Mac: Make ScopedTypeRef require explicit constructors

device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "device/bluetooth/test/mock_bluetooth_cbperipheral_mac.h"
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
 #include "device/bluetooth/test/bluetooth_test_mac.h"
 #include "device/bluetooth/test/mock_bluetooth_cbservice_mac.h"
@@ skipping 58 matching lines @@
   if (aClass == [CBPeripheral class] ||
       [aClass isSubclassOfClass:[CBPeripheral class]]) {
     return YES;
   }
   return [super isKindOfClass:aClass];
 }
 
 - (void)setState:(CBPeripheralState)state {
   _state = state;
   if (_state == CBPeripheralStateDisconnected) {
-    _services = nil;
+    _services.reset();
   }
 }
 
 - (void)discoverServices:(NSArray*)serviceUUIDs {
   if (_bluetoothTestMac) {
     _bluetoothTestMac->OnFakeBluetoothServiceDiscovery();
   }
 }
 
 - (void)removeAllServices {
@@ skipping 41 matching lines @@
 
 - (NSArray*)services {
   return _services.get();
 }
 
 - (CBPeripheral*)peripheral {
   return ObjCCast<CBPeripheral>(self);
 }
 
 @end