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

chromeos/dbus/image_burner_client.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/image_burner_client.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
@@ skipping 27 matching lines @@
         base::Bind(&ImageBurnerClientImpl::OnBurnProgressUpdate,
                    weak_ptr_factory_.GetWeakPtr()),
         base::Bind(&ImageBurnerClientImpl::OnSignalConnected,
                    weak_ptr_factory_.GetWeakPtr()));
   }
   virtual ~ImageBurnerClientImpl() {}
 
   // ImageBurnerClient override.
   virtual void BurnImage(const std::string& from_path,
                          const std::string& to_path,
-                         ErrorCallback error_callback) OVERRIDE {
+                         const ErrorCallback& error_callback) OVERRIDE {
     dbus::MethodCall method_call(imageburn::kImageBurnServiceInterface,
                                  imageburn::kBurnImage);
     dbus::MessageWriter writer(&method_call);
     writer.AppendString(from_path);
     writer.AppendString(to_path);
     proxy_->CallMethod(&method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
                        base::Bind(&ImageBurnerClientImpl::OnBurnImage,
                                   weak_ptr_factory_.GetWeakPtr(),
                                   error_callback));
   }
 
   // ImageBurnerClient override.
   virtual void SetEventHandlers(
-      BurnFinishedHandler burn_finished_handler,
-      BurnProgressUpdateHandler burn_progress_update_handler) OVERRIDE {
+      const BurnFinishedHandler& burn_finished_handler,
+      const BurnProgressUpdateHandler& burn_progress_update_handler) OVERRIDE {
     burn_finished_handler_ = burn_finished_handler;
     burn_progress_update_handler_ = burn_progress_update_handler;
   }
 
   // ImageBurnerClient override.
   virtual void ResetEventHandlers() OVERRIDE {
     burn_finished_handler_.Reset();
     burn_progress_update_handler_.Reset();
   }
 
@@ skipping 55 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ImageBurnerClientImpl);
 };
 
 // A stub implementaion of ImageBurnerClient.
 class ImageBurnerClientStubImpl : public ImageBurnerClient {
  public:
   ImageBurnerClientStubImpl() {}
   virtual ~ImageBurnerClientStubImpl() {}
   virtual void BurnImage(const std::string& from_path,
                          const std::string& to_path,
-                         ErrorCallback error_callback) OVERRIDE {}
+                         const ErrorCallback& error_callback) OVERRIDE {}
   virtual void SetEventHandlers(
-      BurnFinishedHandler burn_finished_handler,
-      BurnProgressUpdateHandler burn_progress_update_handler) OVERRIDE {}
+      const BurnFinishedHandler& burn_finished_handler,
+      const BurnProgressUpdateHandler& burn_progress_update_handler) OVERRIDE {}
   virtual void ResetEventHandlers() OVERRIDE {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ImageBurnerClientStubImpl);
 };
 
 }  // namespace
 
 ImageBurnerClient::ImageBurnerClient() {
 }
 
 ImageBurnerClient::~ImageBurnerClient() {
 }
 
 // static
 ImageBurnerClient* ImageBurnerClient::Create(DBusClientImplementationType type,
                                              dbus::Bus* bus) {
   if (type == REAL_DBUS_CLIENT_IMPLEMENTATION)
     return new ImageBurnerClientImpl(bus);
   DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
   return new ImageBurnerClientStubImpl();
 }
 
 }  // chromeos