[Sync:USS] Implement PasswordSyncBridge::GetClientTag()

Bug: 902349
Change-Id: I9128f04839decd324ad6f766b9a700edf5fa6fa8
Reviewed-on: https://chromium-review.googlesource.com/c/1402565
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621620}
3 files changed