Adding pref to store the user-selected proximity threshold.

components/proximity_auth/proximity_monitor_impl.h

Index: components/proximity_auth/proximity_monitor_impl.h
diff --git a/components/proximity_auth/proximity_monitor_impl.h b/components/proximity_auth/proximity_monitor_impl.h
index 1aebd2ed06ef542ae8861cf48c9df031cb50330b..61d7e3b7c145a923bc8ff26ea6cf31d5c3580985 100644
--- a/components/proximity_auth/proximity_monitor_impl.h
+++ b/components/proximity_auth/proximity_monitor_impl.h
@@ -16,6 +16,8 @@
 #include "components/proximity_auth/proximity_monitor.h"
 #include "device/bluetooth/bluetooth_device.h"
 
+class PrefService;
+
 namespace base {
 class TickClock;
 }
@@ -33,7 +35,8 @@ class ProximityMonitorImpl : public ProximityMonitor {
  public:
   // The |connection| is not owned, and must outlive |this| instance.
   ProximityMonitorImpl(cryptauth::Connection* connection,
-                       std::unique_ptr<base::TickClock> clock);
+                       std::unique_ptr<base::TickClock> clock,
+                       PrefService* pref_service);
   ~ProximityMonitorImpl() override;
 
   // ProximityMonitor:
@@ -82,6 +85,10 @@ class ProximityMonitorImpl : public ProximityMonitor {
   // samples. Notifies |observers_| on a change.
   void CheckForProximityStateChange();
 
+  // Gets the user-selected proximity threshold and converts it to a
+  // RSSI value.
+  void GetRssiThresholdFromPrefs();
+
   // The current connection being monitored. Not owned and must outlive this
   // instance.
   cryptauth::Connection* connection_;
@@ -100,6 +107,9 @@ class ProximityMonitorImpl : public ProximityMonitor {
   // for proximity to the remote device.
   bool is_active_;
 
+  // When the RSSI is below this value the phone the unlock is not allowed.
+  int rssi_threshold_;
+
   // 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
@@ -109,6 +119,10 @@ class ProximityMonitorImpl : public ProximityMonitor {
   // Used to access non-decreasing time measurements.
   std::unique_ptr<base::TickClock> clock_;
 
+  // Contains perferences that outlive the lifetime of this object and across
+  // process restarts. Not owned and must outlive this instance.
+  PrefService* pref_service_;
+
   // 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.