Make CPWL_Wnd own its pAttachedData.

This requires moving it out of CreateParams, since that must be
a copyable struct, and implies that currently there is some
questionable sharing going on. To resolve this, introduce a
Clone() method so that each window gets its own copy.

Make GetAttachedData() return a const pointer, so that callers
can't free it behind our back.

Tidy initializations along the way.

Change-Id: Iadc97688b4692bf4fafefe8cff88af88672f7110
Reviewed-on: https://pdfium-review.googlesource.com/c/44590
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

21 files changed, 149 insertions, 134 deletions

diff --git a/fpdfsdk/pwl/cpwl_appstream.cpp b/fpdfsdk/pwl/cpwl_appstream.cpp
index d57619e82f..ebd47befc0 100644
--- a/fpdfsdk/pwl/cpwl_appstream.cpp
+++ b/fpdfsdk/pwl/cpwl_appstream.cpp
@@ -683,7 +683,7 @@ ByteString GenerateIconAppStream(CPDF_IconFit& fit,
   if (rcIcon.IsEmpty() || !pIconStream)
     return ByteString();
 
-  CPWL_Icon icon;
+  CPWL_Icon icon(nullptr);
   CPWL_Wnd::CreateParams cp;
   cp.dwFlags = PWS_VISIBLE;
   icon.Create(cp);
diff --git a/fpdfsdk/pwl/cpwl_button.cpp b/fpdfsdk/pwl/cpwl_button.cpp
index bdf56a21ae..766e8c49ad 100644
--- a/fpdfsdk/pwl/cpwl_button.cpp
+++ b/fpdfsdk/pwl/cpwl_button.cpp
@@ -6,11 +6,14 @@
 
 #include "fpdfsdk/pwl/cpwl_button.h"
 
+#include <utility>
+
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
-CPWL_Button::CPWL_Button() : m_bMouseDown(false) {}
+CPWL_Button::CPWL_Button(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)) {}
 
-CPWL_Button::~CPWL_Button() {}
+CPWL_Button::~CPWL_Button() = default;
 
 void CPWL_Button::OnCreate(CreateParams* pParamsToAdjust) {
   pParamsToAdjust->eCursorType = FXCT_HAND;
diff --git a/fpdfsdk/pwl/cpwl_button.h b/fpdfsdk/pwl/cpwl_button.h
index b327371c7f..cf53ff906c 100644
--- a/fpdfsdk/pwl/cpwl_button.h
+++ b/fpdfsdk/pwl/cpwl_button.h
@@ -7,11 +7,13 @@
 #ifndef FPDFSDK_PWL_CPWL_BUTTON_H_
 #define FPDFSDK_PWL_CPWL_BUTTON_H_
 
+#include <memory>
+
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
 class CPWL_Button : public CPWL_Wnd {
  public:
-  CPWL_Button();
+  explicit CPWL_Button(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_Button() override;
 
   // CPWL_Wnd
@@ -20,7 +22,7 @@ class CPWL_Button : public CPWL_Wnd {
   bool OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) override;
 
  protected:
-  bool m_bMouseDown;
+  bool m_bMouseDown = false;
 };
 
 #endif  // FPDFSDK_PWL_CPWL_BUTTON_H_
diff --git a/fpdfsdk/pwl/cpwl_caret.cpp b/fpdfsdk/pwl/cpwl_caret.cpp
index 24ecb17533..63fb1ce2b5 100644
--- a/fpdfsdk/pwl/cpwl_caret.cpp
+++ b/fpdfsdk/pwl/cpwl_caret.cpp
@@ -7,6 +7,7 @@
 #include "fpdfsdk/pwl/cpwl_caret.h"
 
 #include <sstream>
+#include <utility>
 
 #include "core/fxge/cfx_graphstatedata.h"
 #include "core/fxge/cfx_pathdata.h"
@@ -15,9 +16,10 @@
 
 #define PWL_CARET_FLASHINTERVAL 500
 
-CPWL_Caret::CPWL_Caret() : m_bFlash(false), m_fWidth(0.4f), m_nDelay(0) {}
+CPWL_Caret::CPWL_Caret(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)) {}
 
-CPWL_Caret::~CPWL_Caret() {}
+CPWL_Caret::~CPWL_Caret() = default;
 
 void CPWL_Caret::DrawThisAppearance(CFX_RenderDevice* pDevice,
                                     const CFX_Matrix& mtUser2Device) {
diff --git a/fpdfsdk/pwl/cpwl_caret.h b/fpdfsdk/pwl/cpwl_caret.h
index 27418ec868..c85a8776f3 100644
--- a/fpdfsdk/pwl/cpwl_caret.h
+++ b/fpdfsdk/pwl/cpwl_caret.h
@@ -7,11 +7,13 @@
 #ifndef FPDFSDK_PWL_CPWL_CARET_H_
 #define FPDFSDK_PWL_CPWL_CARET_H_
 
+#include <memory>
+
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
 class CPWL_Caret final : public CPWL_Wnd {
  public:
-  CPWL_Caret();
+  explicit CPWL_Caret(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_Caret() override;
 
