MDL-55593 core: Drag & drop accessible menu uses aria attributes

Part of MDL-55071

lib/yui/src/dragdrop/js/dragdrop.js

@@ -358,9 +358,25 @@ Y.extend(DRAGDROP, Y.Base, {
      * @return {string} The text of the first text-like child node of n.
      */
     find_element_text: function(n) {
+        var text = '';
+
+        // Try to resolve using aria-label first.
+        text = n.get('aria-label') || '';
+        if (text.length > 0) {
+            return text;
+        }
+
+        // Now try to resolve using aria-labelledby.
+        var labelledByNode = n.get('aria-labelledby');
+        if (labelledByNode) {
+            var labelNode = Y.one('#' + labelledByNode);
+            if (labelNode && labelNode.get('text').length > 0) {
+                return labelNode.get('text');
+            }
+        }
+
         // The valid node types to get text from.
         var nodes = n.all('h2, h3, h4, h5, span:not(.actions):not(.menu-action-text), p, div.no-overflow, div.dimmed_text');
-        var text = '';
 
         nodes.each(function() {
             if (text === '') {