Native IME/keyboard event handlers of each widget should use TextEventDispatcher when they dispatch keyboard events and composition events. At this time, even during composition, keyboard events should be passed to TextEventDispatcher. Then, TextEventDispatcher should decide if the keyboard events should be dispatched. With this change, we can improve following things: 1. We can make DOM event dispatcher XP level code in widget. This means that we will reduce the maintenance cost when composition or keyboard event spec is changed. 2. We can avoid conflicting with nsITextInputProcessor users (addons or Firefox OS). Dispatching all key and composition events from TextEventDispatcher makes us be able to disconnect from native IME or keyboard when JS-IME has composition. #2 is very edge case, it's not so important. But #1 is very important.