[RN] Implement full screen mode while in a conference

The implementation varies across platforms, with the same goal: allow the app to
use the entire screen real state while in a conference.

On Android we use immersive mode, which  will hide the status and navigation bars.

https://developer.android.com/training/system-ui/immersive.html

On iOS the status bar is hidden, with a slide effect.

android/app/build.gradle

 }
 
 dependencies {
+    compile project(':react-native-immersive')
     compile project(':react-native-keep-awake')
     compile project(':react-native-vector-icons')
     compile project(':react-native-webrtc')

android/app/src/main/java/org/jitsi/meet/MainApplication.java

                 new com.facebook.react.shell.MainReactPackage(),
                 new com.oblador.vectoricons.VectorIconsPackage(),
                 new com.oney.WebRTCModule.WebRTCModulePackage(),
+                new com.rnimmersive.RNImmersivePackage(),
                 new org.jitsi.meet.audiomode.AudioModePackage()
             );
         }

android/settings.gradle

 rootProject.name = 'jitsi-meet-react'
+include ':react-native-immersive'
+project(':react-native-immersive').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-immersive/android')
 
 include ':app'
 include ':react-native-keep-awake'

package.json

     "bootstrap": "3.1.1",
     "i18next": "3.4.4",
     "i18next-xhr-backend": "1.1.0",
+    "jQuery-Impromptu": "trentrichardson/jQuery-Impromptu#v6.0.0",
     "jitsi-meet-logger": "jitsi/jitsi-meet-logger",
     "jquery": "~2.1.1",
     "jquery-contextmenu": "*",
     "jquery-i18next": "1.1.0",
-    "jQuery-Impromptu": "trentrichardson/jQuery-Impromptu#v6.0.0",
     "jquery-ui": "1.10.5",
     "jssha": "1.5.0",
     "jws": "*",
     "react": "15.4.2",
     "react-dom": "15.4.2",
     "react-native": "0.41.2",
+    "react-native-immersive": "0.0.4",
     "react-native-keep-awake": "^2.0.2",
     "react-native-prompt": "^1.0.0",
     "react-native-vector-icons": "^4.0.0",

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

 
 import { Platform } from '../../base/react';
 import '../../audio-mode';
+import '../../full-screen';
 import '../../wake-lock';
 
 import { AbstractApp } from './AbstractApp';

react/features/full-screen/index.js

+import './middleware';

react/features/full-screen/middleware.js

+import { StatusBar } from 'react-native';
+import { Immersive } from 'react-native-immersive';
+
+import {
+    CONFERENCE_FAILED,
+    CONFERENCE_LEFT,
+    CONFERENCE_WILL_JOIN
+} from '../base/conference';
+import { Platform } from '../base/react';
+import { MiddlewareRegistry } from '../base/redux';
+
+/**
+ * Middleware that captures conference actions and activates or deactivates the
+ * full screen mode.  On iOS it hides the status bar, and on Android it uses the
+ * immersive mode:
+ * https://developer.android.com/training/system-ui/immersive.html
+ * In immersive mode the status and navigation bars are hidden and thus the
+ * entire screen will be covered by our application.
+ *
+ * @param {Store} store - Redux store.
+ * @returns {Function}
+ */
+MiddlewareRegistry.register(store => next => action => {
+    let useFullScreen;
+
+    switch (action.type) {
+    case CONFERENCE_WILL_JOIN: {
+        const state = store.getState()['features/base/conference'];
+
+        useFullScreen = !state.audioOnly;
+        break;
+    }
+
+    case CONFERENCE_FAILED:
+    case CONFERENCE_LEFT:
+        useFullScreen = false;
+        break;
+
+    default:
+        useFullScreen = null;
+        break;
+    }
+
+    if (useFullScreen !== null) {
+        setFullScreen(useFullScreen)
+            .catch(err => {
+                console.warn(`Error setting full screen mode: ${err}`);
+            });
+    }
+
+    return next(action);
+});
+
+/**
+ * Activates/deactivates the full screen mode. On iOS it will hide the status
+ * bar and On Android this will turn on immersive mode.
+ *
+ * @param {boolean} enabled - True to set full screen mode, false to
+ * deactivate it.
+ * @returns {Promise}
+ */
+function setFullScreen(enabled) {
+    // XXX The Immersive module is only implemented on Android and throws on
+    // other platforms.
+    if (Platform.OS === 'android') {
+        if (enabled) {
+            return Immersive.on();
+        }
+
+        return Immersive.off();
+    }
+
+    StatusBar.setHidden(enabled, 'slide');
+
+    return Promise.resolve();
+}