Follow minikin::FontFamily constructor signature change.

minikin::FontFamily no longer has addFont function, instead it accept
vector of Fonts in its constructor. To follow this signature change,
holding minikin::Font instance in native and build minikin::FontFamily
instance in FontFamily.freeze() method.

Test: hwui test passed
Change-Id: Id10ca97f6f6f5bbe4999c1ad2736423a204d6e87