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

mojo/shell/public/cpp/shell_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_PUBLIC_CPP_SHELL_CONNECTION_H_
 #define MOJO_SHELL_PUBLIC_CPP_SHELL_CONNECTION_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 41 matching lines @@
 
   // Block the calling thread until the Initialize() method is called by the
   // shell.
   void WaitForInitialize();
 
   Connector* connector() { return connector_.get(); }
 
  private:
   // shell::mojom::ShellClient:
   void Initialize(shell::mojom::ConnectorPtr connector,
-                  const String& name,
-                  const String& user_id,
+                  shell::mojom::IdentityPtr identity,
                   uint32_t id) override;
   void AcceptConnection(
-      const String& requestor_name,
-      const String& requestor_user_id,
-      uint32_t requestor_id,
+      shell::mojom::IdentityPtr source,
+      uint32_t source_id,
       shell::mojom::InterfaceProviderRequest remote_interfaces,
       shell::mojom::InterfaceProviderPtr local_interfaces,
       Array<String> allowed_interfaces,
       const String& name) override;
 
   void OnConnectionError();
 
   // We track the lifetime of incoming connection registries as it more
   // convenient for the client.
   ScopedVector<Connection> incoming_connections_;
   mojo::ShellClient* client_;
   Binding<shell::mojom::ShellClient> binding_;
   scoped_ptr<Connector> connector_;
   base::WeakPtrFactory<ShellConnection> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellConnection);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_PUBLIC_CPP_SHELL_CONNECTION_H_