Move SyncPlay code to plugin directory

src/plugins/syncPlay/ui/playbackPermissionManager.js

@@ -0,0 +1,52 @@
+import { appHost } from '../../../components/apphost';
+
+/**
+ * Creates an audio element that plays a silent sound.
+ * @returns {HTMLMediaElement} The audio element.
+ */
+function createTestMediaElement () {
+    const elem = document.createElement('audio');
+    elem.classList.add('testMediaPlayerAudio');
+    elem.classList.add('hide');
+
+    document.body.appendChild(elem);
+
+    elem.volume = 1; // Volume should not be zero to trigger proper permissions
+    elem.src = 'assets/audio/silence.mp3'; // Silent sound
+
+    return elem;
+}
+
+/**
+ * Destroys a media element.
+ * @param {HTMLMediaElement} elem The element to destroy.
+ */
+function destroyTestMediaElement (elem) {
+    elem.pause();
+    elem.remove();
+}
+
+/**
+ * Class that manages the playback permission.
+ */
+class PlaybackPermissionManager {
+    /**
+     * Tests playback permission. Grabs the permission when called inside a click event (or any other valid user interaction).
+     * @returns {Promise} Promise that resolves succesfully if playback permission is allowed.
+     */
+    check () {
+        if (appHost.supports('htmlaudioautoplay')) {
+            return Promise.resolve(true);
+        }
+
+        const media = createTestMediaElement();
+
+        return media.play()
+            .finally(() => {
+                destroyTestMediaElement(media);
+            });
+    }
+}
+
+/** PlaybackPermissionManager singleton. */
+export default new PlaybackPermissionManager();