Widgets: Forcibly limit Video widget to only accept oEmbed URLs from YouTube and Vimeo (for now).

Merges [40939] onto 4.8 branch.
Amends [40640].
Props timmydcrawford.
See #34115, #39994.
Fixes #40935 for 4.8.1.

Built from https://develop.svn.wordpress.org/branches/4.8@41056


git-svn-id: http://core.svn.wordpress.org/branches/4.8@40906 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/widgets/media-widgets.js

@@ -184,6 +184,12 @@ wp.mediaWidgets = ( function( $ ) {
 							return;
 						}
 
+						// If video, test for Vimeo and YouTube, otherwise, renderFail(). This should be removed once #34115 is resolved.
+						if ( 'video' === this.controller.options.mimeType && ! /vimeo|youtu\.?be/.test( urlParser.host ) ) {
+							embedLinkView.renderFail();
+							return;
+						}
+
 						embedLinkView.dfd = $.ajax({
 							url: wp.media.view.settings.oEmbedProxyUrl,
 							data: {