Bluetooth: macOS: DidModifyServices can happens while scanning

device/bluetooth/test/bluetooth_test_mac.mm

Index: device/bluetooth/test/bluetooth_test_mac.mm
diff --git a/device/bluetooth/test/bluetooth_test_mac.mm b/device/bluetooth/test/bluetooth_test_mac.mm
index 777e91339cf66d8d512b200378f7e9f0ebc7f116..593179edf1f7d37ddbfdd4c87069ed6bb1b7c998 100644
--- a/device/bluetooth/test/bluetooth_test_mac.mm
+++ b/device/bluetooth/test/bluetooth_test_mac.mm
@@ -377,7 +377,7 @@ void BluetoothTestMac::SimulateGattDescriptor(
   MockCBCharacteristic* characteristic_mock =
       GetCBMockCharacteristic(characteristic);
   CBUUID* cb_uuid = [CBUUID UUIDWithString:@(uuid.c_str())];
-  [characteristic_mock simulateDescriptorWithUUID:cb_uuid];
+  [characteristic_mock addDescriptorWithUUID:cb_uuid];
   MockCBPeripheral* peripheral_mock = GetMockCBPeripheral(characteristic);
   [peripheral_mock didModifyServices:@[]];
   // After -[MockCBPeripheral didModifyServices:], BluetoothLowEnergyDeviceMac
@@ -463,13 +463,64 @@ void BluetoothTestMac::ExpectedNotifyValue(
   }
 }
 
-void BluetoothTestMac::SimulateDidDiscoverServices(
-    BluetoothDevice* device,
-    const std::vector<std::string>& uuids) {
-  AddServicesToDevice(device, uuids);
+void BluetoothTestMac::SimulateDidDiscoverServices(BluetoothDevice* device) {
   [GetMockCBPeripheral(device) mockDidDiscoverServices];
 }
 
+void BluetoothTestMac::SimulateDidDiscoverCharacteristics(
+    BluetoothRemoteGattService* service) {
+  BluetoothRemoteGattServiceMac* mac_gatt_service =
+      static_cast<BluetoothRemoteGattServiceMac*>(service);
+  CBService* cb_service = mac_gatt_service->GetService();
+  [GetMockCBPeripheral(service)
+      mockDidDiscoverCharacteristicsForService:cb_service];
+}
+
+void BluetoothTestMac::SimulateDidDiscoverDescriptors(
+    BluetoothRemoteGattCharacteristic* characteristic) {
+  BluetoothRemoteGattCharacteristicMac* mac_gatt_characteristic =
+      static_cast<BluetoothRemoteGattCharacteristicMac*>(characteristic);
+  CBCharacteristic* cb_characteristic =
+      mac_gatt_characteristic->GetCBCharacteristic();
+  [GetMockCBPeripheral(characteristic)
+      mockDidDiscoverDescriptorsForCharacteristic:cb_characteristic];
+}
+
+void BluetoothTest::AddServicesToDevice(BluetoothDevice* device,
+                                        const std::vector<std::string>& uuids) {
+  scoped_nsobject<NSMutableArray> services([[NSMutableArray alloc] init]);
+  for (auto uuid : uuids) {
+    CBUUID* cb_service_uuid = [CBUUID UUIDWithString:@(uuid.c_str())];
+    [services addObject:cb_service_uuid];
+  }
+  [GetMockCBPeripheral(device) addServices:services];
+}
+
+void BluetoothTestMac::AddCharacteristicToService(
+    BluetoothRemoteGattService* service,
+    const std::string& characteristic_uuid,
+    int properties) {
+  BluetoothRemoteGattServiceMac* mac_gatt_service =
+      static_cast<BluetoothRemoteGattServiceMac*>(service);
+  CBService* cb_service = mac_gatt_service->GetService();
+  MockCBService* service_mock = ObjCCast<MockCBService>(cb_service);
+  CBUUID* cb_uuid = [CBUUID UUIDWithString:@(characteristic_uuid.c_str())];
+  [service_mock addCharacteristicWithUUID:cb_uuid properties:properties];
+}
+
+void BluetoothTestMac::AddDescriptorToCharacteristic(
+    BluetoothRemoteGattCharacteristic* characteristic,
+    const std::string& uuid) {
+  BluetoothRemoteGattCharacteristicMac* mac_gatt_characteristic =
+      static_cast<BluetoothRemoteGattCharacteristicMac*>(characteristic);
+  CBCharacteristic* cb_characteristic =
+      mac_gatt_characteristic->GetCBCharacteristic();
+  MockCBCharacteristic* characteristic_mock =
+      ObjCCast<MockCBCharacteristic>(cb_characteristic);
+  CBUUID* cb_uuid = [CBUUID UUIDWithString:@(uuid.c_str())];
+  [characteristic_mock addDescriptorWithUUID:cb_uuid];
+}
+
 void BluetoothTestMac::OnFakeBluetoothDeviceConnectGattCalled() {
   gatt_connection_attempts_++;
 }
@@ -550,16 +601,6 @@ MockCBCharacteristic* BluetoothTest::GetCBMockCharacteristic(
   return ObjCCast<MockCBCharacteristic>(cb_characteristic);
 }
 
-void BluetoothTest::AddServicesToDevice(BluetoothDevice* device,
-                                        const std::vector<std::string>& uuids) {
-  scoped_nsobject<NSMutableArray> services([[NSMutableArray alloc] init]);
-  for (auto uuid : uuids) {
-    CBUUID* cb_service_uuid = [CBUUID UUIDWithString:@(uuid.c_str())];
-    [services addObject:cb_service_uuid];
-  }
-  [GetMockCBPeripheral(device) addServices:services];
-}
-
 // Utility function for generating new (CBUUID, address) pairs where CBUUID
 // hashes to address. For use when adding a new device address to the testing
 // suite because CoreBluetooth peripherals have CBUUIDs in place of addresses,