Add opaque "layout item" to widgets for caller's use.

xfa/fwl/basewidget/fwl_editimp.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_editimp.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 1619 matching lines @@
 
 void CFWL_EditImp::InitEngine() {
   if (!m_pEdtEngine)
     m_pEdtEngine = new CFDE_TxtEdtEngine;
 }
 
 FX_BOOL FWL_ShowCaret(IFWL_Widget* pWidget,
                       FX_BOOL bVisible,
                       const CFX_RectF* pRtAnchor) {
   CXFA_FFWidget* pXFAWidget =
-      static_cast<CXFA_FFWidget*>(pWidget->GetPrivateData(pWidget));
+      static_cast<CXFA_FFWidget*>(pWidget->GetLayoutItem());
   if (!pXFAWidget)
     return FALSE;
 
   IXFA_DocProvider* pDocProvider = pXFAWidget->GetDoc()->GetDocProvider();
   if (!pDocProvider)
     return FALSE;
 
   if (bVisible) {
     CFX_Matrix mt;
     pXFAWidget->GetRotateMatrix(mt);
@@ skipping 535 matching lines @@
     }
     CFX_RectF rect;
     m_pOwner->GetWidgetRect(rect);
     CFX_RectF rtInvalidate;
     rtInvalidate.Set(0, 0, rect.width + 2, rect.height + 2);
     m_pOwner->Repaint(&rtInvalidate);
   }
   return TRUE;
 }
 void CFWL_EditImpDelegate::DoCursor(CFWL_MsgMouse* pMsg) {}