TextLinks API updates.

1. Add get/setReferenceTime to TextLinks
2. Make TextLinks.getText() public

Bug: 143873595
Test: atest FrameworksCoreTests:android.view.textclassifier
Test: atest android.view.textclassifier.cts.TextClassifierValueObjectsTest
Change-Id: I720e0e1fe9e4d05de0d7a1427f7d7ded01287aff
3 files changed