DevTools: Support regex search and case sensitive search in sources panel

R=pfeldman, lushnikov
BUG=352174

Review URL: https://codereview.chromium.org/658403002

git-svn-id: svn://svn.chromium.org/blink/trunk@184042 bbb929c8-8fbe-4397-9dbb-9b2b20218538