Smart Lock: Implement Unlock performance metrics.

Create performance metrics for the Unlock case. The primary metric,
StartScanToReceiveUnlockableRemoteStatus, captures the user perception
of Smart Lock's latency: the time it takes to observe the Smart Lock
icon becoming green, after locking the screen.

The other metric, AuthenticationToReceiveUnlockableRemoteStatus,
captures how long it takes after establishing an secure connection to
receive the message that allows the Smart Lock icon to become green.

10 local runs reveal current *average* Smart Lock latency (and
breakdown of it):

* StartScanToReceiveUnlockableRemoteStatus:		9007.0 ms
* AuthenticationToReceiveUnlockableRemoteStatus:	 179.3 ms

Bug: 905438
Change-Id: Ieef819ac646a0b768a1658f142097e37057cba27
Commit-Queue: Ryan Hansberry <>
Reviewed-by: Robert Kaplow <>
Reviewed-by: Kyle Horimoto <>
Cr-Commit-Position: refs/heads/master@{#631838}
3 files changed