Add a user id parameter to connections

mojo/shell/identity.h

 // Copyright 2015 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_IDENTITY_H_
 #define MOJO_SHELL_IDENTITY_H_
 
 #include "mojo/shell/capability_filter.h"
 #include "url/gurl.h"
 
 namespace mojo {
 namespace shell {
 
 // Represents the identity of an application.
 // |url| is the URL of the application.
 // |qualifier| is a string that allows to tie a specific instance of an
 // application to another. A typical use case of qualifier is to control process
 // grouping for a given application URL. For example, the core services are
 // grouped into "Core"/"Files"/"Network"/etc. using qualifier; content handler's
 // qualifier is derived from the origin of the content.
 class Identity {
  public:
   Identity();
+  // Assumes user = mojom::Shell::kUserRoot.
+  // Used in tests or for shell-initiated connections.
   explicit Identity(const GURL& in_url);
-  Identity(const GURL& in_url, const std::string& in_qualifier);
   Identity(const GURL& in_url,
            const std::string& in_qualifier,
+           uint32_t user_id);
+  Identity(const GURL& in_url,
+           const std::string& in_qualifier,
+           uint32_t user,
            CapabilityFilter filter);
   ~Identity();
 
   bool operator<(const Identity& other) const;
   bool is_null() const { return url_.is_empty(); }
   bool operator==(const Identity& other) const;
 
   const GURL& url() const { return url_; }
+  const uint32_t user_id() const { return user_id_; }
+  void set_user_id(uint32_t user_id) { user_id_ = user_id; }
   const std::string& qualifier() const { return qualifier_; }
   const CapabilityFilter& filter() const { return filter_; }
 
  private:
   GURL url_;
   std::string qualifier_;
 
+  uint32_t user_id_;
+
   // TODO(beng): CapabilityFilter is not currently included in equivalence
   //             checks for Identity since we're not currently clear on the
   //             policy for instance disambiguation. Need to figure this out.
   //             This field is supplied because it is logically part of the
   //             instance identity of an application.
   CapabilityFilter filter_;
 };
 
 // Creates an identity for the Shell, used when the Shell connects to
 // applications.
 Identity CreateShellIdentity();
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_IDENTITY_H_