Added a special badge to wifi-networks behind a captive portal.

BUG=240237
TEST=manual tests on Lumpy
R=oshima@chromium.org, stevenjb@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254079

Review URL: https://codereview.chromium.org/175053003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254447 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254447