Hook up new API for easy unlock to update lock screen

chrome/browser/signin/easy_unlock_service.h

 // Copyright 2014 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 CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_
 #define CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
+class EasyUnlockScreenlockStateHandler;
 class Profile;
 
 class EasyUnlockService : public KeyedService {
  public:
   explicit EasyUnlockService(Profile* profile);
   virtual ~EasyUnlockService();
 
   // Gets EasyUnlockService instance.
   static EasyUnlockService* Get(Profile* profile);
 
   // Registers Easy Unlock profile preferences.
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Launches Easy Unlock Setup app.
   void LaunchSetup();
 
   // Whether easy unlock is allowed to be used. If the controlling preference
   // is set (from policy), this returns the preference value. Otherwise, it is
   // permitted either the flag is enabled or its field trial is enabled.
   bool IsAllowed();
 
+  // Gets |screenlock_state_handler_|. Returns NULL if Easy Unlock is not
+  // allowed. Otherwise, if |screenlock_state_handler_| is not set, an instance
+  // is created. Do not cache the returned value, as it may go away if Easy
+  // Unlock gets disabled.
+  EasyUnlockScreenlockStateHandler* GetScreenlockStateHandler();
+
  private:
   void Initialize();
   void LoadApp();
   void UnloadApp();
   void OnPrefsChanged();
 
   Profile* profile_;
   PrefChangeRegistrar registrar_;
+  // Created lazily in |GetScreenlockStateHandler|.
+  scoped_ptr<EasyUnlockScreenlockStateHandler> screenlock_state_handler_;
   base::WeakPtrFactory<EasyUnlockService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EasyUnlockService);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_H_