Remove pParentWnd field entirely from CreateParams.

Put it into CPWL_Wnd directly, and set/clear it when a child
is added/removed from a parent.

Change-Id: I7a8cd0cf22dbd6173e64bec5d844df56ad373722
Reviewed-on: https://pdfium-review.googlesource.com/c/44692
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

6 files changed, 8 insertions, 14 deletions

diff --git a/fpdfsdk/formfiller/cffl_formfiller.cpp b/fpdfsdk/formfiller/cffl_formfiller.cpp
index 76421368b2..91e16e8169 100644
--- a/fpdfsdk/formfiller/cffl_formfiller.cpp
+++ b/fpdfsdk/formfiller/cffl_formfiller.cpp
@@ -329,7 +329,6 @@ bool CFFL_FormFiller::IsValid() const {
 
 CPWL_Wnd::CreateParams CFFL_FormFiller::GetCreateParam() {
   CPWL_Wnd::CreateParams cp;
-  cp.pParentWnd = nullptr;
   cp.pProvider.Reset(this);
   cp.rcRectWnd = GetPDFWindowRect();
 
diff --git a/fpdfsdk/pwl/cpwl_combo_box.cpp b/fpdfsdk/pwl/cpwl_combo_box.cpp
index db1def0758..70893ca437 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.cpp
+++ b/fpdfsdk/pwl/cpwl_combo_box.cpp
@@ -277,7 +277,6 @@ void CPWL_ComboBox::CreateEdit(const CreateParams& cp) {
   AddChild(m_pEdit.Get());
 
   CreateParams ecp = cp;
-  ecp.pParentWnd = this;
   ecp.dwFlags = PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PES_CENTER |
                 PES_AUTOSCROLL | PES_UNDO;
 
@@ -301,7 +300,6 @@ void CPWL_ComboBox::CreateButton(const CreateParams& cp) {
   AddChild(m_pButton.Get());
 
   CreateParams bcp = cp;
-  bcp.pParentWnd = this;
   bcp.dwFlags = PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PWS_BACKGROUND;
   bcp.sBackgroundColor = CFX_Color(CFX_Color::kRGB, 220.0f / 255.0f,
                                    220.0f / 255.0f, 220.0f / 255.0f);
@@ -321,7 +319,6 @@ void CPWL_ComboBox::CreateListBox(const CreateParams& cp) {
   AddChild(m_pList.Get());
 
   CreateParams lcp = cp;
-  lcp.pParentWnd = this;
   lcp.dwFlags =
       PWS_CHILD | PWS_BORDER | PWS_BACKGROUND | PLBS_HOVERSEL | PWS_VSCROLL;
   lcp.nBorderStyle = BorderStyle::SOLID;
diff --git a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
index ea48c45376..8bf13a73d0 100644
--- a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
+++ b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
@@ -93,7 +93,6 @@ void CPWL_EditCtrl::CreateEditCaret(const CreateParams& cp) {
   AddChild(m_pEditCaret);
 
   CreateParams ecp = cp;
-  ecp.pParentWnd = this;
   ecp.dwFlags = PWS_CHILD | PWS_NOREFRESHCLIP;
   ecp.dwBorderWidth = 0;
   ecp.nBorderStyle = BorderStyle::SOLID;
diff --git a/fpdfsdk/pwl/cpwl_scroll_bar.cpp b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
index 3e52e0d81b..34154aaa98 100644
--- a/fpdfsdk/pwl/cpwl_scroll_bar.cpp
+++ b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
@@ -535,7 +535,6 @@ void CPWL_ScrollBar::NotifyMouseMove(CPWL_Wnd* child, const CFX_PointF& pos) {
 
