add QR code display

src/widgets/show-qrcode.jsx

@@ -0,0 +1,34 @@
+import QRCode from 'qrcodejs';
+import React from 'react';
+import { FormattedMessage } from 'react-intl';
+
+import { QRCODE_SIZE } from '../config';
+
+export default class ShowQRCode extends React.PureComponent {
+  constructor(props) {
+    super(props);
+    this.qrCodeRef = React.createRef();
+  }
+
+  componentDidMount() {
+    new QRCode(this.qrCodeRef.current, {
+      text: this.props.uri,
+      width: QRCODE_SIZE,
+      height: QRCODE_SIZE,
+    });
+  }
+
+  render() {
+    return (
+      <div className="panel-form-column">
+        <br />
+        <div className="qr-code" ref={this.qrCodeRef} />
+        <div className="dialog-buttons">
+          <button className="outline" onClick={this.props.onCancel}>
+            <FormattedMessage id="button_ok" defaultMessage="OK" description="Button [OK]" />
+          </button>
+        </div>
+      </div>
+    );
+  }
+};