Remove unused FWL Panel code.

xfa/fwl/basewidget/fwl_datetimepickerimp.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/basewidget/fwl_datetimepickerimp.h"
 
 #include "xfa/fwl/basewidget/fwl_editimp.h"
 #include "xfa/fwl/basewidget/fwl_formproxyimp.h"
 #include "xfa/fwl/basewidget/fwl_monthcalendarimp.h"
 #include "xfa/fwl/basewidget/ifwl_spinbutton.h"
 #include "xfa/fwl/core/cfwl_message.h"
 #include "xfa/fwl/core/cfwl_themebackground.h"
 #include "xfa/fwl/core/fwl_formimp.h"
 #include "xfa/fwl/core/fwl_noteimp.h"
-#include "xfa/fwl/core/fwl_panelimp.h"
 #include "xfa/fwl/core/fwl_targetimp.h"
 #include "xfa/fwl/core/fwl_widgetimp.h"
 #include "xfa/fwl/core/fwl_widgetmgrimp.h"
 #include "xfa/fwl/core/ifwl_themeprovider.h"
 
 #define FWL_DTP_WIDTH 100
 #define FWL_DTP_HEIGHT 20
 
 // static
 IFWL_DateTimePicker* IFWL_DateTimePicker::Create(
@@ skipping 1127 matching lines @@
     }
     if (m_pOwner->m_pEdit->GetStates() & FWL_WGTSTATE_Focused) {
       pMsg->m_pSrcTarget = m_pOwner->m_pEdit.get();
       IFWL_WidgetDelegate* pDelegate = m_pOwner->m_pEdit->SetDelegate(NULL);
       pDelegate->OnProcessMessage(pMsg);
     }
   }
   rtInvalidate.Inflate(2, 2);
   m_pOwner->Repaint(&rtInvalidate);
 }