mus: Add UserActivityMonitor.

components/mus/ws/user_activity_monitor.cc

Index: components/mus/ws/user_activity_monitor.cc
diff --git a/components/mus/ws/user_activity_monitor.cc b/components/mus/ws/user_activity_monitor.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3cd66419a27456442c3604193ea93759eddad86b
--- /dev/null
+++ b/components/mus/ws/user_activity_monitor.cc
@@ -0,0 +1,134 @@
+// 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.
+
+#include "components/mus/ws/user_activity_monitor.h"
+
+#include "base/bind.h"
+#include "base/time/default_tick_clock.h"
+
+namespace mus {
+namespace ws {
+
+UserActivityMonitor::UserActivityMonitor(std::unique_ptr<base::TickClock> clock)
+    : now_clock_(std::move(clock)) {
+  if (!now_clock_)
+    now_clock_ = base::WrapUnique(new base::DefaultTickClock);
+  last_activity_ = now_clock_->NowTicks();
+}
+
+UserActivityMonitor::~UserActivityMonitor() {}
+
+void UserActivityMonitor::OnUserActivity() {
+  base::TimeTicks now = now_clock_->NowTicks();
+  for (auto& pair : activity_observers_) {
+    ActivityObserverInfo* info = &(pair.first);
+    if (info->last_activity_notification.is_null() ||
+        (now - info->last_activity_notification) > info->delay) {
+      pair.second->OnUserActivity();
+      info->last_activity_notification = now;
+    }
+  }
+
+  // Wake up all the 'idle' observers.
+  for (auto& pair : idle_observers_) {
+    IdleObserverInfo* info = &(pair.first);
+    if (info->idle_state == mojom::UserIdleObserver::IdleState::ACTIVE)
+      continue;
+    info->last_idle_state_notification = now;
+    info->idle_state = mojom::UserIdleObserver::IdleState::ACTIVE;
+    pair.second->OnUserIdleStateChanged(info->idle_state);
+  }
+
+  last_activity_ = now;
+
+  // Start the timer if there are some idle observers.
+  if (idle_timer_.IsRunning())
+    idle_timer_.Reset();
+}
+
+void UserActivityMonitor::Add(mojom::UserActivityMonitorRequest request) {
+  bindings_.AddBinding(this, std::move(request));
+}
+
+void UserActivityMonitor::AddUserActivityObserver(
+    uint32_t delay_between_notify_secs,
+    mojom::UserActivityObserverPtr observer) {
+  ActivityObserverInfo info;
+  info.delay = base::TimeDelta::FromSeconds(delay_between_notify_secs);
+  observer.set_connection_error_handler(
+      base::Bind(&UserActivityMonitor::OnActivityObserverDisconnected,
+                 base::Unretained(this), observer.get()));
+  activity_observers_.push_back(std::make_pair(info, std::move(observer)));
+}
+
+void UserActivityMonitor::AddUserIdleObserver(
+    uint32_t idleness_in_minutes,
+    mojom::UserIdleObserverPtr observer) {
+  IdleObserverInfo info;
+  info.idle_duration = base::TimeDelta::FromMinutes(idleness_in_minutes);
+  base::TimeTicks now = now_clock_->NowTicks();
+  DCHECK(!last_activity_.is_null());
+  bool user_is_active = (now - last_activity_ < info.idle_duration);
+  info.idle_state = user_is_active ? mojom::UserIdleObserver::IdleState::ACTIVE
+                                   : mojom::UserIdleObserver::IdleState::IDLE;
+  info.last_idle_state_notification = now;
+  observer->OnUserIdleStateChanged(info.idle_state);
+  observer.set_connection_error_handler(
+      base::Bind(&UserActivityMonitor::OnIdleObserverDisconnected,
+                 base::Unretained(this), observer.get()));
+  idle_observers_.push_back(std::make_pair(info, std::move(observer)));
+  if (user_is_active)
+    ActivateIdleTimer();
+}
+
+void UserActivityMonitor::ActivateIdleTimer() {
+  if (idle_timer_.IsRunning())
+    return;
+  idle_timer_.Start(FROM_HERE, base::TimeDelta::FromMinutes(1), this,
+                    &UserActivityMonitor::OnMinuteTimer);
+}
+
+void UserActivityMonitor::OnMinuteTimer() {
+  base::TimeTicks now = now_clock_->NowTicks();
+  bool active_observer = false;
+  for (auto& pair : idle_observers_) {
+    IdleObserverInfo* info = &(pair.first);
+    if (info->idle_state == mojom::UserIdleObserver::IdleState::IDLE)
+      continue;
+    if (now - info->last_idle_state_notification < info->idle_duration) {
+      active_observer = true;
+      continue;
+    }
+    info->last_idle_state_notification = now;
+    info->idle_state = mojom::UserIdleObserver::IdleState::IDLE;
+    pair.second->OnUserIdleStateChanged(info->idle_state);
+  }
+  // All observers are already notified of IDLE. No point running the timer
+  // anymore.
+  if (!active_observer)
+    idle_timer_.Stop();
+}
+
+void UserActivityMonitor::OnActivityObserverDisconnected(
+    mojom::UserActivityObserver* observer) {
+  activity_observers_.erase(std::remove_if(
+      activity_observers_.begin(), activity_observers_.end(),
+      [observer](const std::pair<ActivityObserverInfo,
+                                 mojom::UserActivityObserverPtr>& pair) {
+        return pair.second.get() == observer;
+      }));
+}
+
+void UserActivityMonitor::OnIdleObserverDisconnected(
+    mojom::UserIdleObserver* observer) {
+  idle_observers_.erase(std::remove_if(
+      idle_observers_.begin(), idle_observers_.end(),
+      [observer](
+          const std::pair<IdleObserverInfo, mojom::UserIdleObserverPtr>& pair) {
+        return pair.second.get() == observer;
+      }));
+}
+
+}  // namespace ws
+}  // namespace mus