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

mash/example/window_type_launcher/window_type_launcher.h

Index: mash/example/window_type_launcher/window_type_launcher.h
diff --git a/mash/example/window_type_launcher/window_type_launcher.h b/mash/example/window_type_launcher/window_type_launcher.h
index bee66f16f8797616e30d9df937bad77d2431cb15..b1663a68e40052fd5ab0c4dfbad535a39a18047a 100644
--- a/mash/example/window_type_launcher/window_type_launcher.h
+++ b/mash/example/window_type_launcher/window_type_launcher.h
@@ -12,6 +12,10 @@
 #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"
+
+namespace service_manager {
+class ServiceContext;
+}
 
 namespace views {
 class AuraInit;
@@ -30,7 +34,7 @@
 
  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;
 
@@ -41,6 +45,8 @@
   void Create(const service_manager::Identity& remote_identity,
               mash::mojom::LaunchableRequest request) override;
 
+  service_manager::ServiceContext* context_ = nullptr;
+
   mojo::BindingSet<mash::mojom::Launchable> bindings_;
   std::vector<views::Widget*> windows_;