Fix HasDataEditor.createEditorForTraversal so it doesn't cause side effects.
(Previously it would shorten the list each time it's traversed.)

Also adds assertions to make sure editor indexes aren't negative.

Review at http://gwt-code-reviews.appspot.com/1587803/

Fixes issue: 6959
Contributed by: t.broyer

Review by: mdempsky@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@11462 8db76d5a-ed1c-0410-87a9-c151d255dfc7
5 files changed