Add notification and observer to copy the file between other users.

chrome/common/extensions/api/file_browser_private.idl

 // 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.
 
 // fileBrowserPrivate API.
 // This is a private API used by the file browser of ChromeOS.
 [platforms=("chromeos"),
  implemented_in="chrome/browser/chromeos/extensions/file_manager/file_browser_private_api_functions.h"]
 namespace fileBrowserPrivate {
 // Type of the mounted volume.
@@ skipping 803 matching lines @@
 
   static void onDirectoryChanged(FileWatchEvent event);
 
   static void onPreferencesChanged();
 
   static void onDriveConnectionStatusChanged();
 
   static void onDeviceChanged(DeviceEvent event);
 
   static void onDriveSyncError(DriveSyncErrorEvent event);
+
+  // Dispatched when a profile is added.
+  static void onProfileAdded();
 };
 };