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

mash/webtest/webtest.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 MASH_WEBTEST_WEBTEST_H_
 #define MASH_WEBTEST_WEBTEST_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "mash/public/interfaces/launchable.mojom.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/service_manager/public/cpp/interface_factory.h"
 #include "services/service_manager/public/cpp/service.h"
 #include "services/tracing/public/cpp/provider.h"
 
+namespace service_manager {
+class ServiceContext;
+}
+
 namespace views {
 class AuraInit;
 class Widget;
 class WindowManagerConnection;
 }
 
 namespace mash {
 namespace webtest {
 
 class Webtest : public service_manager::Service,
                 public mojom::Launchable,
                 public service_manager::InterfaceFactory<mojom::Launchable> {
  public:
   Webtest();
   ~Webtest() override;
 
   void AddWindow(views::Widget* window);
   void RemoveWindow(views::Widget* window);
 
  private:
   // service_manager::Service:
-  void OnStart() override;
+  void OnStart(service_manager::ServiceContext* context) override;
   bool OnConnect(const service_manager::ServiceInfo& remote_info,
                  service_manager::InterfaceRegistry* registry) override;
 
   // mojom::Launchable:
   void Launch(uint32_t what, mojom::LaunchMode how) override;
 
   // service_manager::InterfaceFactory<mojom::Launchable>:
   void Create(const service_manager::Identity& remote_identity,
               mojom::LaunchableRequest request) override;
 
+  service_manager::ServiceContext* context_ = nullptr;
+
   mojo::BindingSet<mojom::Launchable> bindings_;
   std::vector<views::Widget*> windows_;
 
   tracing::Provider tracing_;
   std::unique_ptr<views::AuraInit> aura_init_;
   std::unique_ptr<views::WindowManagerConnection> window_manager_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(Webtest);
 };
 
 }  // namespace webtest
 }  // namespace mash
 
 #endif  // MASH_WEBTEST_WEBTEST_H_