Properly ref-count CFGAS_GEFont with CFX_RetainPtr.

xfa/fde/cfde_txtedttextset.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 XFA_FDE_CFDE_TXTEDTTEXTSET_H_
 #define XFA_FDE_CFDE_TXTEDTTEXTSET_H_
 
 #include "xfa/fde/fde_visualset.h"
 
 class CFDE_TxtEdtPage;
 
 class CFDE_TxtEdtTextSet : public IFDE_TextSet {
  public:
   explicit CFDE_TxtEdtTextSet(CFDE_TxtEdtPage* pPage);
   ~CFDE_TxtEdtTextSet() override;
 
   // IFDE_VisualSet
   FDE_VISUALOBJTYPE GetType() override;
   void GetRect(FDE_TEXTEDITPIECE* hVisualObj, CFX_RectF& rt) override;
 
   // IFDE_TextSet
   int32_t GetString(FDE_TEXTEDITPIECE* pPiece, CFX_WideString& wsText) override;
-  CFGAS_GEFont* GetFont() override;
+  CFX_RetainPtr<CFGAS_GEFont> GetFont() override;
   FX_FLOAT GetFontSize() override;
   FX_ARGB GetFontColor() override;
   int32_t GetDisplayPos(FDE_TEXTEDITPIECE* pPiece,
                         FXTEXT_CHARPOS* pCharPos,
                         bool bCharCode = false,
                         CFX_WideString* pWSForms = nullptr) override;
   int32_t GetCharRects(const FDE_TEXTEDITPIECE* pPiece,
                        CFX_RectFArray& rtArray,
                        bool bBBox) override;
 
  private:
   CFDE_TxtEdtPage* const m_pPage;
 };
 
 #endif  // XFA_FDE_CFDE_TXTEDTTEXTSET_H_