Hook up AppLifeTimeManager::Observer to turn off discoverability for Smart Lock.

chrome/browser/signin/easy_unlock_service.cc

Index: chrome/browser/signin/easy_unlock_service.cc
diff --git a/chrome/browser/signin/easy_unlock_service.cc b/chrome/browser/signin/easy_unlock_service.cc
index e974e90cbe89852cd55abf00c4a878d58bc0e882..74b3da4b63ea76d67589f8f73afe9ba837a5e57b 100644
--- a/chrome/browser/signin/easy_unlock_service.cc
+++ b/chrome/browser/signin/easy_unlock_service.cc
@@ -90,11 +90,15 @@ class EasyUnlockService::BluetoothDetector
   explicit BluetoothDetector(EasyUnlockService* service)
       : service_(service),
         weak_ptr_factory_(this) {
+    apps::AppLifetimeMonitorFactory::GetForProfile(service_->profile())
+        ->AddObserver(this);
   }
 
   ~BluetoothDetector() override {
     if (adapter_.get())
       adapter_->RemoveObserver(this);
+    apps::AppLifetimeMonitorFactory::GetForProfile(service_->profile())
+        ->RemoveObserver(this);
   }
 
   void Initialize() {