Fix order-dependent timeouts of inspector/styles/css-live-edit.html

R=pfeldman, vsevik
BUG=305047

Review URL: https://codereview.chromium.org/26841005

git-svn-id: svn://svn.chromium.org/blink/trunk@159439 bbb929c8-8fbe-4397-9dbb-9b2b20218538