Remove IXFA_* interfaces.

xfa/fxfa/app/xfa_rendercontext.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_FXFA_APP_XFA_RENDERCONTEXT_H_
-#define XFA_FXFA_APP_XFA_RENDERCONTEXT_H_
-
-#include "xfa/include/fxfa/fxfa.h"
-
-class CXFA_RenderContext : public IXFA_RenderContext {
- public:
-  CXFA_RenderContext();
-  virtual ~CXFA_RenderContext();
-  virtual void Release() { delete this; }
-  virtual int32_t StartRender(IXFA_PageView* pPageView,
-                              CFX_Graphics* pGS,
-                              const CFX_Matrix& matrix,
-                              const CXFA_RenderOptions& options);
-  virtual int32_t DoRender(IFX_Pause* pPause = NULL);
-  virtual void StopRender();
-
- protected:
-  IXFA_WidgetIterator* m_pWidgetIterator;
-  IXFA_Widget* m_pWidget;
-  IXFA_PageView* m_pPageView;
-  CFX_Graphics* m_pGS;
-  CFX_Matrix m_matrix;
-  CXFA_RenderOptions m_options;
-  uint32_t m_dwStatus;
-  CFX_RectF m_rtClipRect;
-};
-
-#endif  // XFA_FXFA_APP_XFA_RENDERCONTEXT_H_