa/cxfa_ffwidgethandler.h"
 #include "xfa/fxfa/cxfa_fontmgr.h"
 
-CXFA_FFApp::CXFA_FFApp(IXFA_AppProvider* pProvider)
-    : m_pProvider(pProvider),
-      m_pWidgetMgrDelegate(nullptr),
-      m_pFWLApp(pdfium::MakeUnique<CFWL_App>(this)) {}
+CXFA_FFApp::CXFA_FFApp(IXFA_AppProvider* pProvider) : m_pProvider(pProvider) {
+  // Ensure fully initialized before making an app based on |this|.
+  m_pFWLApp = pdfium::MakeUnique<CFWL_App>(this);
+}
 
 CXFA_FFApp::~CXFA_FFApp() {}
 
diff --git a/xfa/fxfa/cxfa_ffapp.h b/xfa/fxfa/cxfa_ffapp.h
index 0a6409d3d1..1ae2073d82 100644
--- a/xfa/fxfa/cxfa_ffapp.h
+++ b/xfa/fxfa/cxfa_ffapp.h
@@ -13,6 +13,7 @@
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfapi/parser/cpdf_stream_acc.h"
 #include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "xfa/fgas/font/cfgas_fontmgr.h"
 #include "xfa/fwl/cfwl_app.h"
 #include "xfa/fxfa/fxfa.h"
@@ -44,7 +45,7 @@ class CXFA_FFApp {
   IFWL_AdapterTimerMgr* GetTimerMgr() const;
   CXFA_FontMgr* GetXFAFontMgr() const;
   CFWL_WidgetMgrDelegate* GetWidgetMgrDelegate() const {
-    return m_pWidgetMgrDelegate;
+    return m_pWidgetMgrDelegate.Get();
   }
 
   void ClearEventTargets();
@@ -70,12 +71,15 @@ class CXFA_FFApp {
   std::unique_ptr<CFX_FontSourceEnum_File> m_pFontSource;
 #endif
   std::unique_ptr<CXFA_FWLAdapterWidgetMgr> m_pAdapterWidgetMgr;
-  CFWL_WidgetMgrDelegate* m_pWidgetMgrDelegate;  // not owned.
 
   // |m_pFWLApp| has to be released first, then |m_pFWLTheme| since the former
   // may refers to theme manager and the latter refers to font manager.
   std::unique_ptr<CXFA_FWLTheme> m_pFWLTheme;
   std::unique_ptr<CFWL_App> m_pFWLApp;
+
+  // |m_pWidgetMgrDelegate| has to be released before |m_pFWLApp|, since
+  // |m_pFWLApp| is its owner.
+  CFX_UnownedPtr<CFWL_WidgetMgrDelegate> m_pWidgetMgrDelegate;
 };
 
 #endif  // XFA_FXFA_CXFA_FFAPP_H_
diff --git a/xfa/fxfa/cxfa_ffdoc.cpp b/xfa/fxfa/cxfa_ffdoc.cpp
index bddc02a9ce..f7bad38934 100644
--- a/xfa/fxfa/cxfa_ffdoc.cpp
+++ b/xfa/fxfa/cxfa_ffdoc.cpp
@@ -321,21 +321,20 @@ bool CXFA_FFDoc::OpenDoc(CPDF_Document* pPDFDoc) {
   return true;
 }
 
-bool CXFA_FFDoc::CloseDoc() {
-  if (m_DocView)
+void CXFA_FFDoc::CloseDoc() {
+  if (m_DocView) {
     m_DocView->RunDocClose();
-
+    m_DocView.reset();
+  }
   CXFA_Document* doc =
       m_pDocumentParser ? m_pDocumentParser->GetDocument() : nullptr;
   if (doc)
     doc->ClearLayoutData();
 
-  m_DocView.reset();
-  m_pNotify.reset(nullptr);
+  m_pNotify.reset();
   m_pApp->GetXFAFontMgr()->ReleaseDocFonts(this);
   m_HashToDibDpiMap.clear();
   m_pApp->ClearEventTargets();
-  return true;
 }
 
