Move device monitors out of //media/capture into //media/device_monitors

media/capture/device_monitor_udev.h

-// Copyright 2013 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.
-
-// This class is used to detect device change and notify base::SystemMonitor
-// on Linux.
-
-#ifndef MEDIA_CAPTURE_DEVICE_MONITOR_UDEV_H_
-#define MEDIA_CAPTURE_DEVICE_MONITOR_UDEV_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop.h"
-#include "base/single_thread_task_runner.h"
-#include "media/capture/capture_export.h"
-
-extern "C" {
-struct udev_device;
-}
-
-namespace device {
-class UdevLinux;
-}
-
-namespace media {
-
-class CAPTURE_EXPORT DeviceMonitorLinux
-    : public base::MessageLoop::DestructionObserver {
- public:
-  explicit DeviceMonitorLinux(
-      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
-  ~DeviceMonitorLinux() override;
-
-  // TODO(mcasas): Consider adding a StartMonitoring() method like
-  // DeviceMonitorMac to reduce startup impact time.
-
- private:
-  // This object is deleted on the constructor thread after |io_task_runner_|
-  // has been destroyed. Need to know when the latter is being destroyed so that
-  // we can delete |udev_|.
-  void WillDestroyCurrentMessageLoop() override;
-
-  void Initialize();
-  void OnDevicesChanged(udev_device* device);
-
-  const scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
-
-  std::unique_ptr<device::UdevLinux> udev_;
-
-  DISALLOW_COPY_AND_ASSIGN(DeviceMonitorLinux);
-};
-
-}  // namespace media
-
-#endif  // MEDIA_CAPTURE_DEVICE_MONITOR_UDEV_H_