   // CPWL_Wnd
@@ -29,11 +31,11 @@ class CPWL_Caret final : public CPWL_Wnd {
  private:
   CFX_FloatRect GetCaretRect() const;
 
-  bool m_bFlash;
+  bool m_bFlash = false;
   CFX_PointF m_ptHead;
   CFX_PointF m_ptFoot;
-  float m_fWidth;
-  int32_t m_nDelay;
+  float m_fWidth = 0.4f;
+  int32_t m_nDelay = 0;
   CFX_FloatRect m_rcInvalid;
 };
 
diff --git a/fpdfsdk/pwl/cpwl_combo_box.cpp b/fpdfsdk/pwl/cpwl_combo_box.cpp
index 341bd93e41..bb5890b519 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.cpp
+++ b/fpdfsdk/pwl/cpwl_combo_box.cpp
@@ -8,6 +8,7 @@
 
 #include <algorithm>
 #include <sstream>
+#include <utility>
 
 #include "core/fxge/cfx_pathdata.h"
 #include "core/fxge/cfx_renderdevice.h"
@@ -26,6 +27,11 @@ constexpr int kDefaultButtonWidth = 13;
 
 }  // namespace
 
+CPWL_CBListBox::CPWL_CBListBox(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_ListBox(std::move(pAttachedData)) {}
+
+CPWL_CBListBox::~CPWL_CBListBox() = default;
+
 bool CPWL_CBListBox::OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) {
   CPWL_Wnd::OnLButtonUp(point, nFlag);
 
@@ -94,6 +100,11 @@ bool CPWL_CBListBox::OnCharNotify(uint16_t nChar, uint32_t nFlag) {
   return OnNotifySelectionChanged(true, nFlag);
 }
 
+CPWL_CBButton::CPWL_CBButton(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)) {}
+
+CPWL_CBButton::~CPWL_CBButton() = default;
+
 void CPWL_CBButton::DrawThisAppearance(CFX_RenderDevice* pDevice,
                                        const CFX_Matrix& mtUser2Device) {
   CPWL_Wnd::DrawThisAppearance(pDevice, mtUser2Device);
@@ -132,7 +143,6 @@ bool CPWL_CBButton::OnLButtonDown(const CFX_PointF& point, uint32_t nFlag) {
   CPWL_Wnd::OnLButtonDown(point, nFlag);
 
   SetCapture();
-
   if (CPWL_Wnd* pParent = GetParentWindow())
     pParent->NotifyLButtonDown(this, point);
 
@@ -143,13 +153,13 @@ bool CPWL_CBButton::OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) {
   CPWL_Wnd::OnLButtonUp(point, nFlag);
 
   ReleaseCapture();
-
   return true;
 }
 
-CPWL_ComboBox::CPWL_ComboBox() {}
+CPWL_ComboBox::CPWL_ComboBox(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)) {}
 
-CPWL_ComboBox::~CPWL_ComboBox() {}
+CPWL_ComboBox::~CPWL_ComboBox() = default;
 
 void CPWL_ComboBox::OnCreate(CreateParams* pParamsToAdjust) {
   pParamsToAdjust->dwFlags &= ~PWS_HSCROLL;
@@ -262,7 +272,7 @@ void CPWL_ComboBox::CreateEdit(const CreateParams& cp) {
   if (m_pEdit)
     return;
 
-  m_pEdit = new CPWL_Edit();
+  m_pEdit = new CPWL_Edit(CloneAttachedData());
   m_pEdit->AttachFFLData(m_pFormFiller.Get());
 
   CreateParams ecp = cp;
@@ -286,7 +296,7 @@ void CPWL_ComboBox::CreateButton(const CreateParams& cp) {
   if (m_pButton)
     return;
 
-  m_pButton = new CPWL_CBButton;
+  m_pButton = new CPWL_CBButton(CloneAttachedData());
 
   CreateParams bcp = cp;
   bcp.pParentWnd = this;
@@ -304,7 +314,7 @@ void CPWL_ComboBox::CreateListBox(const CreateParams& cp) {
   if (m_pList)
     return;
 
-  m_pList = new CPWL_CBListBox();
+  m_pList = new CPWL_CBListBox(CloneAttachedData());
   m_pList->AttachFFLData(m_pFormFiller.Get());
 
   CreateParams lcp = cp;
diff --git a/fpdfsdk/pwl/cpwl_combo_box.h b/fpdfsdk/pwl/cpwl_combo_box.h
index 2e66b515b0..e3a3ff38ca 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.h
+++ b/fpdfsdk/pwl/cpwl_combo_box.h
@@ -7,6 +7,8 @@
 #ifndef FPDFSDK_PWL_CPWL_COMBO_BOX_H_
 #define FPDFSDK_PWL_CPWL_COMBO_BOX_H_
 
