Split ExtensionSystem interface from ExtensionSystemImpl implementation, part 1.

chrome/chrome_browser_extensions.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': 'browser_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 731 matching lines @@
         'browser/extensions/extension_resource_protocols.cc',
         'browser/extensions/extension_resource_protocols.h',
         'browser/extensions/extension_service.cc',
         'browser/extensions/extension_service.h',
         'browser/extensions/extension_special_storage_policy.cc',
         'browser/extensions/extension_special_storage_policy.h',
         'browser/extensions/extension_sync_service.cc',
         'browser/extensions/extension_sync_service.h',
         'browser/extensions/extension_sync_service_factory.cc',
         'browser/extensions/extension_sync_service_factory.h',
-        'browser/extensions/extension_system.cc',
-        'browser/extensions/extension_system.h',
+        'browser/extensions/extension_system_impl.cc',
+        'browser/extensions/extension_system_impl.h',
         'browser/extensions/extension_sync_bundle.cc',
         'browser/extensions/extension_sync_bundle.h',
         'browser/extensions/extension_system_factory.cc',
         'browser/extensions/extension_system_factory.h',
         'browser/extensions/extension_sync_data.cc',
         'browser/extensions/extension_sync_data.h',
         'browser/extensions/extension_tab_util.cc',
         'browser/extensions/extension_tab_util.h',
         'browser/extensions/extension_toolbar_model.cc',
         'browser/extensions/extension_toolbar_model.h',
@@ skipping 466 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/chromeos/contacts',
             'proto_out_dir': 'chrome/browser/chromeos/contacts',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],  # 'chromeos=1'
   ],  # 'conditions'
 }