Theme Customizer: Properly change state when theme is switched. fixes #20610, see #19910.

* Causes the Manage Themes page to refresh if the customizer is closed after the active theme is switched.
* Changes the text of the 'Save and Activate' button once the theme has been activated.
* Improves the naming of the customize control settings.
* Add events to customize.Loader and make callbacks more flexible.
* Makes the customize-loader l10n compatible with non-admin settings.
* Adds WP_Customize->is_current_theme_active().
* Minor style corrections, including jQuery.attr/prop changes.



git-svn-id: https://develop.svn.wordpress.org/trunk@20802 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/class-wp-customize.php

@@ -144,6 +144,15 @@ final class WP_Customize {
 		do_action( 'stop_previewing_theme', $this );
 	}
 
+	/**
+	 * Checks if the current theme is active.
+	 *
+	 * @since 3.4.0
+	 */
+	public function is_current_theme_active() {
+		return $this->get_stylesheet() == $this->original_stylesheet;
+	}
+
 	/**
 	 * Register styles/scripts and initialize the preview of each setting
 	 *