Implements secure sockets on Mac OS with SecureTransport API

tests/standalone/io/secure_builtin_roots_test.dart

Index: tests/standalone/io/secure_builtin_roots_test.dart
diff --git a/tests/standalone/io/secure_builtin_roots_test.dart b/tests/standalone/io/secure_builtin_roots_test.dart
index 6cb85d655cf93094385fe517d5b5ce10f49d20a6..ce89d11aecabfe61ce8872fc272f4a5ba8af2916 100644
--- a/tests/standalone/io/secure_builtin_roots_test.dart
+++ b/tests/standalone/io/secure_builtin_roots_test.dart
@@ -13,7 +13,7 @@ Future testGoogleUrl(SecurityContext context, String outcome) async {
   // We need to use an external server that is backed by a
   // built-in root certificate authority.
   try {
-  // First, check if the lookup works.
+    // First, check if the lookup works.
     await InternetAddress.lookup('www.google.com');
     var request = await client.getUrl(Uri.parse('https://www.google.com'));
     request.followRedirects = false;