Enable screen sharing easter-egg in desktop app

electron/src/electron-main.js

@@ -148,6 +148,8 @@ process.on('uncaughtException', function (error) {
 
 electron.ipcMain.on('install_update', installUpdate);
 
+electron.app.commandLine.appendSwitch('--enable-usermedia-screen-capturing');
+
 electron.app.on('ready', () => {
     if (vectorConfig.update_base_url) {
         console.log("Starting auto update with base URL: " + vectorConfig.update_base_url);

src/vector/platform/ElectronPlatform.js

@@ -127,4 +127,8 @@ export default class ElectronPlatform extends VectorBasePlatform {
     getDefaultDeviceDisplayName() {
         return "Riot Desktop on " + platformFriendlyName();
     }
+
+    screenCaptureErrorString() {
+        return null;
+    }
 }

src/vector/platform/WebPlatform.js

@@ -196,4 +196,12 @@ export default class WebPlatform extends VectorBasePlatform {
         return app_name + " via " + ua.getBrowser().name +
             " on " + ua.getOS().name;
     }
+
+    screenCaptureErrorString() {
+        // it won't work at all if you're not on HTTPS so whine whine whine
+        if (!global.window || global.window.location.protocol !== "https:") {
+            return "You need to be using HTTPS to place a screen-sharing call.";
+        }
+        return null;
+    }
 }