Make Service own ServiceContext.

ash/touch_hud/mus/touch_hud_application.h

Index: ash/touch_hud/mus/touch_hud_application.h
diff --git a/ash/touch_hud/mus/touch_hud_application.h b/ash/touch_hud/mus/touch_hud_application.h
index bfe0b39df39ffdb3ef0f7d5ba5604b85a11c81f9..c23e8571d29ba803aa6cf245c2d03afc8f7ba6ef 100644
--- a/ash/touch_hud/mus/touch_hud_application.h
+++ b/ash/touch_hud/mus/touch_hud_application.h
@@ -31,9 +31,7 @@ class TouchHudApplication
 
  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;
 
   // mojom::Launchable:
@@ -43,7 +41,6 @@ class TouchHudApplication
   void Create(const shell::Identity& remote_identity,
               mash::mojom::LaunchableRequest request) override;
 
-  shell::Connector* connector_ = nullptr;
   mojo::Binding<mash::mojom::Launchable> binding_;
   views::Widget* widget_ = nullptr;