bluetooth: Refactor (Add|Remove)Observer impls into BluetoothAdapter.

device/bluetooth/bluetooth_adapter_win.h

 // Copyright (c) 2012 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 DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_WIN_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_WIN_H_
 
 #include <hash_set>
 #include <set>
 #include <string>
@@ skipping 23 matching lines @@
 class BluetoothSocketThread;
 
 class DEVICE_BLUETOOTH_EXPORT BluetoothAdapterWin
     : public BluetoothAdapter,
       public BluetoothTaskManagerWin::Observer {
  public:
   static base::WeakPtr<BluetoothAdapter> CreateAdapter(
       const InitCallback& init_callback);
 
   // BluetoothAdapter:
-  virtual void AddObserver(BluetoothAdapter::Observer* observer) override;
-  virtual void RemoveObserver(BluetoothAdapter::Observer* observer) override;
   virtual std::string GetAddress() const override;
   virtual std::string GetName() const override;
   virtual void SetName(const std::string& name,
                        const base::Closure& callback,
                        const ErrorCallback& error_callback) override;
   virtual bool IsInitialized() const override;
   virtual bool IsPresent() const override;
   virtual bool IsPowered() const override;
   virtual void SetPowered(
       bool discoverable,
@@ skipping 89 matching lines @@
       on_start_discovery_callbacks_;
   std::vector<base::Closure> on_stop_discovery_callbacks_;
   size_t num_discovery_listeners_;
 
   scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
   scoped_refptr<BluetoothSocketThread> socket_thread_;
   scoped_refptr<BluetoothTaskManagerWin> task_manager_;
 
   base::ThreadChecker thread_checker_;
 
-  // List of observers interested in event notifications from us.
-  ObserverList<BluetoothAdapter::Observer> observers_;
-
   // NOTE: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<BluetoothAdapterWin> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothAdapterWin);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_WIN_H_