Hook up ProximityAuthSystem in EasyUnlockService.

chrome/browser/signin/easy_unlock_auth_attempt.cc

Index: chrome/browser/signin/easy_unlock_auth_attempt.cc
diff --git a/chrome/browser/signin/easy_unlock_auth_attempt.cc b/chrome/browser/signin/easy_unlock_auth_attempt.cc
index 9b82890ce93d815b901065c7efcdf6ee19b42990..922ec204b9220c65fd14d9951e1bcfdaebf33010 100644
--- a/chrome/browser/signin/easy_unlock_auth_attempt.cc
+++ b/chrome/browser/signin/easy_unlock_auth_attempt.cc
@@ -118,15 +118,7 @@ bool EasyUnlockAuthAttempt::Start() {
 
   state_ = STATE_RUNNING;
 
-  // We need this workaround for ProximityAuthBleSystem, which is already
-  // notified in EasyUnlockService. No notification is sent when only the
-  // |kEnableBluetoothLowEnergyDiscovery| flag is set, and
-  // |app_manager_->SendAuthAttemptEvent()| returns false. As a result, the auth
-  // attempt will always fail.
-  // TODO(sacomoto): Remove this when it's not needed anymore.
-  if (!app_manager_->SendAuthAttemptEvent() &&
-      !base::CommandLine::ForCurrentProcess()->HasSwitch(
-          proximity_auth::switches::kEnableBluetoothLowEnergyDiscovery)) {
+  if (!app_manager_->SendAuthAttemptEvent()) {
     Cancel(user_id_);
     return false;
   }