Refactoring: de-couple Extensions from "script injection System" [render side]:3

extensions/extensions.gypi

 # Copyright 2015 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': {
     'extensions_common_constants_sources': [
       'common/constants.cc',
       'common/constants.h',
     ],
@@ skipping 952 matching lines @@
       'renderer/user_script_set.cc',
       'renderer/user_script_set.h',
       'renderer/user_script_set_manager.cc',
       'renderer/user_script_set_manager.h',
       'renderer/utils_native_handler.cc',
       'renderer/utils_native_handler.h',
       'renderer/v8_context_native_handler.cc',
       'renderer/v8_context_native_handler.h',
       'renderer/v8_schema_registry.cc',
       'renderer/v8_schema_registry.h',
+      'renderer/web_ui_injection_host.cc',
+      'renderer/web_ui_injection_host.h',
     ],
     'extensions_utility_sources': [
       'utility/unpacker.cc',
       'utility/unpacker.h',
       'utility/utility_handler.cc',
       'utility/utility_handler.h',
     ],
     'extensions_test_support_sources': [
       'browser/api/cast_channel/cast_test_util.cc',
       'browser/api/cast_channel/cast_test_util.h',
@@ skipping 39 matching lines @@
       'test/result_catcher.h',
       'test/test_content_utility_client.cc',
       'test/test_content_utility_client.h',
       'test/test_extensions_client.cc',
       'test/test_extensions_client.h',
       'test/test_permission_message_provider.cc',
       'test/test_permission_message_provider.h',
     ],
   },
 }