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

ash/touch_hud/mus/touch_hud_application.cc

Index: ash/touch_hud/mus/touch_hud_application.cc
diff --git a/ash/touch_hud/mus/touch_hud_application.cc b/ash/touch_hud/mus/touch_hud_application.cc
index d6ab7cb2ec87686f75706483c61662d34fa3c7ff..03e01fc4484b05e45bc7a4dd12a76596e8bba782 100644
--- a/ash/touch_hud/mus/touch_hud_application.cc
+++ b/ash/touch_hud/mus/touch_hud_application.cc
@@ -67,11 +67,11 @@
 TouchHudApplication::TouchHudApplication() : binding_(this) {}
 TouchHudApplication::~TouchHudApplication() {}
 
-void TouchHudApplication::OnStart() {
+void TouchHudApplication::OnStart(service_manager::ServiceContext* context) {
   aura_init_ = base::MakeUnique<views::AuraInit>(
-      context()->connector(), context()->identity(), "views_mus_resources.pak");
+      context->connector(), context->identity(), "views_mus_resources.pak");
   window_manager_connection_ = views::WindowManagerConnection::Create(
-      context()->connector(), context()->identity());
+      context->connector(), context->identity());
 }
 
 bool TouchHudApplication::OnConnect(