[Proximity Auth] Port the UnlockManager class.

components/proximity_auth/metrics.h

 // Copyright 2015 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 COMPONENTS_PROXIMITY_AUTH_METRICS_H
 #define COMPONENTS_PROXIMITY_AUTH_METRICS_H
 
 #include "base/time/time.h"
 
 namespace proximity_auth {
 namespace metrics {
 
 extern const char kUnknownDeviceModel[];
 extern const int kUnknownProximityValue;
 
+// Possible states of the remote device's security settings. This enum is used
+// to back a histogram, and hence should be treated as append-only.
+enum class RemoteSecuritySettingsState {
+  UNKNOWN,
+  SCREEN_LOCK_DISABLED_TRUST_AGENT_UNSUPPORTED,
+  SCREEN_LOCK_DISABLED_TRUST_AGENT_DISABLED,
+  SCREEN_LOCK_DISABLED_TRUST_AGENT_ENABLED,
+  SCREEN_LOCK_ENABLED_TRUST_AGENT_UNSUPPORTED,
+  SCREEN_LOCK_ENABLED_TRUST_AGENT_DISABLED,
+  SCREEN_LOCK_ENABLED_TRUST_AGENT_ENABLED,
+  COUNT
+};
+
 // Records the current |rolling_rssi| reading, upon a successful auth attempt.
 // |rolling_rssi| should be set to |kUnknownProximityValue| if no RSSI readings
 // are available.
 void RecordAuthProximityRollingRssi(int rolling_rssi);
 
 // Records the difference between the transmit power and maximum transmit power,
 // upon a successful auth attempt. |transmit_power_delta| should be set to
 // |kUnknownProximityValue| if no Tx power readings are available.
 void RecordAuthProximityTransmitPowerDelta(int transmit_power_delta);
 
 // Records the time elapsed since the last zero RSSI value was read, upon a
 // successful auth attempt.
 void RecordAuthProximityTimeSinceLastZeroRssi(
     base::TimeDelta time_since_last_zero_rssi);
 
 // Records the phone model used for a successful auth attempt. The model is
 // recorded as a 32-bit hash due to the limits of UMA. |device_model| should be
 // set to |kUnknownDeviceModel| if the device model could not be read.
 void RecordAuthProximityRemoteDeviceModelHash(const std::string& device_model);
 
+// Records the screen lock and trust agent settings state of the remote device,
+// as received in a status update from the remote device.
+void RecordRemoteSecuritySettingsState(RemoteSecuritySettingsState state);
+
 }  // namespace metrics
 }  // namespace proximity_auth
 
 #endif  // COMPONENTS_PROXIMITY_AUTH_METRICS_H