[ObjC ARC] Converts ios/chrome/browser/browser_state:browser_state_impl.

ios/chrome/browser/browser_state/BUILD.gn

 # Copyright 2016 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.
 
 source_set("browser_state") {
   sources = [
     "browser_state_otr_helper.cc",
     "browser_state_otr_helper.h",
     "chrome_browser_state.h",
     "chrome_browser_state.mm",
@@ skipping 27 matching lines @@
     "chrome_browser_state_manager.h",
     "chrome_browser_state_manager_impl.cc",
     "chrome_browser_state_manager_impl.h",
     "chrome_browser_state_removal_controller.h",
     "chrome_browser_state_removal_controller.mm",
     "off_the_record_chrome_browser_state_impl.cc",
     "off_the_record_chrome_browser_state_impl.h",
     "off_the_record_chrome_browser_state_io_data.h",
     "off_the_record_chrome_browser_state_io_data.mm",
   ]
+
+  configs += [ "//build/config/compiler:enable_arc" ]
+
   deps = [
     ":browser_state",
     "//base",
     "//base:i18n",
     "//components/about_handler",
     "//components/bookmarks/browser",
     "//components/browser_sync",
     "//components/content_settings/core/browser",
     "//components/content_settings/core/common",
     "//components/cookie_config",
@@ skipping 84 matching lines @@
     "//ios/chrome/browser/history",
     "//ios/chrome/browser/net",
     "//ios/chrome/browser/prefs",
     "//ios/chrome/browser/sync/glue",
     "//ios/chrome/test:test_support",
     "//ios/public/provider/chrome/browser",
     "//ios/web",
     "//net:test_support",
   ]
 }