Remove remaining calls to deprecated MessageLoop methods.

remoting/protocol/authenticator_test_base.h

Index: remoting/protocol/authenticator_test_base.h
diff --git a/remoting/protocol/authenticator_test_base.h b/remoting/protocol/authenticator_test_base.h
index 16b4a14bac95507fef6c617fc52f04be45dae25b..32bd59b163abe9f7d04693334f32634cc7b7795a 100644
--- a/remoting/protocol/authenticator_test_base.h
+++ b/remoting/protocol/authenticator_test_base.h
@@ -50,8 +50,6 @@ class AuthenticatorTestBase : public testing::Test {
   void OnHostConnected(int error, std::unique_ptr<P2PStreamSocket> socket);
   void OnClientConnected(int error, std::unique_ptr<P2PStreamSocket> socket);
 
-  base::MessageLoop message_loop_;
-
   scoped_refptr<RsaKeyPair> key_pair_;
   std::string host_public_key_;
   std::string host_cert_;
@@ -66,6 +64,9 @@ class AuthenticatorTestBase : public testing::Test {
   std::unique_ptr<P2PStreamSocket> client_socket_;
   std::unique_ptr<P2PStreamSocket> host_socket_;
 
+ private:
+  base::MessageLoop message_loop_;
+
   DISALLOW_COPY_AND_ASSIGN(AuthenticatorTestBase);
 };