1 files changed, 51 insertions, 0 deletions
diff --git a/base/system_monitor/system_monitor.cc b/base/system_monitor/system_monitor.cc
new file mode 100644
index 0000000000..71e4f07847
--- /dev/null
+++ b/base/system_monitor/system_monitor.cc
@@ -0,0 +1,51 @@
+// Copyright (c) 2012 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 "base/system_monitor/system_monitor.h"
+
+#include <utility>
+
+#include "base/logging.h"
+#include "base/time/time.h"
+
+namespace base {
+
+static SystemMonitor* g_system_monitor = nullptr;
+
+SystemMonitor::SystemMonitor()
+    :  devices_changed_observer_list_(
+          new ObserverListThreadSafe<DevicesChangedObserver>()) {
+  DCHECK(!g_system_monitor);
+  g_system_monitor = this;
+}
+
+SystemMonitor::~SystemMonitor() {
+  DCHECK_EQ(this, g_system_monitor);
+  g_system_monitor = nullptr;
+}
+
+// static
+SystemMonitor* SystemMonitor::Get() {
+  return g_system_monitor;
+}
+
+void SystemMonitor::ProcessDevicesChanged(DeviceType device_type) {
+  NotifyDevicesChanged(device_type);
+}
+
+void SystemMonitor::AddDevicesChangedObserver(DevicesChangedObserver* obs) {
+  devices_changed_observer_list_->AddObserver(obs);
+}
+
+void SystemMonitor::RemoveDevicesChangedObserver(DevicesChangedObserver* obs) {
+  devices_changed_observer_list_->RemoveObserver(obs);
+}
+
+void SystemMonitor::NotifyDevicesChanged(DeviceType device_type) {
+  DVLOG(1) << "DevicesChanged with device type " << device_type;
+  devices_changed_observer_list_->Notify(
+      FROM_HERE, &DevicesChangedObserver::OnDevicesChanged, device_type);
+}
+
+}  // namespace base