arc-bridge: Introduce the ArcService class

components/arc/power/arc_power_bridge.cc

 // Copyright 2015 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 "components/arc/power/arc_power_bridge.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/logging.h"
 #include "chromeos/dbus/power_policy_controller.h"
 #include "components/arc/arc_service_manager.h"
 
 namespace arc {
 
 ArcPowerBridge::ArcPowerBridge(ArcBridgeService* arc_bridge_service)
     : arc_bridge_service_(arc_bridge_service), binding_(this) {
-  arc_bridge_service->AddObserver(this);
-  if (arc_bridge_service->power_instance())
+  DCHECK(arc_bridge_service_);
+  arc_bridge_service_->AddObserver(this);
+  if (arc_bridge_service_->power_instance())
     OnPowerInstanceReady();
 }
 
 ArcPowerBridge::~ArcPowerBridge() {
   arc_bridge_service_->RemoveObserver(this);
   ReleaseAllDisplayWakeLocks();
 }
 
 void ArcPowerBridge::OnStateChanged(ArcBridgeService::State state) {
   if (state == ArcBridgeService::State::STOPPING)
@@ skipping 69 matching lines @@
   chromeos::PowerPolicyController* controller =
       chromeos::PowerPolicyController::Get();
 
   for (const auto& it : wake_locks_) {
     controller->RemoveWakeLock(it.second);
   }
   wake_locks_.clear();
 }
 
 }  // namespace arc