Customizer: Don't hide controls the preview frame has no information about.

props kovshenin.
see #27993.
Built from https://develop.svn.wordpress.org/trunk@29329


git-svn-id: http://core.svn.wordpress.org/trunk@29109 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/customize-controls.js

@@ -589,13 +589,6 @@
 					return;
 				}
 
-				// Any controls not even registered on the previewed URL are not active either
-				api.control.each( function ( control ) {
-					if ( typeof data.activeControls[ control.id ] === 'undefined' ) {
-						data.activeControls[ control.id ] = false;
-					}
-				} );
-
 				$.each( data.activeControls, function ( id, active ) {
 					var control = api.control( id );
 					if ( control ) {