Fix issue 6834.

Repost of Reitveld issue 1563803.
Patch by: Daniel Kurka

Review at http://gwt-code-reviews.appspot.com/1609804

Review by: rice@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10858 8db76d5a-ed1c-0410-87a9-c151d255dfc7