[ARC] Converts part of ios/web/ui to ARC.

ios/web/web_state/blocked_popup_info.mm

 // Copyright 2014 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/web/web_state/blocked_popup_info.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 BlockedPopupInfo::BlockedPopupInfo(const GURL& url,
                                    const Referrer& referrer,
                                    NSString* window_name,
                                    ProceduralBlock show_popup_handler)
     : url_(url),
       referrer_(referrer),
       window_name_([window_name copy]),
       show_popup_handler_([show_popup_handler copy]) {
@@ skipping 13 matching lines @@
 }
 
 void BlockedPopupInfo::operator=(const BlockedPopupInfo& blocked_popup_info) {
   url_ = blocked_popup_info.url_;
   referrer_ = blocked_popup_info.referrer_;
   window_name_.reset([blocked_popup_info.window_name_ copy]);
   show_popup_handler_ = [blocked_popup_info.show_popup_handler_ copy];
 }
 
 }  // namespace web