fix(iframeAPI): startShareVideo command.

modules/API/API.js

 import { startScreenShareFlow, startAudioScreenShareFlow } from '../../react/features/screen-share/actions';
 import { toggleScreenshotCaptureSummary } from '../../react/features/screenshot-capture';
 import { playSharedVideo, stopSharedVideo } from '../../react/features/shared-video/actions.any';
+import { extractYoutubeIdOrURL } from '../../react/features/shared-video/functions';
 import { toggleTileView, setTileView } from '../../react/features/video-layout';
 import { muteAllParticipants } from '../../react/features/video-menu/actions';
 import { setVideoQuality } from '../../react/features/video-quality';
         'start-share-video': url => {
             logger.debug('Share video command received');
             sendAnalytics(createApiEvent('share.video.start'));
-            APP.store.dispatch(playSharedVideo(url));
+            const id = extractYoutubeIdOrURL(url);
+
+            if (id) {
+                APP.store.dispatch(playSharedVideo(id));
+            }
         },
 
         'stop-share-video': () => {

react/features/shared-video/components/AbstractSharedVideoDialog.js

 import { Component } from 'react';
 import type { Dispatch } from 'redux';
 
-import { getYoutubeId } from '../functions';
+import { extractYoutubeIdOrURL } from '../functions';
 
 /**
  * The type of the React {@code Component} props of
      * @returns {boolean}
      */
     _onSetVideoLink(link: string) {
-        if (!link) {
-            return false;
-        }
-
-        const trimmedLink = link.trim();
-
-        if (!trimmedLink) {
-            return false;
-        }
-
         const { onPostSubmit } = this.props;
-        const youtubeId = getYoutubeId(trimmedLink);
 
-        if (youtubeId) {
-            onPostSubmit(youtubeId);
-
-            return true;
-        }
+        const id = extractYoutubeIdOrURL(link);
 
-        // Check if the URL is valid, native may crash otherwise.
-        try {
-            // eslint-disable-next-line no-new
-            new URL(trimmedLink);
-        } catch (_) {
+        if (!id) {
             return false;
         }
 
-        onPostSubmit(trimmedLink);
+        onPostSubmit(id);
 
         return true;
     }

react/features/shared-video/functions.js

  * @param {string} url - The entered video link.
  * @returns {string} The youtube video id if matched.
  */
-export function getYoutubeId(url: string) {
+function getYoutubeId(url: string) {
     if (!url) {
         return null;
     }
     return videoPlaying;
 }
 
+/**
+ * Extracts a Youtube id or URL from the user input.
+ *
+ * @param {string} input - The user input.
+ * @returns {string|undefined}
+ */
+export function extractYoutubeIdOrURL(input: string) {
+    if (!input) {
+        return;
+    }
+
+    const trimmedLink = input.trim();
+
+    if (!trimmedLink) {
+        return;
+    }
+
+    const youtubeId = getYoutubeId(trimmedLink);
+
+    if (youtubeId) {
+        return youtubeId;
+    }
+
+    // Check if the URL is valid, native may crash otherwise.
+    try {
+        // eslint-disable-next-line no-new
+        new URL(trimmedLink);
+    } catch (_) {
+        return;
+    }
+
+    return trimmedLink;
+}
+