[ObjC ARC] Converts ios/chrome/browser/ui/ntp:ntp_internal to ARC.

ios/chrome/browser/ui/ntp/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.
 
 bundle_data("resources") {
   sources = [
     "resources/bookmarks_bar_bg.png",
     "resources/bookmarks_bar_bg@2x.png",
     "resources/bookmarks_bar_bg@2x~ipad.png",
     "resources/bookmarks_bar_bg_pressed@2x~ipad.png",
@@ skipping 151 matching lines @@
     "//ios/chrome/browser/ui/bookmarks",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/ntp/recent_tabs",
     "//ios/chrome/browser/ui/toolbar",
     "//ios/public/provider/chrome/browser/voice",
     "//ui/base",
   ]
 }
 
 source_set("ntp_internal") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "centering_scrollview.h",
     "centering_scrollview.mm",
     "google_landing_consumer.h",
     "google_landing_mediator.h",
     "google_landing_mediator.mm",
     "google_landing_view_controller.h",
     "google_landing_view_controller.mm",
     "incognito_panel_controller.h",
     "incognito_panel_controller.mm",
@@ skipping 152 matching lines @@
     "new_tab_page_perftest.mm",
   ]
   deps = [
     "//base/test:test_support",
     "//ios/chrome/browser/sessions",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/test:perf_test_support",
     "//ios/chrome/browser/ui:ui_internal",
   ]
 }