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

mash/example/window_type_launcher/window_type_launcher.cc

Index: mash/example/window_type_launcher/window_type_launcher.cc
diff --git a/mash/example/window_type_launcher/window_type_launcher.cc b/mash/example/window_type_launcher/window_type_launcher.cc
index c650f06cbbacfc6182a909c594a892ac7f965eef..dba68c410fc58706fd1ce4b98b08265882f1342d 100644
--- a/mash/example/window_type_launcher/window_type_launcher.cc
+++ b/mash/example/window_type_launcher/window_type_launcher.cc
@@ -473,10 +473,9 @@ void WindowTypeLauncher::RemoveWindow(views::Widget* window) {
     base::MessageLoop::current()->QuitWhenIdle();
 }
 
-void WindowTypeLauncher::OnStart(service_manager::ServiceContext* context) {
-  context_ = context;
+void WindowTypeLauncher::OnStart() {
   aura_init_ = base::MakeUnique<views::AuraInit>(
-      context->connector(), context->identity(), "views_mus_resources.pak",
+      context()->connector(), context()->identity(), "views_mus_resources.pak",
       std::string(), nullptr, views::AuraInit::Mode::AURA_MUS);
 }
 
@@ -496,7 +495,7 @@ void WindowTypeLauncher::Launch(uint32_t what, mash::mojom::LaunchMode how) {
   }
   views::Widget* window = new views::Widget;
   views::Widget::InitParams params(views::Widget::InitParams::TYPE_WINDOW);
-  params.delegate = new WindowTypeLauncherView(this, context_->connector());
+  params.delegate = new WindowTypeLauncherView(this, context()->connector());
   window->Init(params);
   window->Show();
   windows_.push_back(window);