[Extensions] Make Event::restrict_to_browser_context const.

chrome/browser/extensions/extension_keybinding_registry.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/extension_keybinding_registry.h"
 
 #include <utility>
 
 #include "base/values.h"
 #include "chrome/browser/extensions/active_tab_permission_granter.h"
@@ skipping 104 matching lines @@
   // not set the delegate as it deals only with named commands (not page/browser
   // actions that are associated with the current page directly).
   ActiveTabPermissionGranter* granter =
       delegate_ ? delegate_->GetActiveTabPermissionGranter() : NULL;
   if (granter)
     granter->GrantIfRequested(extension);
 
   std::unique_ptr<base::ListValue> args(new base::ListValue());
   args->AppendString(command);
 
-  std::unique_ptr<Event> event(new Event(events::COMMANDS_ON_COMMAND,
-                                         kOnCommandEventName, std::move(args)));
-  event->restrict_to_browser_context = browser_context_;
+  auto event =
+      base::MakeUnique<Event>(events::COMMANDS_ON_COMMAND, kOnCommandEventName,
+                              std::move(args), browser_context_);
   event->user_gesture = EventRouter::USER_GESTURE_ENABLED;
   EventRouter::Get(browser_context_)
       ->DispatchEventToExtension(extension_id, std::move(event));
 }
 
 bool ExtensionKeybindingRegistry::IsAcceleratorRegistered(
     const ui::Accelerator& accelerator) const {
   return event_targets_.find(accelerator) != event_targets_.end();
 }
 
@@ skipping 119 matching lines @@
     if (extension_id.empty() || it->first == extension_id) {
       CommandExecuted(it->first, it->second);
       executed = true;
     }
   }
 
   return executed;
 }
 
 }  // namespace extensions