 CPDF_Document* CXFA_FFDoc::GetPDFDoc() {
diff --git a/xfa/fxfa/cxfa_ffdoc.h b/xfa/fxfa/cxfa_ffdoc.h
index 1cfbb50a2c..d40e7ba0c8 100644
--- a/xfa/fxfa/cxfa_ffdoc.h
+++ b/xfa/fxfa/cxfa_ffdoc.h
@@ -60,7 +60,7 @@ class CXFA_FFDoc {
 
   bool OpenDoc(const CFX_RetainPtr<IFX_SeekableStream>& pStream);
   bool OpenDoc(CPDF_Document* pPDFDoc);
-  bool CloseDoc();
+  void CloseDoc();
 
   CXFA_Document* GetXFADoc() { return m_pDocumentParser->GetDocument(); }
   CXFA_FFApp* GetApp() { return m_pApp; }
diff --git a/xfa/fxfa/cxfa_ffdocview.cpp b/xfa/fxfa/cxfa_ffdocview.cpp
index 058116be72..c1a8a67336 100644
--- a/xfa/fxfa/cxfa_ffdocview.cpp
+++ b/xfa/fxfa/cxfa_ffdocview.cpp
@@ -61,9 +61,6 @@ CXFA_FFDocView::CXFA_FFDocView(CXFA_FFDoc* pDoc)
       m_bInLayoutStatus(false),
       m_pDoc(pDoc),
       m_pXFADocLayout(nullptr),
-      m_pFocusAcc(nullptr),
-      m_pFocusWidget(nullptr),
-      m_pOldFocusWidget(nullptr),
       m_iStatus(XFA_DOCVIEW_LAYOUTSTATUS_None),
       m_iLock(0) {}
 
@@ -143,14 +140,16 @@ void CXFA_FFDocView::StopLayout() {
                                  nullptr);
   }
   m_CalculateAccs.clear();
-  if (m_pFocusAcc && !m_pFocusWidget) {
-    SetFocusWidgetAcc(m_pFocusAcc);
-  }
+  if (m_pFocusAcc && !m_pFocusWidget)
+    SetFocusWidgetAcc(m_pFocusAcc.Get());
+
   m_iStatus = XFA_DOCVIEW_LAYOUTSTATUS_End;
 }
+
 int32_t CXFA_FFDocView::GetLayoutStatus() {
   return m_iStatus;
 }
+
 void CXFA_FFDocView::ShowNullTestMsg() {
   int32_t iCount = pdfium::CollectionSize<int32_t>(m_arrNullTestMsg);
   CXFA_FFApp* pApp = m_pDoc->GetApp();
@@ -316,8 +315,8 @@ CXFA_FFDocView::CreateWidgetAccIterator() {
   return pdfium::MakeUnique<CXFA_WidgetAccIterator>(pFormRoot);
 }
 
-CXFA_FFWidget* CXFA_FFDocView::GetFocusWidget() {
-  return m_pFocusWidget;
+CXFA_FFWidget* CXFA_FFDocView::GetFocusWidget() const {
+  return m_pFocusWidget.Get();
 }
 
