Clean up pref change notification handling.

chrome/chrome_common.gypi

 # Copyright (c) 2010 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.
 
 {
   'target_defaults': {
     'variables': {
       'chrome_common_target': 0,
     },
     'target_conditions': [
@@ skipping 270 matching lines @@
         'common/page_zoom.h',
         'common/pepper_plugin_registry.cc',
         'common/pepper_plugin_registry.h',
         'common/plugin_carbon_interpose_constants_mac.cc',
         'common/plugin_carbon_interpose_constants_mac.h',
         'common/plugin_messages.cc',
         'common/plugin_messages.h',
         'common/plugin_messages_internal.h',
         'common/pref_store.cc',
         'common/pref_store.h',
+        'common/pref_store_base.cc',
+        'common/pref_store_base.h',
         'common/render_messages.cc',
         'common/render_messages.h',
         'common/render_messages_internal.h',
         'common/render_messages_params.cc',
         'common/render_messages_params.h',
         'common/renderer_preferences.cc',
         'common/renderer_preferences.h',
         'common/resource_dispatcher.cc',
         'common/resource_dispatcher.h',
         'common/security_filter_peer.cc',
@@ skipping 279 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }