Refactor Udev device support in Ozone and add a DRM hotplug monitor

ui/events/ozone/evdev/device_manager_evdev.h

-// Copyright 2014 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 UI_EVENTS_OZONE_EVDEV_DEVICE_MANAGER_EVDEV_H_
-#define UI_EVENTS_OZONE_EVDEV_DEVICE_MANAGER_EVDEV_H_
-
-#include "base/callback.h"
-#include "base/compiler_specific.h"
-#include "base/files/file_path.h"
-#include "base/memory/scoped_ptr.h"
-
-namespace ui {
-
-typedef base::Callback<void(const base::FilePath& file_path)>
-    EvdevDeviceCallback;
-
-// Interface for scanning & monitoring input devices.
-class DeviceManagerEvdev {
- public:
-  virtual ~DeviceManagerEvdev();
-
-  // Enumerate devices & start watching for changes.
-  // Must be balanced by a call to Stop().
-  virtual void ScanAndStartMonitoring(
-      const EvdevDeviceCallback& device_added,
-      const EvdevDeviceCallback& device_removed) = 0;
-
-  // Stop watching for device changes.
-  virtual void Stop() = 0;
-};
-
-// Create simple DeviceManagerEvdev that scans /dev/input manually.
-scoped_ptr<DeviceManagerEvdev> CreateDeviceManagerManual();
-
-}  // namespace ui
-
-#endif  // UI_EVENTS_OZONE_EVDEV_DEVICE_MANAGER_EVDEV_H_