Use Observer to notify of WebDB load instead of callbacks

components/webdata.gypi

 # Copyright (c) 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.
 
 {
   'targets': [
     {
       'target_name': 'encryptor',
       'type': 'static_library',
       'include_dirs': [
@@ skipping 36 matching lines @@
         '../base/base.gyp:base',
         '../content/content.gyp:content_browser',
         '../sql/sql.gyp:sql',
       ],
       'defines': [
         'WEBDATA_IMPLEMENTATION',
       ],
       'sources': [
         'webdata/common/web_database.cc',
         'webdata/common/web_database.h',
+        'webdata/common/web_database_observer.h',
         'webdata/common/web_database_service.cc',
         'webdata/common/web_database_service.h',
         'webdata/common/web_database_table.cc',
         'webdata/common/web_database_table.h',
         'webdata/common/web_data_request_manager.cc',
         'webdata/common/web_data_request_manager.h',
         'webdata/common/web_data_results.h',
+        'webdata/common/web_data_service_backend.cc',
+        'webdata/common/web_data_service_backend.h',
         'webdata/common/web_data_service_base.cc',
         'webdata/common/web_data_service_base.h',
         'webdata/common/web_data_service_consumer.h',
         'webdata/common/webdata_constants.cc',
         'webdata/common/webdata_constants.h',
         'webdata/common/webdata_export.h'
       ],
     },
   ],
 }