arc: Pass auth token from Chrome to ARC instance.

chrome/browser/chromeos/arc/arc_auth_service_impl.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 "chrome/browser/chromeos/arc/arc_auth_service_impl.h"
 
 #include <utility>
 
+#include "components/arc/arc_service_manager.h"
+#include "components/arc/opt_in/arc_opt_in_manager.h"
+
 namespace arc {
 
 ArcAuthServiceImpl::ArcAuthServiceImpl() : binding_(this) {}
 
 ArcAuthServiceImpl::~ArcAuthServiceImpl() {
   ArcBridgeService::Get()->RemoveObserver(this);
 }
 
 void ArcAuthServiceImpl::StartObservingBridgeServiceChanges() {
   ArcBridgeService::Get()->AddObserver(this);
 }
 
 void ArcAuthServiceImpl::OnAuthInstanceReady() {
   arc::AuthHostPtr host;
   binding_.Bind(GetProxy(&host));
   ArcBridgeService::Get()->auth_instance()->Init(std::move(host));
 }
 
 void ArcAuthServiceImpl::GetAuthCode(const GetAuthCodeCallback& callback) {
-  // TODO(victorhsieh): request auth code from LSO (crbug.com/571146).
-  callback.Run(mojo::String("fake auth code from ArcAuthService in Chrome"));
+  callback.Run(mojo::String(
+      ArcServiceManager::Get()->arc_opt_in_manager()->GetAuthToken()));
 }
 
 }  // namespace arc