mus: Forward user activity from window server to detector.

ash/mus/user_activity_forwarder.cc

Index: ash/mus/user_activity_forwarder.cc
diff --git a/ash/mus/user_activity_forwarder.cc b/ash/mus/user_activity_forwarder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0406d1ab24fbdf5a5aae13493a1d27458f2cab7c
--- /dev/null
+++ b/ash/mus/user_activity_forwarder.cc
@@ -0,0 +1,41 @@
+// 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.
+
+#include "ash/mus/user_activity_forwarder.h"
+
+#include <cmath>
+
+#include "services/service_manager/public/cpp/connector.h"
+#include "services/ui/public/interfaces/constants.mojom.h"
+#include "ui/base/user_activity/user_activity_detector.h"
+
+namespace ash {
+namespace mus {
+
+UserActivityForwarder::UserActivityForwarder(
+    service_manager::Connector* connector,
+    ui::UserActivityDetector* detector)
+    : user_activity_observer_binding_(this), user_activity_detector_(detector) {
+  DCHECK(connector);
+  DCHECK(detector);
+
+  // Round UserActivityDetector's notification interval up to the nearest second
+  // (the granularity exposed by UserActivityMonitor).
+  const uint32_t kNotifyIntervalSec = static_cast<uint32_t>(
+      ceil(ui::UserActivityDetector::kNotifyIntervalMs / 1000.0));
+
+  connector->BindInterface(ui::mojom::kServiceName, &user_activity_monitor_);
+  user_activity_monitor_->AddUserActivityObserver(
+      kNotifyIntervalSec,
+      user_activity_observer_binding_.CreateInterfacePtrAndBind());
+}
+
+UserActivityForwarder::~UserActivityForwarder() {}
+
+void UserActivityForwarder::OnUserActivity() {
+  user_activity_detector_->HandleExternalUserActivity();
+}
+
+}  // namespace mus
+}  // namespace ash