[ObjC ARC] Converts ios/chrome/browser/open_from_clipboard:open_from_clipboard to ARC.Automatical…

ios/chrome/browser/open_from_clipboard/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("open_from_clipboard") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "create_clipboard_recent_content.h",
     "create_clipboard_recent_content.mm",
   ]
   deps = [
     "//base",
     "//components/open_from_clipboard",
     "//ios/chrome/browser",
     "//ios/chrome/common/app_group",
   ]
 }