Change ExternalApplicationRegistrar::Register API

mojo/shell/external_application_registrar.mojom

Index: mojo/shell/external_application_registrar.mojom
diff --git a/mojo/shell/external_application_registrar.mojom b/mojo/shell/external_application_registrar.mojom
index db76aec4526fe0f100b257a683961f6d1017d318..26a284a9d04526f116d069af4a6e239072c34eb1 100644
--- a/mojo/shell/external_application_registrar.mojom
+++ b/mojo/shell/external_application_registrar.mojom
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import "mojo/public/interfaces/application/application.mojom"
 import "mojo/public/interfaces/application/shell.mojom"
 
 module mojo {
@@ -9,10 +10,10 @@ module mojo {
 // This interface allows applications running outside the auspices of a Shell
 // to request registration at the given application_url.
 // The shell implementing this interface will make the calling application
-// available to other apps at that URL and bind the provided Shell& to
+// available to other apps at that URL and pass back a Shell bound to
 // an impl capable of servicing the external application's connection requests.
 interface ExternalApplicationRegistrar {
-  Register(string application_url, Shell& shell) => ();
+  Register(string application_url) => (Shell shell);
 };
 
 }