Create interface "EventPageTracker" for checking an extension's

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 539 matching lines @@
       'browser/declarative_user_script_manager.cc',
       'browser/declarative_user_script_manager.h',
       'browser/declarative_user_script_master.cc',
       'browser/declarative_user_script_master.h',
       'browser/deferred_start_render_host.h',
       'browser/deferred_start_render_host_observer.h',
       'browser/error_map.cc',
       'browser/error_map.h',
       'browser/event_listener_map.cc',
       'browser/event_listener_map.h',
+      'browser/event_page_tracker.h',
       'browser/event_router.cc',
       'browser/event_router.h',
       'browser/extension_error.cc',
       'browser/extension_error.h',
       'browser/extension_function.cc',
       'browser/extension_function.h',
       'browser/extension_function_dispatcher.cc',
       'browser/extension_function_dispatcher.h',
       'browser/extension_function_registry.cc',
       'browser/extension_function_registry.h',
@@ skipping 472 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',
     ],
   },
 }