Service Manager: Remove ServiceContext* arg from Service::OnStart()

ash/mus/window_manager_application.h

Index: ash/mus/window_manager_application.h
diff --git a/ash/mus/window_manager_application.h b/ash/mus/window_manager_application.h
index 9a9cf51c4fdce166290324d6da770a7085efa45d..57c376eaec88cc0524e88f669920d2fd2997c6e2 100644
--- a/ash/mus/window_manager_application.h
+++ b/ash/mus/window_manager_application.h
@@ -29,10 +29,6 @@ class ScopedFakeStatisticsProvider;
 }
 }
 
-namespace service_manager {
-class ServiceContext;
-}
-
 namespace views {
 class AuraInit;
 class SurfaceContextFactory;
@@ -76,15 +72,13 @@ class WindowManagerApplication
   void ShutdownComponents();
 
   // service_manager::Service:
-  void OnStart(service_manager::ServiceContext* context) override;
+  void OnStart() override;
   bool OnConnect(const service_manager::ServiceInfo& remote_info,
                  service_manager::InterfaceRegistry* registry) override;
 
   // session::mojom::ScreenlockStateListener:
   void ScreenlockStateChanged(bool locked) override;
 
-  service_manager::ServiceContext* context_ = nullptr;
-
   tracing::Provider tracing_;
 
   std::unique_ptr<views::AuraInit> aura_init_;