sync: Support nudges from non-blocking sync types

sync/sync_core.gypi

 # Copyright 2013 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.
 
 {
   'include_dirs': [
     '..',
   ],
   'defines': [
     'SYNC_IMPLEMENTATION',
@@ skipping 64 matching lines @@
     'engine/net/server_connection_manager.cc',
     'engine/net/server_connection_manager.h',
     'engine/net/url_translator.cc',
     'engine/net/url_translator.h',
     'engine/non_blocking_sync_common.cc',
     'engine/non_blocking_sync_common.h',
     'engine/non_blocking_type_commit_contribution.cc',
     'engine/non_blocking_type_commit_contribution.h',
     'engine/nudge_source.cc',
     'engine/nudge_source.h',
+    'engine/nudge_handler.cc',
+    'engine/nudge_handler.h',
     'engine/process_updates_util.cc',
     'engine/process_updates_util.h',
     'engine/sync_cycle_event.cc',
     'engine/sync_cycle_event.h',
     'engine/sync_engine_event_listener.cc',
     'engine/sync_engine_event_listener.h',
     'engine/syncer.cc',
     'engine/syncer.h',
     'engine/syncer_proto_util.cc',
     'engine/syncer_proto_util.h',
@@ skipping 114 matching lines @@
     'util/get_session_name_win.cc',
     'util/get_session_name_win.h',
     'util/logging.cc',
     'util/logging.h',
     'util/nigori.cc',
     'util/nigori.h',
     'util/time.cc',
     'util/time.h',
   ],
 }