[EasyUnlock] Observe proximity changes and clean up TX power strategy.

chrome/browser/signin/easy_unlock_metrics.h

 // 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.
 
 #ifndef CHROME_BROWSER_SIGNIN_EASY_UNLOCK_METRICS_H_
 #define CHROME_BROWSER_SIGNIN_EASY_UNLOCK_METRICS_H_
 
 namespace base {
 class TimeDelta;
 }
@@ skipping 31 matching lines @@
   PASSWORD_ENTRY_PHONE_NOT_LOCKABLE = 11,
   // Password is used because phone is not close enough (roughly, at least 30
   // feet away).
   PASSWORD_ENTRY_RSSI_TOO_LOW = 12,
   // Password is used because phone is not supported.
   PASSWORD_ENTRY_PHONE_UNSUPPORTED = 13,
   // Password is used because user types in password. This is unlikely to happen
   // though.
   PASSWORD_ENTRY_WITH_AUTHENTICATED_PHONE = 14,
   // Password is used because phone is not right next to the Chromebook.
-  PASSWORD_ENTRY_TX_POWER_TOO_HIGH = 15,
+  PASSWORD_ENTRY_TX_POWER_TOO_HIGH = 15,  // DEPRECATED
   // Password is used because Easy sign-in failed.
   PASSWORD_ENTRY_LOGIN_FAILED = 16,
   // Password is used because pairing data is changed for a "new" Chromebook
   // (where there was no previous pairing data).
   PASSWORD_ENTRY_PAIRING_ADDED = 17,
   // Password is used because there is no screenlock state handler. Most likely
   // because EasyUnlock is disabled, e.g. Bluetooth adapter not ready.
   PASSWORD_ENTRY_NO_SCREENLOCK_STATE_HANDLER = 18,
   // Password is used because the phone is (a) locked, and (b) not right next to
   // the Chromebook.
-  PASSWORD_ENTRY_PHONE_LOCKED_AND_TX_POWER_TOO_HIGH = 19,
+  PASSWORD_ENTRY_PHONE_LOCKED_AND_RSSI_TOO_LOW = 19,
 
   EASY_UNLOCK_AUTH_EVENT_COUNT  // Must be the last entry.
 };
 
 enum EasyUnlockTrialRunEvent {
   // A trial run was initiated from the Easy Unlock setup app.
   EASY_UNLOCK_TRIAL_RUN_EVENT_LAUNCHED = 0,
   // The user clicked on the lock icon during the trial run.
   EASY_UNLOCK_TRIAL_RUN_EVENT_CLICKED_LOCK_ICON = 1,
   EASY_UNLOCK_TRIAL_RUN_EVENT_COUNT  // Must be the last entry.
 };
 
 void RecordEasyUnlockDidUserManuallyUnlockPhone(bool did_unlock);
 void RecordEasyUnlockSigninDuration(const base::TimeDelta& duration);
 void RecordEasyUnlockSigninEvent(EasyUnlockAuthEvent event);
 void RecordEasyUnlockScreenUnlockDuration(const base::TimeDelta& duration);
 void RecordEasyUnlockScreenUnlockEvent(EasyUnlockAuthEvent event);
 void RecordEasyUnlockTrialRunEvent(EasyUnlockTrialRunEvent event);
 
 #endif  // CHROME_BROWSER_SIGNIN_EASY_UNLOCK_METRICS_H_