Mac: Make ScopedTypeRef require explicit constructors

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 4a27f3be741b9b46614d225762a8a071b70e8f58..903dc53b0b026e2c525b82e41e301df7ff51d7c3 100644
--- a/device/bluetooth/test/bluetooth_test_mac.mm
+++ b/device/bluetooth/test/bluetooth_test_mac.mm
@@ -41,7 +41,8 @@ explicit ScopedMockCentralManager(MockCentralManager* mock_central_manager) {
 
 namespace {
 
-NSDictionary* CreateAdvertisementData(NSString* name, NSArray* uuids) {
+scoped_nsobject<NSDictionary> CreateAdvertisementData(NSString* name,
+                                                      NSArray* uuids) {
   NSMutableDictionary* advertisement_data =
       [NSMutableDictionary dictionaryWithDictionary:@{
         CBAdvertisementDataLocalNameKey : name,
@@ -52,7 +53,7 @@ explicit ScopedMockCentralManager(MockCentralManager* mock_central_manager) {
     [advertisement_data setObject:uuids
                            forKey:CBAdvertisementDataServiceUUIDsKey];
   }
-  return [advertisement_data retain];
+  return scoped_nsobject<NSDictionary>([advertisement_data retain]);
 }
 
 }  // namespace
@@ -229,7 +230,7 @@ explicit ScopedMockCentralManager(MockCentralManager* mock_central_manager) {
       static_cast<BluetoothLowEnergyDeviceMac*>(device);
   CBPeripheral* peripheral = device_mac->GetPeripheral();
   MockCBPeripheral* peripheral_mock = ObjCCast<MockCBPeripheral>(peripheral);
-  scoped_nsobject<NSMutableArray> services = [[NSMutableArray alloc] init];
+  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];