DevTools: [Styles] Reflect the element pseudo-state in the Styles pane

R=aandrey, pfeldman, vsevik
BUG=250608

Review URL: https://codereview.chromium.org/88533002

git-svn-id: svn://svn.chromium.org/blink/trunk@162705 bbb929c8-8fbe-4397-9dbb-9b2b20218538