Added unsuported browser and plugin required pages

react/features/unsupported-browser/components/PluginRequiredBrowser.js

@@ -0,0 +1,44 @@
+import React, { Component } from 'react';
+
+import { CHROME, CHROMIUM, FIREFOX } from './browserLinks';
+
+/**
+ * React component representing plugin installation required page.
+ *
+ * @class PluginRequiredBrowser
+ */
+export default class PluginRequiredBrowser extends Component {
+
+    /**
+     * Renders the component.
+     *
+     * @returns {ReactElement}
+     */
+    render() {
+        const ns = 'unsupported-desktop-browser';
+
+        return (
+            <div className = { ns }>
+                <h2 className = { `${ns}__title` }>
+                    Your browser requires a plugin for this conversation.
+                </h2>
+                <p className = { `${ns}__description_small` }>
+                    Once you install the plugin, it will be possible for you
+                    to have your conversation here. For best experience,
+                    however, we strongly recommend that you do that using
+                    the&nbsp;
+                    <a
+                        className = { `${ns}__link` }
+                        href = { CHROME }>Chrome</a>,&nbsp;
+                    <a
+                        className = { `${ns}__link` }
+                        href = { CHROMIUM }>Chromium</a> or&nbsp;
+                    <a
+                        className = { `${ns}__link` }
+                        href = { FIREFOX }>Firefox</a> browsers.
+                </p>
+            </div>
+        );
+    }
+}
+