 void CXFA_FFDocView::KillFocus() {
@@ -329,12 +328,13 @@ void CXFA_FFDocView::KillFocus() {
   m_pFocusWidget = nullptr;
   m_pOldFocusWidget = nullptr;
 }
+
 bool CXFA_FFDocView::SetFocus(CXFA_FFWidget* hWidget) {
   CXFA_FFWidget* pNewFocus = hWidget;
-  if (m_pOldFocusWidget == pNewFocus) {
+  if (m_pOldFocusWidget == pNewFocus)
     return false;
-  }
-  CXFA_FFWidget* pOldFocus = m_pOldFocusWidget;
+
+  CXFA_FFWidget* pOldFocus = m_pOldFocusWidget.Get();
   m_pOldFocusWidget = pNewFocus;
   if (pOldFocus) {
     if (m_pFocusWidget != m_pOldFocusWidget &&
@@ -345,15 +345,15 @@ bool CXFA_FFDocView::SetFocus(CXFA_FFWidget* hWidget) {
       if (!pOldFocus->IsLoaded()) {
         pOldFocus->LoadWidget();
       }
-      pOldFocus->OnSetFocus(m_pFocusWidget);
+      pOldFocus->OnSetFocus(m_pFocusWidget.Get());
       m_pFocusWidget = pOldFocus;
       pOldFocus->OnKillFocus(pNewFocus);
     }
   }
-  if (m_pFocusWidget == m_pOldFocusWidget) {
+  if (m_pFocusWidget == m_pOldFocusWidget)
     return false;
-  }
-  pNewFocus = m_pOldFocusWidget;
+
+  pNewFocus = m_pOldFocusWidget.Get();
   if (m_pListFocusWidget && pNewFocus == m_pListFocusWidget) {
     m_pFocusAcc = nullptr;
     m_pFocusWidget = nullptr;
@@ -362,29 +362,30 @@ bool CXFA_FFDocView::SetFocus(CXFA_FFWidget* hWidget) {
     return false;
   }
   if (pNewFocus && (pNewFocus->GetStatus() & XFA_WidgetStatus_Visible)) {
-    if (!pNewFocus->IsLoaded()) {
+    if (!pNewFocus->IsLoaded())
       pNewFocus->LoadWidget();
-    }
-    pNewFocus->OnSetFocus(m_pFocusWidget);
+    pNewFocus->OnSetFocus(m_pFocusWidget.Get());
   }
   m_pFocusAcc = pNewFocus ? pNewFocus->GetDataAcc() : nullptr;
   m_pFocusWidget = pNewFocus;
   m_pOldFocusWidget = m_pFocusWidget;
   return true;
 }
+
 CXFA_WidgetAcc* CXFA_FFDocView::GetFocusWidgetAcc() {
-  return m_pFocusAcc;
+  return m_pFocusAcc.Get();
 }
+
 void CXFA_FFDocView::SetFocusWidgetAcc(CXFA_WidgetAcc* pWidgetAcc) {
   CXFA_FFWidget* pNewFocus =
       pWidgetAcc ? pWidgetAcc->GetNextWidget(nullptr) : nullptr;
   if (SetFocus(pNewFocus)) {
     m_pFocusAcc = pWidgetAcc;
-    if (m_iStatus == XFA_DOCVIEW_LAYOUTSTATUS_End) {
-      m_pDoc->GetDocEnvironment()->SetFocusWidget(m_pDoc, m_pFocusWidget);
-    }
+    if (m_iStatus == XFA_DOCVIEW_LAYOUTSTATUS_End)
+      m_pDoc->GetDocEnvironment()->SetFocusWidget(m_pDoc, m_pFocusWidget.Get());
   }
 }
+
 void CXFA_FFDocView::DeleteLayoutItem(CXFA_FFWidget* pWidget) {
   if (m_pFocusAcc == pWidget->GetDataAcc()) {
     m_pFocusAcc = nullptr;
@@ -392,6 +393,7 @@ void CXFA_FFDocView::DeleteLayoutItem(CXFA_FFWidget* pWidget) {
     m_pOldFocusWidget = nullptr;
   }
 }
+
 static int32_t XFA_ProcessEvent(CXFA_FFDocView* pDocView,
                                 CXFA_WidgetAcc* pWidgetAcc,
                                 CXFA_EventParam* pParam) {
diff --git a/xfa/fxfa/cxfa_ffdocview.h b/xfa/fxfa/cxfa_ffdocview.h
index 761397c4b0..83d077b548 100644
--- a/xfa/fxfa/cxfa_ffdocview.h
+++ b/xfa/fxfa/cxfa_ffdocview.h
@@ -11,6 +11,7 @@
 #include <memory>
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "xfa/fxfa/cxfa_eventparam.h"
 #include "xfa/fxfa/cxfa_ffdoc.h"
 
@@ -56,7 +57,7 @@ class CXFA_FFDocView {
                              CXFA_WidgetAcc* pWidgetAcc);
   CXFA_FFWidgetHandler* GetWidgetHandler();
   std::unique_ptr<CXFA_WidgetAccIterator> CreateWidgetAccIterator();
-  CXFA_FFWidget* GetFocusWidget();
+  CXFA_FFWidget* GetFocusWidget() const;
   void KillFocus();
   bool SetFocus(CXFA_FFWidget* hWidget);
   CXFA_FFWidget* GetWidgetByName(const CFX_WideString& wsName,
@@ -117,10 +118,10 @@ class CXFA_FFDocView {
 
