Replace base::CallbackList with base::ObserverList in CastConfigDelegate

ash/system/cast/tray_cast.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 ASH_SYSTEM_CAST_TRAY_CAST_H_
 #define ASH_SYSTEM_CAST_TRAY_CAST_H_
 
 #include "ash/cast_config_delegate.h"
 #include "ash/shell_observer.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "base/macros.h"
-#include "base/memory/weak_ptr.h"
 
 namespace ash {
 namespace tray {
 class CastTrayView;
 class CastSelectDefaultView;
 class CastDetailedView;
 class CastDuplexView;
 }  // namespace tray
 
-class ASH_EXPORT TrayCast : public SystemTrayItem, public ShellObserver {
+class ASH_EXPORT TrayCast : public SystemTrayItem,
+                            public ShellObserver,
+                            public CastConfigDelegate::Observer {
  public:
   explicit TrayCast(SystemTray* system_tray);
   ~TrayCast() override;
 
  private:
   // Helper/utility methods for testing.
   friend class TrayCastTestAPI;
   void StartCastForTest(const std::string& receiver_id);
   void StopCastForTest();
   // Returns the id of the item we are currently displaying in the cast view.
   // This assumes that the cast view is active.
   const std::string& GetDisplayedCastId();
   const views::View* GetDefaultView() const;
   enum ChildViewId { TRAY_VIEW = 1, SELECT_VIEW, CAST_VIEW };
 
   // Overridden from SystemTrayItem.
   views::View* CreateTrayView(user::LoginStatus status) override;
   views::View* CreateDefaultView(user::LoginStatus status) override;
   views::View* CreateDetailedView(user::LoginStatus status) override;
   void DestroyTrayView() override;
   void DestroyDefaultView() override;
   void DestroyDetailedView() override;
   void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) override;
 
   // Overridden from ShellObserver.
   void OnCastingSessionStartedOrStopped(bool started) override;
 
+  // Overridden from CastConfigDelegate::Observer.
+  void OnDevicesUpdated(
+      const CastConfigDelegate::ReceiversAndActivities& devices) override;
+
   // Returns true if the cast extension was detected.
   bool HasCastExtension();
 
-  // Callback used to enable/disable the begin casting view depending on
-  // if we have any cast receivers.
-  void OnReceiversUpdated(
-      const CastConfigDelegate::ReceiversAndActivities& receivers_activities);
-
   // This makes sure that the current view displayed in the tray is the correct
   // one, depending on if we are currently casting. If we're casting, then a
   // view with a stop button is displayed; otherwise, a view that links to a
   // detail view is displayed instead that allows the user to easily begin a
   // casting session.
   void UpdatePrimaryView();
 
   CastConfigDelegate::ReceiversAndActivities receivers_and_activities_;
-  CastConfigDelegate::DeviceUpdateSubscription device_update_subscription_;
   bool is_casting_ = false;
 
+  bool added_observer_ = false;
+
   // Not owned.
   tray::CastTrayView* tray_ = nullptr;
   tray::CastDuplexView* default_ = nullptr;
   tray::CastDetailedView* detailed_ = nullptr;
 
-  base::WeakPtrFactory<TrayCast> weak_ptr_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(TrayCast);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CAST_TRAY_CAST_H_