Remove stl_util's deletion function use from message center notifier settings.

ui/message_center/notifier_settings.h

Index: ui/message_center/notifier_settings.h
diff --git a/ui/message_center/notifier_settings.h b/ui/message_center/notifier_settings.h
index 9bbb87ab9efa6cf09047d7bce5cfc872dbe380e9..5e4c7a1c28c402b0f212dff3c1aada987dcd6df8 100644
--- a/ui/message_center/notifier_settings.h
+++ b/ui/message_center/notifier_settings.h
@@ -178,9 +178,9 @@ class MESSAGE_CENTER_EXPORT NotifierSettingsProvider {
   virtual const message_center::NotifierGroup& GetActiveNotifierGroup()
       const = 0;
 
-  // Collects the current notifier list and fills to |notifiers|. Caller takes
-  // the ownership of the elements of |notifiers|.
-  virtual void GetNotifierList(std::vector<Notifier*>* notifiers) = 0;
+  // Provides the current notifier list in |notifiers|.
+  virtual void GetNotifierList(
+      std::vector<std::unique_ptr<Notifier>>* notifiers) = 0;
 
   // Called when the |enabled| for the |notifier| has been changed by user
   // operation.