[Extensions] Make Event::restrict_to_browser_context const.

chrome/browser/extensions/api/mdns/mdns_api.cc

 // Copyright 2013 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 "chrome/browser/extensions/api/mdns/mdns_api.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/lazy_instance.h"
@@ skipping 156 matching lines @@
     }
     mdns::MDnsService mdns_service;
     mdns_service.service_name = service.service_name;
     mdns_service.service_host_port = service.service_host_port;
     mdns_service.ip_address = service.ip_address;
     mdns_service.service_data = service.service_data;
     args.push_back(std::move(mdns_service));
   }
 
   std::unique_ptr<base::ListValue> results = mdns::OnServiceList::Create(args);
-  std::unique_ptr<Event> event(new Event(events::MDNS_ON_SERVICE_LIST,
-                                         mdns::OnServiceList::kEventName,
-                                         std::move(results)));
-  event->restrict_to_browser_context = browser_context_;
+  auto event = base::MakeUnique<Event>(events::MDNS_ON_SERVICE_LIST,
+                                       mdns::OnServiceList::kEventName,
+                                       std::move(results), browser_context_);
   event->filter_info.SetServiceType(service_type);
 
   // TODO(justinlin): To avoid having listeners without filters getting all
   // events, modify API to have this event require filters.
   // TODO(reddaly): If event isn't on whitelist, ensure it does not get
   // broadcast to extensions.
   extensions::EventRouter::Get(browser_context_)
       ->BroadcastEvent(std::move(event));
 }
 
@@ skipping 78 matching lines @@
 AsyncApiFunction::ResponseAction MdnsForceDiscoveryFunction::Run() {
   MDnsAPI* api = MDnsAPI::Get(browser_context());
   if (!api) {
     return RespondNow(Error("Unknown error."));
   }
   api->ForceDiscovery();
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions