[fsp] Add support for observing entries and notifying about changes.

chrome/chrome_tests_unit.gypi

 # Copyright 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.
 {
   'variables': {
     'chrome_unit_tests_sources': [
       '../apps/saved_devices_service_unittest.cc',
       '../apps/saved_files_service_unittest.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.h',
@@ skipping 145 matching lines @@
       'browser/chromeos/file_system_provider/fileapi/provider_async_file_util_unittest.cc',
       'browser/chromeos/file_system_provider/mount_path_util_unittest.cc',
       'browser/chromeos/file_system_provider/operations/abort_unittest.cc',
       'browser/chromeos/file_system_provider/operations/close_file_unittest.cc',
       'browser/chromeos/file_system_provider/operations/copy_entry_unittest.cc',
       'browser/chromeos/file_system_provider/operations/create_directory_unittest.cc',
       'browser/chromeos/file_system_provider/operations/create_file_unittest.cc',
       'browser/chromeos/file_system_provider/operations/delete_entry_unittest.cc',
       'browser/chromeos/file_system_provider/operations/get_metadata_unittest.cc',
       'browser/chromeos/file_system_provider/operations/move_entry_unittest.cc',
+      'browser/chromeos/file_system_provider/operations/observe_directory_unittest.cc',
       'browser/chromeos/file_system_provider/operations/open_file_unittest.cc',
       'browser/chromeos/file_system_provider/operations/read_directory_unittest.cc',
       'browser/chromeos/file_system_provider/operations/read_file_unittest.cc',
       'browser/chromeos/file_system_provider/operations/test_util.cc',
       'browser/chromeos/file_system_provider/operations/test_util.cc',
       'browser/chromeos/file_system_provider/operations/test_util.h',
       'browser/chromeos/file_system_provider/operations/test_util.h',
       'browser/chromeos/file_system_provider/operations/truncate_unittest.cc',
       'browser/chromeos/file_system_provider/operations/unmount_unittest.cc',
+      'browser/chromeos/file_system_provider/operations/unobserve_entry_unittest.cc',
       'browser/chromeos/file_system_provider/operations/write_file_unittest.cc',
       'browser/chromeos/file_system_provider/request_manager_unittest.cc',
       'browser/chromeos/file_system_provider/service_unittest.cc',
       'browser/chromeos/fileapi/external_file_url_request_job_unittest.cc',
       'browser/chromeos/fileapi/external_file_url_util_unittest.cc',
       'browser/chromeos/fileapi/file_access_permissions_unittest.cc',
       'browser/chromeos/fileapi/file_system_backend_unittest.cc',
       'browser/chromeos/geolocation/simple_geolocation_unittest.cc',
       'browser/chromeos/imageburner/burn_device_handler_unittest.cc',
       'browser/chromeos/imageburner/burn_manager_unittest.cc',
@@ skipping 2690 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }