Add metrics to all items in the 'wrench' menu

chrome/browser/ui/views/toolbar/wrench_menu.h

Index: chrome/browser/ui/views/toolbar/wrench_menu.h
diff --git a/chrome/browser/ui/views/toolbar/wrench_menu.h b/chrome/browser/ui/views/toolbar/wrench_menu.h
index 267f1deb9f4e4527e01984cc97f94573562aab6d..6dfbe1a071d2417d53851bed77dbaf61a3c4fcf4 100644
--- a/chrome/browser/ui/views/toolbar/wrench_menu.h
+++ b/chrome/browser/ui/views/toolbar/wrench_menu.h
@@ -10,6 +10,8 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
+#include "base/time/time.h"
+#include "base/timer/elapsed_timer.h"
 #include "components/bookmarks/browser/base_bookmark_model_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ -184,6 +186,9 @@ class WrenchMenu : public views::MenuDelegate,
 
   ObserverList<WrenchMenuObserver> observer_list_;
 
+  // Records the time from when menu opens to when the user selects a menu item.
+  base::ElapsedTimer menu_opened_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(WrenchMenu);
 };