Introduce has_header_image() to check whether a header image is set.

props GunGeekATX, voldemortensen.
fixes #16268.
Built from https://develop.svn.wordpress.org/trunk@31224


git-svn-id: http://core.svn.wordpress.org/trunk@31205 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/theme.php

@@ -1034,6 +1034,17 @@ function display_header_text() {
 	return 'blank' != $text_color;
 }
 
+/**
+ * Check whether a header image is set or not.
+ *
+ * @since 4.2.0
+ *
+ * @return bool
+ */
+function has_header_image() {
+	return (bool) get_header_image();
+}
+
 /**
  * Retrieve header image for custom header.
  *

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31223';
+$wp_version = '4.2-alpha-31224';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.