Add the recovered reason into metrics

- Add the RecoveredReason enum
- Add the new function for new data stack in Android T.

Bug: 213394622
Test: build and statsd_testdrive
      atest DataStallRecoveryManagerTest
Merged-In: I71ce81b3ad754325a6183c8c3f1dd4255cda65fc
Change-Id: I71ce81b3ad754325a6183c8c3f1dd4255cda65fc
2 files changed