Fix the settings button and UMA metrics for the message center

ui/message_center/notification_delegate.h

Index: ui/message_center/notification_delegate.h
diff --git a/ui/message_center/notification_delegate.h b/ui/message_center/notification_delegate.h
index b9432fb12bcd523ff00a32cc810d005cdffcd70d..a66d3760e690d8c03458ee9266f1be928a03269c 100644
--- a/ui/message_center/notification_delegate.h
+++ b/ui/message_center/notification_delegate.h
@@ -49,7 +49,8 @@ class MESSAGE_CENTER_EXPORT NotificationDelegate
                                     const base::string16& reply);
 
   // To be called when the user clicks the settings button in a notification.
-  virtual void SettingsClick();
+  // Returns whether the settings click was handled by the delegate.
+  virtual bool SettingsClick();
 
   // To be called in order to detect if a settings button should be displayed.
   virtual bool ShouldDisplaySettingsButton();