Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/xfa_ffcheckbutton.cpp

Index: xfa/fxfa/app/xfa_ffcheckbutton.cpp
diff --git a/xfa/fxfa/app/xfa_ffcheckbutton.cpp b/xfa/fxfa/app/xfa_ffcheckbutton.cpp
index 9dfb12fa789a30186a4a0bc41617e7f9573c9420..83d068e858801172f25d00ce0b4b995f2ebcbac1 100644
--- a/xfa/fxfa/app/xfa_ffcheckbutton.cpp
+++ b/xfa/fxfa/app/xfa_ffcheckbutton.cpp
@@ -6,10 +6,12 @@
 
 #include "xfa/fxfa/app/xfa_ffcheckbutton.h"
 
+#include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/cfwl_checkbox.h"
 #include "xfa/fwl/core/cfwl_message.h"
 #include "xfa/fwl/core/cfwl_widgetmgr.h"
 #include "xfa/fwl/core/fwl_noteimp.h"
+#include "xfa/fxfa/app/cxfa_ffcheckbuttondelegate.h"
 #include "xfa/fxfa/app/xfa_ffexclgroup.h"
 #include "xfa/fxfa/app/xfa_fffield.h"
 #include "xfa/fxfa/xfa_ffapp.h"
@@ -20,7 +22,7 @@
 
 CXFA_FFCheckButton::CXFA_FFCheckButton(CXFA_FFPageView* pPageView,
                                        CXFA_WidgetAcc* pDataAcc)
-    : CXFA_FFField(pPageView, pDataAcc), m_pOldDelegate(nullptr) {
+    : CXFA_FFField(pPageView, pDataAcc) {
   m_rtCheckBox.Set(0, 0, 0, 0);
 }
 
@@ -36,8 +38,8 @@ FX_BOOL CXFA_FFCheckButton::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_FFCheckButtonDelegate>(
+      m_pNormalWidget->ReleaseDelegate(), this));
 
   if (m_pDataAcc->IsRadioButton())
     pCheckBox->ModifyStylesEx(FWL_STYLEEXT_CKB_RadioButton, 0xFFFFFFFF);
@@ -295,46 +297,3 @@ FX_BOOL CXFA_FFCheckButton::UpdateFWLData() {
   m_pNormalWidget->Update();
   return TRUE;
 }
-
-void CXFA_FFCheckButton::OnProcessMessage(CFWL_Message* pMessage) {
-  m_pOldDelegate->OnProcessMessage(pMessage);
-}
-
-void CXFA_FFCheckButton::OnProcessEvent(CFWL_Event* pEvent) {
-  CXFA_FFField::OnProcessEvent(pEvent);
-  switch (pEvent->GetClassID()) {
-    case CFWL_EventType::CheckStateChanged: {
-      CXFA_EventParam eParam;
-      eParam.m_eType = XFA_EVENT_Change;
-      m_pDataAcc->GetValue(eParam.m_wsNewText, XFA_VALUEPICTURE_Raw);
-      CXFA_WidgetAcc* pFFExclGroup = m_pDataAcc->GetExclGroup();
-      if (ProcessCommittedData()) {
-        eParam.m_pTarget = pFFExclGroup;
-        if (pFFExclGroup) {
-          m_pDocView->AddValidateWidget(pFFExclGroup);
-          m_pDocView->AddCalculateWidgetAcc(pFFExclGroup);
-          pFFExclGroup->ProcessEvent(XFA_ATTRIBUTEENUM_Change, &eParam);
-        }
-        eParam.m_pTarget = m_pDataAcc;
-        m_pDataAcc->ProcessEvent(XFA_ATTRIBUTEENUM_Change, &eParam);
-      } else {
-        SetFWLCheckState(m_pDataAcc->GetCheckState());
-      }
-      if (pFFExclGroup) {
-        eParam.m_pTarget = pFFExclGroup;
-        pFFExclGroup->ProcessEvent(XFA_ATTRIBUTEENUM_Click, &eParam);
-      }
-      eParam.m_pTarget = m_pDataAcc;
-      m_pDataAcc->ProcessEvent(XFA_ATTRIBUTEENUM_Click, &eParam);
-      break;
-    }
-    default:
-      break;
-  }
-  m_pOldDelegate->OnProcessEvent(pEvent);
-}
-
-void CXFA_FFCheckButton::OnDrawWidget(CFX_Graphics* pGraphics,
-                                      const CFX_Matrix* pMatrix) {
-  m_pOldDelegate->OnDrawWidget(pGraphics, pMatrix);
-}