mus: Add UserActivityMonitor.

components/mus/ws/user_activity_monitor.h

+// 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 COMPONENTS_MUS_WS_USER_ACTIVITY_MONITOR_H_
+#define COMPONENTS_MUS_WS_USER_ACTIVITY_MONITOR_H_
+
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "components/mus/public/interfaces/user_activity_monitor.mojom.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+#include "mojo/public/cpp/bindings/interface_ptr_set.h"
+
+namespace mus {
+namespace ws {
+
+namespace test {
+class UserActivityMonitorTestApi;
+}
+
+class UserActivityMonitor : public mojom::UserActivityMonitor {
+ public:
+  // |now_clock| is used to get the timestamp. If |now_clock| is nullptr, then
+  // DefaultTickClock is used.
+  explicit UserActivityMonitor(std::unique_ptr<base::TickClock> now_clock);
+  ~UserActivityMonitor() override;
+
+  void OnUserActivity();

[sky, 2016/06/27 15:54:26]

nit: add descriptions for functions (including OnMinuteTimer below).

[sadrul, 2016/06/27 20:46:13]

Done.

+  void Add(mojom::UserActivityMonitorRequest request);
+
+  // mojom::UserActivityMonitor:
+  void AddUserActivityObserver(
+      uint32_t delay_between_notify_secs,
+      mojom::UserActivityObserverPtr observer) override;
+  void AddUserIdlenessObserver(
+      uint32_t idleness_in_minutes,
+      mojom::UserIdlenessObserverPtr observer) override;
+
+ private:
+  friend class test::UserActivityMonitorTestApi;
+
+  void OnMinuteTimer();
+
+  mojo::BindingSet<mojom::UserActivityMonitor> bindings_;
+  std::unique_ptr<base::TickClock> now_clock_;
+
+  struct ActivityObserverInfo {
+    base::TimeTicks last_activity_notification;
+    base::TimeDelta delay;
+  };
+  std::vector<std::pair<ActivityObserverInfo, mojom::UserActivityObserverPtr>>
+      activity_observers_;
+
+  struct IdlenessObserverInfo {
+    base::TimeTicks last_idle_state_notification;
+    base::TimeDelta idle_duration;
+    mojom::UserIdlenessObserver::IdleState idle_state;
+  };
+  std::vector<std::pair<IdlenessObserverInfo, mojom::UserIdlenessObserverPtr>>
+      idleness_observers_;
+  base::RepeatingTimer idle_timer_;

[sky, 2016/06/27 15:54:26]

You should avoid running this timer if not necessary. By that I mean if there
are no observers or all observers have been notified of idle then then you don't
need to keep running the timer.

[sadrul, 2016/06/27 20:46:13]

Good point! Done.

+  base::TimeTicks last_activity_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserActivityMonitor);
+};
+
+}  // namespace ws
+}  // namespace mus
+
+#endif  // COMPONENTS_MUS_WS_USER_ACTIVITY_MONITOR_H_