From fbda6f7c0a11c5ddc294669291522ee36bbd3bda Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Fri, 4 Jul 2014 16:16:46 +0000
Subject: [PATCH] Add is_customize_preview(), a conditional function to check
 if the site is being previewed in the Customizer.

props sammybeats, mattwiebe.
fixes #23509.

git-svn-id: https://develop.svn.wordpress.org/trunk@28999 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/theme.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/wp-includes/theme.php b/src/wp-includes/theme.php
index 40acf6b5a3..9bab1fd624 100644
--- a/src/wp-includes/theme.php
+++ b/src/wp-includes/theme.php
@@ -1938,3 +1938,16 @@ function wp_customize_support_script() {
 	</script>
 	<?php
 }
+
+/**
+ * Whether the site is being previewed in the Customizer.
+ *
+ * @since 4.0.0
+ *
+ * @return bool True if the site is being previewed in the Customizer, false otherwise.
+ */
+function is_customize_preview() {
+	global $wp_customize;
+
+	return is_a( $wp_customize, 'WP_Customize_Manager' ) && $wp_customize->is_preview();
+}