Refactor of Authenticator to allow it to ProcessMessage asynchronously and then call a callback

remoting/protocol/v2_authenticator_unittest.cc

 // Copyright (c) 2012 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 "remoting/protocol/v2_authenticator.h"
 
 #include "base/bind.h"
 #include "net/base/net_errors.h"
 #include "remoting/protocol/authenticator_test_base.h"
 #include "remoting/protocol/channel_authenticator.h"
@@ skipping 67 matching lines @@
   ASSERT_EQ(Authenticator::REJECTED, client_->state());
 
   // Change |client_| so that we can get the last message.
   reinterpret_cast<V2Authenticator*>(client_.get())->state_ =
       Authenticator::MESSAGE_READY;
 
   scoped_ptr<buzz::XmlElement> message(client_->GetNextMessage());
   ASSERT_TRUE(message.get());
 
   ASSERT_EQ(Authenticator::WAITING_MESSAGE, client_->state());
-  host_->ProcessMessage(message.get());
+  host_->ProcessMessage(message.get(), base::Bind(&base::DoNothing));
+  // This assumes that V2Authenticator::ProcessMessage runs synchronously.
   ASSERT_EQ(Authenticator::REJECTED, host_->state());
 }
 
 }  // namespace protocol
 }  // namespace remoting