Add upstream

wp-content/plugins/jetpack/modules/related-posts/related-posts-customizer.js

@@ -0,0 +1,28 @@
+/**
+ * Adds functionality for Related Posts controls in Customizer.
+ */
+( function( api ) {
+	'use strict';
+
+	api( 'jetpack_relatedposts[show_headline]', function( showHeadlineSetting ) {
+		var setupHeadlineControl = function( headlineControl ) {
+			var setActiveState, isDisplayed;
+
+			isDisplayed = function() {
+				return showHeadlineSetting.findControls()[ 0 ].active.get() && showHeadlineSetting.get();
+			};
+
+			setActiveState = function() {
+				headlineControl.active.set( isDisplayed() );
+			};
+
+			headlineControl.active.validate = isDisplayed;
+
+			setActiveState();
+
+			showHeadlineSetting.bind( setActiveState );
+		};
+
+		api.control( 'jetpack_relatedposts[headline]', setupHeadlineControl );
+	} );
+} )( wp.customize );