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

mojo/shell/public/cpp/identity.h

Index: mojo/shell/public/cpp/identity.h
diff --git a/mojo/shell/public/cpp/identity.h b/mojo/shell/public/cpp/identity.h
new file mode 100644
index 0000000000000000000000000000000000000000..90f4608fa898d469e219289618c0417487d3885a
--- /dev/null
+++ b/mojo/shell/public/cpp/identity.h
@@ -0,0 +1,55 @@
+// Copyright 2016 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_IDENTITY_H_
+#define MOJO_SHELL_PUBLIC_CPP_IDENTITY_H_
+
+#include <string>
+
+#include "mojo/shell/public/interfaces/connector.mojom.h"
+
+namespace mojo {
+
+// Represents the identity of an application.
+// |name| is the structured name of the application.
+// |instance| is a string that allows to tie a specific instance to another. A
+// typical use case of instance is to control process grouping for a given name.
+class Identity {
+ public:
+  Identity();
+  Identity(const std::string& name,
+           const std::string& user_id);
+  Identity(const std::string& name,
+           const std::string& user_id,
+           const std::string& instance);
+  Identity(const Identity& other);
+  ~Identity();
+
+  bool operator<(const Identity& other) const;
+  bool is_null() const { return name_.empty(); }
+  bool operator==(const Identity& other) const;
+
+  const std::string& name() const { return name_; }
+  const std::string& user_id() const { return user_id_; }
+  void set_user_id(const std::string& user_id) { user_id_ = user_id; }
+  const std::string& instance() const { return instance_; }
+
+ private:
+  std::string name_;
+  std::string user_id_;
+  std::string instance_;
+};
+
+template <>
+struct TypeConverter<shell::mojom::IdentityPtr, Identity> {
+  static shell::mojom::IdentityPtr Convert(const Identity& input);
+};
+template <>
+struct TypeConverter<Identity, shell::mojom::IdentityPtr> {
+  static Identity Convert(const shell::mojom::IdentityPtr& input);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_SHELL_PUBLIC_CPP_IDENTITY_H_