chromeos: Convert D-Bus client classes' callback arguments to const reference

chromeos/dbus/flimflam_client_unittest_base.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 "chromeos/dbus/flimflam_client_unittest_base.h"
 
 #include "base/bind.h"
 #include "dbus/message.h"
 #include "dbus/object_path.h"
 #include "dbus/values_util.h"
@@ skipping 49 matching lines @@
   // ShutdownAndBlock() will be called in TearDown().
   EXPECT_CALL(*mock_bus_, ShutdownAndBlock()).WillOnce(Return());
 }
 
 void FlimflamClientUnittestBase::TearDown() {
   mock_bus_->ShutdownAndBlock();
 }
 
 void FlimflamClientUnittestBase::PrepareForMethodCall(
     const std::string& method_name,
-    ArgumentCheckCallback argument_checker,
+    const ArgumentCheckCallback& argument_checker,
     dbus::Response* response) {
   expected_method_name_ = method_name;
   argument_checker_ = argument_checker;
   response_ = response;
 }
 
 void FlimflamClientUnittestBase::SendPropertyChangedSignal(
     dbus::Signal* signal) {
   ASSERT_FALSE(property_changed_handler_.is_null());
   property_changed_handler_.Run(signal);
@@ skipping 59 matching lines @@
     const base::DictionaryValue* expected_result,
     DBusMethodCallStatus call_status,
     const base::DictionaryValue& result) {
   EXPECT_EQ(DBUS_METHOD_CALL_SUCCESS, call_status);
   EXPECT_TRUE(expected_result->Equals(&result));
 }
 
 void FlimflamClientUnittestBase::OnConnectToSignal(
     const std::string& interface_name,
     const std::string& signal_name,
-    dbus::ObjectProxy::SignalCallback signal_callback,
-    dbus::ObjectProxy::OnConnectedCallback on_connected_callback) {
+    const dbus::ObjectProxy::SignalCallback& signal_callback,
+    const dbus::ObjectProxy::OnConnectedCallback& on_connected_callback) {
   property_changed_handler_ = signal_callback;
   const bool success = true;
   message_loop_.PostTask(FROM_HERE,
                          base::Bind(on_connected_callback,
                                     interface_name,
                                     signal_name,
                                     success));
 }
 
 void FlimflamClientUnittestBase::OnCallMethod(
     dbus::MethodCall* method_call,
     int timeout_ms,
-    dbus::ObjectProxy::ResponseCallback response_callback) {
+    const dbus::ObjectProxy::ResponseCallback& response_callback) {
   EXPECT_EQ(interface_name_, method_call->GetInterface());
   EXPECT_EQ(expected_method_name_, method_call->GetMember());
   dbus::MessageReader reader(method_call);
   argument_checker_.Run(&reader);
   message_loop_.PostTask(FROM_HERE,
                          base::Bind(response_callback, response_));
 }
 
 }  // namespace chromeos