Override SigninManager::SignOut if force-signin is enabled.

chrome/browser/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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 2503 matching lines @@
       "profiles/profile_statistics_aggregator.cc",
       "profiles/profile_statistics_aggregator.h",
       "profiles/profile_statistics_common.cc",
       "profiles/profile_statistics_common.h",
       "profiles/profile_statistics_factory.cc",
       "profiles/profile_statistics_factory.h",
       "signin/cross_device_promo.cc",
       "signin/cross_device_promo.h",
       "signin/cross_device_promo_factory.cc",
       "signin/cross_device_promo_factory.h",
+      "signin/force_signin_manager.cc",
+      "signin/force_signin_manager.h",
       "signin/signin_global_error.cc",
       "signin/signin_global_error.h",
       "signin/signin_global_error_factory.cc",
       "signin/signin_global_error_factory.h",
       "sync/sync_global_error.cc",
       "sync/sync_global_error.h",
       "sync/sync_global_error_factory.cc",
       "sync/sync_global_error_factory.h",
       "upgrade_detector_impl.cc",
       "upgrade_detector_impl.h",
@@ skipping 1796 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }