Introduce is_https_url() for testing whether the scheme for a given URL is https. See #28487.

git-svn-id: https://develop.svn.wordpress.org/trunk@28894 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.php

@@ -3359,6 +3359,18 @@ function is_ssl() {
 	return false;
 }
 
+/**
+ * Determine if the scheme of the given URL is https.
+ *
+ * @since 4.0.0
+ * 
+ * @param  string  $url The URL
+ * @return boolean      True if the given URL uses https, false if not (or if the URL is not valid).
+ */
+function is_https_url( $url ) {
+	return ( 'https' === parse_url( $url, PHP_URL_SCHEME ) );
+}
+
 /**
  * Whether SSL login should be forced.
  *