Make TextClock.refresh() a public API

Starting from R, apps in /product are not allowed to use hidden API.
TextClock.refresh() is used in FloralClock which is in /product.

We need to make it a public API.

Bug: 132750099
Test: make
Change-Id: I20adbff79270ce9d13f3323386d3636c322012f1
2 files changed