Use Array.prototype.slice in JX.$A

Summary: Being bold. I think it is fine to do this in 2011.

Test Plan: Run the new specs.

Reviewers: mroch, tomo, epriestley

Reviewed By: epriestley

Subscribers: chad, epriestley, aran

Differential Revision: https://secure.phabricator.com/D835

webroot/rsrc/externals/javelin/core/util.js

@@ -48,15 +48,8 @@ JX.$E = function(message) {
  *
  * @group util
  */
-JX.$A = function(mysterious_arraylike_object) {
+JX.$A = function(object) {
-  // NOTE: This avoids the Array.slice() trick because some bizarre COM object
+  return Array.prototype.slice.call(object);
-  // I dug up somewhere was freaking out when I tried to do it and it made me
-  // very upset, so do not replace this with Array.slice() cleverness.
-  var r = [];
-  for (var ii = 0; ii < mysterious_arraylike_object.length; ii++) {
-    r.push(mysterious_arraylike_object[ii]);
-  }
-  return r;
 };