Implement <webview>.addContentScript/removeContentScript API [1]

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 642 matching lines @@
       'browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.cc',
       'browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h',
       'browser/guest_view/surface_worker/surface_worker_constants.cc',
       'browser/guest_view/surface_worker/surface_worker_constants.h',
       'browser/guest_view/surface_worker/surface_worker_guest.cc',
       'browser/guest_view/surface_worker/surface_worker_guest.h',
       'browser/guest_view/web_view/javascript_dialog_helper.cc',
       'browser/guest_view/web_view/javascript_dialog_helper.h',
       'browser/guest_view/web_view/web_view_constants.cc',
       'browser/guest_view/web_view/web_view_constants.h',
+      'browser/guest_view/web_view/web_view_content_script_manager.cc',
+      'browser/guest_view/web_view/web_view_content_script_manager.h',
       'browser/guest_view/web_view/web_view_find_helper.cc',
       'browser/guest_view/web_view/web_view_find_helper.h',
       'browser/guest_view/web_view/web_view_guest.cc',
       'browser/guest_view/web_view/web_view_guest.h',
       'browser/guest_view/web_view/web_view_guest_delegate.h',
       'browser/guest_view/web_view/web_view_permission_helper.cc',
       'browser/guest_view/web_view/web_view_permission_helper.h',
       'browser/guest_view/web_view/web_view_permission_helper_delegate.cc',
       'browser/guest_view/web_view/web_view_permission_helper_delegate.h',
       'browser/guest_view/web_view/web_view_permission_types.h',
@@ skipping 353 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',
     ],
   },
 }