Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/xfa_ffchoicelist.cpp

Index: xfa/fxfa/app/xfa_ffchoicelist.cpp
diff --git a/xfa/fxfa/app/xfa_ffchoicelist.cpp b/xfa/fxfa/app/xfa_ffchoicelist.cpp
index 06bbc38eb96cbd8bae6e3ccf924ae9eb70da2623..07134641f333c62c376fcff0e38be5d0c74628c9 100644
--- a/xfa/fxfa/app/xfa_ffchoicelist.cpp
+++ b/xfa/fxfa/app/xfa_ffchoicelist.cpp
@@ -6,11 +6,14 @@
 
 #include "xfa/fxfa/app/xfa_ffchoicelist.h"
 
+#include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/cfwl_combobox.h"
 #include "xfa/fwl/core/cfwl_listbox.h"
 #include "xfa/fwl/core/fwl_noteimp.h"
 #include "xfa/fwl/core/ifwl_app.h"
 #include "xfa/fwl/core/ifwl_edit.h"
+#include "xfa/fxfa/app/cxfa_ffcomboboxdelegate.h"
+#include "xfa/fxfa/app/cxfa_fflistboxdelegate.h"
 #include "xfa/fxfa/app/xfa_fffield.h"
 #include "xfa/fxfa/app/xfa_fwladapter.h"
 #include "xfa/fxfa/cxfa_eventparam.h"
@@ -21,7 +24,7 @@
 
 CXFA_FFListBox::CXFA_FFListBox(CXFA_FFPageView* pPageView,
                                CXFA_WidgetAcc* pDataAcc)
-    : CXFA_FFField(pPageView, pDataAcc), m_pOldDelegate(nullptr) {}
+    : CXFA_FFField(pPageView, pDataAcc) {}
 
 CXFA_FFListBox::~CXFA_FFListBox() {
   if (m_pNormalWidget) {
@@ -43,8 +46,8 @@ FX_BOOL CXFA_FFListBox::LoadWidget() {
   CFWL_NoteDriver* pNoteDriver = pWidget->GetOwnerApp()->GetNoteDriver();
   pNoteDriver->RegisterEventTarget(pWidget, pWidget);
 
-  m_pOldDelegate = m_pNormalWidget->GetCurrentDelegate();
-  m_pNormalWidget->SetCurrentDelegate(this);
+  m_pNormalWidget->SetDelegate(pdfium::MakeUnique<CXFA_FFListBoxDelegate>(
+      m_pNormalWidget->ReleaseDelegate(), this));
   m_pNormalWidget->LockUpdate();
 
   CFX_WideStringArray wsLabelArray;
@@ -185,31 +188,9 @@ void CXFA_FFListBox::DeleteItem(int32_t nIndex) {
   AddInvalidateRect();
 }
 
-void CXFA_FFListBox::OnProcessMessage(CFWL_Message* pMessage) {
-  m_pOldDelegate->OnProcessMessage(pMessage);
-}
-
-void CXFA_FFListBox::OnProcessEvent(CFWL_Event* pEvent) {
-  CXFA_FFField::OnProcessEvent(pEvent);
-  switch (pEvent->GetClassID()) {
-    case CFWL_EventType::SelectChanged: {
-      CFX_Int32Array arrSels;
-      OnSelectChanged(m_pNormalWidget->GetWidget(), arrSels);
-      break;
-    }
-    default:
-      break;
-  }
-  m_pOldDelegate->OnProcessEvent(pEvent);
-}
-void CXFA_FFListBox::OnDrawWidget(CFX_Graphics* pGraphics,
-                                  const CFX_Matrix* pMatrix) {
-  m_pOldDelegate->OnDrawWidget(pGraphics, pMatrix);
-}
-
 CXFA_FFComboBox::CXFA_FFComboBox(CXFA_FFPageView* pPageView,
                                  CXFA_WidgetAcc* pDataAcc)
-    : CXFA_FFField(pPageView, pDataAcc), m_pOldDelegate(nullptr) {}
+    : CXFA_FFField(pPageView, pDataAcc) {}
 
 CXFA_FFComboBox::~CXFA_FFComboBox() {}
 
@@ -242,8 +223,8 @@ FX_BOOL CXFA_FFComboBox::LoadWidget() {
   CFWL_NoteDriver* pNoteDriver = pWidget->GetOwnerApp()->GetNoteDriver();
   pNoteDriver->RegisterEventTarget(pWidget, pWidget);
 
-  m_pOldDelegate = m_pNormalWidget->GetCurrentDelegate();
-  m_pNormalWidget->SetCurrentDelegate(this);
+  m_pNormalWidget->SetDelegate(pdfium::MakeUnique<CXFA_FFComboBoxDelegate>(
+      m_pNormalWidget->ReleaseDelegate(), this));
   m_pNormalWidget->LockUpdate();
 
   CFX_WideStringArray wsLabelArray;
@@ -504,40 +485,3 @@ void CXFA_FFComboBox::OnPostOpen(IFWL_Widget* pWidget) {
   eParam.m_pTarget = m_pDataAcc;
   m_pDataAcc->ProcessEvent(XFA_ATTRIBUTEENUM_PostOpen, &eParam);
 }
-
-void CXFA_FFComboBox::OnProcessMessage(CFWL_Message* pMessage) {
-  m_pOldDelegate->OnProcessMessage(pMessage);
-}
-
-void CXFA_FFComboBox::OnProcessEvent(CFWL_Event* pEvent) {
-  CXFA_FFField::OnProcessEvent(pEvent);
-  switch (pEvent->GetClassID()) {
-    case CFWL_EventType::SelectChanged: {
-      CFWL_EvtCmbSelChanged* postEvent = (CFWL_EvtCmbSelChanged*)pEvent;
-      OnSelectChanged(m_pNormalWidget->GetWidget(), postEvent->iArraySels,
-                      postEvent->bLButtonUp);
-      break;
-    }
-    case CFWL_EventType::EditChanged: {
-      CFX_WideString wsChanged;
-      OnTextChanged(m_pNormalWidget->GetWidget(), wsChanged);
-      break;
-    }
-    case CFWL_EventType::PreDropDown: {
-      OnPreOpen(m_pNormalWidget->GetWidget());
-      break;
-    }
-    case CFWL_EventType::PostDropDown: {
-      OnPostOpen(m_pNormalWidget->GetWidget());
-      break;
-    }
-    default:
-      break;
-  }
-  m_pOldDelegate->OnProcessEvent(pEvent);
-}
-
-void CXFA_FFComboBox::OnDrawWidget(CFX_Graphics* pGraphics,
-                                   const CFX_Matrix* pMatrix) {
-  m_pOldDelegate->OnDrawWidget(pGraphics, pMatrix);
-}