[Smart Lock] Add UMA metrics to measure duration of unlock.

chrome/browser/signin/easy_unlock_metrics.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/signin/easy_unlock_metrics.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 
+void RecordEasyUnlockSigninDuration(const base::TimeDelta& duration) {
+  UMA_HISTOGRAM_MEDIUM_TIMES("EasyUnlock.AuthEvent.SignIn.Duration", duration);
+}
+
 void RecordEasyUnlockSigninEvent(EasyUnlockAuthEvent event) {
   DCHECK_LT(event, EASY_UNLOCK_AUTH_EVENT_COUNT);
   UMA_HISTOGRAM_ENUMERATION("EasyUnlock.AuthEvent.SignIn", event,
                             EASY_UNLOCK_AUTH_EVENT_COUNT);
 }
 
+void RecordEasyUnlockScreenUnlockDuration(const base::TimeDelta& duration) {
+  UMA_HISTOGRAM_MEDIUM_TIMES("EasyUnlock.AuthEvent.Unlock.Duration", duration);
+}
+
 void RecordEasyUnlockScreenUnlockEvent(EasyUnlockAuthEvent event) {
   DCHECK_LT(event, EASY_UNLOCK_AUTH_EVENT_COUNT);
   UMA_HISTOGRAM_ENUMERATION("EasyUnlock.AuthEvent.Unlock", event,
                             EASY_UNLOCK_AUTH_EVENT_COUNT);
 }
 
 void RecordEasyUnlockTrialRunEvent(EasyUnlockTrialRunEvent event) {
   DCHECK_LT(event, EASY_UNLOCK_TRIAL_RUN_EVENT_COUNT);
   UMA_HISTOGRAM_ENUMERATION("EasyUnlock.TrialRun.Events",
                             event,
                             EASY_UNLOCK_TRIAL_RUN_EVENT_COUNT);
 }