Add screensharing behind a feature flag

ts/components/CallingScreenSharingController.tsx

@@ -0,0 +1,39 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import React from 'react';
+import { Button, ButtonVariant } from './Button';
+import { LocalizerType } from '../types/Util';
+
+export type PropsType = {
+  i18n: LocalizerType;
+  onCloseController: () => unknown;
+  onStopSharing: () => unknown;
+  presentedSourceName: string;
+};
+
+export const CallingScreenSharingController = ({
+  i18n,
+  onCloseController,
+  onStopSharing,
+  presentedSourceName,
+}: PropsType): JSX.Element => {
+  return (
+    <div className="module-CallingScreenSharingController">
+      <div className="module-CallingScreenSharingController__text">
+        {i18n('calling__presenting--info', [presentedSourceName])}
+      </div>
+      <div className="module-CallingScreenSharingController__buttons">
+        <Button onClick={onStopSharing} variant={ButtonVariant.Destructive}>
+          {i18n('calling__presenting--stop')}
+        </Button>
+        <button
+          aria-label={i18n('close')}
+          className="module-CallingScreenSharingController__close"
+          onClick={onCloseController}
+          type="button"
+        />
+      </div>
+    </div>
+  );
+};