Reduce FOR_EACH_OBSERVER usage in extensions

extensions/renderer/user_script_set_manager.cc

 // 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 "extensions/renderer/user_script_set_manager.h"
 
 #include "components/crx_file/id_util.h"
 #include "content/public/renderer/render_thread.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/renderer/dispatcher.h"
@@ skipping 133 matching lines @@
         all_hosts.insert(HostID(HostID::EXTENSIONS, extension_id));
     } else {
       all_hosts.insert(host_id);
     }
     effective_hosts = &all_hosts;
   }
 
   if (scripts->UpdateUserScripts(shared_memory,
                                  *effective_hosts,
                                  whitelisted_only)) {
-    FOR_EACH_OBSERVER(Observer, observers_,
-                      OnUserScriptsUpdated(*effective_hosts));
+    for (auto& observer : observers_)
+      observer.OnUserScriptsUpdated(*effective_hosts);
   }
 }
 
 }  // namespace extensions