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

ios/chrome/browser/ui/stack_view/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/border_frame_bottom.png",
     "resources/border_frame_bottom@2x.png",
     "resources/border_frame_bottom@3x.png",
     "resources/border_frame_incognito_bottom.png",
@@ skipping 34 matching lines @@
     "resources/stack_view_background_noise@2x~ipad.jpg",
     "resources/stack_view_background_noise@3x.jpg",
     "resources/stack_view_background_noise~ipad.jpg",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }
 
 source_set("stack_view") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "card_set.h",
     "card_set.mm",
     "card_stack_layout_manager.h",
     "card_stack_layout_manager.mm",
     "card_stack_pinch_gesture_recognizer.h",
     "card_stack_pinch_gesture_recognizer.mm",
     "card_view.h",
     "card_view.mm",
     "close_button.h",
@@ skipping 99 matching lines @@
     "//ios/chrome/browser/snapshots",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/test:perf_test_support",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui:ui_internal",
     "//ios/web",
     "//net",
   ]
   libs = [ "UIKit.framework" ]
 }