Change IFWL_Widget to store a single delegate.

xfa/fwl/core/ifwl_datetimepicker.cpp

Index: xfa/fwl/core/ifwl_datetimepicker.cpp
diff --git a/xfa/fwl/core/ifwl_datetimepicker.cpp b/xfa/fwl/core/ifwl_datetimepicker.cpp
index 844eb9ebe677fcba88ea30873b8fdceece94f561..aac9c646cf5ab9749712d612a7e4fab9c7f8cf9a 100644
--- a/xfa/fwl/core/ifwl_datetimepicker.cpp
+++ b/xfa/fwl/core/ifwl_datetimepicker.cpp
@@ -520,7 +520,7 @@ void IFWL_DateTimePicker::DisForm_ShowMonthCalendar(FX_BOOL bActivate) {
     CFWL_MsgSetFocus msg;
     msg.m_pDstTarget = m_pMonthCal.get();
     msg.m_pSrcTarget = m_pEdit.get();
-    m_pEdit->GetCurrentDelegate()->OnProcessMessage(&msg);
+    m_pEdit->GetDelegate()->OnProcessMessage(&msg);
   }
   CFX_RectF rtInvalidate, rtCal;
   rtInvalidate.Set(0, 0, m_pProperties->m_rtWidget.width,
@@ -686,7 +686,7 @@ void CFWL_DateTimePickerImpDelegate::OnProcessMessage(CFWL_Message* pMessage) {
     }
     case CFWL_MessageType::Key: {
       if (m_pOwner->m_pEdit->GetStates() & FWL_WGTSTATE_Focused) {
-        m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(pMessage);
+        m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(pMessage);
         return;
       }
       break;
@@ -789,7 +789,7 @@ void CFWL_DateTimePickerImpDelegate::DisForm_OnFocusChanged(CFWL_Message* pMsg,
     }
     rtInvalidate = m_pOwner->m_rtBtn;
     pMsg->m_pDstTarget = m_pOwner->m_pEdit.get();
-    m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(pMsg);
+    m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(pMsg);
   } else {
     m_pOwner->m_pProperties->m_dwStates &= ~FWL_WGTSTATE_Focused;
     m_pOwner->m_rtBtn.Set(0, 0, 0, 0);
@@ -798,7 +798,7 @@ void CFWL_DateTimePickerImpDelegate::DisForm_OnFocusChanged(CFWL_Message* pMsg,
     }
     if (m_pOwner->m_pEdit->GetStates() & FWL_WGTSTATE_Focused) {
       pMsg->m_pSrcTarget = m_pOwner->m_pEdit.get();
-      m_pOwner->m_pEdit->GetCurrentDelegate()->OnProcessMessage(pMsg);
+      m_pOwner->m_pEdit->GetDelegate()->OnProcessMessage(pMsg);
     }
   }
   rtInvalidate.Inflate(2, 2);