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

ios/chrome/browser/translate/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("translate") {
   sources = [
     "after_translate_infobar_controller.h",
     "after_translate_infobar_controller.mm",
     "before_translate_infobar_controller.h",
     "before_translate_infobar_controller.mm",
@@ skipping 34 matching lines @@
     "//ios/chrome/browser/ui/infobars",
     "//ios/web",
     "//ui/base",
     "//ui/gfx",
     "//url",
   ]
   allow_circular_includes_from = [ "//ios/chrome/browser/infobars" ]
 }
 
 source_set("unit_tests") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   testonly = true
   sources = [
     "js_language_detection_manager_unittest.mm",
     "translate_service_ios_unittest.cc",
   ]
   deps = [
     ":translate",
     "//base",
     "//base/test:test_support",
     "//components/translate/ios/browser",
@@ skipping 30 matching lines @@
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing:ios_test_support",
     "//ios/third_party/earl_grey",
     "//ios/web:test_support",
     "//net",
     "//ui/base",
   ]
   libs = [ "XCTest.framework" ]
 }