Secure embeds in the editor (first run):

- When the user pastes an embeddable http URL, try to get the https embed.
- If an embed provider doesn't support ssl embeds, show a placeholder/error message.
- Revise the way we return error messages.
See #28195, #28507.

git-svn-id: https://develop.svn.wordpress.org/trunk@28919 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-embed.php

@@ -12,6 +12,12 @@ class WP_Embed {
 	public $usecache = true;
 	public $linkifunknown = true;
 
+	/**
+	 * When an URL cannot be embedded, return false instead of returning a link
+	 * or the URL. Bypasses the 'embed_maybe_make_link' filter.
+	 */	 	 	
+	public $return_false_on_fail = false;
+
 	/**
 	 * Constructor
 	 */
@@ -322,6 +328,10 @@ class WP_Embed {
 	 * @return string Linked URL or the original URL.
 	 */
 	public function maybe_make_link( $url ) {
+		if ( $this->return_false_on_fail ) {
+			return false;
+		}
+
 		$output = ( $this->linkifunknown ) ? '<a href="' . esc_url($url) . '">' . esc_html($url) . '</a>' : $url;
 
 		/**