+#include <memory>
+
 #include "core/fxcrt/unowned_ptr.h"
 #include "fpdfsdk/pwl/cpwl_edit.h"
 #include "fpdfsdk/pwl/cpwl_list_box.h"
@@ -14,8 +16,8 @@
 
 class CPWL_CBListBox final : public CPWL_ListBox {
  public:
-  CPWL_CBListBox() {}
-  ~CPWL_CBListBox() override {}
+  explicit CPWL_CBListBox(std::unique_ptr<PrivateData> pAttachedData);
+  ~CPWL_CBListBox() override;
 
   // CPWL_ListBox
   bool OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) override;
@@ -28,8 +30,8 @@ class CPWL_CBListBox final : public CPWL_ListBox {
 
 class CPWL_CBButton final : public CPWL_Wnd {
  public:
-  CPWL_CBButton() {}
-  ~CPWL_CBButton() override {}
+  explicit CPWL_CBButton(std::unique_ptr<PrivateData> pAttachedData);
+  ~CPWL_CBButton() override;
 
   // CPWL_Wnd
   void DrawThisAppearance(CFX_RenderDevice* pDevice,
@@ -40,7 +42,7 @@ class CPWL_CBButton final : public CPWL_Wnd {
 
 class CPWL_ComboBox final : public CPWL_Wnd {
  public:
-  CPWL_ComboBox();
+  explicit CPWL_ComboBox(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_ComboBox() override;
 
   CPWL_Edit* GetEdit() const { return m_pEdit.Get(); }
@@ -77,9 +79,7 @@ class CPWL_ComboBox final : public CPWL_Wnd {
   void ClearSelection();
   void SelectAll();
   bool IsPopup() const;
-
   void SetSelectText();
-
   void AttachFFLData(CFFL_FormFiller* pData) { m_pFormFiller = pData; }
 
  private:
diff --git a/fpdfsdk/pwl/cpwl_edit.cpp b/fpdfsdk/pwl/cpwl_edit.cpp
index c3a5797304..d0922cdf0d 100644
--- a/fpdfsdk/pwl/cpwl_edit.cpp
+++ b/fpdfsdk/pwl/cpwl_edit.cpp
@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <memory>
 #include <sstream>
+#include <utility>
 #include <vector>
 
 #include "core/fpdfapi/font/cpdf_font.h"
@@ -26,7 +27,8 @@
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 #include "public/fpdf_fwlevent.h"
 
-CPWL_Edit::CPWL_Edit() : m_bFocus(false) {}
+CPWL_Edit::CPWL_Edit(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_EditCtrl(std::move(pAttachedData)) {}
 
 CPWL_Edit::~CPWL_Edit() {
   ASSERT(!m_bFocus);
diff --git a/fpdfsdk/pwl/cpwl_edit.h b/fpdfsdk/pwl/cpwl_edit.h
index d890834aac..c996437dd1 100644
--- a/fpdfsdk/pwl/cpwl_edit.h
+++ b/fpdfsdk/pwl/cpwl_edit.h
@@ -7,6 +7,7 @@
 #ifndef FPDFSDK_PWL_CPWL_EDIT_H_
 #define FPDFSDK_PWL_CPWL_EDIT_H_
 
+#include <memory>
 #include <utility>
 
 #include "core/fpdfdoc/cpvt_wordrange.h"
@@ -18,30 +19,31 @@ class IPWL_Filler_Notify {
   virtual ~IPWL_Filler_Notify() = default;
 
   // Must write to |bBottom| and |fPopupRet|.
-  virtual void QueryWherePopup(CPWL_Wnd::PrivateData* pAttached,
+  virtual void QueryWherePopup(const CPWL_Wnd::PrivateData* pAttached,
                                float fPopupMin,
                                float fPopupMax,
                                bool* bBottom,
                                float* fPopupRet) = 0;
   virtual std::pair<bool, bool> OnBeforeKeyStroke(
-      CPWL_Wnd::PrivateData* pAttached,
+      const CPWL_Wnd::PrivateData* pAttached,
       WideString& strChange,
       const WideString& strChangeEx,
       int nSelStart,
       int nSelEnd,
       bool bKeyDown,
       uint32_t nFlag) = 0;
+
 #ifdef PDF_ENABLE_XFA
-  virtual bool OnPopupPreOpen(CPWL_Wnd::PrivateData* pAttached,
+  virtual bool OnPopupPreOpen(const CPWL_Wnd::PrivateData* pAttached,
                               uint32_t nFlag) = 0;
-  virtual bool OnPopupPostOpen(CPWL_Wnd::PrivateData* pAttached,
+  virtual bool OnPopupPostOpen(const CPWL_Wnd::PrivateData* pAttached,
                                uint32_t nFlag) = 0;
 #endif  // PDF_ENABLE_XFA
 };
 
 class CPWL_Edit final : public CPWL_EditCtrl {
  public:
-  CPWL_Edit();
+  explicit CPWL_Edit(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_Edit() override;
 
   // CPWL_EditCtrl
@@ -118,7 +120,7 @@ class CPWL_Edit final : public CPWL_EditCtrl {
                                    bool bLatin,
                                    bool bArabic) const;
 
