device/bluetooth: Move GATT observer methods to BluetoothAdapter::Observer.

device/bluetooth/bluetooth_device_mac.mm

Index: device/bluetooth/bluetooth_device_mac.mm
diff --git a/device/bluetooth/bluetooth_device_mac.mm b/device/bluetooth/bluetooth_device_mac.mm
index a913300837784744b83df7a3a76c380cae546ac4..888ae69adcd759843984a901367e3cbd40c828ae 100644
--- a/device/bluetooth/bluetooth_device_mac.mm
+++ b/device/bluetooth/bluetooth_device_mac.mm
@@ -63,18 +63,6 @@ BluetoothDeviceMac::BluetoothDeviceMac(IOBluetoothDevice* device)
 BluetoothDeviceMac::~BluetoothDeviceMac() {
 }
 
-void BluetoothDeviceMac::AddObserver(
-    device::BluetoothDevice::Observer* observer) {
-  DCHECK(observer);
-  observers_.AddObserver(observer);
-}
-
-void BluetoothDeviceMac::RemoveObserver(
-    device::BluetoothDevice::Observer* observer) {
-  DCHECK(observer);
-  observers_.RemoveObserver(observer);
-}
-
 uint32 BluetoothDeviceMac::GetBluetoothClass() const {
   return [device_ classOfDevice];
 }