   CXFA_FFDoc* const m_pDoc;
   std::unique_ptr<CXFA_FFWidgetHandler> m_pWidgetHandler;
-  CXFA_LayoutProcessor* m_pXFADocLayout;  // not owned.
-  CXFA_WidgetAcc* m_pFocusAcc;            // not owned.
-  CXFA_FFWidget* m_pFocusWidget;          // not owned.
-  CXFA_FFWidget* m_pOldFocusWidget;       // not owned.
+  CXFA_LayoutProcessor* m_pXFADocLayout;  // Not owned.
+  CFX_UnownedPtr<CXFA_WidgetAcc> m_pFocusAcc;
+  CFX_UnownedPtr<CXFA_FFWidget> m_pFocusWidget;
+  CFX_UnownedPtr<CXFA_FFWidget> m_pOldFocusWidget;
   std::map<CXFA_FFPageView*, std::unique_ptr<CFX_RectF>> m_mapPageInvalidate;
   std::vector<CXFA_WidgetAcc*> m_ValidateAccs;
   std::vector<CXFA_WidgetAcc*> m_CalculateAccs;
diff --git a/xfa/fxfa/cxfa_widgetacciterator.cpp b/xfa/fxfa/cxfa_widgetacciterator.cpp
index 373fba99dc..ed780853df 100644
--- a/xfa/fxfa/cxfa_widgetacciterator.cpp
+++ b/xfa/fxfa/cxfa_widgetacciterator.cpp
@@ -19,7 +19,7 @@ CXFA_WidgetAcc* CXFA_WidgetAccIterator::MoveToNext() {
   while (pItem) {
     m_pCurWidgetAcc = static_cast<CXFA_WidgetAcc*>(pItem->GetWidgetData());
     if (m_pCurWidgetAcc)
-      return m_pCurWidgetAcc;
+      return m_pCurWidgetAcc.Get();
     pItem = m_ContentIterator.MoveToNext();
   }
   return nullptr;
diff --git a/xfa/fxfa/cxfa_widgetacciterator.h b/xfa/fxfa/cxfa_widgetacciterator.h
index ab18e833c2..0ad94260f3 100644
--- a/xfa/fxfa/cxfa_widgetacciterator.h
+++ b/xfa/fxfa/cxfa_widgetacciterator.h
@@ -7,6 +7,7 @@
 #ifndef XFA_FXFA_CXFA_WIDGETACCITERATOR_H_
 #define XFA_FXFA_CXFA_WIDGETACCITERATOR_H_
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "xfa/fxfa/parser/cxfa_traversestrategy_xfacontainernode.h"
 
 class CXFA_Node;
@@ -22,7 +23,7 @@ class CXFA_WidgetAccIterator {
 
  private:
   CXFA_ContainerIterator m_ContentIterator;
-  CXFA_WidgetAcc* m_pCurWidgetAcc;  // not owned.
+  CFX_UnownedPtr<CXFA_WidgetAcc> m_pCurWidgetAcc;
 };
 
 #endif  // XFA_FXFA_CXFA_WIDGETACCITERATOR_H_
diff --git a/xfa/fxfa/parser/cxfa_resolveprocessor.cpp b/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
index d17a1bab50..add8cb8fcb 100644
--- a/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
+++ b/xfa/fxfa/parser/cxfa_resolveprocessor.cpp
@@ -103,7 +103,7 @@ int32_t CXFA_ResolveProcessor::ResolveAnyChild(CXFA_ResolveNodesData& rnd) {
     return pdfium::CollectionSize<int32_t>(rnd.m_Objects);
   }
   std::vector<CXFA_Node*> tempNodes;
-  for (CXFA_Object* pObject : rnd.m_Objects)
+  for (auto* pObject : rnd.m_Objects)
     tempNodes.push_back(pObject->AsNode());
   m_pNodeHelper->CountSiblings(findNode, XFA_LOGIC_Transparent, &tempNodes,
                                bClassName);