Name core/fxge/android files appropriately and use one file per class

core/fxge/android/cfx_androidfontinfo.h

-// Copyright 2014 PDFium Authors. All rights reserved.
+// 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_ANDROID_FX_ANDROID_FONT_H_
-#define CORE_FXGE_ANDROID_FX_ANDROID_FONT_H_
+#ifndef CORE_FXGE_ANDROID_CFX_ANDROIDFONTINFO_H_
+#define CORE_FXGE_ANDROID_CFX_ANDROIDFONTINFO_H_
 
 #include "core/fxcrt/fx_system.h"
-
-#if _FX_OS_ == _FX_ANDROID_
-
 #include "core/fxge/cfx_fontmapper.h"
 #include "core/fxge/fx_font.h"
 #include "core/fxge/ifx_systemfontinfo.h"
 
 class CFPF_SkiaFontMgr;
 
 class CFX_AndroidFontInfo : public IFX_SystemFontInfo {
  public:
   CFX_AndroidFontInfo();
   ~CFX_AndroidFontInfo() override;
@@ skipping 14 matching lines @@
                        uint8_t* buffer,
                        uint32_t size) override;
   FX_BOOL GetFaceName(void* hFont, CFX_ByteString& name) override;
   FX_BOOL GetFontCharset(void* hFont, int& charset) override;
   void DeleteFont(void* hFont) override;
 
  protected:
   CFPF_SkiaFontMgr* m_pFontMgr;
 };
 
-#endif  // _FX_OS_ == _FX_ANDROID_
-
-#endif  // CORE_FXGE_ANDROID_FX_ANDROID_FONT_H_
+#endif  // CORE_FXGE_ANDROID_CFX_ANDROIDFONTINFO_H_