-  bool m_bFocus;
+  bool m_bFocus = false;
   CFX_FloatRect m_rcOldWindow;
   UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
   UnownedPtr<CFFL_FormFiller> m_pFormFiller;
diff --git a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
index 33a83cc349..d27c6cd604 100644
--- a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
+++ b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
@@ -6,6 +6,8 @@
 
 #include "fpdfsdk/pwl/cpwl_edit_ctrl.h"
 
+#include <utility>
+
 #include "core/fpdfdoc/cpvt_word.h"
 #include "core/fxge/fx_font.h"
 #include "fpdfsdk/pwl/cpwl_caret.h"
@@ -16,7 +18,9 @@
 #include "public/fpdf_fwlevent.h"
 #include "third_party/base/ptr_util.h"
 
-CPWL_EditCtrl::CPWL_EditCtrl() : m_pEdit(pdfium::MakeUnique<CPWL_EditImpl>()) {}
+CPWL_EditCtrl::CPWL_EditCtrl(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)),
+      m_pEdit(pdfium::MakeUnique<CPWL_EditImpl>()) {}
 
 CPWL_EditCtrl::~CPWL_EditCtrl() = default;
 
@@ -84,7 +88,7 @@ void CPWL_EditCtrl::CreateEditCaret(const CreateParams& cp) {
   if (m_pEditCaret)
     return;
 
-  m_pEditCaret = new CPWL_Caret;
+  m_pEditCaret = new CPWL_Caret(CloneAttachedData());
   m_pEditCaret->SetInvalidRect(GetClientRect());
 
   CreateParams ecp = cp;
@@ -93,7 +97,6 @@ void CPWL_EditCtrl::CreateEditCaret(const CreateParams& cp) {
   ecp.dwBorderWidth = 0;
   ecp.nBorderStyle = BorderStyle::SOLID;
   ecp.rcRectWnd = CFX_FloatRect();
-
   m_pEditCaret->Create(ecp);
 }
 
diff --git a/fpdfsdk/pwl/cpwl_edit_ctrl.h b/fpdfsdk/pwl/cpwl_edit_ctrl.h
index 741ce9c668..eb8ccb8029 100644
--- a/fpdfsdk/pwl/cpwl_edit_ctrl.h
+++ b/fpdfsdk/pwl/cpwl_edit_ctrl.h
@@ -23,7 +23,7 @@ enum PWL_EDIT_ALIGNFORMAT_V { PEAV_TOP = 0, PEAV_CENTER, PEAV_BOTTOM };
 
 class CPWL_EditCtrl : public CPWL_Wnd {
  public:
-  CPWL_EditCtrl();
+  explicit CPWL_EditCtrl(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_EditCtrl() override;
 
   void SetSelection(int32_t nStartChar, int32_t nEndChar);
diff --git a/fpdfsdk/pwl/cpwl_icon.cpp b/fpdfsdk/pwl/cpwl_icon.cpp
index 407e866766..8d672f58da 100644
--- a/fpdfsdk/pwl/cpwl_icon.cpp
+++ b/fpdfsdk/pwl/cpwl_icon.cpp
@@ -8,15 +8,17 @@
 
 #include <algorithm>
 #include <sstream>
+#include <utility>
 
 #include "core/fpdfapi/parser/cpdf_array.h"
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
-CPWL_Icon::CPWL_Icon() : m_pPDFStream(nullptr), m_pIconFit(nullptr) {}
+CPWL_Icon::CPWL_Icon(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)) {}
 
-CPWL_Icon::~CPWL_Icon() {}
+CPWL_Icon::~CPWL_Icon() = default;
 
 std::pair<float, float> CPWL_Icon::GetImageSize() {
   if (!m_pPDFStream)
diff --git a/fpdfsdk/pwl/cpwl_icon.h b/fpdfsdk/pwl/cpwl_icon.h
index 2cb84ebcf6..83709f7e18 100644
--- a/fpdfsdk/pwl/cpwl_icon.h
+++ b/fpdfsdk/pwl/cpwl_icon.h
@@ -7,6 +7,7 @@
 #ifndef FPDFSDK_PWL_CPWL_ICON_H_
 #define FPDFSDK_PWL_CPWL_ICON_H_
 
+#include <memory>
 #include <utility>
 
 #include "core/fxcrt/fx_string.h"
@@ -15,7 +16,7 @@
 
 class CPWL_Icon final : public CPWL_Wnd {
  public:
-  CPWL_Icon();
+  explicit CPWL_Icon(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_Icon() override;
 
   void SetIconFit(CPDF_IconFit* pIconFit) { m_pIconFit = pIconFit; }
diff --git a/fpdfsdk/pwl/cpwl_list_box.cpp b/fpdfsdk/pwl/cpwl_list_box.cpp
index 11d451c920..4cea17b661 100644
--- a/fpdfsdk/pwl/cpwl_list_box.cpp
+++ b/fpdfsdk/pwl/cpwl_list_box.cpp
@@ -7,6 +7,7 @@
 #include "fpdfsdk/pwl/cpwl_list_box.h"
 
