Fix the settings button and UMA metrics for the message center

ui/message_center/message_center_tray.cc

Index: ui/message_center/message_center_tray.cc
diff --git a/ui/message_center/message_center_tray.cc b/ui/message_center/message_center_tray.cc
index 69cdd6e4fa5ab6db9bb099251efbb69be39de152..9d368b0d430477b83c0587ebf79cb58bc5653b61 100644
--- a/ui/message_center/message_center_tray.cc
+++ b/ui/message_center/message_center_tray.cc
@@ -235,6 +235,11 @@ void MessageCenterTray::OnNotificationButtonClicked(
     OnMessageCenterChanged();
 }
 
+void MessageCenterTray::OnNotificationSettingsClicked(bool handled) {
+  if (!handled)
+    ShowNotifierSettingsBubble();
+}
+
 void MessageCenterTray::OnNotificationDisplayed(
     const std::string& notification_id,
     const DisplaySource source) {