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..c8957f5a7e68d0853960b917d0b425a39701aeed 100644
--- a/device/bluetooth/test/bluetooth_test_mac.mm
+++ b/device/bluetooth/test/bluetooth_test_mac.mm
@@ -41,18 +41,19 @@ explicit ScopedMockCentralManager(MockCentralManager* mock_central_manager) {
 
 namespace {
 
-NSDictionary* CreateAdvertisementData(NSString* name, NSArray* uuids) {
-  NSMutableDictionary* advertisement_data =
+scoped_nsobject<NSDictionary> CreateAdvertisementData(NSString* name,

[jlebel, 2016/06/01 02:50:01]

Nit: Since there is no question about retain/release now, this function can be
renamed to AdvertisementData()

[ccameron, 2016/06/02 23:11:18]

n/a now.

+                                                      NSArray* uuids) {
+  scoped_nsobject<NSMutableDictionary> advertisement_data(
       [NSMutableDictionary dictionaryWithDictionary:@{
         CBAdvertisementDataLocalNameKey : name,
         CBAdvertisementDataServiceDataKey : @{},
         CBAdvertisementDataIsConnectable : @(YES),
-      }];
+      }]);
   if (uuids) {
     [advertisement_data setObject:uuids
                            forKey:CBAdvertisementDataServiceUUIDsKey];
   }
-  return [advertisement_data retain];
+  return scoped_nsobject<NSDictionary>(advertisement_data);

[sky, 2016/06/01 03:35:33]

This seems weird. is there nothing like std::move for scoped_nsobject?

[ccameron, 2016/06/02 23:11:18]

This was a cast from NSMutableDictionary to its superclass NSDictionary.

I've changed this to a base::scoped_policy::RETAIN of the sub-class (see
comments from the thread).

 }
 
 }  // 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];