[Bluetooth] Improve the adapter's awareness of connected devices.

device/bluetooth/bluetooth_channel_mac.mm

 // Copyright 2014 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.
 
 #include "device/bluetooth/bluetooth_channel_mac.h"
 
+#import <IOBluetooth/IOBluetooth.h>
+
 #include "base/logging.h"
+#include "device/bluetooth/bluetooth_device_mac.h"
 
 namespace device {
 
 BluetoothChannelMac::BluetoothChannelMac() : socket_(NULL) {
 }
 
 BluetoothChannelMac::~BluetoothChannelMac() {
 }
 
 void BluetoothChannelMac::SetSocket(BluetoothSocketMac* socket) {
   DCHECK(!socket_);
   socket_ = socket;
 }
 
+std::string BluetoothChannelMac::GetDeviceAddress() {
+  return BluetoothDeviceMac::GetDeviceAddress(GetDevice());
+}
+
 }  // namespace device