Added implementation of SyncEventObserver to route events to Javascript Extension.

chrome/chrome_browser_extensions.gypi

 # 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': 'browser_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 269 matching lines @@
         'browser/extensions/api/serial/serial_port_enumerator_posix.cc',
         'browser/extensions/api/serial/serial_port_enumerator_win.cc',
         'browser/extensions/api/socket/socket.cc',
         'browser/extensions/api/socket/socket.h',
         'browser/extensions/api/socket/socket_api.cc',
         'browser/extensions/api/socket/socket_api.h',
         'browser/extensions/api/socket/tcp_socket.cc',
         'browser/extensions/api/socket/tcp_socket.h',
         'browser/extensions/api/socket/udp_socket.cc',
         'browser/extensions/api/socket/udp_socket.h',
+        'browser/extensions/api/sync_file_system/extension_sync_event_observer.cc',
+        'browser/extensions/api/sync_file_system/extension_sync_event_observer.h',
         'browser/extensions/api/sync_file_system/sync_file_system_api.cc',
         'browser/extensions/api/sync_file_system/sync_file_system_api.h',
         'browser/extensions/api/system_indicator/system_indicator_api.h',
         'browser/extensions/api/system_info_cpu/cpu_info_provider.cc',
         'browser/extensions/api/system_info_cpu/cpu_info_provider.h',
         'browser/extensions/api/system_info_cpu/cpu_info_provider_linux.cc',
         'browser/extensions/api/system_info_cpu/cpu_info_provider_mac.cc',
         'browser/extensions/api/system_info_cpu/cpu_info_provider_win.cc',
         'browser/extensions/api/system_info_cpu/cpu_info_provider_android.cc',
         'browser/extensions/api/system_info_cpu/system_info_cpu_api.cc',
@@ skipping 604 matching lines @@
           'msvs_settings': {
             'VCLinkerTool': {
               'SubSystem': '2',  # Set /SUBSYSTEM:WINDOWS
             },
           },
         },
       ],
     }, ],  # 'OS=="win"'
   ],  # 'conditions'
 }