Add a instance groups to Connect(), and introduce an Identity struct.

mojo/shell/public/cpp/shell_client.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_PUBLIC_CPP_SHELL_CLIENT_H_
 #define MOJO_SHELL_PUBLIC_CPP_SHELL_CLIENT_H_
 
 #include <stdint.h>
 #include <string>
 
 #include "mojo/public/cpp/system/macros.h"
 #include "mojo/shell/public/cpp/connection.h"
+#include "mojo/shell/public/cpp/identity.h"
 
 namespace mojo {
 
 class Connector;
 
 // An interface representing an instance "known to the Mojo Shell". The
 // implementation receives lifecycle messages for the instance and gets the
 // opportunity to handle inbound connections brokered by the Shell. Every client
 // of ShellConnection must implement this interface, and instances of this
 // interface must outlive the ShellConnection.
 class ShellClient {
  public:
   ShellClient();
   virtual ~ShellClient();
 
   // Called once a bidirectional connection with the shell has been established.
-  // |name| is the name used to start the application.
+  // |identity| is the identity of the instance.
   // |id| is a unique identifier the shell uses to identify this specific
   // instance of the application.
-  // |user_id| identifies the user this instance is run as.
   // Called exactly once before any other method.
   virtual void Initialize(Connector* connector,
-                          const std::string& name,
-                          const std::string& user_id,
+                          const Identity& identity,
                           uint32_t id);
 
   // Called when a connection to this client is brokered by the shell. Override
   // to expose services to the remote application. Return true if the connection
   // should succeed. Return false if the connection should be rejected and the
   // underlying pipe closed. The default implementation returns false.
   virtual bool AcceptConnection(Connection* connection);
 
   // Called when ShellConnection's ShellClient binding (i.e. the pipe the
   // Mojo Shell has to talk to us over) is closed. A shell client may use this
   // as a signal to terminate.
   virtual void ShellConnectionLost();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ShellClient);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_PUBLIC_CPP_SHELL_CLIENT_H_