Move shell service to toplevel shell namespace

mash/example/common/mus_views_init.h

Index: mash/example/common/mus_views_init.h
diff --git a/mash/example/common/mus_views_init.h b/mash/example/common/mus_views_init.h
index 04a02ec57657b6bc5637ec1370fec4d6b7531352..1f983926f75f7c64bb43644cd222fb46daa89b36 100644
--- a/mash/example/common/mus_views_init.h
+++ b/mash/example/common/mus_views_init.h
@@ -25,7 +25,7 @@ class AuraInit;
 class MUSViewsInit : public views::ViewsDelegate,
                      public mus::WindowTreeDelegate {
  public:
-  explicit MUSViewsInit(mojo::ShellConnection* app);
+  explicit MUSViewsInit(shell::ShellConnection* app);
   ~MUSViewsInit() override;
 
  private:
@@ -45,7 +45,7 @@ class MUSViewsInit : public views::ViewsDelegate,
   HICON GetSmallWindowIcon() const override;
 #endif
 
-  mojo::ShellConnection* app_;
+  shell::ShellConnection* app_;
   std::unique_ptr<views::AuraInit> aura_init_;
   mus::mojom::WindowManagerPtr window_manager_;