[Doodle] Make DoodleService a KeyedService and add a factory

components/doodle/doodle_service.h

 // Copyright 2017 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 COMPONENTS_DOODLE_DOODLE_SERVICE_H_
 #define COMPONENTS_DOODLE_DOODLE_SERVICE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/optional.h"
 #include "base/time/clock.h"
 #include "base/timer/timer.h"
 #include "components/doodle/doodle_fetcher.h"
 #include "components/doodle/doodle_types.h"
+#include "components/keyed_service/core/keyed_service.h"
 
 class PrefRegistrySimple;
 class PrefService;
 
 namespace base {
 class TimeDelta;
 }
 
 namespace doodle {
 
-class DoodleService {
+class DoodleService : public KeyedService {
  public:
   class Observer {
    public:
     virtual void OnDoodleConfigUpdated(const base::Optional<DoodleConfig>&) = 0;
   };
 
   static void RegisterProfilePrefs(PrefRegistrySimple* pref_registry);
 
   // All parameters must be non-null.
   DoodleService(PrefService* pref_service,
                 std::unique_ptr<DoodleFetcher> fetcher,
                 std::unique_ptr<base::OneShotTimer> expiry_timer,
                 std::unique_ptr<base::Clock> clock);
-  ~DoodleService();
+  ~DoodleService() override;
+
+  // KeyedService implementation.
+  void Shutdown() override;
 
   // Returns the current (cached) config, if any.
   const base::Optional<DoodleConfig>& config() const { return cached_config_; }
 
   // Adds a new observer to the service. It'll only be called when the config
   // changes; to get the current (cached) config, call |config()|.
   void AddObserver(Observer* observer);
 
   // Prevents |observer| from receiving future updates. This is safe to call
   // even when the observer is being notified of an update.
@@ skipping 29 matching lines @@
 
   // The list of observers to be notified when the DoodleConfig changes.
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(DoodleService);
 };
 
 }  // namespace doodle
 
 #endif  // COMPONENTS_DOODLE_DOODLE_SERVICE_H_