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

device/bluetooth/bluetooth_adapter_mac.h

 // Copyright 2013 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_MAC_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_MAC_H_
 
 #include <IOKit/IOReturn.h>
 
 #include <string>
@@ skipping 23 matching lines @@
 
 class BluetoothAdapterMacTest;
 
 class DEVICE_BLUETOOTH_EXPORT BluetoothAdapterMac
     : public BluetoothAdapter,
       public BluetoothDiscoveryManagerMac::Observer {
  public:
   static base::WeakPtr<BluetoothAdapter> CreateAdapter();
 
   // BluetoothAdapter:
-  void AddObserver(BluetoothAdapter::Observer* observer) override;
-  void RemoveObserver(BluetoothAdapter::Observer* observer) override;
   std::string GetAddress() const override;
   std::string GetName() const override;
   void SetName(const std::string& name,
                const base::Closure& callback,
                const ErrorCallback& error_callback) override;
   bool IsInitialized() const override;
   bool IsPresent() const override;
   bool IsPowered() const override;
   void SetPowered(bool powered,
                   const base::Closure& callback,
@@ skipping 66 matching lines @@
   std::string name_;
   bool powered_;
 
   int num_discovery_sessions_;
 
   // Discovery manager for Bluetooth Classic.
   scoped_ptr<BluetoothDiscoveryManagerMac> classic_discovery_manager_;
 
   scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
 
-  // List of observers interested in event notifications from us.
-  ObserverList<BluetoothAdapter::Observer> observers_;
-
   base::WeakPtrFactory<BluetoothAdapterMac> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothAdapterMac);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_MAC_H_