Set up the infrastructure for Extension event metrics.

extensions/browser/api/usb/usb_event_router.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 "extensions/browser/api/usb/usb_event_router.h"
 
 #include "device/core/device_client.h"
 #include "device/usb/usb_device.h"
 #include "extensions/browser/api/device_permissions_manager.h"
 #include "extensions/browser/api/usb/usb_guid_map.h"
@@ skipping 88 matching lines @@
   EventRouter* event_router = EventRouter::Get(browser_context_);
   if (event_router) {
     usb::Device device_obj;
     device_obj.device =
         UsbGuidMap::Get(browser_context_)->GetIdFromGuid(device->guid());
     device_obj.vendor_id = device->vendor_id();
     device_obj.product_id = device->product_id();
 
     scoped_ptr<Event> event;
     if (event_name == usb::OnDeviceAdded::kEventName) {
-      event.reset(new Event(usb::OnDeviceAdded::kEventName,
+      event.reset(new Event(events::UNKNOWN, usb::OnDeviceAdded::kEventName,
                             usb::OnDeviceAdded::Create(device_obj)));
     } else {
       DCHECK(event_name == usb::OnDeviceRemoved::kEventName);
-      event.reset(new Event(usb::OnDeviceRemoved::kEventName,
+      event.reset(new Event(events::UNKNOWN, usb::OnDeviceRemoved::kEventName,
                             usb::OnDeviceRemoved::Create(device_obj)));
     }
 
     event->will_dispatch_callback =
         base::Bind(&WillDispatchDeviceEvent, device);
     event_router->BroadcastEvent(event.Pass());
   }
 }
 
 template <>
 void BrowserContextKeyedAPIFactory<
     UsbEventRouter>::DeclareFactoryDependencies() {
   DependsOn(DevicePermissionsManagerFactory::GetInstance());
   DependsOn(UsbGuidMap::GetFactoryInstance());
 }
 
 }  // extensions