Change IFWL_Widget to store a single delegate.

xfa/fwl/core/ifwl_combobox.cpp

 // Copyright 2014 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.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "xfa/fwl/core/ifwl_combobox.h"
 
 #include "third_party/base/ptr_util.h"
 #include "xfa/fde/cfde_txtedtengine.h"
@@ skipping 447 matching lines @@
   if (m_pWidgetMgr->IsFormDisabled()) {
     return DisForm_ShowDropList(bActivate);
   }
   FX_BOOL bDropList = IsDropListShowed();
   if (bDropList == bActivate) {
     return;
   }
   if (!m_pForm) {
     InitProxyForm();
   }
-  m_pListProxyDelegate->Reset();
+  static_cast<CFWL_ComboProxyImpDelegate*>(m_pForm->GetDelegate())->Reset();
   if (bActivate) {
     m_pListBox->ChangeSelected(m_iCurSel);
     ReSetListItemAlignment();
     uint32_t dwStyleAdd = m_pProperties->m_dwStyleExes &
                           (FWL_STYLEEXT_CMB_Sort | FWL_STYLEEXT_CMB_OwnerDraw);
     m_pListBox->ModifyStylesEx(dwStyleAdd, 0);
     m_pListBox->GetWidgetRect(m_rtList, TRUE);
     FX_FLOAT fHeight = GetListHeight();
     if (fHeight > 0) {
       if (m_rtList.height > GetListHeight()) {
@@ skipping 215 matching lines @@
   if (!m_pListBox)
     return;
 
   CFWL_WidgetImpProperties propForm;
   propForm.m_pOwner = this;
   propForm.m_dwStyles = FWL_WGTSTYLE_Popup;
   propForm.m_dwStates = FWL_WGTSTATE_Invisible;
 
   m_pForm = new IFWL_FormProxy(m_pOwnerApp, propForm, m_pListBox.get());
   m_pListBox->SetParent(m_pForm);
-  m_pListProxyDelegate = new CFWL_ComboProxyImpDelegate(m_pForm, this);
-  m_pForm->SetCurrentDelegate(m_pListProxyDelegate);
+  m_pForm->SetDelegate(
+      pdfium::MakeUnique<CFWL_ComboProxyImpDelegate>(m_pForm, this));
 }
 
 void IFWL_ComboBox::DisForm_InitComboList() {
   if (m_pListBox)
     return;
 
   CFWL_WidgetImpProperties prop;
   prop.m_pParent = this;
   prop.m_dwStyles = FWL_WGTSTYLE_Border | FWL_WGTSTYLE_VScroll;
   prop.m_dwStates = FWL_WGTSTATE_Invisible;
@@ skipping 418 matching lines @@
     m_pOwner->m_iCurSel = iCurSel;
     if (bDropDown && m_pOwner->m_pEdit) {
       m_pOwner->SynchrEditText(m_pOwner->m_iCurSel);
     } else {
       m_pOwner->Repaint(&m_pOwner->m_rtClient);
     }
     return;
   }
   FX_BOOL bDropDown = m_pOwner->IsDropDownStyle();
   if (bDropDown)
-    m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(pMsg);
+    m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(pMsg);
 }
 
 void CFWL_ComboBoxImpDelegate::DisForm_OnProcessMessage(
     CFWL_Message* pMessage) {
   if (!pMessage)
     return;
 
   FX_BOOL backDefault = TRUE;
   switch (pMessage->GetClassID()) {
     case CFWL_MessageType::SetFocus: {
@@ skipping 28 matching lines @@
       CFWL_MsgKey* pKey = static_cast<CFWL_MsgKey*>(pMessage);
       if (pKey->m_dwCmd == FWL_KeyCommand::KeyUp)
         break;
       if (m_pOwner->DisForm_IsDropListShowed() &&
           pKey->m_dwCmd == FWL_KeyCommand::KeyDown) {
         FX_BOOL bListKey = pKey->m_dwKeyCode == FWL_VKEY_Up ||
                            pKey->m_dwKeyCode == FWL_VKEY_Down ||
                            pKey->m_dwKeyCode == FWL_VKEY_Return ||
                            pKey->m_dwKeyCode == FWL_VKEY_Escape;
         if (bListKey) {
-          m_pOwner->m_pListBox->GetCurrentDelegate()->OnProcessMessage(
-              pMessage);
+          m_pOwner->m_pListBox->GetDelegate()->OnProcessMessage(pMessage);
           break;
         }
       }
       DisForm_OnKey(pKey);
       break;
     }
     default:
       break;
   }
   if (backDefault)
@@ skipping 19 matching lines @@
 }
 
 void CFWL_ComboBoxImpDelegate::DisForm_OnFocusChanged(CFWL_Message* pMsg,
                                                       FX_BOOL bSet) {
   if (bSet) {
     m_pOwner->m_pProperties->m_dwStates |= FWL_WGTSTATE_Focused;
     if ((m_pOwner->m_pEdit->GetStates() & FWL_WGTSTATE_Focused) == 0) {
       CFWL_MsgSetFocus msg;
       msg.m_pDstTarget = m_pOwner->m_pEdit.get();
       msg.m_pSrcTarget = nullptr;
-      m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(&msg);
+      m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(&msg);
     }
   } else {
     m_pOwner->m_pProperties->m_dwStates &= ~FWL_WGTSTATE_Focused;
     m_pOwner->DisForm_ShowDropList(FALSE);
     CFWL_MsgKillFocus msg;
     msg.m_pDstTarget = nullptr;
     msg.m_pSrcTarget = m_pOwner->m_pEdit.get();
-    m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(&msg);
+    m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(&msg);
   }
 }
 
 void CFWL_ComboBoxImpDelegate::DisForm_OnKey(CFWL_MsgKey* pMsg) {
   uint32_t dwKeyCode = pMsg->m_dwKeyCode;
   const bool bUp = dwKeyCode == FWL_VKEY_Up;
   const bool bDown = dwKeyCode == FWL_VKEY_Down;
   if (bUp || bDown) {
     IFWL_ComboList* pComboList = m_pOwner->m_pListBox.get();
     int32_t iCount = pComboList->CountItems();
@@ skipping 23 matching lines @@
         iCurSel--;
       } else {
         iCurSel++;
       }
     }
     m_pOwner->m_iCurSel = iCurSel;
     m_pOwner->SynchrEditText(m_pOwner->m_iCurSel);
     return;
   }
   if (m_pOwner->m_pEdit)
-    m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(pMsg);
+    m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(pMsg);
 }
 
 CFWL_ComboProxyImpDelegate::CFWL_ComboProxyImpDelegate(IFWL_Form* pForm,
                                                        IFWL_ComboBox* pComboBox)
     : m_bLButtonDown(FALSE),
       m_bLButtonUpSelf(FALSE),
       m_fStartPos(0),
       m_pForm(pForm),
       m_pComboBox(pComboBox) {}
 
@@ skipping 94 matching lines @@
 }
 
 void CFWL_ComboProxyImpDelegate::OnFocusChanged(CFWL_MsgKillFocus* pMsg,
                                                 FX_BOOL bSet) {
   if (!bSet) {
     if (!pMsg->m_pSetFocus) {
       m_pComboBox->ShowDropList(FALSE);
     }
   }
 }