Add Media device notification to SystemMonitor and Mac impl

base/system_monitor/mock_devices_changed_observer.h

Index: base/system_monitor/mock_devices_changed_observer.h
diff --git a/base/system_monitor/mock_devices_changed_observer.h b/base/system_monitor/mock_devices_changed_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..ec84496ca7df8561311cd86f727cd3941f986391
--- /dev/null
+++ b/base/system_monitor/mock_devices_changed_observer.h
@@ -0,0 +1,33 @@
+// 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.
+
+#ifndef BASE_SYSTEM_MONITOR_MOCK_DEVICES_CHANGED_OBSERVER_H_
+#define BASE_SYSTEM_MONITOR_MOCK_DEVICES_CHANGED_OBSERVER_H_
+
+#include "base/system_monitor/system_monitor.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace base {
+namespace test {
+
+class MockDevicesChangedObserver :
+  public base::SystemMonitor::DevicesChangedObserver {
+ public:
+  MockDevicesChangedObserver() {};
+
+  MOCK_METHOD0(OnDevicesChanged, void());
+  MOCK_METHOD3(OnMediaDeviceAttached,
+               void(const base::SystemMonitor::DeviceIdType& id,
+                    const std::string& name,
+                    const FilePath& path));
+  MOCK_METHOD1(OnMediaDeviceDetached,
+               void(const base::SystemMonitor::DeviceIdType& id));
+
+  DISALLOW_COPY_AND_ASSIGN(MockDevicesChangedObserver);
+};
+
+}  // namespace test
+}  // namespace base
+
+#endif // BASE_SYSTEM_MONITOR_MOCK_DEVICES_CHANGED_OBSERVER_H_