Mac: Make ScopedTypeRef require explicit constructors

chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm

Index: chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm
diff --git a/chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm b/chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm
index 6ba5bb71f5c6c3226a1ce431ecd0e6d86f5cce42..ce2f5087bd39e5128d41643cd09207bd1e03b7b1 100644
--- a/chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm
+++ b/chrome/browser/local_discovery/service_discovery_client_mac_unittest.mm
@@ -140,7 +140,7 @@ void OnResolveComplete(
   ServiceResolverImplMac* resolver_impl =
       static_cast<ServiceResolverImplMac*>(resolver.get());
   resolver_impl->GetContainerForTesting()->SetServiceForTesting(
-      test_service.release());
+      base::scoped_nsobject<NSNetService>(test_service));

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

Is it worth a template like WrapUnique so we don't need the <class> everywhere?

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

This is a cast from scoped_nsobject<TestNSNetService> to
scoped_nsobject<NSNetService> -- a Wrap would be a good idea to add at some
point, but it wouldn't help here.

Now, because NSNetService is a superclass of TestNSNetService, one could argue
that this should not require an explicit cast. That seems to be to be a good
idea, but it should be implemented at the scoped_nsobject level, because only at
that level are we sure to have the same retain/release behavior.

   resolver->StartResolving();
 
   resolver_impl->GetContainerForTesting()->OnResolveUpdate(