[ObjC ARC] Converts ios/chrome/browser/ui/webui:eg_tests to ARC.

ios/chrome/browser/ui/webui/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("webui") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "about_ui.cc",
     "about_ui.h",
     "crashes_ui.cc",
@@ skipping 65 matching lines @@
     "//ios/chrome/browser/signin",
     "//ios/chrome/browser/ui/webui/gcm",
     "//ios/chrome/browser/ui/webui/net_export",
     "//ios/chrome/browser/ui/webui/sync_internals",
     "//ios/web",
     "//url",
   ]
 }
 
 source_set("eg_tests") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   testonly = true
   sources = [
     "web_ui_egtest.mm",
   ]
   deps = [
     "//base",
     "//components/strings",
     "//components/version_info",
     "//ios/chrome/browser",
     "//ios/chrome/browser/ui/omnibox:omnibox_internal",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing:ios_test_support",
     "//ios/web",
     "//ui/base",
     "//url",
   ]
   libs = [ "XCTest.framework" ]
 }