Add a user id parameter to connections

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"
 
 namespace mojo {
 
 class Shell;
 
 // 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.
-  // |url| is the URL used to start the application. |id| is a unique identifier
-  // the shell uses to identify this specific instance of the application.
+  // |url| is the URL used to start the application.
+  // |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(Shell* shell, const std::string& url, uint32_t id);
+  virtual void Initialize(Shell* shell,
+                          const std::string& url,
+                          uint32_t id,
+                          uint32_t user_id = 0);
 
   // 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 pipe to the Mojo Shell is closed.
   //
   // Returning true from this method will cause the ShellConnection instance to
@@ skipping 10 matching lines @@
   // the delegate can no longer rely on the main run loop still running.
   virtual void Quit();
 
  private:
   MOJO_DISALLOW_COPY_AND_ASSIGN(ShellClient);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_PUBLIC_CPP_SHELL_CLIENT_H_