Add a user id parameter to connections

mojo/shell/public/interfaces/shell.mojom

 // 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.
 
 module mojo.shell.mojom;
 
 import "mojo/shell/public/interfaces/interface_provider.mojom";
 
 // Specifies a whitelist of applications and services an application can connect
 // to. Connections to applications not explicitly specified here as a key are
 // rejected. Connections to services not specified in an application's allowed
 // interfaces value are not made.
 // A "*" value as the only key in an otherwise empty map means the application
 // may connect to any other application.
 // A "*" value as the only string in an otherwise empty array of interface names
 // means the application may connect to any service in that application.
 // An empty interface name array means the application may not connect to any
 // services exposed by the application it is connecting to.
 struct CapabilityFilter {
   map<string, array<string>> filter;
 };
 
 // An interface through which a Mojo application may communicate with the Mojo
 // system and request connections to other applications.
 interface Shell {
   const uint32 kInvalidApplicationID = 0;
+  const uint32 kUserRoot = 0;
+  const uint32 kUserInherit = 1;
 
   // Establishes a connection with another application ("target application")
   // (located at |url|) through which the calling application and the
   // target application may request services from one another.
   //
   // If the calling application would like to request services from the target
   // application, it should pass a valid interface request in the |services|
   // parameter (i.e. one containing a valid message pipe endpoint). If the
   // target application does not wish to offer services, it may either not bind
   // an implementation to the interface request, or else bind an implementation
   // that will reject some or all service requests.
   //
   // If the calling application would like to offer services to the target
   // application, it should pass a bound interface through the
   // |exposed_services| parameter. The target application may then request
   // services through that interface.
   //
   // At least one of |services| or |exposed_services| should be valid/bound in
   // the call.
   //
   // If the |application_url| does not contain a domain, but is of the form
   // "mojo:{service}", it is up to the Mojo shell to select an appropriate
   // application for the service. Currently, the shell does this based on the
   // value of its --origin flag.
   //
   // |filter| is a whitelist of application URLs and services that the target
   // application is permitted to connect to. See documentation for
   // CapabilityFilter above.
   Connect(string url,
+          uint32 user_id,

[sky, 2016/02/23 21:15:13]

Document what user_id means and how it's used.

           InterfaceProvider&? remote_interfaces,
           InterfaceProvider? local_interfaces,
           CapabilityFilter filter) => (uint32 application_id);
 
   // When there are no more instantiated services in an application, it should
   // start its shutdown process by calling this method. Additionally, it should
   // keep track of any new service requests that come in. The shell will then
   // call Application::OnQuitRequested and start queueing new service requests.
   // If the application didn't get any new service requests in the meantime, it
   // should call the callback with a true value. Otherwise it should call it
   // with false.
   QuitApplication();
 };