GC_Customize_Widgets::export_preview_data()

	public function export_preview_data() {
		global $gc_registered_sidebars, $gc_registered_widgets;

		$switched_locale = switch_to_locale( get_user_locale() );

		$l10n = array(
			'widgetTooltip' => __( 'Shift-click to edit this widget.' ),
		);

		if ( $switched_locale ) {
			restore_previous_locale();
		}

		$rendered_sidebars = array_filter( $this->rendered_sidebars );
		$rendered_widgets  = array_filter( $this->rendered_widgets );

		// Prepare Customizer settings to pass to JavaScript.
		$settings = array(
			'renderedSidebars'            => array_fill_keys( array_keys( $rendered_sidebars ), true ),
			'renderedWidgets'             => array_fill_keys( array_keys( $rendered_widgets ), true ),
			'registeredSidebars'          => array_values( $gc_registered_sidebars ),
			'registeredWidgets'           => $gc_registered_widgets,
			'l10n'                        => $l10n,
			'selectiveRefreshableWidgets' => $this->get_selective_refreshable_widgets(),
		);

		foreach ( $settings['registeredWidgets'] as &$registered_widget ) {
			unset( $registered_widget['callback'] ); // May not be JSON-serializeable.
		}

		?>
		<script type="text/javascript">
			var _gcWidgetCustomizerPreviewSettings = <?php echo gc_json_encode( $settings ); ?>;
		</script>
		<?php
	}