Set up the infrastructure for Extension event metrics.

extensions/browser/event_router.cc

 // Copyright (c) 2012 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/event_router.h"
 
 #include <utility>
 
 #include "base/atomic_sequence_num.h"
 #include "base/bind.h"
@@ skipping 776 matching lines @@
     listeners_.LoadFilteredLazyListeners(extension->id(), *filtered_events);
 }
 
 void EventRouter::OnExtensionUnloaded(content::BrowserContext* browser_context,
                                       const Extension* extension,
                                       UnloadedExtensionInfo::Reason reason) {
   // Remove all registered listeners from our cache.
   listeners_.RemoveListenersForExtension(extension->id());
 }
 
-Event::Event(const std::string& event_name,
+Event::Event(events::HistogramValue histogram_value,
+             const std::string& event_name,
              scoped_ptr<base::ListValue> event_args)
-    : event_name(event_name),
+    : histogram_value(histogram_value),
+      event_name(event_name),
       event_args(event_args.Pass()),
       restrict_to_browser_context(NULL),
       user_gesture(EventRouter::USER_GESTURE_UNKNOWN) {
   DCHECK(this->event_args.get());
 }
 
-Event::Event(const std::string& event_name,
+Event::Event(events::HistogramValue histogram_value,
+             const std::string& event_name,
              scoped_ptr<base::ListValue> event_args,
              BrowserContext* restrict_to_browser_context)
-    : event_name(event_name),
+    : histogram_value(histogram_value),
+      event_name(event_name),
       event_args(event_args.Pass()),
       restrict_to_browser_context(restrict_to_browser_context),
       user_gesture(EventRouter::USER_GESTURE_UNKNOWN) {
   DCHECK(this->event_args.get());
 }
 
-Event::Event(const std::string& event_name,
+Event::Event(events::HistogramValue histogram_value,
+             const std::string& event_name,
              scoped_ptr<ListValue> event_args,
              BrowserContext* restrict_to_browser_context,
              const GURL& event_url,
              EventRouter::UserGestureState user_gesture,
              const EventFilteringInfo& filter_info)
-    : event_name(event_name),
+    : histogram_value(histogram_value),
+      event_name(event_name),
       event_args(event_args.Pass()),
       restrict_to_browser_context(restrict_to_browser_context),
       event_url(event_url),
       user_gesture(user_gesture),
       filter_info(filter_info) {
   DCHECK(this->event_args.get());
 }
 
 Event::~Event() {}
 
 Event* Event::DeepCopy() {
-  Event* copy = new Event(event_name,
+  Event* copy = new Event(histogram_value, event_name,
                           scoped_ptr<base::ListValue>(event_args->DeepCopy()),
-                          restrict_to_browser_context,
-                          event_url,
-                          user_gesture,
+                          restrict_to_browser_context, event_url, user_gesture,
                           filter_info);
   copy->will_dispatch_callback = will_dispatch_callback;
   return copy;
 }
 
 EventListenerInfo::EventListenerInfo(const std::string& event_name,
                                      const std::string& extension_id,
                                      const GURL& listener_url,
                                      content::BrowserContext* browser_context)
     : event_name(event_name),
       extension_id(extension_id),
       listener_url(listener_url),
       browser_context(browser_context) {
 }
 
 }  // namespace extensions