Adding pref to store the user-selected proximity threshold.

components/proximity_auth/unlock_manager_impl.cc

Index: components/proximity_auth/unlock_manager_impl.cc
diff --git a/components/proximity_auth/unlock_manager_impl.cc b/components/proximity_auth/unlock_manager_impl.cc
index 92afbacee4338f8f51a3897338f6f18cf1d18196..7aece06ab96d2347b4100ee15981678b999241f7 100644
--- a/components/proximity_auth/unlock_manager_impl.cc
+++ b/components/proximity_auth/unlock_manager_impl.cc
@@ -158,7 +158,8 @@ void UnlockManagerImpl::OnLifeCycleStateChanged() {
   if (state == RemoteDeviceLifeCycle::State::SECURE_CHANNEL_ESTABLISHED) {
     DCHECK(life_cycle_->GetConnection());
     DCHECK(GetMessenger());
-    proximity_monitor_ = CreateProximityMonitor(life_cycle_->GetConnection());
+    proximity_monitor_ = CreateProximityMonitor(
+        life_cycle_->GetConnection(), proximity_auth_client_->GetPrefService());
     GetMessenger()->AddObserver(this);
   }
 
@@ -326,9 +327,10 @@ void UnlockManagerImpl::OnAuthAttempted(mojom::AuthType auth_type) {
 }
 
 std::unique_ptr<ProximityMonitor> UnlockManagerImpl::CreateProximityMonitor(
-    cryptauth::Connection* connection) {
+    cryptauth::Connection* connection,
+    PrefService* pref_service) {
   return base::MakeUnique<ProximityMonitorImpl>(
-      connection, base::WrapUnique(new base::DefaultTickClock()));
+      connection, base::WrapUnique(new base::DefaultTickClock()), pref_service);
 }
 
 void UnlockManagerImpl::SendSignInChallenge() {