Reapply r50859 with chromeos fixes.

chrome/browser/gtk/notifications/notification_options_menu_model.cc

Index: chrome/browser/gtk/notifications/notification_options_menu_model.cc
diff --git a/chrome/browser/gtk/notifications/notification_options_menu_model.cc b/chrome/browser/gtk/notifications/notification_options_menu_model.cc
index 0cbb81ea1b4355803157a5867245ac8f82c16130..9b5225af8aa3f084429479d35df5a973fc65cd0d 100644
--- a/chrome/browser/gtk/notifications/notification_options_menu_model.cc
+++ b/chrome/browser/gtk/notifications/notification_options_menu_model.cc
@@ -64,6 +64,11 @@ bool NotificationOptionsMenuModel::GetIconAt(int index, SkBitmap* icon) const {
   return false;
 }
 
+menus::ButtonMenuItemModel* NotificationOptionsMenuModel::GetButtonMenuItemAt(
+    int index) const {
+  return NULL;
+}
+
 bool NotificationOptionsMenuModel::IsEnabledAt(int index) const {
   return true;
 }