Code re-factor related to WeakPtrFactory in src/component module

components/storage_monitor/volume_mount_watcher_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.
 
 #ifndef COMPONENTS_STORAGE_MONITOR_VOLUME_MOUNT_WATCHER_WIN_H_
 #define COMPONENTS_STORAGE_MONITOR_VOLUME_MOUNT_WATCHER_WIN_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 94 matching lines @@
 
   // Maintain a set of device attribute check calls in-flight. Only accessed
   // on the UI thread. This is to try and prevent the same device from
   // occupying our worker pool in case of windows API call hangs.
   std::set<base::FilePath> pending_device_checks_;
 
   // A map from device mount point to device metadata. Only accessed on the UI
   // thread.
   MountPointDeviceMetadataMap device_metadata_;
 
-  base::WeakPtrFactory<VolumeMountWatcherWin> weak_factory_;
-
   // The notifications object to use to signal newly attached volumes. Only
   // removable devices will be notified.
   StorageMonitor::Receiver* notifications_;
 
+  base::WeakPtrFactory<VolumeMountWatcherWin> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(VolumeMountWatcherWin);
 };
 
 }  // namespace storage_monitor
 
 #endif  // COMPONENTS_STORAGE_MONITOR_VOLUME_MOUNT_WATCHER_WIN_H_