Fix 33130 by checking whether the tab is closed when closing login propmt
Fix 33130 by checking whether the tab is closed when
closing login propmt

BUG=33130 
TEST=existing test passes

Review URL: http://codereview.chromium.org/576010

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@38165 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