Notify the BluetoothAdapter::Observer when a bluetooth peripheral disconnects on Android and Mac.

device/bluetooth/bluez/bluetooth_adapter_bluez.cc

Index: device/bluetooth/bluez/bluetooth_adapter_bluez.cc
diff --git a/device/bluetooth/bluez/bluetooth_adapter_bluez.cc b/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
index 0ab81e4746454401a5ec801f07e6a28784da5664..b228200cbf7bb51821da301a98f075604e83e354 100644
--- a/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
+++ b/device/bluetooth/bluez/bluetooth_adapter_bluez.cc
@@ -989,14 +989,6 @@ void BluetoothAdapterBlueZ::PresentChanged(bool present) {
                     AdapterPresentChanged(this, present));
 }
 
-void BluetoothAdapterBlueZ::NotifyDeviceChanged(BluetoothDeviceBlueZ* device) {
-  DCHECK(device);
-  DCHECK(device->adapter_ == this);
-
-  FOR_EACH_OBSERVER(BluetoothAdapter::Observer, observers_,
-                    DeviceChanged(this, device));
-}
-
 void BluetoothAdapterBlueZ::NotifyDeviceAddressChanged(
     BluetoothDeviceBlueZ* device,
     const std::string& old_address) {