[ObjC ARC] Converts ios/chrome/browser/passwords:passwords to ARC.

ios/chrome/browser/passwords/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.
 
 import("//ios/web/js_compile.gni")
 
 source_set("passwords") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "ios_chrome_password_manager_client.h",
     "ios_chrome_password_manager_client.mm",
     "ios_chrome_password_manager_driver.h",
     "ios_chrome_password_manager_driver.mm",
     "ios_chrome_password_manager_infobar_delegate.h",
     "ios_chrome_password_manager_infobar_delegate.mm",
     "ios_chrome_password_manager_setting_migrator_service_factory.cc",
     "ios_chrome_password_manager_setting_migrator_service_factory.h",
     "ios_chrome_password_store_factory.cc",
@@ skipping 134 matching lines @@
     "//ios/chrome/app/strings",
     "//ios/chrome/app/theme",
     "//ios/chrome/browser/ui",
     "//ios/chrome/common",
     "//ios/third_party/material_components_ios",
     "//ios/third_party/material_roboto_font_loader_ios",
     "//ui/base",
   ]
   libs = [ "UIKit.framework" ]
 }