Add pop-out player for audio/video in web UI (#14870)

Fix #11160

app/javascript/mastodon/features/picture_in_picture/components/header.js

@@ -0,0 +1,40 @@
+import React from 'react';
+import { connect } from 'react-redux';
+import ImmutablePureComponent from 'react-immutable-pure-component';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import PropTypes from 'prop-types';
+import IconButton from 'mastodon/components/icon_button';
+import { Link } from 'react-router-dom';
+import Avatar from 'mastodon/components/avatar';
+import DisplayName from 'mastodon/components/display_name';
+
+const mapStateToProps = (state, { accountId }) => ({
+  account: state.getIn(['accounts', accountId]),
+});
+
+export default @connect(mapStateToProps)
+class Header extends ImmutablePureComponent {
+
+  static propTypes = {
+    accountId: PropTypes.string.isRequired,
+    statusId: PropTypes.string.isRequired,
+    account: ImmutablePropTypes.map.isRequired,
+    onClose: PropTypes.func.isRequired,
+  };
+
+  render () {
+    const { account, statusId, onClose } = this.props;
+
+    return (
+      <div className='picture-in-picture__header'>
+        <Link to={`/statuses/${statusId}`} className='picture-in-picture__header__account'>
+          <Avatar account={account} size={36} />
+          <DisplayName account={account} />
+        </Link>
+
+        <IconButton icon='times' onClick={onClose} title='Close' />
+      </div>
+    );
+  }
+
+}