Remove include only fwl.h and IWYU.

xfa/include/fwl/basewidget/fwl_caret.h

 // 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
 
 #ifndef XFA_INCLUDE_FWL_BASEWIDGET_FWL_CARET_H_
 #define XFA_INCLUDE_FWL_BASEWIDGET_FWL_CARET_H_
 
-class CFWL_WidgetImpProperties;
-class IFWL_Widget;
-class IFWL_Caret;
+#include "xfa/include/fwl/core/fwl_widget.h"
+
 #define FWL_CLASS_Caret L"FWL_CARET"
 #define FWL_CLASSHASH_Caret 671181879
 #define FWL_STATE_CAT_HightLight 1
 #define FWL_PART_CAT_Background 1
 #define FWL_PARTSTATE_CAT_HightLight 1
 
 class IFWL_Caret : public IFWL_Widget {
  public:
   static IFWL_Caret* Create(const CFWL_WidgetImpProperties& properties,
                             IFWL_Widget* pOuter);
 
   FWL_ERR ShowCaret(FX_BOOL bFlag = TRUE);
   FWL_ERR GetFrequency(FX_DWORD& elapse);
   FWL_ERR SetFrequency(FX_DWORD elapse);
   FWL_ERR SetColor(CFX_Color crFill);
 
  protected:
   IFWL_Caret();
 };
 
 #endif  // XFA_INCLUDE_FWL_BASEWIDGET_FWL_CARET_H_