Introduce Platform in React

React Native provides Platform.

react/features/app/components/App.native.js

 /* global __DEV__ */
 
 import React from 'react';
-import { Linking, Navigator, Platform } from 'react-native';
+import { Linking, Navigator } from 'react-native';
 import { Provider } from 'react-redux';
 
+import { Platform } from '../../base/react';
+
 import { _getRouteToRender } from '../functions';
 import { AbstractApp } from './AbstractApp';
 

react/features/base/lib-jitsi-meet/native/RTCPeerConnection.js

-import { Platform } from 'react-native';
-import {
-    RTCPeerConnection,
-    RTCSessionDescription
-} from 'react-native-webrtc';
+import { RTCPeerConnection, RTCSessionDescription } from 'react-native-webrtc';
 
+import { Platform } from '../../react';
 import { POSIX } from '../../react-native';
 
 // XXX At the time of this writing extending RTCPeerConnection using ES6 'class'

react/features/base/media/components/native/Video.js

 import React, { Component } from 'react';
-import { Platform, View } from 'react-native';
+import { View } from 'react-native';
 import { RTCView } from 'react-native-webrtc';
 
+import { Platform } from '../../../react';
+
 import { styles } from './styles';
 
 /**

react/features/base/react/Platform.native.js

+// Re-export react-native's Platform because we want to provide a minimal
+// equivalent on Web.
+import { Platform } from 'react-native';
+export default Platform;

react/features/base/react/Platform.web.js

+const userAgent = navigator.userAgent;
+let OS;
+
+if (userAgent.match(/Android/i)) {
+    OS = 'android';
+} else if (userAgent.match(/iP(ad|hone|od)/i)) {
+    OS = 'ios';
+}
+
+/**
+ * Provides a minimal equivalent of react-native's Platform abstraction.
+ */
+export default {
+    /**
+     * The operating system on which the application is executing.
+     *
+     * @type {string}
+     */
+    OS
+};

react/features/base/react/index.js

 export * from './components';
 export * from './functions';
+export { default as Platform } from './Platform';
 export { default as Symbol } from './Symbol';