Method constructor

test/browser/refs.test.jsx:349–353

(props, context)

		class Child extends Component {
			constructor(props, context) {
				super(props, context);
				this.state = { show: false };
				inst = this;
			}
			handleMount() {}
			render(_, { show }) {
				if (!show) return <div id="div" ref={this.handleMount} />;