dbus: Stop accessing ObjectProxy::name_owner_changed_callback_ on the D-Bus thread

dbus/signal_sender_verification_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 "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_samples.h"
 #include "base/metrics/statistics_recorder.h"
@@ skipping 102 matching lines @@
         FROM_HERE,
         base::Bind(&SignalSenderVerificationTest::OnOwnershipInternal,
                    base::Unretained(this)));
   }
 
   void OnOwnershipInternal() {
     on_ownership_called_ = true;
     message_loop_.Quit();
   }
 
-  void OnNameOwnerChanged(bool* called_flag, Signal* signal) {
-    MessageReader reader(signal);
-    std::string name, old_owner, new_owner;
-    ASSERT_TRUE(reader.PopString(&name));
-    ASSERT_TRUE(reader.PopString(&old_owner));
-    ASSERT_TRUE(reader.PopString(&new_owner));
+  void OnNameOwnerChanged(bool* called_flag,
+                          const std::string& old_owner,
+                          const std::string& new_owner) {
     latest_name_owner_ = new_owner;
     *called_flag = true;
     message_loop_.Quit();
   }
 
   // Called when the "Test" signal is received, in the main thread.
   // Copy the string payload to |test_signal_string_|.
   void OnTestSignal(Signal* signal) {
     MessageReader reader(signal);
     ASSERT_TRUE(reader.PopString(&test_signal_string_));
@@ skipping 236 matching lines @@
 
   // Now the second service owns the name.
   const char kNewMessage[] = "hello, new world";
 
   test_service2_->SendTestSignal(kNewMessage);
   WaitForTestSignal();
   ASSERT_EQ(kNewMessage, test_signal_string_);
 }
 
 }  // namespace dbus