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

ios/chrome/browser/open_from_clipboard/create_clipboard_recent_content.mm

 // Copyright 2015 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.
 
 #include "ios/chrome/browser/open_from_clipboard/create_clipboard_recent_content.h"
 
 #include "base/memory/ptr_util.h"
 #import "components/open_from_clipboard/clipboard_recent_content_ios.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #include "ios/chrome/common/app_group/app_group_constants.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 std::unique_ptr<ClipboardRecentContent> CreateClipboardRecentContentIOS() {
   return base::MakeUnique<ClipboardRecentContentIOS>(
       kChromeUIScheme, app_group::GetGroupUserDefaults());
 }