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

device/bluetooth/bluetooth_channel_mac.mm

Index: device/bluetooth/bluetooth_channel_mac.mm
diff --git a/device/bluetooth/bluetooth_channel_mac.mm b/device/bluetooth/bluetooth_channel_mac.mm
index 63b8f6843737a8152df28da7448442b075d23993..50f31b991fc3655445a1e9ccb4a49bf6dd129373 100644
--- a/device/bluetooth/bluetooth_channel_mac.mm
+++ b/device/bluetooth/bluetooth_channel_mac.mm
@@ -4,7 +4,10 @@
 
 #include "device/bluetooth/bluetooth_channel_mac.h"
 
+#import <IOBluetooth/IOBluetooth.h>
+
 #include "base/logging.h"
+#include "device/bluetooth/bluetooth_device_mac.h"
 
 namespace device {
 
@@ -19,4 +22,8 @@ void BluetoothChannelMac::SetSocket(BluetoothSocketMac* socket) {
   socket_ = socket;
 }
 
+std::string BluetoothChannelMac::GetDeviceAddress() {
+  return BluetoothDeviceMac::GetDeviceAddress(GetDevice());
+}
+
 }  // namespace device