 #include <sstream>
+#include <utility>
 
 #include "core/fxge/cfx_renderdevice.h"
 #include "fpdfsdk/pwl/cpwl_edit.h"
@@ -64,13 +65,11 @@ void CPWL_List_Notify::IOnInvalidateRect(CFX_FloatRect* pRect) {
   m_pList->InvalidateRect(pRect);
 }
 
-CPWL_ListBox::CPWL_ListBox()
-    : m_pList(new CPWL_ListCtrl),
-      m_bMouseDown(false),
-      m_bHoverSel(false),
-      m_pFillerNotify(nullptr) {}
+CPWL_ListBox::CPWL_ListBox(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Wnd(std::move(pAttachedData)),
+      m_pList(pdfium::MakeUnique<CPWL_ListCtrl>()) {}
 
-CPWL_ListBox::~CPWL_ListBox() {}
+CPWL_ListBox::~CPWL_ListBox() = default;
 
 void CPWL_ListBox::OnCreated() {
   m_pList->SetFontMap(GetFontMap());
diff --git a/fpdfsdk/pwl/cpwl_list_box.h b/fpdfsdk/pwl/cpwl_list_box.h
index 6a58982aee..cbfca4585f 100644
--- a/fpdfsdk/pwl/cpwl_list_box.h
+++ b/fpdfsdk/pwl/cpwl_list_box.h
@@ -38,7 +38,7 @@ class CPWL_List_Notify {
 
 class CPWL_ListBox : public CPWL_Wnd {
  public:
-  CPWL_ListBox();
+  explicit CPWL_ListBox(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_ListBox() override;
 
   // CPWL_Wnd
@@ -92,10 +92,10 @@ class CPWL_ListBox : public CPWL_Wnd {
   void AttachFFLData(CFFL_FormFiller* pData) { m_pFormFiller = pData; }
 
  protected:
+  bool m_bMouseDown = false;
+  bool m_bHoverSel = false;
   std::unique_ptr<CPWL_ListCtrl> m_pList;
   std::unique_ptr<CPWL_List_Notify> m_pListNotify;
-  bool m_bMouseDown;
-  bool m_bHoverSel;
   UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
 
  private:
diff --git a/fpdfsdk/pwl/cpwl_scroll_bar.cpp b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
index ced049a175..4051d7be51 100644
--- a/fpdfsdk/pwl/cpwl_scroll_bar.cpp
+++ b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
@@ -105,15 +105,14 @@ void PWL_SCROLL_PRIVATEDATA::SubBig() {
     SetPos(ScrollRange.fMin);
 }
 
-CPWL_SBButton::CPWL_SBButton(PWL_SCROLLBAR_TYPE eScrollBarType,
-                             PWL_SBBUTTON_TYPE eButtonType) {
-  m_eScrollBarType = eScrollBarType;
-  m_eSBButtonType = eButtonType;
+CPWL_SBButton::CPWL_SBButton(std::unique_ptr<PrivateData> pAttachedData,
+                             PWL_SCROLLBAR_TYPE eScrollBarType,
+                             PWL_SBBUTTON_TYPE eButtonType)
+    : CPWL_Wnd(std::move(pAttachedData)),
+      m_eScrollBarType(eScrollBarType),
+      m_eSBButtonType(eButtonType) {}
 
-  m_bMouseDown = false;
-}
-
-CPWL_SBButton::~CPWL_SBButton() {}
+CPWL_SBButton::~CPWL_SBButton() = default;
 
 void CPWL_SBButton::OnCreate(CreateParams* pParamsToAdjust) {
   pParamsToAdjust->eCursorType = FXCT_ARROW;
@@ -299,16 +298,11 @@ bool CPWL_SBButton::OnMouseMove(const CFX_PointF& point, uint32_t nFlag) {
   return true;
 }
 
-CPWL_ScrollBar::CPWL_ScrollBar(PWL_SCROLLBAR_TYPE sbType)
-    : m_sbType(sbType),
-      m_pMinButton(nullptr),
-      m_pMaxButton(nullptr),
-      m_pPosButton(nullptr),
-      m_bMouseDown(false),
-      m_bMinOrMax(false),
-      m_bNotifyForever(true) {}
+CPWL_ScrollBar::CPWL_ScrollBar(std::unique_ptr<PrivateData> pAttachedData,
+                               PWL_SCROLLBAR_TYPE sbType)
+    : CPWL_Wnd(std::move(pAttachedData)), m_sbType(sbType) {}
 
