Make sure that Content Handled application can be connected multiple times.

mojo/shell/view_manager_loader.h

Index: mojo/shell/view_manager_loader.h
diff --git a/mojo/shell/view_manager_loader.h b/mojo/shell/view_manager_loader.h
index 83c5f31f506002feeb6ea99c5157610bcbcaa41b..dec36ae4b510af47fc540e91376f55b2a191b391 100644
--- a/mojo/shell/view_manager_loader.h
+++ b/mojo/shell/view_manager_loader.h
@@ -32,7 +32,7 @@ class ViewManagerLoader : public ApplicationLoader,
   // ApplicationLoader overrides:
   virtual void Load(ApplicationManager* manager,
                     const GURL& url,
-                    scoped_refptr<LoadCallbacks> callbacks) override;
+                    LoadCallback callbacks) override;
   virtual void OnApplicationError(ApplicationManager* manager,
                                   const GURL& url) override;