[fsp] Add requestUnmount() method together with the request manager.

chrome/common/extensions/api/api.gyp

 # Copyright (c) 2012 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.
 
 {
   'targets': [
     {
       'target_name': 'chrome_api',
       'type': 'static_library',
       'sources': [
@@ skipping 51 matching lines @@
               'dial.idl',
               'downloads.idl',
               'downloads_internal.idl',
               'echo_private.json',
               'enterprise_platform_keys_private.json',
               'events.json',
               'feedback_private.idl',
               'file_browser_private.idl',
               'file_system.idl',
               'file_system_provider.idl',
+              'file_system_provider_internal.idl',
               'font_settings.json',
               'gcm.json',
               'hangouts_private.idl',
               'hid.idl',
               'history.json',
               'hotword_private.idl',
               'i18n.json',
               'identity.idl',
               'identity_private.idl',
               'idle.json',
@@ skipping 101 matching lines @@
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '<(DEPTH)/chrome/chrome.gyp:drive_proto',
           ],
         }],
       ],
     },
   ],
 }