DevTools: matched styles respect :visited/:link pseudo classes

Method StyleResolver::pseudoCSSRulesForElement is used from both WebPlatform
(via window.getMatchedCSSRules) and inspector in its styles sidebar pane.
Due to security reasons, this method "lies" about css rules applied for
visited and unvisited links so that it is impossible to sniff user history.

This patch makes inspector to adjust method results so that it knows which
rules are actually applied and which are not.

BUG=356999

Review URL: https://codereview.chromium.org/228673002

git-svn-id: svn://svn.chromium.org/blink/trunk@171074 bbb929c8-8fbe-4397-9dbb-9b2b20218538