Remove explicit singletonness of ArcBridgeService part 5.

components/arc/test/fake_arc_bridge_service.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/test/fake_arc_bridge_service.h"
 
 namespace arc {
 
-extern ArcBridgeService* g_arc_bridge_service;
-
-FakeArcBridgeService::FakeArcBridgeService() {
-  DCHECK(!g_arc_bridge_service);
-  g_arc_bridge_service = this;
-}
+FakeArcBridgeService::FakeArcBridgeService() = default;
 
 FakeArcBridgeService::~FakeArcBridgeService() {
-  DCHECK(g_arc_bridge_service == this);
-  g_arc_bridge_service = nullptr;
   SetStopped();
 }
 
 void FakeArcBridgeService::RequestStart() {
   SetReady();
 }
 
 void FakeArcBridgeService::RequestStop() {
   SetStopped();
 }
@@ skipping 10 matching lines @@
 void FakeArcBridgeService::SetStopped() {
   if (state() != State::STOPPED)
     SetState(State::STOPPED);
 }
 
 bool FakeArcBridgeService::HasObserver(const Observer* observer) {
   return observer_list().HasObserver(observer);
 }
 
 }  // namespace arc