Convert enable_one_click_signin to new buildflag system

build/config/features.gni

 # 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.
 
 # This file contains Chrome-feature-related build flags (see ui.gni for
 # UI-related ones). These should theoretically be moved to the build files of
 # the features themselves.
 #
 # However, today we have many "bad" dependencies on some of these flags from,
 # e.g. base, so they need to be global to match the GYP configuration. Also,
@@ skipping 54 matching lines @@
   enable_session_service = !is_android && !is_ios
 
   enable_plugin_installation = is_win || is_mac
 
   enable_app_list = !is_ios && !is_android
 
   enable_supervised_users = !is_ios
 
   enable_autofill_dialog = !is_ios
 
-  enable_one_click_signin = is_win || is_mac || (is_linux && !is_chromeos)
-
   enable_remoting = !is_ios && !is_chromecast && !is_headless
 
   # Enable hole punching for the protected video.
   enable_video_hole = is_android
 
   # Enables browser side Content Decryption Modules. Required for embedders
   # (e.g. Android and ChromeCast) that use a browser side CDM.
   enable_browser_cdms = is_android || is_chromecast
 
   # Hangout services is an extension that adds extra features to Hangouts.
@@ skipping 92 matching lines @@
 
 # Option controlling the use of GConf (the classic GNOME configuration
 # system).
 use_gconf = is_linux && !is_chromeos && !is_chromecast && !is_headless
 
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android
 
 use_gio = is_linux && !is_chromeos && !is_chromecast && !is_headless