[Extensions] Make Event::restrict_to_browser_context const.

chrome/browser/extensions/api/extension_action/extension_action_api.cc

 // Copyright (c) 2012 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/extension_action/extension_action_api.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/lazy_instance.h"
@@ skipping 256 matching lines @@
 
 void ExtensionActionAPI::DispatchEventToExtension(
     content::BrowserContext* context,
     const std::string& extension_id,
     events::HistogramValue histogram_value,
     const std::string& event_name,
     std::unique_ptr<base::ListValue> event_args) {
   if (!EventRouter::Get(context))
     return;
 
-  std::unique_ptr<Event> event(
-      new Event(histogram_value, event_name, std::move(event_args)));
-  event->restrict_to_browser_context = context;
+  auto event = base::MakeUnique<Event>(histogram_value, event_name,
+                                       std::move(event_args), context);
   event->user_gesture = EventRouter::USER_GESTURE_ENABLED;
   EventRouter::Get(context)
       ->DispatchEventToExtension(extension_id, std::move(event));
 }
 
 void ExtensionActionAPI::NotifyPageActionsChanged(
     content::WebContents* web_contents) {
   Browser* browser = chrome::FindBrowserWithWebContents(web_contents);
   if (!browser)
     return;
@@ skipping 325 matching lines @@
   if (host->extension_host_type() != VIEW_TYPE_EXTENSION_POPUP ||
       host->extension()->id() != extension_->id())
     return;
 
   SendResponse(true);
   response_sent_ = true;
   registrar_.RemoveAll();
 }
 
 }  // namespace extensions