-CPWL_ScrollBar::~CPWL_ScrollBar() {}
+CPWL_ScrollBar::~CPWL_ScrollBar() = default;
 
 void CPWL_ScrollBar::OnCreate(CreateParams* pParamsToAdjust) {
   pParamsToAdjust->eCursorType = FXCT_ARROW;
@@ -544,27 +538,24 @@ void CPWL_ScrollBar::CreateButtons(const CreateParams& cp) {
   scp.pParentWnd = this;
   scp.dwBorderWidth = 2;
   scp.nBorderStyle = BorderStyle::BEVELED;
-
   scp.dwFlags =
       PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PWS_BACKGROUND | PWS_NOREFRESHCLIP;
 
   if (!m_pMinButton) {
-    m_pMinButton = new CPWL_SBButton(m_sbType, PSBT_MIN);
+    m_pMinButton = new CPWL_SBButton(CloneAttachedData(), m_sbType, PSBT_MIN);
     m_pMinButton->Create(scp);
   }
 
   if (!m_pMaxButton) {
-    m_pMaxButton = new CPWL_SBButton(m_sbType, PSBT_MAX);
+    m_pMaxButton = new CPWL_SBButton(CloneAttachedData(), m_sbType, PSBT_MAX);
     m_pMaxButton->Create(scp);
   }
 
   if (!m_pPosButton) {
-    m_pPosButton = new CPWL_SBButton(m_sbType, PSBT_POS);
-
+    m_pPosButton = new CPWL_SBButton(CloneAttachedData(), m_sbType, PSBT_POS);
     ObservedPtr thisObserved(this);
-    if (!m_pPosButton->SetVisible(false) || !thisObserved)
-      return;
-    m_pPosButton->Create(scp);
+    if (m_pPosButton->SetVisible(false) && thisObserved)
+      m_pPosButton->Create(scp);
   }
 }
 
diff --git a/fpdfsdk/pwl/cpwl_scroll_bar.h b/fpdfsdk/pwl/cpwl_scroll_bar.h
index 3592423a7d..40660db1f6 100644
--- a/fpdfsdk/pwl/cpwl_scroll_bar.h
+++ b/fpdfsdk/pwl/cpwl_scroll_bar.h
@@ -7,6 +7,8 @@
 #ifndef FPDFSDK_PWL_CPWL_SCROLL_BAR_H_
 #define FPDFSDK_PWL_CPWL_SCROLL_BAR_H_
 
+#include <memory>
+
 #include "core/fxcrt/unowned_ptr.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
@@ -44,7 +46,8 @@ enum PWL_SBBUTTON_TYPE { PSBT_MIN, PSBT_MAX, PSBT_POS };
 
 class CPWL_SBButton final : public CPWL_Wnd {
  public:
-  CPWL_SBButton(PWL_SCROLLBAR_TYPE eScrollBarType,
+  CPWL_SBButton(std::unique_ptr<PrivateData> pAttachedData,
+                PWL_SCROLLBAR_TYPE eScrollBarType,
                 PWL_SBBUTTON_TYPE eButtonType);
   ~CPWL_SBButton() override;
 
@@ -59,7 +62,7 @@ class CPWL_SBButton final : public CPWL_Wnd {
  private:
   PWL_SCROLLBAR_TYPE m_eScrollBarType;
   PWL_SBBUTTON_TYPE m_eSBButtonType;
-  bool m_bMouseDown;
+  bool m_bMouseDown = false;
 };
 
 struct PWL_FLOATRANGE {
@@ -114,7 +117,8 @@ struct PWL_SCROLL_PRIVATEDATA {
 
 class CPWL_ScrollBar final : public CPWL_Wnd {
  public:
-  explicit CPWL_ScrollBar(PWL_SCROLLBAR_TYPE sbType);
+  CPWL_ScrollBar(std::unique_ptr<PrivateData> pAttachedData,
+                 PWL_SCROLLBAR_TYPE sbType);
   ~CPWL_ScrollBar() override;
 
   // CPWL_Wnd:
@@ -171,11 +175,11 @@ class CPWL_ScrollBar final : public CPWL_Wnd {
   UnownedPtr<CPWL_SBButton> m_pMaxButton;
   UnownedPtr<CPWL_SBButton> m_pPosButton;
   PWL_SCROLL_PRIVATEDATA m_sData;
-  bool m_bMouseDown;
-  bool m_bMinOrMax;
-  bool m_bNotifyForever;
-  float m_nOldPos;
-  float m_fOldPosButton;
+  bool m_bMouseDown = false;
+  bool m_bMinOrMax = false;
+  bool m_bNotifyForever = true;
+  float m_nOldPos = 0.0f;
+  float m_fOldPosButton = 0.0f;
 };
 
 #endif  // FPDFSDK_PWL_CPWL_SCROLL_BAR_H_
diff --git a/fpdfsdk/pwl/cpwl_special_button.cpp b/fpdfsdk/pwl/cpwl_special_button.cpp
index 061d024382..8e5f1b8d48 100644
--- a/fpdfsdk/pwl/cpwl_special_button.cpp
+++ b/fpdfsdk/pwl/cpwl_special_button.cpp
@@ -6,29 +6,25 @@
 
 #include "fpdfsdk/pwl/cpwl_special_button.h"
 
+#include <utility>
+
 #include "fpdfsdk/pwl/cpwl_button.h"
 #include "fpdfsdk/pwl/cpwl_wnd.h"
 
-CPWL_PushButton::CPWL_PushButton() {}
+CPWL_PushButton::CPWL_PushButton(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Button(std::move(pAttachedData)) {}
 
-CPWL_PushButton::~CPWL_PushButton() {}
+CPWL_PushButton::~CPWL_PushButton() = default;
 