 void CPWL_ScrollBar::CreateButtons(const CreateParams& cp) {
   CreateParams scp = cp;
-  scp.pParentWnd = this;
   scp.dwBorderWidth = 2;
   scp.nBorderStyle = BorderStyle::BEVELED;
   scp.dwFlags =
diff --git a/fpdfsdk/pwl/cpwl_wnd.cpp b/fpdfsdk/pwl/cpwl_wnd.cpp
index d5d2102997..66e5cfa0b6 100644
--- a/fpdfsdk/pwl/cpwl_wnd.cpp
+++ b/fpdfsdk/pwl/cpwl_wnd.cpp
@@ -173,9 +173,8 @@ void CPWL_Wnd::Destroy() {
         delete pChild;
       }
     }
-    if (m_CreationParams.pParentWnd)
-      m_CreationParams.pParentWnd->RemoveChild(this);
-
+    if (m_pParent)
+      m_pParent->RemoveChild(this);
     m_bCreated = false;
   }
   DestroyMsgControl();
@@ -379,10 +378,14 @@ bool CPWL_Wnd::OnMouseWheel(short zDelta,
 }
 
 void CPWL_Wnd::AddChild(CPWL_Wnd* pWnd) {
+  ASSERT(!pWnd->m_pParent);
+  pWnd->m_pParent = this;
   m_Children.push_back(pWnd);
 }
 
 void CPWL_Wnd::RemoveChild(CPWL_Wnd* pWnd) {
+  ASSERT(pWnd->m_pParent == this);
+  pWnd->m_pParent = nullptr;
   for (auto it = m_Children.rbegin(); it != m_Children.rend(); ++it) {
     if (*it && *it == pWnd) {
       m_Children.erase(std::next(it).base());
@@ -492,7 +495,6 @@ void CPWL_Wnd::CreateVScrollBar(const CreateParams& cp) {
   scp.dwFlags =
       PWS_CHILD | PWS_BACKGROUND | PWS_AUTOTRANSPARENT | PWS_NOREFRESHCLIP;
 
-  scp.pParentWnd = this;
   scp.sBackgroundColor = PWL_DEFAULT_WHITECOLOR;
   scp.eCursorType = FXCT_ARROW;
   scp.nTransparency = PWL_SCROLLBAR_TRANSPARENCY;
diff --git a/fpdfsdk/pwl/cpwl_wnd.h b/fpdfsdk/pwl/cpwl_wnd.h
index 8d7eebc5e9..3a4c9a5914 100644
--- a/fpdfsdk/pwl/cpwl_wnd.h
+++ b/fpdfsdk/pwl/cpwl_wnd.h
@@ -127,7 +127,6 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
     int32_t nTransparency;                            // optional
     float fFontSize;                                  // optional
     CPWL_Dash sDash;                                  // optional
-    UnownedPtr<CPWL_Wnd> pParentWnd;                  // ignore
     CPWL_MsgControl* pMsgControl;                     // ignore
     int32_t eCursorType;                              // ignore
     CFX_Matrix mtChild;                               // ignore
@@ -215,9 +214,7 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
   void SetClipRect(const CFX_FloatRect& rect);
   const CFX_FloatRect& GetClipRect() const;
 
-  CPWL_Wnd* GetParentWindow() const {
-    return m_CreationParams.pParentWnd.Get();
-  }
+  CPWL_Wnd* GetParentWindow() const { return m_pParent.Get(); }
   const PrivateData* GetAttachedData() const { return m_pAttachedData.get(); }
   std::unique_ptr<PrivateData> CloneAttachedData() const;
 
@@ -308,6 +305,7 @@ class CPWL_Wnd : public CPWL_TimerHandler, public Observable<CPWL_Wnd> {
 
   CreateParams m_CreationParams;
   std::unique_ptr<PrivateData> m_pAttachedData;
+  UnownedPtr<CPWL_Wnd> m_pParent;
   std::vector<CPWL_Wnd*> m_Children;
   UnownedPtr<CPWL_ScrollBar> m_pVScrollBar;
   CFX_FloatRect m_rcWindow;