Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/cxfa_ffdatetimeeditdelegate.cpp

+// Copyright 2016 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/fxfa/app/cxfa_ffdatetimeeditdelegate.h"
+
+#include "xfa/fwl/core/cfwl_event.h"
+#include "xfa/fwl/core/ifwl_datetimepicker.h"
+#include "xfa/fxfa/app/xfa_fftextedit.h"
+
+CXFA_FFDateTimeEditDelegate::CXFA_FFDateTimeEditDelegate(
+    std::unique_ptr<IFWL_WidgetDelegate> pDelegate,
+    CXFA_FFDateTimeEdit* const pWidget)
+    : CXFA_FFTextEditDelegate(std::move(pDelegate), pWidget) {}
+
+CXFA_FFDateTimeEditDelegate::~CXFA_FFDateTimeEditDelegate() {}
+
+void CXFA_FFDateTimeEditDelegate::OnProcessEvent(CFWL_Event* pEvent) {
+  if (pEvent->GetClassID() == CFWL_EventType::SelectChanged) {
+    CXFA_FFDateTimeEdit* widget = static_cast<CXFA_FFDateTimeEdit*>(m_pWidget);
+    CFWL_Event_DtpSelectChanged* event =
+        static_cast<CFWL_Event_DtpSelectChanged*>(pEvent);
+
+    widget->OnSelectChanged(widget->GetNormalWidget()->GetWidget(),
+                            event->iYear, event->iMonth, event->iDay);
+    return;
+  }
+  CXFA_FFTextEditDelegate::OnProcessEvent(pEvent);
+}