Componentize protocol_event_observer

components/sync_driver/BUILD.gn

 # Copyright 2014 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.
 
 static_library("sync_driver") {
   sources = [
     "backend_data_type_configurer.cc",
     "backend_data_type_configurer.h",
     "backend_migrator.cc",
     "backend_migrator.h",
@@ skipping 33 matching lines @@
     "non_blocking_data_type_manager.cc",
     "non_blocking_data_type_manager.h",
     "non_ui_data_type_controller.cc",
     "non_ui_data_type_controller.h",
     "open_tabs_ui_delegate.cc",
     "open_tabs_ui_delegate.h",
     "pref_names.cc",
     "pref_names.h",
     "profile_sync_auth_provider.cc",
     "profile_sync_auth_provider.h",
+    "protocol_event_observer.cc",
+    "protocol_event_observer.h",
     "proxy_data_type_controller.cc",
     "proxy_data_type_controller.h",
     "shared_change_processor.cc",
     "shared_change_processor.h",
     "shared_change_processor_ref.cc",
     "shared_change_processor_ref.h",
     "sync_api_component_factory.h",
     "sync_frontend.cc",
     "sync_frontend.h",
     "sync_prefs.cc",
@@ skipping 42 matching lines @@
   deps = [
     ":sync_driver",
     "//base",
     "//components/sessions",
     "//sync",
     "//sync:test_support_sync_internal_api",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }