Prevent scrolling beneath modals on mobile devices by removing overflow from #wpwrap when a modal is open.

Fixes #29909
Props avryl


git-svn-id: https://develop.svn.wordpress.org/trunk@30707 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/js/wplink.js

@@ -77,6 +77,8 @@ var wpLink;
 		open: function( editorId ) {
 			var ed;
 
+			$( document.body ).addClass( 'modal-open' );
+
 			wpLink.range = null;
 
 			if ( editorId ) {
@@ -166,6 +168,8 @@ var wpLink;
 		},
 
 		close: function() {
+			$( document.body ).removeClass( 'modal-open' );
+
 			if ( ! wpLink.isMCE() ) {
 				wpLink.textarea.focus();