Make the I in IFormFiller explicit

fpdfsdk/include/cpdfsdk_widgethandler.h

 // Copyright 2016 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 FPDFSDK_INCLUDE_CPDFSDK_WIDGETHANDLER_H_
 #define FPDFSDK_INCLUDE_CPDFSDK_WIDGETHANDLER_H_
 
 #include "core/fxcrt/include/fx_basic.h"
 #include "core/fxcrt/include/fx_coordinates.h"
 #include "fpdfsdk/include/ipdfsdk_annothandler.h"
 
-class CFFL_IFormFiller;
+class CFFL_InteractiveFormFiller;
 class CFX_Matrix;
 class CFX_RenderDevice;
 class CPDF_Annot;
 class CPDFSDK_Annot;
 class CPDFSDK_Environment;
 class CPDFSDK_PageView;
 
 #ifdef PDF_ENABLE_XFA
 class CXFA_FFWidget;
 #endif  // PDF_ENABLE_XFA
@@ skipping 71 matching lines @@
   FX_BOOL OnKeyUp(CPDFSDK_Annot* pAnnot, int nKeyCode, int nFlag) override;
   void OnDeSelected(CPDFSDK_Annot* pAnnot) override {}
   void OnSelected(CPDFSDK_Annot* pAnnot) override {}
   FX_BOOL OnSetFocus(CPDFSDK_Annot* pAnnot, uint32_t nFlag) override;
   FX_BOOL OnKillFocus(CPDFSDK_Annot* pAnnot, uint32_t nFlag) override;
 #ifdef PDF_ENABLE_XFA
   FX_BOOL OnXFAChangedFocus(CPDFSDK_Annot* pOldAnnot,
                             CPDFSDK_Annot* pNewAnnot) override;
 #endif  // PDF_ENABLE_XFA
 
-  void SetFormFiller(CFFL_IFormFiller* pFiller) { m_pFormFiller = pFiller; }
-  CFFL_IFormFiller* GetFormFiller() { return m_pFormFiller; }
+  void SetFormFiller(CFFL_InteractiveFormFiller* pFiller) {
+    m_pFormFiller = pFiller;
+  }
+  CFFL_InteractiveFormFiller* GetFormFiller() { return m_pFormFiller; }
 
  private:
   CPDFSDK_Environment* m_pApp;
-  CFFL_IFormFiller* m_pFormFiller;
+  CFFL_InteractiveFormFiller* m_pFormFiller;
 };
 
 #endif  // FPDFSDK_INCLUDE_CPDFSDK_WIDGETHANDLER_H_