Move Android SkFontMgr::Factory to its own file.

include/ports/SkFontMgr_android.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkFontMgr_android_DEFINED
 #define SkFontMgr_android_DEFINED
 
 #include "SkTypes.h"
 
 class SkFontMgr;
 
+/**
+ *  For test only -- this only affects the default factory.
+ *  Load font config from given xml files, instead of those from Android system.
+ */
+SK_API void SkUseTestFontConfigFile(const char* mainconf, const char* fallbackconf,
+                                    const char* fontsdir);
+
 struct SkFontMgr_Android_CustomFonts {
     /** When specifying custom fonts, indicates how to use system fonts. */
     enum SystemFontUse {
         kOnlyCustom, /** Use only custom fonts. NDK compliant. */
         kPreferCustom, /** Use custom fonts before system fonts. */
         kPreferSystem /** Use system fonts before custom fonts. */
     };
     /** Whether or not to use system fonts. */
     SystemFontUse fSystemFontUse;
 
     /** Base path to resolve relative font file names. If a directory, should end with '/'. */
     const char* fBasePath;
 
     /** Optional custom configuration file to use. */
     const char* fFontsXml;
 
     /** Optional custom configuration file for fonts which provide fallback.
      *  In the new style (version > 21) fontsXml format is used, this should be NULL.
      */
     const char* fFallbackFontsXml;
 };
 
 /** Create a font manager for Android. If 'custom' is NULL, use only system fonts. */
 SK_API SkFontMgr* SkFontMgr_New_Android(const SkFontMgr_Android_CustomFonts* custom);
 
 #endif // SkFontMgr_android_DEFINED