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

services/ui/demo/mus_demo.h

 // Copyright 2016 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.
 
 #ifndef SERVICES_UI_DEMO_MUS_DEMO_H_
 #define SERVICES_UI_DEMO_MUS_DEMO_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 19 matching lines @@
 // a simple way to demonstrate that the graphic stack works as intended.
 class MusDemo : public service_manager::Service,
                 public WindowTreeClientDelegate,
                 public WindowManagerDelegate {
  public:
   MusDemo();
   ~MusDemo() override;
 
  private:
   // 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;
 
   // WindowTreeClientDelegate:
   void OnEmbed(Window* root) override;
   void OnEmbedRootDestroyed(Window* root) override;
   void OnLostConnection(WindowTreeClient* client) override;
   void OnPointerEventObserved(const PointerEvent& event,
                               Window* target) override;
 
@@ skipping 42 matching lines @@
   // Last time a frame was drawn.
   base::TimeTicks last_draw_frame_time_;
 
   DISALLOW_COPY_AND_ASSIGN(MusDemo);
 };
 
 }  // namespace demo
 }  // namespace ui
 
 #endif  // SERVICES_UI_DEMO_MUS_DEMO_H_