Use --multi-profiles to work-around a bug that causes a bad-profile popup.

Also:
* use username/password instead of hardcoded test@test.test and ''
* Improve logging.

BUG=308224
TEST=No longer see bad profile popup with this change.
NOTRY=True

Review URL: https://codereview.chromium.org/56533007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233178 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233178