Make WaitForInfobarCount() robust
Make WaitForInfobarCount() robust

Make WaitForInfobarCount() robust to failures in the case of missing tabs or
windows.

BUG=
TEST=

Review URL: http://codereview.chromium.org/3529016

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@62307 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