Remove DeviceMonitorLinux::WillDestroyCurrentMessageLoop().

device/base/device_monitor_linux.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 DEVICE_BASE_DEVICE_MONITOR_LINUX_H_
 #define DEVICE_BASE_DEVICE_MONITOR_LINUX_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
 #include "base/files/file_descriptor_watcher_posix.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "device/base/device_base_export.h"
 #include "device/udev_linux/scoped_udev.h"
 
 struct udev_device;
 
 namespace device {
 
 // This class listends for notifications from libudev about
 // connected/disconnected devices. This class is *NOT* thread-safe.
-class DEVICE_BASE_EXPORT DeviceMonitorLinux
-    : public base::MessageLoop::DestructionObserver {
+class DEVICE_BASE_EXPORT DeviceMonitorLinux {
  public:
   typedef base::Callback<void(udev_device* device)> EnumerateCallback;
 
   class Observer {
    public:
     virtual ~Observer() {}
     virtual void OnDeviceAdded(udev_device* device) = 0;
     virtual void OnDeviceRemoved(udev_device* device) = 0;
-    virtual void WillDestroyMonitorMessageLoop() = 0;
   };
 
   DeviceMonitorLinux();
 
   static DeviceMonitorLinux* GetInstance();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   void Enumerate(const EnumerateCallback& callback);
 
-  // Implements base::MessageLoop::DestructionObserver
-  void WillDestroyCurrentMessageLoop() override;
-
  private:
   friend std::default_delete<DeviceMonitorLinux>;
 
-  ~DeviceMonitorLinux() override;
+  ~DeviceMonitorLinux();
 
   void OnMonitorCanReadWithoutBlocking();
 
   ScopedUdevPtr udev_;
   ScopedUdevMonitorPtr monitor_;
   int monitor_fd_;
   std::unique_ptr<base::FileDescriptorWatcher::Controller>
       monitor_watch_controller_;
 
   base::ObserverList<Observer, true> observers_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorLinux);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BASE_DEVICE_MONITOR_LINUX_H_