Set up the infrastructure for Extension event metrics.

chrome/browser/extensions/api/processes/processes_api.cc

Index: chrome/browser/extensions/api/processes/processes_api.cc
diff --git a/chrome/browser/extensions/api/processes/processes_api.cc b/chrome/browser/extensions/api/processes/processes_api.cc
index 23dffa19607b1857a6066f4d803411eb568496dd..a80b6043b8f5be9fbd43c492614bf0528b709749 100644
--- a/chrome/browser/extensions/api/processes/processes_api.cc
+++ b/chrome/browser/extensions/api/processes/processes_api.cc
@@ -469,7 +469,7 @@ void ProcessesEventRouter::DispatchEvent(
   EventRouter* event_router = EventRouter::Get(browser_context_);
   if (event_router) {
     scoped_ptr<extensions::Event> event(new extensions::Event(
-        event_name, event_args.Pass()));
+        extensions::events::UNKNOWN, event_name, event_args.Pass()));
     event_router->BroadcastEvent(event.Pass());
   }
 }