Previously external/libphonenumber accepted lower case
country codes (e.g. "us") but now it doesn't for performance reason.
Actually ISO 3166-1 doesn't allow lower cases, so we should not rely
on them.
Need to fix unit tests for PhoneNumberUtils, as it implicitly
relies on the previous behavior.
See also I3a3e6db84ed0d24290b1be19651fa9a82de4cc39
Bug: 4941319
Change-Id: If16f6531f274a0faf5e28724854409ca9b00a669
a. The CountryDetector detects the country the user is in
in order of mobile network, location, sim card or locale.
It will be used by contact and contact provider.
b. All added APIs are hidden at this stage.
Change-Id: I4ba278571ffb6ab6ded0996d4f440a18534f8ed4
