athena: Add the concept of Activity and related managers.

athena/task/public/task_manager.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 ATHENA_TASK_TASK_MANAGER_H_
+#define ATHENA_TASK_TASK_MANAGER_H_
+
+#include "athena/athena_export.h"
+
+namespace athena {
+
+class Task;
+
+// Manages a set of tasks.

[Mr4D (OOO till 08-26), 2014/05/27 20:12:42]

As stated above - could you please explain further what this exactly is?

+class ATHENA_EXPORT TaskManager {
+ public:
+  static TaskManager* Create();
+  static TaskManager* Get();
+  static void Shutdown();
+
+  virtual ~TaskManager() {}
+
+  // Adds/Removes a task.
+  virtual void AddTask(Task* task) = 0;
+  virtual void RemoveTask(Task* task) = 0;
+
+  // Updates the UI when the task color/title changes.
+  virtual void UpdateTask(Task* task) = 0;
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_TASK_TASK_MANAGER_H_