Implemented the rest of loading/parsing logic for extension i18n:...

chrome/chrome.gyp

 # Copyright (c) 2009 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': {
     'chromium_code': 1,
 
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
@@ skipping 1047 matching lines @@
         'browser/extensions/extension_function.cc',
         'browser/extensions/extension_function.h',
         'browser/extensions/extension_function_dispatcher.cc',
         'browser/extensions/extension_function_dispatcher.h',
         'browser/extensions/extension_host.cc',
         'browser/extensions/extension_host.h',
         'browser/extensions/extension_install_ui.cc',
         'browser/extensions/extension_install_ui.h',
         'browser/extensions/extension_l10n_util.cc',
         'browser/extensions/extension_l10n_util.h',
+        'browser/extensions/extension_message_handler.cc',
+        'browser/extensions/extension_message_handler.h',
         'browser/extensions/extension_message_service.cc',
         'browser/extensions/extension_message_service.h',
         'browser/extensions/extension_browser_event_router.cc',
         'browser/extensions/extension_browser_event_router.h',
         'browser/extensions/extension_page_actions_module.cc',
         'browser/extensions/extension_page_actions_module.h',
         'browser/extensions/extension_page_actions_module_constants.cc',
         'browser/extensions/extension_page_actions_module_constants.h',
         'browser/extensions/extension_prefs.cc',
         'browser/extensions/extension_prefs.h',
@@ skipping 2870 matching lines @@
         'browser/command_updater_unittest.cc',
         'browser/debugger/devtools_manager_unittest.cc',
         'browser/dom_ui/dom_ui_theme_source_unittest.cc',
         'browser/dom_ui/dom_ui_unittest.cc',
         'browser/download/download_manager_unittest.cc',
         'browser/download/download_request_manager_unittest.cc',
         'browser/download/save_package_unittest.cc',
         'browser/encoding_menu_controller_unittest.cc',
         'browser/extensions/extension_file_util_unittest.cc',
         'browser/extensions/extension_l10n_util_unittest.cc',
+        'browser/extensions/extension_message_handler_unittest.cc',
         'browser/extensions/extension_messages_unittest.cc',
         'browser/extensions/extension_process_manager_unittest.cc',
         'browser/extensions/extension_ui_unittest.cc',
         'browser/extensions/extension_updater_unittest.cc',
         'browser/extensions/extensions_service_unittest.cc',
         'browser/extensions/user_script_master_unittest.cc',
         'browser/find_backend_unittest.cc',
         'browser/first_run_migration_mac_unittest.mm',
         'browser/global_keyboard_shortcuts_mac_unittest.cc',
         'browser/google_url_tracker_unittest.cc',
@@ skipping 1855 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],
   ],  # 'conditions'
 }