Simplify ArcServiceManager by stop deriving it from ArcIntentHelperObserver

components/arc/arc_service_manager.h

 // Copyright 2015 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_ARC_ARC_SERVICE_MANAGER_H_
 #define COMPONENTS_ARC_ARC_SERVICE_MANAGER_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "components/arc/intent_helper/activity_icon_loader.h"
-#include "components/arc/intent_helper/arc_intent_helper_observer.h"
 #include "components/arc/intent_helper/local_activity_resolver.h"
 
 namespace arc {
 
 class ArcBridgeService;
+class ArcIntentHelperObserver;
 class ArcService;
 
 // Manages creation and destruction of services that communicate with the ARC
 // instance via the ArcBridgeService.
-class ArcServiceManager : public arc::ArcIntentHelperObserver {
+class ArcServiceManager {
  public:
   class Observer {
    public:
     // Called when app's intent filter is updated.
     virtual void OnAppsUpdated() = 0;
 
    protected:
     virtual ~Observer() = default;
   };
 
   explicit ArcServiceManager(
       scoped_refptr<base::TaskRunner> blocking_task_runner);
-  ~ArcServiceManager() override;
+  ~ArcServiceManager();
 
   // |arc_bridge_service| can only be accessed on the thread that this
   // class was created on.
   ArcBridgeService* arc_bridge_service();
 
   // Adds a service to the managed services list.
   void AddService(std::unique_ptr<ArcService> service);
 
   // Gets the global instance of the ARC Service Manager. This can only be
   // called on the thread that this class was created on.
   static ArcServiceManager* Get();
 
   // Returns if the ARC Service Manager instance exists.
   static bool IsInitialized();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
-  // arc::ArcIntentHelperObserver overrides.
-  void OnAppsUpdated() override;
-
   // Called to shut down all ARC services.
   void Shutdown();
 
   scoped_refptr<base::TaskRunner> blocking_task_runner() const {
     return blocking_task_runner_;
   }
 
   // Set ArcBridgeService instance for testing. Call before ArcServiceManager
   // creation. ArcServiceManager owns |arc_bridge_service|.
   static void SetArcBridgeServiceForTesting(
       std::unique_ptr<ArcBridgeService> arc_bridge_service);
 
   // Returns the icon loader owned by ArcServiceManager and shared by services.
   scoped_refptr<ActivityIconLoader> icon_loader() { return icon_loader_; }
 
   // Returns the activity resolver owned by ArcServiceManager.
   scoped_refptr<LocalActivityResolver> activity_resolver() {
     return activity_resolver_;
   }
 
+  // Returns the IntentHelperObserver instance owned by ArcServiceManager.
+  ArcIntentHelperObserver* intent_helper_observer() {
+    return intent_helper_observer_.get();
+  }
+
  private:
+  class IntentHelperObserverImpl;  // implemented in arc_service_manager.cc.

[hidehiko, 2016/12/14 09:06:08]

This can be just a standalone class in anonymous namespace in .cc file, IIUC.
Could you also read my comment in .cc file for member accessibility?

[Yusuke Sato, 2016/12/15 00:52:33]

Based on your second comment on the .cc side, I guess I can keep this as-is to
keep intent_helper_observer_ private. Please let me know if I'm missing
something.

[hidehiko, 2016/12/15 00:58:49]

Yes, I'm fine to skip this as well.

+
   base::ThreadChecker thread_checker_;
   scoped_refptr<base::TaskRunner> blocking_task_runner_;
 
+  // An object for observing the ArcIntentHelper instance in |services_|.
+  std::unique_ptr<ArcIntentHelperObserver> intent_helper_observer_;
+
   std::unique_ptr<ArcBridgeService> arc_bridge_service_;
   std::vector<std::unique_ptr<ArcService>> services_;
   scoped_refptr<ActivityIconLoader> icon_loader_;
   scoped_refptr<LocalActivityResolver> activity_resolver_;
 
   base::ObserverList<Observer> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcServiceManager);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_ARC_SERVICE_MANAGER_H_