Change ExternalApplicationRegistrar::Register API

mojo/shell/external_application_registrar_connection.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SHELL_EXTERNAL_APPLICATION_REGISTRAR_CONNECTION_H_
 #define MOJO_SHELL_EXTERNAL_APPLICATION_REGISTRAR_CONNECTION_H_
 
 #include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 23 matching lines @@
   // Implementation of ErrorHandler
   virtual void OnConnectionError() override;
 
   // Connects client_socket_ and binds it to registrar_.
   // Status code is passed to callback upon success or failure.
   // May return either synchronously or asynchronously, depending on the
   // status of the underlying socket.
   void Connect(const net::CompletionCallback& callback);
 
   // Registers this app with the shell at the provided URL.
-  // shell is not ready for use until register_complete_callback fires.
-  // TODO(cmasone): Once the pipe for shell can be placed in a FIFO relationship
-  // with the one underlying registrar_, the callback becomes unneeded.
   void Register(const GURL& app_url,
-                ShellPtr* shell,
-                base::Closure register_complete_callback);
+                base::Callback<void(ShellPtr)> register_complete_callback);
 
  private:
   // Handles the result of Connect(). If it was successful, promotes the socket
   // to a MessagePipe and binds it to registrar_.
   // Hands rv to callback regardless.
   void OnConnect(net::CompletionCallback callback, int rv);
 
   scoped_ptr<net::UnixDomainClientSocket> client_socket_;
   mojo::embedder::ChannelInit channel_init_;
   ExternalApplicationRegistrarPtr registrar_;
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_EXTERNAL_APPLICATION_REGISTRAR_CONNECTION_H_