Work on GN build of Chrome.

components/copresence/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("copresence") {
   sources = [
     "copresence_constants.cc",
     "copresence_manager.cc",
     "copresence_manager_impl.cc",
+    "copresence_switches.cc",
+    "copresence_switches.h",
     "handlers/audio/audio_directive_handler.cc",
     "handlers/audio/audio_directive_handler.h",
     "handlers/audio/audio_directive_list.cc",
     "handlers/audio/audio_directive_list.h",
     "handlers/directive_handler.cc",
     "handlers/directive_handler.h",
     "mediums/audio/audio_player.cc",
     "mediums/audio/audio_player.h",
     "mediums/audio/audio_recorder.cc",
     "mediums/audio/audio_recorder.h",
     "public/copresence_constants.h",
     "public/copresence_delegate.h",
     "public/copresence_manager.h",
     "public/whispernet_client.h",
     "rpc/http_post.cc",
     "rpc/http_post.h",
     "rpc/rpc_handler.cc",
     "rpc/rpc_handler.h",
     "timed_map.h",
   ]
 
   deps = [
     "//base",
     "//components/copresence/proto",
     "//content",
     "//media",
     "//net",
   ]
 }