Support multiple Observer instances for ArcSupportHost.

chrome/browser/chromeos/arc/arc_support_host.h

 // Copyright 2016 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_CHROMEOS_ARC_ARC_SUPPORT_HOST_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_SUPPORT_HOST_H_
 
 #include <memory>
+#include <string>
 
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "chrome/browser/chromeos/arc/extensions/arc_support_message_host.h"
 #include "extensions/browser/api/messaging/native_message_host.h"
 #include "ui/display/display_observer.h"
 
 class Profile;
 
 // Native interface to control ARC support chrome App.
 // TODO(hidehiko,lhchavez): Move this into extensions/ directory, and put it
 // into "arc" namespace. Add unittests at the time.
 class ArcSupportHost : public arc::ArcSupportMessageHost::Observer,
@@ skipping 18 matching lines @@
     SERVER_COMMUNICATION_ERROR,
     ANDROID_MANAGEMENT_REQUIRED_ERROR,
   };
 
   // Observer to notify UI event.
   class Observer {
    public:
     virtual ~Observer() = default;
 
     // Called when the ARC support window is closed.
-    virtual void OnWindowClosed() = 0;
+    virtual void OnWindowClosed() {}
 
     // Called when the user press AGREE button on ToS page.
     // TODO(hidehiko): Currently, due to implementation reason,
     // this is also called when RETRY on error page is clicked. Fix this.
     virtual void OnTermsAgreed(bool is_metrics_enabled,
                                bool is_backup_and_restore_enabled,
-                               bool is_location_service_enabled) = 0;
+                               bool is_location_service_enabled) {}
 
     // Called when LSO auth token fetch is successfully completed.
-    virtual void OnAuthSucceeded(const std::string& auth_code) = 0;
+    virtual void OnAuthSucceeded(const std::string& auth_code) {}
 
     // Called when "RETRY" button on the error page is clicked.
-    virtual void OnRetryClicked() = 0;
+    virtual void OnRetryClicked() {}
 
     // Called when send feedback button on error page is clicked.
-    virtual void OnSendFeedbackClicked() = 0;
+    virtual void OnSendFeedbackClicked() {}
   };
 
   static const char kHostAppId[];
   static const char kStorageId[];
 
   explicit ArcSupportHost(Profile* profile);
   ~ArcSupportHost() override;
 
-  // Currently only one observer can be added.
-  // TODO(hidehiko): Support RemoveObserver. Support multiple observer.
   void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+  bool HasObserver(Observer* observer);
 
   // Called when the communication to arc_support Chrome App is ready.
   void SetMessageHost(arc::ArcSupportMessageHost* message_host);
 
   // Called when the communication to arc_support Chrome App is closed.
   // The argument message_host is used to check if the given |message_host|
   // is what this instance uses know, to avoid racy case.
   // If |message_host| is different from the one this instance knows,
   // this is no op.
   void UnsetMessageHost(arc::ArcSupportMessageHost* message_host);
@@ skipping 60 matching lines @@
   //   'enabled': is_enabled,
   //   'managed': is_managed
   // }
   void SendPreferenceCheckboxUpdate(const std::string& action_name,
                                     const PreferenceCheckboxData& data);
 
   void DisconnectMessageHost();
 
   Profile* const profile_;
 
-  // Currently Observer is only ArcAuthService, so it is unique.
-  // Use ObserverList when more classes start to observe it.
-  Observer* observer_ = nullptr;
+  base::ObserverList<Observer> observer_list_;
 
   // True, if ARC support app is requested to start, but the connection is not
   // yet established. Reset to false, when the app is started and the
   // connection to the app is established.
   bool app_start_pending_ = false;
 
   // The instance is created and managed by Chrome.
   arc::ArcSupportMessageHost* message_host_ = nullptr;
 
   // The lifetime of the message_host_ is out of control from ARC.
   // Fields below are UI parameter cache in case the value is set before
   // connection to the ARC support Chrome app is established.
   UIPage ui_page_ = UIPage::NO_PAGE;
 
   // These have valid values iff ui_page_ == ERROR.
   Error error_;
   bool should_show_send_feedback_;
 
   bool is_arc_managed_ = false;
 
   PreferenceCheckboxData metrics_checkbox_;
   PreferenceCheckboxData backup_and_restore_checkbox_;
   PreferenceCheckboxData location_services_checkbox_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcSupportHost);
 };
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_SUPPORT_HOST_H_