This change allows TTS V2 API client applications to honor the
"default TTS locale" set by the user in the TTS settings.
Note that the TTS V1 API uses 3 character country/language codes
for locale encoding. It's the only system component that does
that. TTS V2 uses the standard, valid Locale objects. The default
TTS locale setting was stored as a 3 character locale string with
"-" as the separator.
This change switches the TTS locale setting format to the output of
Locale.toString() call (on a valid Locale object). Methods used for
reading this value can interpret both forms and try to return a valid
Locale object as an output.
Change-Id: Ice2e6c25a43eb9dd6e17d371ee582c2dae3329c9
1b5637ee32