Pdfium: Fix fonts leaking on ClosePage.

core/fxge/include/cfx_facecache.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 CORE_FXGE_INCLUDE_CFX_FACECACHE_H_
 #define CORE_FXGE_INCLUDE_CFX_FACECACHE_H_
 
 #include <map>
 
 #include "core/fxge/include/fx_font.h"
 #include "core/fxge/include/fx_freetype.h"
 
 class CFX_FaceCache {
  public:
   explicit CFX_FaceCache(FXFT_Face face);
   ~CFX_FaceCache();
-  const CFX_GlyphBitmap* LoadGlyphBitmap(CFX_Font* pFont,
+  const CFX_GlyphBitmap* LoadGlyphBitmap(const CFX_Font* pFont,
                                          uint32_t glyph_index,
                                          FX_BOOL bFontStyle,
                                          const CFX_Matrix* pMatrix,
                                          int dest_width,
                                          int anti_alias,
                                          int& text_flags);
-  const CFX_PathData* LoadGlyphPath(CFX_Font* pFont,
+  const CFX_PathData* LoadGlyphPath(const CFX_Font* pFont,
                                     uint32_t glyph_index,
                                     int dest_width);
 
 #ifdef _SKIA_SUPPORT_
-  CFX_TypeFace* GetDeviceCache(CFX_Font* pFont);
+  CFX_TypeFace* GetDeviceCache(const CFX_Font* pFont);
 #endif
 
  private:
-  CFX_GlyphBitmap* RenderGlyph(CFX_Font* pFont,
+  CFX_GlyphBitmap* RenderGlyph(const CFX_Font* pFont,
                                uint32_t glyph_index,
                                FX_BOOL bFontStyle,
                                const CFX_Matrix* pMatrix,
                                int dest_width,
                                int anti_alias);
-  CFX_GlyphBitmap* RenderGlyph_Nativetext(CFX_Font* pFont,
+  CFX_GlyphBitmap* RenderGlyph_Nativetext(const CFX_Font* pFont,
                                           uint32_t glyph_index,
                                           const CFX_Matrix* pMatrix,
                                           int dest_width,
                                           int anti_alias);
-  CFX_GlyphBitmap* LookUpGlyphBitmap(CFX_Font* pFont,
+  CFX_GlyphBitmap* LookUpGlyphBitmap(const CFX_Font* pFont,
                                      const CFX_Matrix* pMatrix,
                                      const CFX_ByteString& FaceGlyphsKey,
                                      uint32_t glyph_index,
                                      FX_BOOL bFontStyle,
                                      int dest_width,
                                      int anti_alias);
   void InitPlatform();
   void DestroyPlatform();
 
   FXFT_Face const m_Face;
   std::map<CFX_ByteString, std::unique_ptr<CFX_SizeGlyphCache>> m_SizeMap;
   std::map<uint32_t, std::unique_ptr<CFX_PathData>> m_PathMap;
 #ifdef _SKIA_SUPPORT_
   CFX_TypeFace* m_pTypeface;
 #endif
 };
 
 #endif  //  CORE_FXGE_INCLUDE_CFX_FACECACHE_H_