Move and rename Chrome's AppLauncherId to ash::AppLaunchId.

ash/public/cpp/app_launch_id.h

+// Copyright 2017 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 ASH_PUBLIC_CPP_APP_LAUNCH_ID_H_
+#define ASH_PUBLIC_CPP_APP_LAUNCH_ID_H_
+
+#include <string>
+
+#include "ash/public/cpp/ash_public_export.h"
+
+namespace ash {
+
+// A unique shelf item id composed of an |app_id| and a |launch_id|.
+// |app_id| is the non-empty application id associated with a set of windows.
+// |launch_id| is passed on app launch, to support multiple shelf items per app.
+class ASH_PUBLIC_EXPORT AppLaunchId {

[James Cook, 2017/03/20 20:31:13]

nit: could you add to this comment something like ", for example to support a
remote desktop client that wants each remote application to have its own icon".

Otherwise it's a little confusing why this feature exists.

[msw, 2017/03/20 21:20:59]

Done.

+ public:
+  AppLaunchId(const std::string& app_id, const std::string& launch_id);
+  // Creates an AppLaunchId with an empty |launch_id|.
+  explicit AppLaunchId(const std::string& app_id);
+  // Empty constructor for pre-allocating.
+  AppLaunchId();
+  ~AppLaunchId();
+
+  AppLaunchId(const AppLaunchId& app_launch_id) = default;
+  AppLaunchId(AppLaunchId&& app_launch_id) = default;
+  AppLaunchId& operator=(const AppLaunchId& other) = default;
+
+  const std::string& app_id() const { return app_id_; }
+  const std::string& launch_id() const { return launch_id_; }
+
+ private:
+  // The application id associated with a set of windows.
+  std::string app_id_;

[James Cook, 2017/03/20 20:31:13]

could these be const?

[msw, 2017/03/20 21:20:59]

No, unfortunately that seems to break copy constructor usage.

+  // An id passed on app launch, to support multiple shelf items per app.
+  std::string launch_id_;
+};
+
+}  // namespace ash
+
+#endif  // ASH_PUBLIC_CPP_APP_LAUNCH_ID_H_