Set up the infrastructure for Extension event metrics.

extensions/browser/api/hid/hid_device_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/browser/api/hid/hid_device_manager.h"
 
 #include <limits>
 #include <vector>
 
 #include "base/lazy_instance.h"
@@ skipping 300 matching lines @@
     scoped_ptr<base::ListValue> devices =
         CreateApiDeviceList(params->extension, params->filters);
     params->callback.Run(devices.Pass());
   }
   pending_enumerations_.clear();
 }
 
 void HidDeviceManager::DispatchEvent(const std::string& event_name,
                                      scoped_ptr<base::ListValue> event_args,
                                      scoped_refptr<HidDeviceInfo> device_info) {
-  scoped_ptr<Event> event(new Event(event_name, event_args.Pass()));
+  scoped_ptr<Event> event(
+      new Event(events::UNKNOWN, event_name, event_args.Pass()));
   event->will_dispatch_callback = base::Bind(
       &WillDispatchDeviceEvent, weak_factory_.GetWeakPtr(), device_info);
   event_router_->BroadcastEvent(event.Pass());
 }
 
 }  // namespace extensions