Reduce FakeArcBridgeService usage.

components/arc/arc_bridge_service.cc

Index: components/arc/arc_bridge_service.cc
diff --git a/components/arc/arc_bridge_service.cc b/components/arc/arc_bridge_service.cc
index d8bb59afccdd90eb5ea49bafda93e11c614af318..b9b5d92567f4403bc6aab53dc09e6e1542e90244 100644
--- a/components/arc/arc_bridge_service.cc
+++ b/components/arc/arc_bridge_service.cc
@@ -43,6 +43,18 @@ bool ArcBridgeService::GetAvailable(const base::CommandLine* command_line) {
   return command_line->HasSwitch(chromeos::switches::kArcAvailable);
 }
 
+void ArcBridgeService::RequestStart() {
+  NOTREACHED();
+}
+
+void ArcBridgeService::RequestStop() {
+  NOTREACHED();
+}
+
+void ArcBridgeService::OnShutdown() {
+  NOTREACHED();
+}
+
 void ArcBridgeService::AddObserver(Observer* observer) {
   DCHECK(CalledOnValidThread());
   observer_list_.AddObserver(observer);