Remove usage of FOR_EACH_OBSERVER macro in device/

device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc

Index: device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc
diff --git a/device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc b/device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc
index 3c5591d0ff26d7582a42b5f809ffe307c99e535a..8ee318b1791ae719481681c94b754219523772d5 100644
--- a/device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc
+++ b/device/bluetooth/dbus/fake_bluetooth_gatt_service_client.cc
@@ -181,22 +181,22 @@ void FakeBluetoothGattServiceClient::OnPropertyChanged(
     const std::string& property_name) {
   VLOG(2) << "Fake GATT Service property changed: " << object_path.value()
           << ": " << property_name;
-  FOR_EACH_OBSERVER(BluetoothGattServiceClient::Observer, observers_,
-                    GattServicePropertyChanged(object_path, property_name));
+  for (auto& observer : observers_)
+    observer.GattServicePropertyChanged(object_path, property_name);
 }
 
 void FakeBluetoothGattServiceClient::NotifyServiceAdded(
     const dbus::ObjectPath& object_path) {
   VLOG(2) << "GATT service added: " << object_path.value();
-  FOR_EACH_OBSERVER(BluetoothGattServiceClient::Observer, observers_,
-                    GattServiceAdded(object_path));
+  for (auto& observer : observers_)
+    observer.GattServiceAdded(object_path);
 }
 
 void FakeBluetoothGattServiceClient::NotifyServiceRemoved(
     const dbus::ObjectPath& object_path) {
   VLOG(2) << "GATT service removed: " << object_path.value();
-  FOR_EACH_OBSERVER(BluetoothGattServiceClient::Observer, observers_,
-                    GattServiceRemoved(object_path));
+  for (auto& observer : observers_)
+    observer.GattServiceRemoved(object_path);
 }
 
 void FakeBluetoothGattServiceClient::ExposeHeartRateCharacteristics() {