Support room creation events

For https://github.com/vector-im/riot-web/issues/7164

src/components/views/messages/RoomCreate.js

@@ -0,0 +1,64 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import PropTypes from 'prop-types';
+
+import dis from '../../../dispatcher';
+import sdk from '../../../index';
+import { makeEventPermalink } from '../../../matrix-to';
+import { _t } from '../../../languageHandler';
+
+module.exports = React.createClass({
+    displayName: 'RoomCreate',
+
+    propTypes: {
+        /* the MatrixEvent to show */
+        mxEvent: PropTypes.object.isRequired,
+    },
+
+    _onLinkClicked: function(e) {
+        e.preventDefault();
+
+        const predecessor = this.props.mxEvent.getContent()['predecessor'];
+
+        dis.dispatch({
+            action: 'view_room',
+            event_id: predecessor['event_id'],
+            highlighted: true,
+            room_id: predecessor['room_id'],
+        });
+    },
+
+    render: function() {
+        const predecessor = this.props.mxEvent.getContent()['predecessor'];
+        if (predecessor === undefined) {
+            return <div />; // We should never have been instaniated in this case
+        }
+        return <div className="mx_CreateEvent">
+            <img className="mx_CreateEvent_image" src="img/room-continuation.svg" />
+            <div className="mx_CreateEvent_header">
+                {_t("This room is a continuation of another conversation.")}
+            </div>
+            <a className="mx_CreateEvent_link"
+                href={makeEventPermalink(predecessor['room_id'], predecessor['event_id'])}
+                onClick={this._onLinkClicked}
+            >
+                {_t("Click here to see older messages.")}
+            </a>
+        </div>;
+    },
+});