 CFX_FloatRect CPWL_PushButton::GetFocusRect() const {
   return GetWindowRect().GetDeflated(static_cast<float>(GetBorderWidth()),
                                      static_cast<float>(GetBorderWidth()));
 }
 
-CPWL_CheckBox::CPWL_CheckBox() : m_bChecked(false) {}
-
-CPWL_CheckBox::~CPWL_CheckBox() {}
+CPWL_CheckBox::CPWL_CheckBox(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Button(std::move(pAttachedData)) {}
 
-void CPWL_CheckBox::SetCheck(bool bCheck) {
-  m_bChecked = bCheck;
-}
-
-bool CPWL_CheckBox::IsChecked() const {
-  return m_bChecked;
-}
+CPWL_CheckBox::~CPWL_CheckBox() = default;
 
 bool CPWL_CheckBox::OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) {
   if (IsReadOnly())
@@ -43,9 +39,10 @@ bool CPWL_CheckBox::OnChar(uint16_t nChar, uint32_t nFlag) {
   return true;
 }
 
-CPWL_RadioButton::CPWL_RadioButton() : m_bChecked(false) {}
+CPWL_RadioButton::CPWL_RadioButton(std::unique_ptr<PrivateData> pAttachedData)
+    : CPWL_Button(std::move(pAttachedData)) {}
 
-CPWL_RadioButton::~CPWL_RadioButton() {}
+CPWL_RadioButton::~CPWL_RadioButton() = default;
 
 bool CPWL_RadioButton::OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) {
   if (IsReadOnly())
@@ -55,14 +52,6 @@ bool CPWL_RadioButton::OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) {
   return true;
 }
 
-void CPWL_RadioButton::SetCheck(bool bCheck) {
-  m_bChecked = bCheck;
-}
-
-bool CPWL_RadioButton::IsChecked() const {
-  return m_bChecked;
-}
-
 bool CPWL_RadioButton::OnChar(uint16_t nChar, uint32_t nFlag) {
   SetCheck(true);
   return true;
diff --git a/fpdfsdk/pwl/cpwl_special_button.h b/fpdfsdk/pwl/cpwl_special_button.h
index 606be78f31..28c2a6b14c 100644
--- a/fpdfsdk/pwl/cpwl_special_button.h
+++ b/fpdfsdk/pwl/cpwl_special_button.h
@@ -7,47 +7,49 @@
 #ifndef FPDFSDK_PWL_CPWL_SPECIAL_BUTTON_H_
 #define FPDFSDK_PWL_CPWL_SPECIAL_BUTTON_H_
 
+#include <memory>
+
 #include "fpdfsdk/pwl/cpwl_button.h"
 
 class CPWL_PushButton final : public CPWL_Button {
  public:
-  CPWL_PushButton();
+  explicit CPWL_PushButton(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_PushButton() override;
 
-  // CPWL_Button
+  // CPWL_Button:
   CFX_FloatRect GetFocusRect() const override;
 };
 
 class CPWL_CheckBox final : public CPWL_Button {
  public:
-  CPWL_CheckBox();
+  explicit CPWL_CheckBox(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_CheckBox() override;
 
-  // CPWL_Button
+  // CPWL_Button:
   bool OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) override;
   bool OnChar(uint16_t nChar, uint32_t nFlag) override;
 
-  void SetCheck(bool bCheck);
-  bool IsChecked() const;
+  bool IsChecked() const { return m_bChecked; }
+  void SetCheck(bool bCheck) { m_bChecked = bCheck; }
 
  private:
-  bool m_bChecked;
+  bool m_bChecked = false;
 };
 
 class CPWL_RadioButton final : public CPWL_Button {
  public:
-  CPWL_RadioButton();
+  explicit CPWL_RadioButton(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_RadioButton() override;
 
   // CPWL_Button
   bool OnLButtonUp(const CFX_PointF& point, uint32_t nFlag) override;
   bool OnChar(uint16_t nChar, uint32_t nFlag) override;
 
-  void SetCheck(bool bCheck);
-  bool IsChecked() const;
+  bool IsChecked() const { return m_bChecked; }
+  void SetCheck(bool bCheck) { m_bChecked = bCheck; }
 
  private:
-  bool m_bChecked;
+  bool m_bChecked = false;
 };
 
 #endif  // FPDFSDK_PWL_CPWL_SPECIAL_BUTTON_H_
diff --git a/fpdfsdk/pwl/cpwl_wnd.cpp b/fpdfsdk/pwl/cpwl_wnd.cpp
index 1fc2bd8157..6767164073 100644
--- a/fpdfsdk/pwl/cpwl_wnd.cpp
+++ b/fpdfsdk/pwl/cpwl_wnd.cpp
@@ -8,6 +8,7 @@
 
 #include <map>
 #include <sstream>
+#include <utility>
 #include <vector>
 
 #include "core/fxge/cfx_renderdevice.h"
@@ -110,13 +111,8 @@ class CPWL_MsgControl final : public Observable<CPWL_MsgControl> {
   UnownedPtr<CPWL_Wnd> m_pMainKeyboardWnd;
 };
 
