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

chromeos/dbus/power_manager_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/power_manager_client.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 206 matching lines @@
   }
 
   virtual void RequestActiveNotification() OVERRIDE {
     RequestIdleNotification(0);
   }
 
   virtual void RequestPowerStateOverrides(
       uint32 request_id,
       uint32 duration,
       int overrides,
-      PowerStateRequestIdCallback callback) OVERRIDE {
+      const PowerStateRequestIdCallback& callback) OVERRIDE {
     dbus::MethodCall method_call(power_manager::kPowerManagerInterface,
                                  power_manager::kStateOverrideRequest);
     dbus::MessageWriter writer(&method_call);
 
     PowerStateControl protobuf;
     protobuf.set_request_id(request_id);
     protobuf.set_duration(duration);
     protobuf.set_disable_idle_dim(overrides & DISABLE_IDLE_DIM);
     protobuf.set_disable_idle_blank(overrides & DISABLE_IDLE_BLANK);
     protobuf.set_disable_idle_suspend(overrides & DISABLE_IDLE_SUSPEND);
@@ skipping 299 matching lines @@
       OVERRIDE {
     callback.Run(0);
   }
 
   virtual void RequestIdleNotification(int64 threshold) OVERRIDE {}
   virtual void RequestActiveNotification() OVERRIDE {}
   virtual void RequestPowerStateOverrides(
       uint32 request_id,
       uint32 duration,
       int overrides,
-      PowerStateRequestIdCallback callback) OVERRIDE {}
+      const PowerStateRequestIdCallback& callback) OVERRIDE {}
 
   virtual void NotifyScreenLockRequested() OVERRIDE {
     FOR_EACH_OBSERVER(Observer, observers_, LockScreen());
   }
   virtual void NotifyScreenLockCompleted() OVERRIDE {}
   virtual void NotifyScreenUnlockRequested() OVERRIDE {
     FOR_EACH_OBSERVER(Observer, observers_, UnlockScreen());
   }
 
   virtual void NotifyScreenUnlockCompleted() OVERRIDE {}
@@ skipping 50 matching lines @@
 PowerManagerClient* PowerManagerClient::Create(
     DBusClientImplementationType type,
     dbus::Bus* bus) {
   if (type == REAL_DBUS_CLIENT_IMPLEMENTATION)
     return new PowerManagerClientImpl(bus);
   DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
   return new PowerManagerClientStubImpl();
 }
 
 }  // namespace chromeos