Make Service own ServiceContext.

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 95e287aa67bc9025866b347455d5a2768fe27380..7d74eaf4e9d45bf1bed4ac7b8fcfa939ecbd4634 100644
--- a/mash/example/window_type_launcher/window_type_launcher.h
+++ b/mash/example/window_type_launcher/window_type_launcher.h
@@ -30,9 +30,7 @@ class WindowTypeLauncher
 
  private:
   // shell::Service:
-  void OnStart(shell::Connector* connector,
-               const shell::Identity& identity,
-               uint32_t id) override;
+  void OnStart(const shell::Identity& identity) override;
   bool OnConnect(shell::Connection* connection) override;
 
   // mash::mojom::Launchable:
@@ -42,7 +40,6 @@ class WindowTypeLauncher
   void Create(const shell::Identity& remote_identity,
               mash::mojom::LaunchableRequest request) override;
 
-  shell::Connector* connector_ = nullptr;
   mojo::BindingSet<mash::mojom::Launchable> bindings_;
   std::vector<views::Widget*> windows_;