[EasyUnlock] Update ProximityMonitor to only check for RSSI proximity.

components/proximity_auth/proximity_monitor_impl.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_PROXIMITY_MONITOR_IMPL_H
 #define COMPONENTS_PROXIMITY_AUTH_PROXIMITY_MONITOR_IMPL_H
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "components/cryptauth/connection.h"
 #include "components/cryptauth/remote_device.h"
 #include "components/proximity_auth/proximity_monitor.h"
 #include "device/bluetooth/bluetooth_device.h"
 
 namespace base {
 class TickClock;
-class TimeTicks;
 }
 
 namespace device {
 class BluetoothAdapter;
 }
 
 namespace proximity_auth {
 
 class ProximityMonitorObserver;
 
 // The concrete implemenation of the proximity monitor interface.
 class ProximityMonitorImpl : public ProximityMonitor {
  public:
-  // The |observer| is not owned, and must outlive |this| instance.
-  ProximityMonitorImpl(const cryptauth::RemoteDevice& remote_device,
+  // The |connection| is not owned, and must outlive |this| instance.
+  ProximityMonitorImpl(cryptauth::Connection* connection,
                        std::unique_ptr<base::TickClock> clock);
   ~ProximityMonitorImpl() override;
 
   // ProximityMonitor:
   void Start() override;
   void Stop() override;
-  Strategy GetStrategy() const override;
   bool IsUnlockAllowed() const override;
-  bool IsInRssiRange() const override;
   void RecordProximityMetricsOnAuthSuccess() override;
   void AddObserver(ProximityMonitorObserver* observer) override;
   void RemoveObserver(ProximityMonitorObserver* observer) override;
 
- protected:
-  // Sets the proximity detection strategy. Exposed for testing.
-  // TODO(isherman): Stop exposing this for testing once prefs are properly
-  // hooked up.
-  virtual void SetStrategy(Strategy strategy);
-
  private:
-  struct TransmitPowerReading {
-    TransmitPowerReading(int transmit_power, int max_transmit_power);
-
-    // Returns true if |this| transmit power reading indicates proximity.
-    bool IsInProximity() const;
-
-    // The current transmit power.
-    int transmit_power;
-
-    // The maximum possible transmit power.
-    int max_transmit_power;
-  };
-
   // Callback for asynchronous initialization of the Bluetooth adpater.
   void OnAdapterInitialized(scoped_refptr<device::BluetoothAdapter> adapter);
 
   // Ensures that the app is periodically polling for the proximity status
   // between the remote and the local device iff it should be, based on the
   // current app state.
   void UpdatePollingState();
 
   // Performs a scheduled |UpdatePollingState()| operation. This method is
   // used to distinguish periodically scheduled calls to |UpdatePollingState()|
   // from event-driven calls, which should be handled differently.
   void PerformScheduledUpdatePollingState();
 
   // Returns |true| iff the app should be periodically polling for the proximity
   // status between the remote and the local device.
   bool ShouldPoll() const;
 
   // Polls the connection information.
   void Poll();
 
   // Callback to received the polled-for connection info.
   void OnConnectionInfo(
       const device::BluetoothDevice::ConnectionInfo& connection_info);
 
   // Resets the proximity state to |false|, and clears all member variables
   // tracking the proximity state.
   void ClearProximityState();
 
   // Updates the proximity state with a new |connection_info| sample of the
-  // current RSSI and Tx power, and the device's maximum Tx power.
+  // current RSSI.
   void AddSample(
       const device::BluetoothDevice::ConnectionInfo& connection_info);
 
   // Checks whether the proximity state has changed based on the current
   // samples. Notifies |observers_| on a change.
   void CheckForProximityStateChange();
 
-  // The remote device being monitored.
-  const cryptauth::RemoteDevice remote_device_;
+  // The current connection being monitored. Not owned and must outlive this
+  // instance.
+  cryptauth::Connection* connection_;
 
   // The observers attached to the ProximityMonitor.
   base::ObserverList<ProximityMonitorObserver> observers_;
 
   // The Bluetooth adapter that will be polled for connection info.
   scoped_refptr<device::BluetoothAdapter> bluetooth_adapter_;
 
-  // The strategy used to determine whether the remote device is in proximity.
-  Strategy strategy_;
-
   // Whether the remote device is currently in close proximity to the local
   // device.
   bool remote_device_is_in_proximity_;
 
   // Whether the proximity monitor is active, i.e. should possibly be scanning
   // for proximity to the remote device.
   bool is_active_;
 
   // The exponentailly weighted rolling average of the RSSI, used to smooth the
   // RSSI readings. Null if the monitor is inactive, has not recently observed
   // an RSSI reading, or the most recent connection info included an invalid
   // measurement.
   std::unique_ptr<double> rssi_rolling_average_;
 
-  // The last TX power reading. Null if the monitor is inactive, has not
-  // recently observed a TX power reading, or the most recent connection info
-  // included an invalid measurement.
-  std::unique_ptr<TransmitPowerReading> last_transmit_power_reading_;
-
-  // The timestamp of the last zero RSSI reading. An RSSI value of 0 is special
-  // because both devices adjust their transmit powers such that the RSSI is in
-  // this golden range, if possible. Null if the monitor is inactive, has not
-  // recently observed an RSSI reading, or the most recent connection info
-  // included an invalid measurement.
-  std::unique_ptr<base::TimeTicks> last_zero_rssi_timestamp_;
-
   // Used to access non-decreasing time measurements.
   std::unique_ptr<base::TickClock> clock_;
 
   // Used to vend weak pointers for polling. Using a separate factory for these
   // weak pointers allows the weak pointers to be invalidated when polling
   // stops, which effectively cancels the scheduled tasks.
   base::WeakPtrFactory<ProximityMonitorImpl> polling_weak_ptr_factory_;
 
   // Used to vend all other weak pointers.
   base::WeakPtrFactory<ProximityMonitorImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ProximityMonitorImpl);
 };
 
 }  // namespace proximity_auth
 
 #endif  // COMPONENTS_PROXIMITY_AUTH_PROXIMITY_MONITOR_IMPL_H