Change default font family name

Signed-off-by: MuHong Byun <mh.byun@samsung.com>

Author: bwikbs

third_party/txt/src/txt/platform_linux.cc

@@ -13,6 +13,9 @@
 namespace txt {
 
 std::vector<std::string> GetDefaultFontFamilies() {
+#ifdef FLUTTER_USE_FONTCONFIG
+  return {"TizenDefaultFont"};
+#else
   return {
       "SamsungOneUI",
       "SamsungOneUIArabic",
@@ -72,11 +75,12 @@ std::vector<std::string> GetDefaultFontFamilies() {
       "BreezeSansFallback",
       "BreezeColorEmoji",
   };
+#endif
 }
 
 sk_sp<SkFontMgr> GetDefaultFontManager() {
 #ifdef FLUTTER_USE_FONTCONFIG
-  return SkFontMgr_New_FontConfig(nullptr);
+  return SkFontMgr::RefDefault();
 #else
   return SkFontMgr_New_Custom_Directory("/usr/share/fonts");
 #endif