-CPWL_Wnd::CPWL_Wnd()
-    : m_rcWindow(),
-      m_rcClip(),
-      m_bCreated(false),
-      m_bVisible(false),
-      m_bNotifying(false),
-      m_bEnabled(true) {}
+CPWL_Wnd::CPWL_Wnd(std::unique_ptr<PrivateData> pAttachedData)
+    : m_pAttachedData(std::move(pAttachedData)) {}
 
 CPWL_Wnd::~CPWL_Wnd() {
   ASSERT(!m_bCreated);
@@ -504,7 +500,7 @@ void CPWL_Wnd::CreateVScrollBar(const CreateParams& cp) {
   scp.eCursorType = FXCT_ARROW;
   scp.nTransparency = PWL_SCROLLBAR_TRANSPARENCY;
 
-  m_pVScrollBar = new CPWL_ScrollBar(SBT_VSCROLL);
+  m_pVScrollBar = new CPWL_ScrollBar(CloneAttachedData(), SBT_VSCROLL);
   m_pVScrollBar->Create(scp);
 }
 
@@ -541,6 +537,10 @@ void CPWL_Wnd::OnSetFocus() {}
 
 void CPWL_Wnd::OnKillFocus() {}
 
+std::unique_ptr<CPWL_Wnd::PrivateData> CPWL_Wnd::CloneAttachedData() const {
+  return m_pAttachedData ? m_pAttachedData->Clone() : nullptr;
+}
+
 bool CPWL_Wnd::WndHitTest(const CFX_PointF& point) const {
   return IsValid() && IsVisible() && GetWindowRect().Contains(point);
 }
diff --git a/fpdfsdk/pwl/cpwl_wnd.h b/fpdfsdk/pwl/cpwl_wnd.h
index 93938db648..921693f148 100644
--- a/fpdfsdk/pwl/cpwl_wnd.h
+++ b/fpdfsdk/pwl/cpwl_wnd.h
@@ -7,6 +7,7 @@
 #ifndef FPDFSDK_PWL_CPWL_WND_H_
 #define FPDFSDK_PWL_CPWL_WND_H_
 
+#include <memory>
 #include <vector>
 
 #include "core/fpdfdoc/cpdf_formcontrol.h"
@@ -86,8 +87,9 @@ struct CPWL_Dash {
 class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
  public:
   class PrivateData {
-   protected:
-    ~PrivateData() {}
+   public:
+    virtual ~PrivateData() = default;
+    virtual std::unique_ptr<PrivateData> Clone() const = 0;
   };
 
   class ProviderIface : public Observable<ProviderIface> {
@@ -95,7 +97,7 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
     virtual ~ProviderIface() = default;
 
     // get a matrix which map user space to CWnd client space
-    virtual CFX_Matrix GetWindowMatrix(PrivateData* pAttached) = 0;
+    virtual CFX_Matrix GetWindowMatrix(const PrivateData* pAttached) = 0;
   };
 
   class FocusHandlerIface {
@@ -125,14 +127,13 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
     int32_t nTransparency;                            // optional
     float fFontSize;                                  // optional
     CPWL_Dash sDash;                                  // optional
-    UnownedPtr<PrivateData> pAttachedData;            // optional
     UnownedPtr<CPWL_Wnd> pParentWnd;                  // ignore
     CPWL_MsgControl* pMsgControl;                     // ignore
     int32_t eCursorType;                              // ignore
     CFX_Matrix mtChild;                               // ignore
   };
 
-  CPWL_Wnd();
+  explicit CPWL_Wnd(std::unique_ptr<PrivateData> pAttachedData);
   ~CPWL_Wnd() override;
 
   // Returns |true| iff this instance is still allocated.
@@ -216,9 +217,8 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
   CPWL_Wnd* GetParentWindow() const {
     return m_CreationParams.pParentWnd.Get();
   }
-  PrivateData* GetAttachedData() const {
-    return m_CreationParams.pAttachedData.Get();
-  }
+  const PrivateData* GetAttachedData() const { return m_pAttachedData.get(); }
+  std::unique_ptr<PrivateData> CloneAttachedData() const;
 
   bool WndHitTest(const CFX_PointF& point) const;
   bool ClientHitTest(const CFX_PointF& point) const;
@@ -309,14 +309,15 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
   CPWL_MsgControl* GetMsgControl() const;
 
   CreateParams m_CreationParams;
+  std::unique_ptr<PrivateData> m_pAttachedData;
   std::vector<CPWL_Wnd*> m_Children;
   UnownedPtr<CPWL_ScrollBar> m_pVScrollBar;
   CFX_FloatRect m_rcWindow;
   CFX_FloatRect m_rcClip;
-  bool m_bCreated;
-  bool m_bVisible;
-  bool m_bNotifying;
-  bool m_bEnabled;
+  bool m_bCreated = false;
+  bool m_bVisible = false;
+  bool m_bNotifying = false;
+  bool m_bEnabled = true;
 };
 
 #endif  // FPDFSDK_PWL_CPWL_WND_H_