[Extensions] Make Event::restrict_to_browser_context const.

chrome/browser/extensions/api/input_ime/input_ime_api_chromeos.cc

 // 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 "chrome/browser/extensions/api/input_ime/input_ime_api.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 199 matching lines @@
           return;
         extensions::ProcessManager* process_manager =
             extensions::ProcessManager::Get(profile_);
         if (extensions::BackgroundInfo::HasBackgroundPage(extension) &&
             !process_manager->GetBackgroundHostForExtension(extension_id_)) {
           return;
         }
       }
     }
 
-    std::unique_ptr<extensions::Event> event(
-        new extensions::Event(histogram_value, event_name, std::move(args)));
-    event->restrict_to_browser_context = profile_;
+    auto event = base::MakeUnique<extensions::Event>(
+        histogram_value, event_name, std::move(args), profile_);
     extensions::EventRouter::Get(profile_)
         ->DispatchEventToExtension(extension_id_, std::move(event));
   }
 
   // The component IME extensions need to know the current screen type (e.g.
   // lock screen, login screen, etc.) so that its on-screen keyboard page
   // won't open new windows/pages. See crbug.com/395621.
   std::string GetCurrentScreenType() override {
     switch (chromeos::input_method::InputMethodManager::Get()
                 ->GetUISessionState()) {
@@ skipping 411 matching lines @@
     return;
   InputMethodEngine* engine =
       GetActiveEngine(Profile::FromBrowserContext(details.browser_context),
                       details.extension_id);
   // Notifies the IME extension for IME ready with onActivate/onFocus events.
   if (engine)
     engine->Enable(engine->GetActiveComponentId());
 }
 
 }  // namespace extensions