Merge IFWL and CFWL classes.

xfa/fwl/core/ifwl_themeprovider.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_FWL_CORE_IFWL_THEMEPROVIDER_H_
 #define XFA_FWL_CORE_IFWL_THEMEPROVIDER_H_
 
 #include "core/fxcrt/fx_coordinates.h"
 #include "xfa/fwl/theme/cfwl_widgettp.h"
 
 class CFWL_ThemeBackground;
 class CFWL_ThemePart;
 class CFWL_ThemeText;
-class IFWL_Widget;
+class CFWL_Widget;
 
 class IFWL_ThemeProvider {
  public:
   virtual ~IFWL_ThemeProvider() {}
 
   virtual void DrawBackground(CFWL_ThemeBackground* pParams) = 0;
   virtual void DrawText(CFWL_ThemeText* pParams) = 0;
   virtual void* GetCapacity(CFWL_ThemePart* pThemePart,
                             CFWL_WidgetCapacity dwCapacity) = 0;
   virtual void CalcTextRect(CFWL_ThemeText* pParams, CFX_RectF& rect) = 0;
 };
 
 #endif  // XFA_FWL_CORE_IFWL_THEMEPROVIDER_H_