Set up the infrastructure for Extension event metrics.

chrome/browser/extensions/api/automation_internal/automation_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 "chrome/browser/extensions/api/automation_internal/automation_event_router.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 55 matching lines @@
   }
 }
 
 void AutomationEventRouter::DispatchTreeDestroyedEvent(
     int tree_id,
     content::BrowserContext* browser_context) {
   std::string event_name(
       api::automation_internal::OnAccessibilityTreeDestroyed::kEventName);
   scoped_ptr<base::ListValue> args(
       api::automation_internal::OnAccessibilityTreeDestroyed::Create(tree_id));
-  scoped_ptr<Event> event(new Event(event_name, args.Pass()));
+  scoped_ptr<Event> event(new Event(events::UNKNOWN, event_name, args.Pass()));
   event->restrict_to_browser_context = browser_context;
   EventRouter::Get(browser_context)->BroadcastEvent(event.Pass());
 }
 
 AutomationEventRouter::AutomationListener::AutomationListener() {
 }
 
 AutomationEventRouter::AutomationListener::~AutomationListener() {
 }
 
@@ skipping 43 matching lines @@
   int process_id = rph->GetID();
   std::remove_if(
       listeners_.begin(),
       listeners_.end(),
       [process_id](AutomationListener& item) {
         return item.process_id = process_id;
       });
 }
 
 }  // namespace extensions