Update {virtual,override} to follow C++11 style in components.

components/storage_monitor/test_storage_monitor_win.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.
 //
 // This file contains a subclass of StorageMonitorWin to simulate device
 // changed events for testing.
 
 #ifndef COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_WIN_H_
 #define COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_WIN_H_
 
 #include <windows.h>
 
 #include "base/memory/ref_counted.h"
 #include "components/storage_monitor/storage_monitor_win.h"
 
 namespace storage_monitor {
 
 class TestPortableDeviceWatcherWin;
 class TestVolumeMountWatcherWin;
 
 class TestStorageMonitorWin: public StorageMonitorWin {
  public:
   TestStorageMonitorWin(
       TestVolumeMountWatcherWin* volume_mount_watcher,
       TestPortableDeviceWatcherWin* portable_device_watcher);
 
-  virtual ~TestStorageMonitorWin();
+  ~TestStorageMonitorWin() override;
 
   void InjectDeviceChange(UINT event_type, DWORD data);
 
   VolumeMountWatcherWin* volume_mount_watcher();
 
-  virtual Receiver* receiver() const override;
+  Receiver* receiver() const override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestStorageMonitorWin);
 };
 
 }  // namespace storage_monitor
 
 #endif  // COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_WIN_H_