Set up the infrastructure for Extension event metrics.

chrome/browser/extensions/api/gcm/gcm_api.cc

Index: chrome/browser/extensions/api/gcm/gcm_api.cc
diff --git a/chrome/browser/extensions/api/gcm/gcm_api.cc b/chrome/browser/extensions/api/gcm/gcm_api.cc
index 75d7d18867aac2004a1dcc67f3e11e3f2eeaf617..7380fad1d3bfa20dbcaed9e014908aae94195e2c 100644
--- a/chrome/browser/extensions/api/gcm/gcm_api.cc
+++ b/chrome/browser/extensions/api/gcm/gcm_api.cc
@@ -215,18 +215,16 @@ void GcmJsEventRouter::OnMessage(
   if (!message.collapse_key.empty())
     message_arg.collapse_key.reset(new std::string(message.collapse_key));
 
-  scoped_ptr<Event> event(new Event(
-      api::gcm::OnMessage::kEventName,
-      api::gcm::OnMessage::Create(message_arg).Pass(),
-      profile_));
+  scoped_ptr<Event> event(
+      new Event(events::UNKNOWN, api::gcm::OnMessage::kEventName,
+                api::gcm::OnMessage::Create(message_arg).Pass(), profile_));
   EventRouter::Get(profile_)->DispatchEventToExtension(app_id, event.Pass());
 }
 
 void GcmJsEventRouter::OnMessagesDeleted(const std::string& app_id) {
-  scoped_ptr<Event> event(new Event(
-      api::gcm::OnMessagesDeleted::kEventName,
-      api::gcm::OnMessagesDeleted::Create().Pass(),
-      profile_));
+  scoped_ptr<Event> event(
+      new Event(events::UNKNOWN, api::gcm::OnMessagesDeleted::kEventName,
+                api::gcm::OnMessagesDeleted::Create().Pass(), profile_));
   EventRouter::Get(profile_)->DispatchEventToExtension(app_id, event.Pass());
 }
 
@@ -238,10 +236,9 @@ void GcmJsEventRouter::OnSendError(
   error.error_message = GcmResultToError(send_error_details.result);
   error.details.additional_properties = send_error_details.additional_data;
 
-  scoped_ptr<Event> event(new Event(
-      api::gcm::OnSendError::kEventName,
-      api::gcm::OnSendError::Create(error).Pass(),
-      profile_));
+  scoped_ptr<Event> event(
+      new Event(events::UNKNOWN, api::gcm::OnSendError::kEventName,
+                api::gcm::OnSendError::Create(error).Pass(), profile_));
   EventRouter::Get(profile_)->DispatchEventToExtension(app_id, event.Pass());
 }