Fix a browser crasher with negative index set on select popups.
Fix a browser crasher with negative index set on select popups.

BUG=63774
TEST=Visit http://vescam.com/select_crasher.html and try all the selects
     in that page.

Review URL: http://codereview.chromium.org/5302009

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@67969 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser