Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/cxfa_ffnumericeditdelegate.h

+// 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
+
+#ifndef XFA_FXFA_APP_CXFA_FFNUMERICEDITDELEGATE_H_
+#define XFA_FXFA_APP_CXFA_FFNUMERICEDITDELEGATE_H_
+
+#include "core/fxcrt/fx_coordinates.h"
+#include "xfa/fwl/core/cfwl_event.h"
+#include "xfa/fwl/core/cfwl_message.h"
+#include "xfa/fxfa/app/cxfa_fftexteditdelegate.h"
+#include "xfa/fxfa/app/xfa_fftextedit.h"
+#include "xfa/fxfa/xfa_ffwidget.h"
+#include "xfa/fxgraphics/cfx_graphics.h"
+
+class CXFA_FFNumericEditDelegate : public CXFA_FFTextEditDelegate {
+ public:
+  CXFA_FFNumericEditDelegate(std::unique_ptr<IFWL_WidgetDelegate> pDelegate,
+                             CXFA_FFNumericEdit* const pWidget);
+  ~CXFA_FFNumericEditDelegate() override;
+
+  // CXFA_FFTextEditDelegate.
+  void OnProcessEvent(CFWL_Event* pEvent) override;
+};
+
+#endif  // XFA_FXFA_APP_CXFA_FFNUMERICEDITDELEGATE_H_