No blur event fired when button is disabled/removed

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
When a focussed button becomes disabled, React does not dispatch a blur event.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/reactjs/69z2wepo/).

1. Attach a blur event to a button
2. Focus the button
3. Make the button disabled or remove it from the DOM

What is the expected behavior?
A blur event will be dispatched.

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?
15.1.0, not sure if it worked in previous versions.

Isolated test case: http://jsbin.com/fuvite/1/edit?html,css,js,output

http://jsbin.com/fuvite/1/edit の分離されたテストケースから始め、React 15.1.0 を使用して動作を再現します。フォーカスを取得した後に無効化または削除されるボタンの focus と blur の処理を確認します。両方のシナリオで期待される blur イベントがディスパッチされ、報告された手順に対するリグレッションテストのカバレッジがあることを完了条件とします。